Fix MSVC /W4 unreachable-code error in v3 C dtoa

When TG3JSON_USE_STDLIB_FPCONV is enabled (auto-selected on MSVC), the
stdlib float-formatting block in tg3json__dtoa_c() always returns, making
the manual long-double formatting fallback dead code. MSVC /W4 /WX turned
the resulting C4702 (unreachable code) into a build error.

Make the manual fallback an #else branch of the stdlib path so neither
configuration contains unreachable code, and guard the fallback-only
locals and helpers (tg3json__utoa, tg3json__write_exp,
tg3json__format_decimal_digits) under !TG3JSON_USE_STDLIB_FPCONV to avoid
unused-function/variable warnings on the stdlib path.

Verified with gcc -Wall -Wextra -Werror across all v3 C test sources in
both fpconv configurations, plus runtime runs of tester_v3_json_c.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,45 @@
+## Description
+
+What does this PR do? Provide a brief summary of the changes. 
+
+## Type of Change
+
+- [ ] Bug fix
+- [ ] New feature
+- [ ] Refactoring (no functional changes)
+- [ ] Documentation update
+- [ ] Other (please describe):
+
+## Checklist
+
+### Required for All PRs
+
+- [ ] Reproducible glTF test file(s) are included (e.g., `models/regression/`, `tests/issue-***.gltf`, etc.)
+- [ ] Unit tests are written and pass locally (`cd tests && ./tester`)
+
+### Required for Feature PRs
+
+- [ ] Specification document is included (e.g., `docs/spec/<feature-name>.md`)
+  - The spec should cover: purpose, API design, usage examples, and edge cases
+
+### Security Policy
+
+This project manages CVE assignments exclusively through GitHub Security Advisories.
+PRs that include or reference independently obtained CVE IDs or external vulnerability disclosures will be closed.
+
+## Test Instructions
+
+How can reviewers verify your changes? 
+
+```
+# Example:
+cd build && cmake .. && make test
+```
+
+## Related Issues
+
+Link related issues: 
+
+## Additional Notes
+
+Any other context, screenshots, or information relevant to the review.

.github/workflows/c-cpp.yml

@@ -14,7 +14,7 @@ jobs:
 
   #  steps:
   #    - name: Checkout
-  #      uses: actions/checkout@v1
+  #      uses: actions/checkout@v5
 
   #    - name: Build
   #      run: |
@@ -40,7 +40,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v5
 
       - name: Build
         run: |
@@ -60,16 +60,18 @@ jobs:
     # https://help.github.com/en/actions/reference/software-installed-on-github-hosted-runners
     steps:
       - name: Checkout
-        uses: actions/checkout@v1
+        uses: actions/checkout@v5
       - name: Configure
         run: |
           mkdir build
           cd build
           cmake --help
-          cmake -G "Visual Studio 17 2022" -A x64 -DTINYGLTF_BUILD_LOADER_EXAMPLE=On -DTINYGLTF_BUILD_GL_EXAMPLES=Off -DTINYGLTF_BUILD_VALIDATOR_EXAMPLE=On ..
+          cmake -G "Visual Studio 17 2022" -A x64 -DTINYGLTF_BUILD_LOADER_EXAMPLE=On -DTINYGLTF_BUILD_GL_EXAMPLES=Off -DTINYGLTF_BUILD_VALIDATOR_EXAMPLE=On -DTINYGLTF_BUILD_TESTS=ON ..
           cd ..
       - name: Build
         run: cmake --build build --config Release
+      - name: Run tests
+        run: ctest --test-dir build -C Release --output-on-failure
 
 
   build-linux:
@@ -78,7 +80,7 @@ jobs:
     name: Buld with gcc
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v5
     - name: build
       run: |
         g++ -std=c++11 -o loader_example loader_example.cc
@@ -100,6 +102,23 @@ jobs:
         ./tester_noexcept
         cd ..
 
+    - name: v3_c_tests
+      run: |
+        cd tests
+        cc -I../ -std=c11 -g -O0 -DTINYGLTF3_ENABLE_FS \
+           -o tester_v3_c tester_v3_c.c ../tiny_gltf_v3.c
+        ./tester_v3_c
+        cc -I../ -std=c11 -g -O0 -DTINYGLTF3_ENABLE_FS \
+           -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+        ./tester_v3_c_v1port
+        cc -I../ -std=c11 -g -O0 \
+           -o tester_v3_json_c tester_v3_json_c.c
+        ./tester_v3_json_c
+        cc -I../ -std=c11 -ffreestanding -g -O0 \
+           -o tester_v3_freestanding tester_v3_freestanding.c
+        ./tester_v3_freestanding
+        cd ..
+
 
   build-rapidjson-linux:
 
@@ -107,7 +126,7 @@ jobs:
     name: Buld with gcc + rapidjson
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v5
     - name: build
       run: |
         git clone https://github.com/Tencent/rapidjson
@@ -140,7 +159,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v5
       - name: Build
         run: |
             sudo apt-get update
@@ -158,7 +177,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v1
+        uses: actions/checkout@v5
       - name: Build
         run: |
             clang++ -std=c++11 -g -O0 -o loader_example loader_example.cc
@@ -166,4 +185,3 @@ jobs:
 
             git clone https://github.com/Tencent/rapidjson
             clang++ -DTINYGLTF_USE_RAPIDJSON -I./rapidjson/include/rapidjson -std=c++11 -g -O0 -o loader_example loader_example.cc
-

.github/workflows/ci.yml

@@ -0,0 +1,537 @@
+name: Comprehensive CI
+
+on:
+  push:
+    branches:
+      - master
+      - release
+      - devel
+  pull_request:
+    branches:
+      - master
+      - release
+      - devel
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  # Linux x64 - GCC
+  linux-gcc-x64:
+    runs-on: ubuntu-latest
+    name: Linux x64 (GCC)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Configure
+        run: cmake -B build -DTINYGLTF_BUILD_LOADER_EXAMPLE=ON -DTINYGLTF_BUILD_TESTS=ON
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Run loader_example
+        run: ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # Linux x64 - Clang 21
+  linux-clang-x64:
+    runs-on: ubuntu-24.04
+    name: Linux x64 (Clang 21)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Install Clang 21
+        run: |
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 21
+
+      - name: Configure
+        run: |
+          cmake -B build -DCMAKE_C_COMPILER=clang-21 -DCMAKE_CXX_COMPILER=clang++-21 -DTINYGLTF_BUILD_LOADER_EXAMPLE=ON -DTINYGLTF_BUILD_TESTS=ON
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Run loader_example
+        run: |
+          ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # Linux ARM64 - GCC (native)
+  linux-arm64:
+    runs-on: ubuntu-24.04-arm
+    name: Linux ARM64 (GCC)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Configure
+        run: cmake -B build -DTINYGLTF_BUILD_LOADER_EXAMPLE=ON -DTINYGLTF_BUILD_TESTS=ON
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Run loader_example
+        run: ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # macOS ARM64 Apple Silicon
+  macos-arm64:
+    runs-on: macos-14
+    name: macOS ARM64 Apple Silicon (Clang)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Configure
+        run: cmake -B build -DTINYGLTF_BUILD_LOADER_EXAMPLE=ON -DTINYGLTF_BUILD_TESTS=ON
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Run loader_example
+        run: ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # Windows x64 - MSVC
+  windows-msvc-x64:
+    runs-on: windows-latest
+    name: Windows x64 (MSVC)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Configure
+        run: |
+          mkdir build
+          cd build
+          cmake -G "Visual Studio 17 2022" -A x64 -DTINYGLTF_BUILD_LOADER_EXAMPLE=On -DTINYGLTF_BUILD_GL_EXAMPLES=Off -DTINYGLTF_BUILD_VALIDATOR_EXAMPLE=Off -DTINYGLTF_BUILD_TESTS=ON ..
+
+      - name: Build
+        run: cmake --build build --config Release
+
+      - name: Run loader_example
+        run: |
+          .\build\Release\loader_example.exe models\Cube\Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build -C Release --output-on-failure
+
+  # Windows x86 - MSVC
+  windows-msvc-x86:
+    runs-on: windows-latest
+    name: Windows x86 (MSVC)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Configure
+        run: |
+          mkdir build
+          cd build
+          cmake -G "Visual Studio 17 2022" -A Win32 -DTINYGLTF_BUILD_LOADER_EXAMPLE=On -DTINYGLTF_BUILD_GL_EXAMPLES=Off -DTINYGLTF_BUILD_VALIDATOR_EXAMPLE=Off -DTINYGLTF_BUILD_TESTS=ON ..
+
+      - name: Build
+        run: cmake --build build --config Release
+
+      - name: Run tests
+        run: ctest --test-dir build -C Release --output-on-failure
+
+  # Windows ARM64 - MSVC (cross-compile)
+  windows-msvc-arm64:
+    runs-on: windows-latest
+    name: Windows ARM64 (MSVC) - Cross-compile
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Configure
+        run: |
+          mkdir build
+          cd build
+          cmake -G "Visual Studio 17 2022" -A ARM64 -DTINYGLTF_BUILD_LOADER_EXAMPLE=On -DTINYGLTF_BUILD_GL_EXAMPLES=Off -DTINYGLTF_BUILD_VALIDATOR_EXAMPLE=Off ..
+
+      - name: Build
+        run: cmake --build build --config Release
+
+  # Windows MinGW - MSYS2
+  windows-mingw-msys2:
+    runs-on: windows-latest
+    name: Windows x64 (MinGW MSYS2)
+    defaults:
+      run:
+        shell: msys2 {0}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Setup MSYS2
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: UCRT64
+          install: base-devel
+          pacboy: >-
+            cc:p cmake:p ninja:p
+          update: true
+          release: false
+
+      - name: Build with CMake
+        run: |
+          cmake -G"Ninja" -S . -B build -DTINYGLTF_BUILD_TESTS=ON
+          cmake --build build
+
+      - name: Run loader_example
+        run: |
+          ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # Linux -> Windows MinGW Cross-compile
+  linux-mingw-cross:
+    runs-on: ubuntu-latest
+    name: Linux→Windows (MinGW Cross) - Build Only
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Install MinGW
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y build-essential mingw-w64
+
+      - name: Build
+        run: |
+          x86_64-w64-mingw32-g++ -std=c++11 -o loader_example.exe loader_example.cc
+
+  # Special Configuration: No Exceptions
+  linux-noexception:
+    runs-on: ubuntu-latest
+    name: Linux x64 (GCC) - No Exceptions
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build loader_example
+        run: |
+          g++ -DTINYGLTF_NOEXCEPTION -std=c++11 -o loader_example loader_example.cc
+
+      - name: Run loader_example
+        run: |
+          ./loader_example models/Cube/Cube.gltf
+
+      - name: Build and run unit tests
+        run: |
+          cd tests
+          g++ -DTINYGLTF_NOEXCEPTION -I../ -std=c++11 -g -O0 -o tester_noexcept tester.cc
+          ./tester_noexcept
+
+  # Special Configuration: Header-Only Mode
+  linux-header-only:
+    runs-on: ubuntu-latest
+    name: Linux x64 (GCC) - Header-Only Mode
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build with CMake Header-Only
+        run: |
+          mkdir build
+          cmake -B build -DTINYGLTF_HEADER_ONLY=ON -DTINYGLTF_BUILD_LOADER_EXAMPLE=ON -DTINYGLTF_BUILD_TESTS=ON
+          cmake --build build
+
+      - name: Run loader_example
+        run: |
+          ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # v3 C tests through Meson on the primary desktop platforms.
+  v3-c-meson:
+    runs-on: ${{ matrix.os }}
+    name: v3 C Meson (${{ matrix.os }})
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Install Meson
+        run: python -m pip install meson ninja
+
+      - name: Configure
+        run: meson setup build-meson -Dtests=true
+
+      - name: Build
+        run: meson compile -C build-meson
+
+      - name: Run v3 C tests
+        run: meson test -C build-meson --print-errorlogs
+
+  # Special Configuration: RapidJSON Backend
+  linux-rapidjson:
+    runs-on: ubuntu-latest
+    name: Linux x64 (GCC) - RapidJSON Backend
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Clone RapidJSON
+        run: |
+          git clone https://github.com/Tencent/rapidjson
+
+      - name: Configure
+        run: |
+          cmake -B build -DTINYGLTF_USE_RAPIDJSON=ON -DTINYGLTF_BUILD_LOADER_EXAMPLE=ON -DTINYGLTF_BUILD_TESTS=ON -DCMAKE_PREFIX_PATH=$PWD/rapidjson
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Run loader_example
+        run: |
+          ./build/loader_example models/Cube/Cube.gltf
+
+      - name: Run tests
+        run: ctest --test-dir build --output-on-failure
+
+  # Special Configuration: AddressSanitizer
+  linux-asan:
+    runs-on: ubuntu-latest
+    name: Linux x64 (Clang) - AddressSanitizer
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build loader_example with ASan
+        run: |
+          clang++ -fsanitize=address -std=c++11 -g -O1 -o loader_example loader_example.cc
+
+      - name: Run loader_example
+        run: |
+          ./loader_example models/Cube/Cube.gltf
+
+      - name: Build and run unit tests with ASan
+        run: |
+          cd tests
+          clang++ -fsanitize=address -I../ -std=c++11 -g -O1 -o tester tester.cc
+          ./tester
+
+  # Special Configuration: UndefinedBehaviorSanitizer
+  linux-ubsan:
+    runs-on: ubuntu-latest
+    name: Linux x64 (Clang) - UndefinedBehaviorSanitizer
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build loader_example with UBSan
+        run: |
+          clang++ -fsanitize=undefined -std=c++11 -g -O1 -o loader_example loader_example.cc
+
+      - name: Run loader_example
+        run: |
+          ./loader_example models/Cube/Cube.gltf
+
+      - name: Build and run unit tests with UBSan
+        run: |
+          cd tests
+          clang++ -fsanitize=undefined -I../ -std=c++11 -g -O1 -o tester tester.cc
+          ./tester
+
+  # v3 C runtime: internal security regression tests + ported v1 unit tests.
+  v3-c-tests:
+    runs-on: ubuntu-latest
+    name: v3 C tests (Linux x64, GCC)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build tester_v3_c
+        run: |
+          cd tests
+          cc -I../ -std=c11 -g -O0 -Wall -Wextra -Wpedantic -Werror -DTINYGLTF3_ENABLE_FS \
+             -o tester_v3_c tester_v3_c.c ../tiny_gltf_v3.c
+
+      - name: Build tester_v3_c_v1port
+        run: |
+          cd tests
+          cc -I../ -std=c11 -g -O0 -Wall -Wextra -Wpedantic -Werror -DTINYGLTF3_ENABLE_FS \
+             -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+
+      - name: Run tester_v3_c (security regressions)
+        run: |
+          cd tests
+          ./tester_v3_c
+
+      - name: Run tester_v3_c_v1port (18 ported unit tests)
+        run: |
+          cd tests
+          ./tester_v3_c_v1port
+
+  # v3 C runtime under stock Ubuntu clang.
+  v3-c-tests-clang:
+    runs-on: ubuntu-latest
+    name: v3 C tests (Linux x64, Clang)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Install clang
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y clang
+
+      - name: Build tester_v3_c
+        run: |
+          cd tests
+          clang -I../ -std=c11 -g -O0 -Werror -Weverything \
+                -Wno-padded -Wno-unsafe-buffer-usage -Wno-switch-default \
+                -Wno-format-nonliteral -Wno-float-equal -Wno-cast-align \
+                -Wno-declaration-after-statement -Wno-unknown-warning-option \
+                -Wno-pre-c11-compat \
+                -DTINYGLTF3_ENABLE_FS \
+                -o tester_v3_c tester_v3_c.c ../tiny_gltf_v3.c
+
+      - name: Build tester_v3_c_v1port
+        run: |
+          cd tests
+          clang -I../ -std=c11 -g -O0 -Werror -Weverything \
+                -Wno-padded -Wno-unsafe-buffer-usage -Wno-switch-default \
+                -Wno-format-nonliteral -Wno-float-equal -Wno-cast-align \
+                -Wno-declaration-after-statement -Wno-unknown-warning-option \
+                -Wno-pre-c11-compat \
+                -DTINYGLTF3_ENABLE_FS \
+                -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+
+      - name: Run tester_v3_c
+        run: |
+          cd tests
+          ./tester_v3_c
+
+      - name: Run tester_v3_c_v1port
+        run: |
+          cd tests
+          ./tester_v3_c_v1port
+
+  # v3 C runtime under bleeding-edge clang 21 (matches local dev environment).
+  v3-c-tests-clang21:
+    runs-on: ubuntu-24.04
+    name: v3 C tests (Linux x64, Clang 21)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Install clang 21
+        run: |
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 21
+
+      - name: Build tester_v3_c
+        run: |
+          cd tests
+          clang-21 -I../ -std=c11 -g -O0 -Werror -Weverything \
+                   -Wno-padded -Wno-unsafe-buffer-usage -Wno-switch-default \
+                   -Wno-format-nonliteral -Wno-float-equal -Wno-cast-align \
+                   -Wno-declaration-after-statement -Wno-unknown-warning-option \
+                -Wno-pre-c11-compat \
+                   -DTINYGLTF3_ENABLE_FS \
+                   -o tester_v3_c tester_v3_c.c ../tiny_gltf_v3.c
+
+      - name: Build tester_v3_c_v1port
+        run: |
+          cd tests
+          clang-21 -I../ -std=c11 -g -O0 -Werror -Weverything \
+                   -Wno-padded -Wno-unsafe-buffer-usage -Wno-switch-default \
+                   -Wno-format-nonliteral -Wno-float-equal -Wno-cast-align \
+                   -Wno-declaration-after-statement -Wno-unknown-warning-option \
+                -Wno-pre-c11-compat \
+                   -DTINYGLTF3_ENABLE_FS \
+                   -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+
+      - name: Run tester_v3_c
+        run: |
+          cd tests
+          ./tester_v3_c
+
+      - name: Run tester_v3_c_v1port
+        run: |
+          cd tests
+          ./tester_v3_c_v1port
+
+  # v3 C runtime built with MSVC at warning-level 4 (/W4 /WX).
+  v3-c-tests-msvc:
+    runs-on: windows-latest
+    name: v3 C tests (Windows x64, MSVC /W4)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build and run tester_v3_c
+        shell: cmd
+        run: |
+          call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
+          cd tests
+          cl /nologo /W4 /WX /std:c11 /Zi /Od /D_CRT_SECURE_NO_WARNINGS /DTINYGLTF3_ENABLE_FS /I.. tester_v3_c.c ..\tiny_gltf_v3.c /Fe:tester_v3_c.exe
+          tester_v3_c.exe
+
+      - name: Build and run tester_v3_c_v1port
+        shell: cmd
+        run: |
+          call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
+          cd tests
+          cl /nologo /W4 /WX /std:c11 /Zi /Od /D_CRT_SECURE_NO_WARNINGS /DTINYGLTF3_ENABLE_FS /I.. tester_v3_c_v1port.c ..\tiny_gltf_v3.c /Fe:tester_v3_c_v1port.exe
+          tester_v3_c_v1port.exe
+
+  # v3 C runtime under ASan + UBSan for memory-safety + UB checks.
+  v3-c-tests-sanitizers:
+    runs-on: ubuntu-latest
+    name: v3 C tests (Clang ASan + UBSan)
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Build tester_v3_c with ASan + UBSan
+        run: |
+          cd tests
+          clang -I../ -std=c11 -g -O1 -DTINYGLTF3_ENABLE_FS \
+                -fsanitize=address,undefined -fno-omit-frame-pointer \
+                -o tester_v3_c tester_v3_c.c ../tiny_gltf_v3.c
+
+      - name: Build tester_v3_c_v1port with ASan + UBSan
+        run: |
+          cd tests
+          clang -I../ -std=c11 -g -O1 -DTINYGLTF3_ENABLE_FS \
+                -fsanitize=address,undefined -fno-omit-frame-pointer \
+                -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+
+      - name: Run tester_v3_c
+        env:
+          ASAN_OPTIONS: detect_leaks=1:halt_on_error=1
+          UBSAN_OPTIONS: print_stacktrace=1:halt_on_error=1
+        run: |
+          cd tests
+          ./tester_v3_c
+
+      - name: Run tester_v3_c_v1port
+        env:
+          ASAN_OPTIONS: detect_leaks=1:halt_on_error=1
+          UBSAN_OPTIONS: print_stacktrace=1:halt_on_error=1
+        run: |
+          cd tests
+          ./tester_v3_c_v1port

.github/workflows/codeql-analysis.yml

@@ -1,72 +0,0 @@
-# For most projects, this workflow file will not need changing; you simply need
-# to commit it to your repository.
-#
-# You may wish to alter this file to override the set of languages analyzed,
-# or to provide custom queries or build logic.
-#
-# ******** NOTE ********
-# We have attempted to detect the languages in your repository. Please check
-# the `language` matrix defined below to confirm you have the correct set of
-# supported CodeQL languages.
-#
-name: "CodeQL"
-
-on:
-  push:
-    branches: [ "master" ]
-  pull_request:
-    # The branches below must be a subset of the branches above
-    branches: [ "master" ]
-  schedule:
-    - cron: '21 20 * * 5'
-
-jobs:
-  analyze:
-    name: Analyze
-    runs-on: ubuntu-latest
-    permissions:
-      actions: read
-      contents: read
-      security-events: write
-
-    strategy:
-      fail-fast: false
-      matrix:
-        language: [ 'cpp', 'python' ]
-        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
-        # Learn more about CodeQL language support at https://aka.ms/codeql-docs/language-support
-
-    steps:
-    - name: Checkout repository
-      uses: actions/checkout@v3
-
-    # Initializes the CodeQL tools for scanning.
-    - name: Initialize CodeQL
-      uses: github/codeql-action/init@v2
-      with:
-        languages: ${{ matrix.language }}
-        # If you wish to specify custom queries, you can do so here or in a config file.
-        # By default, queries listed here will override any specified in a config file.
-        # Prefix the list here with "+" to use these queries and those in the config file.
-        
-        # Details on CodeQL's query packs refer to : https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-code-scanning#using-queries-in-ql-packs
-        # queries: security-extended,security-and-quality
-
-        
-    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
-    # If this step fails, then you should remove it and run the build manually (see below)
-    - name: Autobuild
-      uses: github/codeql-action/autobuild@v2
-
-    # ℹ️ Command-line programs to run using the OS shell.
-    # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
-
-    #   If the Autobuild fails above, remove it and uncomment the following three lines. 
-    #   modify them (or add more) to build your code if your project, please refer to the EXAMPLE below for guidance.
-
-    # - run: |
-    #   echo "Run, Build Application using script"
-    #   ./location_of_script_within_repo/buildscript.sh
-
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v2

.github/workflows/mingw-w64-msys2.yml

@@ -0,0 +1,53 @@
+name: MSYS2 MinGW-w64 Windows 64bit Build
+
+on:
+  push:
+    branches:
+      - release
+      - devel
+    paths:
+    - 'tiny_gltf.*'
+    - 'tinygltf_json_c.h'
+    - 'CMakeLists.txt'
+    - 'meson.build'
+    - 'meson_options.txt'
+    - 'tests/tester_v3*.c'
+    - '.github/workflows/mingw-w64-msys2.yml'
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  mingw-w64-msys2-build:
+    name: MSYS2 MinGW-w64 Windows Build
+    runs-on: windows-latest
+    defaults:
+      run:
+        shell: msys2 {0}
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Install core & build dependencies
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: UCRT64
+          install: base-devel
+          pacboy: >-
+            cc:p cmake:p ninja:p
+          update: true
+          release: false
+
+      - name: Configure
+        run: |
+          cmake \
+            -G"Ninja" \
+            -S . \
+            -B build \
+            -DTINYGLTF_BUILD_TESTS=ON
+
+      - name: Build
+        run: |
+          cmake --build build
+
+      - name: Run tests
+        run: |
+          ctest --test-dir build --output-on-failure

.gitignore

@@ -1,4 +1,5 @@
 # CMake
+/build/
 CMakeCache.txt
 CMakeFiles
 CMakeScripts
@@ -21,6 +22,9 @@ premake5.tar.gz
 *.vcxproj*
 .vs
 
+# default cmake build dir
+build/
+
 #binary directories
 bin/
 obj/
@@ -68,8 +72,22 @@ imgui.ini
 loader_example
 tests/tester
 tests/tester_noexcept
+tests/tester_intensive_customjson
 tests/issue-97.gltf
 tests/issue-261.gltf
+tests/issue-495-external.gltf
+# Test-generated output files (written by tester.cc during test run)
+tests/Cube.gltf
+tests/Cube.bin
+tests/Cube.glb
+tests/Cube_BaseColor.png
+tests/Cube_MetallicRoughness.png
+tests/Cube_with_embedded_images.gltf
+tests/Cube_with_image_files.gltf
+tests/tmp.glb
+tests/ issue-236.gltf
+tests/ issue-236.bin
+tests/ 2x2 image  has multiple      spaces.png
 
 # unignore
 !Makefile

.travis-before-install.sh

@@ -1,10 +0,0 @@
-#!/bin/bash
-
-if [[ "$TRAVIS_OS_NAME" == "osx" ]]
-then
-    brew upgrade
-    curl -o premake5.tar.gz https://github.com/premake/premake-core/releases/download/v5.0.0-alpha12/premake-5.0.0-alpha12-macosx.tar.gz
-else
-    wget https://github.com/premake/premake-core/releases/download/v5.0.0-alpha12/premake-5.0.0-alpha12-linux.tar.gz -O premake5.tar.gz
-fi
-tar xzf premake5.tar.gz

.travis.yml

@@ -1,63 +0,0 @@
-language: cpp
-sudo: false
-matrix:
-  include:
-  - addons: &1
-      apt:
-        sources:
-        - george-edison55-precise-backports
-        - ubuntu-toolchain-r-test
-        - llvm-toolchain-trusty-3.9
-        packages:
-        - g++-4.9
-        - clang-3.9
-    compiler: clang
-    env: COMPILER_VERSION=3.9 BUILD_TYPE=Debug
-  - addons: *1
-    compiler: clang
-    env: COMPILER_VERSION=3.9 BUILD_TYPE=Release
-  - addons: &2
-      apt:
-        sources:
-        - george-edison55-precise-backports
-        - ubuntu-toolchain-r-test
-        packages:
-        - g++-4.9
-    compiler: gcc
-    env: COMPILER_VERSION=4.9 BUILD_TYPE=Debug EXTRA_CXXFLAGS="-fsanitize=address"
-  - addons: *2
-    compiler: gcc
-    env: COMPILER_VERSION=4.9 BUILD_TYPE=Release EXTRA_CXXFLAGS="-fsanitize=address"
-  - addons: *1
-    compiler: clang
-    env: COMPILER_VERSION=3.9 BUILD_TYPE=Debug CFLAGS="-O0" CXXFLAGS="-O0"
-  - addons: &3
-      apt:
-        sources:
-        - ubuntu-toolchain-r-test
-        packages:
-        - g++-4.8
-    compiler: gcc
-    env: COMPILER_VERSION=4.8 BUILD_TYPE=Debug
-  - addons: *3
-    compiler: gcc
-    env: COMPILER_VERSION=4.8 BUILD_TYPE=Release
-
-before_install:
-  - ./.travis-before-install.sh
-
-
-script:
-  - export CC="${CC}-${COMPILER_VERSION}"
-  - export CXX="${CXX}-${COMPILER_VERSION}"
-  - ${CC} -v
-  - ${CXX} ${EXTRA_CXXFLAGS} -std=c++11 -Wall -g -o loader_example loader_example.cc
-  - ./loader_example ./models/Cube/Cube.gltf
-  - cd tests
-  - clang++ -v
-  - make
-  - ./tester
-  - ./tester_noexcept
-  - cd ../examples/raytrace
-  - ../../premake5 gmake
-  - make

CMakeLists.txt

@@ -14,8 +14,11 @@ option(TINYGLTF_BUILD_LOADER_EXAMPLE "Build loader_example(load glTF and dump in
 option(TINYGLTF_BUILD_GL_EXAMPLES "Build GL exampels(requires glfw, OpenGL, etc)" OFF)
 option(TINYGLTF_BUILD_VALIDATOR_EXAMPLE "Build validator exampe" OFF)
 option(TINYGLTF_BUILD_BUILDER_EXAMPLE "Build glTF builder example" OFF)
+option(TINYGLTF_BUILD_TESTS "Build unit tests" OFF)
 option(TINYGLTF_HEADER_ONLY "On: header-only mode. Off: create tinygltf library(No TINYGLTF_IMPLEMENTATION required in your project)" OFF)
 option(TINYGLTF_INSTALL "Install tinygltf files during install step. Usually set to OFF if you include tinygltf through add_subdirectory()" ON)
+option(TINYGLTF_INSTALL_VENDOR "Install vendored nlohmann/json and nothings/stb headers" ON)
+option(TINYGLTF_USE_CUSTOM_JSON "Use the built-in fast JSON parser (tinygltf_json.h) instead of nlohmann/json" OFF)
 
 if (TINYGLTF_BUILD_LOADER_EXAMPLE)
   add_executable(loader_example
@@ -36,6 +39,62 @@ if (TINYGLTF_BUILD_BUILDER_EXAMPLE)
   add_subdirectory ( examples/build-gltf )
 endif (TINYGLTF_BUILD_BUILDER_EXAMPLE)
 
+if (TINYGLTF_BUILD_TESTS)
+  enable_testing()
+
+  function(add_tinygltf_v3_c_test target)
+    add_executable(${target} ${ARGN})
+    target_include_directories(${target} PRIVATE
+      ${CMAKE_CURRENT_SOURCE_DIR}
+      ${CMAKE_CURRENT_SOURCE_DIR}/tests
+    )
+    set_target_properties(${target} PROPERTIES
+      C_STANDARD 11
+      C_STANDARD_REQUIRED ON
+      C_EXTENSIONS OFF
+    )
+    add_test(NAME ${target} COMMAND ${target} WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+  endfunction()
+
+  add_executable(tester tests/tester.cc)
+  target_include_directories(tester PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/tests
+  )
+  add_test(NAME tester COMMAND tester WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+
+  # Build and run tests with the custom JSON backend enabled to catch regressions
+  add_executable(tester_customjson tests/tester.cc)
+  target_include_directories(tester_customjson PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/tests
+  )
+  target_compile_definitions(tester_customjson PRIVATE TINYGLTF_USE_CUSTOM_JSON)
+  add_test(NAME tester_customjson COMMAND tester_customjson WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+
+  # Intensive parser tests for the custom JSON backend
+  add_executable(tester_intensive_customjson tests/tester_intensive_customjson.cc)
+  target_include_directories(tester_intensive_customjson PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/tests
+  )
+  target_compile_definitions(tester_intensive_customjson PRIVATE TINYGLTF_USE_CUSTOM_JSON)
+  add_test(NAME tester_intensive_customjson COMMAND tester_intensive_customjson WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/tests)
+
+  add_tinygltf_v3_c_test(tester_v3_c tests/tester_v3_c.c tiny_gltf_v3.c)
+  target_compile_definitions(tester_v3_c PRIVATE TINYGLTF3_ENABLE_FS)
+
+  add_tinygltf_v3_c_test(tester_v3_c_v1port tests/tester_v3_c_v1port.c tiny_gltf_v3.c)
+  target_compile_definitions(tester_v3_c_v1port PRIVATE TINYGLTF3_ENABLE_FS)
+
+  add_tinygltf_v3_c_test(tester_v3_json_c tests/tester_v3_json_c.c)
+
+  add_tinygltf_v3_c_test(tester_v3_freestanding tests/tester_v3_freestanding.c)
+  if (CMAKE_C_COMPILER_ID MATCHES "Clang|GNU")
+    target_compile_options(tester_v3_freestanding PRIVATE -ffreestanding)
+  endif()
+endif (TINYGLTF_BUILD_TESTS)
+
 #
 # for add_subdirectory and standalone build
 #
@@ -59,21 +118,40 @@ else (TINYGLTF_HEADER_ONLY)
           )
 endif (TINYGLTF_HEADER_ONLY)
 
+if (TINYGLTF_USE_CUSTOM_JSON)
+  if (TINYGLTF_HEADER_ONLY)
+    target_compile_definitions(tinygltf INTERFACE TINYGLTF_USE_CUSTOM_JSON)
+  else ()
+    target_compile_definitions(tinygltf PUBLIC TINYGLTF_USE_CUSTOM_JSON)
+  endif ()
+endif ()
+
 if (TINYGLTF_INSTALL)
   install(TARGETS tinygltf EXPORT tinygltfTargets)
-  install(EXPORT tinygltfTargets NAMESPACE tinygltf:: FILE TinyGLTFTargets.cmake DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
+  install(EXPORT tinygltfTargets NAMESPACE tinygltf:: FILE TinyGLTFTargets.cmake DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/tinygltf)
   configure_package_config_file(${CMAKE_CURRENT_SOURCE_DIR}/cmake/TinyGLTFConfig.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/TinyGLTFConfig.cmake INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
-  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/TinyGLTFConfig.cmake DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
+  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/TinyGLTFConfig.cmake DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/tinygltf)
   # Do not install .lib even if !TINYGLTF_HEADER_ONLY
 
   INSTALL ( FILES
-    json.hpp
-    stb_image.h
-    stb_image_write.h
     tiny_gltf.h
+    tiny_gltf_v3.h
+    tiny_gltf_v3.c
+    tinygltf_json.h
+    tinygltf_json_c.h
     ${TINYGLTF_EXTRA_SOUECES}
     DESTINATION
     include
     )
 
+    if(TINYGLTF_INSTALL_VENDOR)
+      INSTALL ( FILES
+        json.hpp
+        stb_image.h
+        stb_image_write.h
+        DESTINATION
+        include
+        )
+    endif()
+
 endif(TINYGLTF_INSTALL)

README.md

@@ -1,15 +1,94 @@
 # Header only C++ tiny glTF library(loader/saver).
 
-`TinyGLTF` is a header only C++11 glTF 2.0 https://github.com/KhronosGroup/glTF library.
+`TinyGLTF` is a header only C++ glTF 2.0 https://github.com/KhronosGroup/glTF library.
 
-`TinyGLTF` uses Niels Lohmann's json library (https://github.com/nlohmann/json), so now it requires C++11 compiler.
-(Also, you can use RadpidJSON as an JSON backend)
-If you are looking for old, C++03 version, please use `devel-picojson` branch (but not maintained anymore).
+## TinyGLTF v3 (new major release)
+
+**`tiny_gltf_v3.h`** is the new major version of TinyGLTF.
+The new C implementation (`tiny_gltf_v3.c` + `tinygltf_json_c.h`) is currently **experimental**.
+
+### What's new in v3
+
+v3 is a ground-up rewrite with a C-centric, low-overhead design:
+
+- **Pure C POD structs** — no STL containers in the public API; easy to bind to other languages.
+- **Arena-based memory management** — all parse-time allocations come from a single arena; a single `tg3_model_free()` frees everything.
+- **Structured error reporting** — `tg3_error_stack` provides machine-readable errors with severity levels and source locations.
+- **Custom JSON backend** — backed by `tinygltf_json_c.h`, a locale-independent pure-C JSON parser/serializer used by the v3 runtime.
+- **Streaming callbacks** — opt-in streaming parse/write via user-supplied callbacks.
+- **No RTTI, no exceptions required** — suitable for embedded and game-engine use.
+- **Opt-in filesystem and image I/O** — `TINYGLTF3_ENABLE_FS` / `TINYGLTF3_ENABLE_STB_IMAGE` are off by default; you control when and how assets are loaded.
+- **C++20 coroutine facade** (optional, auto-detected). C17/C++17 default.
+- **Hardened against untrusted input** — URI sanitization, post-parse index-bounds validation (default-on, opt-out via `tg3_parse_options.validate_indices = 0`), strict numeric range checks; exercised by a libFuzzer harness and by a cross-version verifier that compares parsed output against the v1 C++ reference loader. See *Security model* below and the `Security Considerations` block at the top of `tiny_gltf_v3.h`.
+
+### Quick start (v3)
+
+Copy `tiny_gltf_v3.h`, `tiny_gltf_v3.c`, and `tinygltf_json_c.h` to your project.
+Compile `tiny_gltf_v3.c` as C11 or newer. Define `TINYGLTF3_ENABLE_FS` when
+building `tiny_gltf_v3.c` if you want `tg3_parse_file()` to use stdio-backed
+filesystem helpers. The legacy `TINYGLTF3_IMPLEMENTATION` include path remains
+available for compatibility.
+
+```c
+#include "tiny_gltf_v3.h"
+```
+
+Loading a glTF file:
+
+```c
+tg3_parse_options opts;
+tg3_error_stack errors;
+tg3_model model;
+
+tg3_parse_options_init(&opts);
+tg3_error_stack_init(&errors);
+
+tg3_error_code err = tg3_parse_file(&model, &errors, "scene.gltf", 10, &opts);
+if (err != TG3_OK) {
+    for (uint32_t i = 0; i < errors.count; i++) {
+        fprintf(stderr, "[%d] %s\n", (int)errors.entries[i].severity,
+                errors.entries[i].message ? errors.entries[i].message : "(null)");
+    }
+}
+// ... use model ...
+tg3_model_free(&model);
+tg3_error_stack_free(&errors);
+```
+
+### Security model (v3 C runtime)
+
+The v3 C runtime is built for processing **untrusted glTF/GLB input** (server-side asset pipelines, user uploads, etc.) and ships hardened by default:
+
+- **URI sanitization** — external buffer/image URIs are rejected before any filesystem call if they are empty, contain NUL bytes, begin with `/` or `\`, look like a Windows drive prefix (`X:`), or contain a `..` segment. Production callers SHOULD still provide a custom `tg3_fs_callbacks.read_file` that confines reads to a known directory (e.g. via `openat` plus a `realpath` prefix check) when the input is attacker-controlled.
+- **Index bounds validation** — every `int32_t` index field populated from JSON (accessor.bufferView, primitive.indices/material/attributes, scene.nodes[], skin.joints[], animation channel/sampler refs, KHR_audio + MSFT_lod refs, …) is checked after the structural parse. Out-of-range indices produce `TG3_ERR_INVALID_INDEX`. Default `tg3_parse_options.validate_indices = 1`; set to `0` only when you need raw round-trip and have your own validator.
+- **Buffer/accessor range validation** — declared buffer lengths, bufferView ranges, accessor element spans, sparse accessor spans, component types, and overflow-prone size math are checked before returning a model.
+- **Strict numeric range checks** — JSON numbers feeding integer fields go through finite/round-trip-validated coercion (`tg3__json_number_to_int32` / `_uint64`). `byteStride` is restricted to 0 or [4, 252].
+- **Memory budget** — the arena and C JSON parser enforce `TINYGLTF3_MAX_MEMORY_BYTES` by default; `max_single_alloc` and `TINYGLTF3_MAX_STRING_LENGTH` bound individual allocation and string size.
+- **Opt-in fast paths** — `skip_extras_values` avoids materializing `extras` and unknown extension value trees, and `borrow_input_buffers` lets GLB buffer spans reference caller-owned input bytes instead of copying the BIN chunk.
+- **Image decoding off by default** — the parser does not decode image bytes; use `tg3_parse_options.images_as_is = 1` to skip any decoder entirely when handling untrusted input.
+- **Error message lifetime** — error strings on `tg3_error_stack` are arena-allocated and remain valid until `tg3_model_free()`. Read or copy them BEFORE freeing the model.
+
+See the `Security Considerations` block at the top of `tiny_gltf_v3.h` for the authoritative threat-model summary.
+
+### Testing & verification
+
+The v3 C runtime ships with three layers of automated coverage:
+
+- **`tests/tester_v3_c.c`** — internal unit checks plus security regression tests (path traversal, negative `byteStride`, OOB indices, error-message lifetime, …). Build via `make` in `tests/`; run `./tester_v3_c` for the internal suite or `./tester_v3_c <file.gltf|file.glb>` to parse a single asset.
+- **`test_runner.py`** — a cross-version verifier that runs the v1 C++ reference loader (`loader_example`) and the v3 C tester against every model in `glTF-Sample-Models/2.0`, then diffs a structured DIGEST block (buffer FNV64 hashes, accessor/bufferView fields, primitive attribute maps, node TRS, material PBR factors, skin/animation/scene topology, …). v1 is the ground truth.
+- **`tests/v3/fuzzer/`** — libFuzzer harness with ASan + UBSan (`make run` builds and runs `fuzz_gltf_v3_c`). Crafted regression inputs live in `tests/v3/security/` and are seeded into `tests/v3/fuzzer/corpus/`.
 
 ## Status
 
-Currently TinyGLTF is stable and maintenance mode. No drastic changes and feature additions planned.
+> ⚠️ **v2 deprecation notice:** `tiny_gltf.h` (v2) remains fully functional and is still supported,
+> but it is now in **maintenance mode only** — no new features will be added.
+> v2 will be **sunset after mid-2026**. `tiny_gltf_v3.h` is the intended successor, but the new C v3 runtime is still **experimental**.
 
+TinyGLTF v3's C runtime (`tiny_gltf_v3.h` + `tiny_gltf_v3.c`) is available for evaluation and early adoption,
+but its API/behavior may still change while the implementation matures.
+
+Currently TinyGLTF v2 is stable and in maintenance mode. No drastic changes and feature additions planned.
+ - v2.9.0 Various fixes and improvements. Filesystem callback API change.
  - v2.8.0 Add URICallbacks for custom URI handling in Buffer and Image. PR#397
  - v2.7.0 Change WriteImageDataFunction user callback function signature. PR#393
  - v2.6.0 Support serializing sparse accessor(Thanks to @fynv).
@@ -26,10 +105,6 @@ Currently TinyGLTF is stable and maintenance mode. No drastic changes and featur
 
 ## Builds
 
-[![Build Status](https://travis-ci.org/syoyo/tinygltf.svg?branch=devel)](https://travis-ci.org/syoyo/tinygltf)
-
-[![Build status](https://ci.appveyor.com/api/projects/status/warngenu9wjjhlm8?svg=true)](https://ci.appveyor.com/project/syoyo/tinygltf)
-
 ![C/C++ CI](https://github.com/syoyo/tinygltf/workflows/C/C++%20CI/badge.svg)
 
 ## Features
@@ -94,23 +169,6 @@ Users who want to run TinyGLTF securely and safely(e.g. need to handle malcious
 I recommend to build TinyGLTF for WASM target.
 WASI build example is located in [wasm](wasm) .
 
-## Projects using TinyGLTF
-
-* px_render Single header C++ Libraries for Thread Scheduling, Rendering, and so on... https://github.com/pplux/px
-* Physical based rendering with Vulkan using glTF 2.0 models https://github.com/SaschaWillems/Vulkan-glTF-PBR
-* GLTF loader plugin for OGRE 2.1. Support for PBR materials via HLMS/PBS https://github.com/Ybalrid/Ogre_glTF
-* [TinyGltfImporter](http://doc.magnum.graphics/magnum/classMagnum_1_1Trade_1_1TinyGltfImporter.html) plugin for [Magnum](https://github.com/mosra/magnum), a lightweight and modular C++11/C++14 graphics middleware for games and data visualization.
-* [Diligent Engine](https://github.com/DiligentGraphics/DiligentEngine) - A modern cross-platform low-level graphics library and rendering framework
-* Lighthouse 2: a rendering framework for real-time ray tracing / path tracing experiments. https://github.com/jbikker/lighthouse2
-* [QuickLook GLTF](https://github.com/toshiks/glTF-quicklook) - quicklook plugin for macos. Also SceneKit wrapper for tinygltf.
-* [GlslViewer](https://github.com/patriciogonzalezvivo/glslViewer) - live GLSL coding for MacOS and Linux
-* [Vulkan-Samples](https://github.com/KhronosGroup/Vulkan-Samples) - The Vulkan Samples is collection of resources to help you develop optimized Vulkan applications.
-* [TDME2](https://github.com/andreasdr/tdme2) - TDME2 - ThreeDeeMiniEngine2 is a lightweight 3D engine including tools suited for 3D game development using C++11
-* [SanityEngine](https://github.com/DethRaid/SanityEngine) - A C++/D3D12 renderer focused on the personal and professional development of its developer
-* [Open3D](http://www.open3d.org/) - A Modern Library for 3D Data Processing
-* [Supernova Engine](https://github.com/supernovaengine/supernova) - Game engine for 2D and 3D projects with Lua or C++ in data oriented design.
-* [Wicked Engine<img src="https://github.com/turanszkij/WickedEngine/blob/master/Content/logo_small.png" width="28px" align="center"/>](https://github.com/turanszkij/WickedEngine) - 3D engine with modern graphics 
-* Your projects here! (Please send PR)
 
 ## TODOs
 
@@ -161,9 +219,10 @@ Model model;
 TinyGLTF loader;
 std::string err;
 std::string warn;
+std::string filename = "input.gltf";
 
-bool ret = loader.LoadASCIIFromFile(&model, &err, &warn, argv[1]);
-//bool ret = loader.LoadBinaryFromFile(&model, &err, &warn, argv[1]); // for binary glTF(.glb)
+bool ret = loader.LoadASCIIFromFile(&model, &err, &warn, filename);
+//bool ret = loader.LoadBinaryFromFile(&model, &err, &warn, filename); // for binary glTF(.glb)
 
 if (!warn.empty()) {
   printf("Warn: %s\n", warn.c_str());
@@ -174,8 +233,7 @@ if (!err.empty()) {
 }
 
 if (!ret) {
-  printf("Failed to parse glTF\n");
-  return -1;
+  printf("Failed to parse glTF: %s\n", filename.c_str());
 }
 ```
 
@@ -196,7 +254,6 @@ if (!ret) {
 * `TINYGLTF_NO_INCLUDE_STB_IMAGE `: Disable including `stb_image.h` from within `tiny_gltf.h` because it has been already included before or you want to include it using custom path before including `tiny_gltf.h`.
 * `TINYGLTF_NO_INCLUDE_STB_IMAGE_WRITE `: Disable including `stb_image_write.h` from within `tiny_gltf.h` because it has been already included before or you want to include it using custom path before including `tiny_gltf.h`.
 * `TINYGLTF_USE_RAPIDJSON` : Use RapidJSON as a JSON parser/serializer. RapidJSON files are not included in TinyGLTF repo. Please set an include path to RapidJSON if you enable this feature.
-* `TINYGLTF_USE_CPP14` : Use C++14 feature(requires C++14 compiler). This may give better performance than C++11.
 
 
 ## CMake options
@@ -213,6 +270,11 @@ set(TINYGLTF_INSTALL OFF CACHE INTERNAL "" FORCE)
 add_subdirectory(/path/to/tinygltf)
 ```
 
+NOTE: Using tinygltf as a submodule doesn't automatically add the headers to your include path (as standard for many libraries). To get this functionality, add the following to the CMakeLists.txt file from above:
+
+```
+target_include_directories(${PROJECT_NAME} PRIVATE "/path/to/tinygltf")
+```
 
 ### Saving gltTF 2.0 model
 

SECURITY.md

@@ -0,0 +1,4 @@
+# Security Policy
+
+This project manages CVE assignments exclusively through
+GitHub Security Advisories.

appveyor.yml

@@ -1,18 +0,0 @@
-version: 0.9.{build}
-
-image:
-  - Visual Studio 2015
-
-# scripts that runs after repo cloning.
-install:
-  - vcsetup.bat
-
-platform: x64
-configuration: Release
-
-build:
-  parallel: true
-  project: TinyGLTFSolution.sln
-
-after_build:
-  - examples.bat

benchmark/Makefile

@@ -0,0 +1,70 @@
+# benchmark/Makefile — Build and run tinygltf v3 benchmarks
+#
+# Targets:
+#   make           — build gen_synthetic + bench_v3
+#   make generate  — generate synthetic test scenes
+#   make run       — run benchmarks on all generated scenes
+#   make report    — run benchmarks and produce CSV report
+#   make clean     — remove binaries and generated scenes
+
+CXX       ?= g++
+CXXFLAGS  ?= -O2 -std=c++17 -Wall -Wextra -Wno-unused-function
+CXXFLAGS  += -fno-rtti -fno-exceptions
+INCLUDES  = -I..
+
+BINDIR    = .
+GEN       = $(BINDIR)/gen_synthetic
+BENCH_V3  = $(BINDIR)/bench_v3
+
+# Iteration counts
+ITERATIONS ?= 10
+WARMUP     ?= 2
+PREFIX     ?= synthetic
+
+.PHONY: all generate run report clean
+
+all: $(GEN) $(BENCH_V3)
+
+$(GEN): gen_synthetic.cpp
+	$(CXX) $(CXXFLAGS) -o $@ $<
+
+$(BENCH_V3): bench_v3.cpp ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_c.h
+	$(CXX) $(CXXFLAGS) $(INCLUDES) -o $@ $<
+
+# Generate synthetic scenes of varying sizes
+generate: $(GEN)
+	@echo "=== Generating synthetic scenes ==="
+	./$(GEN) --prefix $(PREFIX)
+	@echo ""
+	@echo "Generated files (binary + GLB):"
+	@ls -lh $(PREFIX)_*.gltf $(PREFIX)_*.glb $(PREFIX)_*.bin 2>/dev/null || true
+
+# Run benchmarks on all generated scenes
+run: $(BENCH_V3) generate
+	@echo ""
+	@echo "================================================================="
+	@echo "  tinygltf v3 Benchmark"
+	@echo "================================================================="
+	@echo ""
+	@for f in $(PREFIX)_*.glb $(PREFIX)_*.gltf; do \
+		if [ -f "$$f" ]; then \
+			./$(BENCH_V3) "$$f" --iterations $(ITERATIONS) --warmup $(WARMUP); \
+			echo ""; \
+		fi; \
+	done
+
+# Run benchmarks and produce CSV report
+report: $(BENCH_V3) generate
+	@echo "file,size_bytes,iterations,parse_min_ms,parse_max_ms,parse_avg_ms,parse_median_ms,throughput_mbs,arena_peak_bytes,meshes,nodes,accessors,materials,animations" > benchmark_report.csv
+	@for f in $(PREFIX)_*.glb $(PREFIX)_*.gltf; do \
+		if [ -f "$$f" ]; then \
+			./$(BENCH_V3) "$$f" --iterations $(ITERATIONS) --warmup $(WARMUP) --csv | tail -1 >> benchmark_report.csv; \
+		fi; \
+	done
+	@echo "=== Report written to benchmark_report.csv ==="
+	@cat benchmark_report.csv | column -t -s,
+
+clean:
+	rm -f $(GEN) $(BENCH_V3)
+	rm -f $(PREFIX)_*.gltf $(PREFIX)_*.glb $(PREFIX)_*.bin
+	rm -f benchmark_report.csv

benchmark/bench_v3.cpp

@@ -0,0 +1,414 @@
+/*
+ * bench_v3.cpp — Benchmark tinygltf v3 parser: parse speed & memory.
+ *
+ * Measures:
+ *   - File read time
+ *   - JSON parse + model build time
+ *   - Peak arena memory usage
+ *   - Throughput (MB/s)
+ *
+ * Usage:
+ *   bench_v3 <file.gltf|file.glb> [--iterations N] [--warmup N] [--quiet]
+ *   bench_v3 --batch <file1> <file2> ... [--iterations N]
+ */
+
+#define TINYGLTF3_IMPLEMENTATION
+#define TINYGLTF3_ENABLE_FS
+#include "tiny_gltf_v3.h"
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <cmath>
+#include <vector>
+#include <string>
+#include <algorithm>
+#include <chrono>
+
+#if defined(__linux__)
+#include <sys/resource.h>
+#endif
+
+/* ------------------------------------------------------------------ */
+/* Timing helpers                                                     */
+/* ------------------------------------------------------------------ */
+
+using Clock = std::chrono::high_resolution_clock;
+using TimePoint = Clock::time_point;
+
+static double elapsed_ms(TimePoint start, TimePoint end) {
+    return std::chrono::duration<double, std::milli>(end - start).count();
+}
+
+/* ------------------------------------------------------------------ */
+/* Memory tracking allocator                                          */
+/* ------------------------------------------------------------------ */
+
+struct MemTracker {
+    size_t current;
+    size_t peak;
+    size_t total_allocs;
+    size_t total_frees;
+};
+
+static void *tracked_alloc(size_t size, void *ud) {
+    MemTracker *mt = (MemTracker *)ud;
+    void *ptr = malloc(size);
+    if (ptr) {
+        mt->current += size;
+        if (mt->current > mt->peak) mt->peak = mt->current;
+        mt->total_allocs++;
+    }
+    return ptr;
+}
+
+static void *tracked_realloc(void *ptr, size_t old_size, size_t new_size, void *ud) {
+    MemTracker *mt = (MemTracker *)ud;
+    void *new_ptr = realloc(ptr, new_size);
+    if (new_ptr) {
+        mt->current -= old_size;
+        mt->current += new_size;
+        if (mt->current > mt->peak) mt->peak = mt->current;
+    }
+    return new_ptr;
+}
+
+static void tracked_free(void *ptr, size_t size, void *ud) {
+    MemTracker *mt = (MemTracker *)ud;
+    if (ptr) {
+        mt->current -= size;
+        mt->total_frees++;
+        free(ptr);
+    }
+}
+
+/* ------------------------------------------------------------------ */
+/* RSS measurement (Linux)                                            */
+/* ------------------------------------------------------------------ */
+
+static size_t get_rss_bytes() {
+#if defined(__linux__)
+    FILE *f = fopen("/proc/self/statm", "r");
+    if (!f) return 0;
+    long pages = 0;
+    if (fscanf(f, "%*s %ld", &pages) != 1) pages = 0;
+    fclose(f);
+    return (size_t)pages * 4096;
+#else
+    return 0;
+#endif
+}
+
+/* ------------------------------------------------------------------ */
+/* Benchmark result                                                   */
+/* ------------------------------------------------------------------ */
+
+struct BenchResult {
+    std::string filename;
+    uint64_t    file_size;
+    int         iterations;
+
+    /* Parse timing (ms) */
+    double parse_min;
+    double parse_max;
+    double parse_avg;
+    double parse_median;
+
+    /* Memory */
+    size_t arena_peak;     /* Peak arena allocation */
+    size_t rss_before;
+    size_t rss_after;
+
+    /* Model stats */
+    uint32_t meshes;
+    uint32_t nodes;
+    uint32_t accessors;
+    uint32_t materials;
+    uint32_t animations;
+    uint32_t buffers;
+    uint32_t buffer_views;
+    uint32_t images;
+    uint32_t textures;
+
+    /* Derived */
+    double throughput_mbs; /* MB/s based on median */
+};
+
+/* ------------------------------------------------------------------ */
+/* Run benchmark for a single file                                    */
+/* ------------------------------------------------------------------ */
+
+static BenchResult bench_file(const char *filename, int iterations, int warmup,
+                               bool quiet, int float32_mode = 0,
+                               int skip_extras_values = 0,
+                               int borrow_input_buffers = 0) {
+    BenchResult r = {};
+    r.filename = filename;
+    r.iterations = iterations;
+
+    /* Read file into memory */
+    FILE *f = fopen(filename, "rb");
+    if (!f) {
+        fprintf(stderr, "ERROR: Cannot open '%s'\n", filename);
+        return r;
+    }
+    fseek(f, 0, SEEK_END);
+    long sz = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    if (sz <= 0) { fclose(f); return r; }
+
+    std::vector<uint8_t> data((size_t)sz);
+    size_t rd = fread(data.data(), 1, (size_t)sz, f);
+    fclose(f);
+    if ((long)rd != sz) { return r; }
+
+    r.file_size = (uint64_t)sz;
+
+    /* Extract base dir */
+    std::string path(filename);
+    std::string base_dir;
+    size_t sep = path.find_last_of("/\\");
+    if (sep != std::string::npos) base_dir = path.substr(0, sep);
+
+    /* Warmup iterations (not measured) */
+    for (int i = 0; i < warmup; ++i) {
+        tg3_model model;
+        tg3_error_stack errors;
+        tg3_error_stack_init(&errors);
+        tg3_parse_auto(&model, &errors, data.data(), data.size(),
+                       base_dir.c_str(), (uint32_t)base_dir.size(), NULL);
+        tg3_model_free(&model);
+        tg3_error_stack_free(&errors);
+    }
+
+    /* Benchmark iterations */
+    std::vector<double> times;
+    times.reserve(iterations);
+
+    MemTracker tracker_best;
+    memset(&tracker_best, 0, sizeof(tracker_best));
+
+    r.rss_before = get_rss_bytes();
+
+    for (int i = 0; i < iterations; ++i) {
+        MemTracker tracker;
+        memset(&tracker, 0, sizeof(tracker));
+
+        tg3_parse_options opts;
+        tg3_parse_options_init(&opts);
+        opts.memory.allocator.alloc = tracked_alloc;
+        opts.memory.allocator.realloc = tracked_realloc;
+        opts.memory.allocator.free = tracked_free;
+        opts.memory.allocator.user_data = &tracker;
+        opts.parse_float32 = float32_mode;
+        opts.skip_extras_values = skip_extras_values;
+        opts.borrow_input_buffers = borrow_input_buffers;
+
+        tg3_model model;
+        tg3_error_stack errors;
+        tg3_error_stack_init(&errors);
+
+        TimePoint t0 = Clock::now();
+
+        tg3_error_code err = tg3_parse_auto(&model, &errors,
+                                             data.data(), data.size(),
+                                             base_dir.c_str(),
+                                             (uint32_t)base_dir.size(),
+                                             &opts);
+
+        TimePoint t1 = Clock::now();
+        double ms = elapsed_ms(t0, t1);
+        times.push_back(ms);
+
+        /* Capture model stats on first successful iteration */
+        if (i == 0 && err == TG3_OK) {
+            r.meshes = model.meshes_count;
+            r.nodes = model.nodes_count;
+            r.accessors = model.accessors_count;
+            r.materials = model.materials_count;
+            r.animations = model.animations_count;
+            r.buffers = model.buffers_count;
+            r.buffer_views = model.buffer_views_count;
+            r.images = model.images_count;
+            r.textures = model.textures_count;
+        }
+
+        if (tracker.peak > tracker_best.peak) {
+            tracker_best = tracker;
+        }
+
+        tg3_model_free(&model);
+        tg3_error_stack_free(&errors);
+
+        if (err != TG3_OK && !quiet) {
+            fprintf(stderr, "  Parse error on iteration %d: code %d\n", i, (int)err);
+        }
+    }
+
+    r.rss_after = get_rss_bytes();
+    r.arena_peak = tracker_best.peak;
+
+    /* Compute stats */
+    std::sort(times.begin(), times.end());
+    r.parse_min = times.front();
+    r.parse_max = times.back();
+    double sum = 0;
+    for (double t : times) sum += t;
+    r.parse_avg = sum / times.size();
+    r.parse_median = times[times.size() / 2];
+
+    /* Throughput: file_size / median_time */
+    if (r.parse_median > 0) {
+        r.throughput_mbs = ((double)r.file_size / (1024.0 * 1024.0)) /
+                           (r.parse_median / 1000.0);
+    }
+
+    return r;
+}
+
+/* ------------------------------------------------------------------ */
+/* Print results                                                      */
+/* ------------------------------------------------------------------ */
+
+static const char *human_bytes(size_t bytes, char *buf, size_t buf_sz) {
+    if (bytes >= 1024ULL * 1024 * 1024)
+        snprintf(buf, buf_sz, "%.2f GB", (double)bytes / (1024.0 * 1024 * 1024));
+    else if (bytes >= 1024 * 1024)
+        snprintf(buf, buf_sz, "%.2f MB", (double)bytes / (1024.0 * 1024));
+    else if (bytes >= 1024)
+        snprintf(buf, buf_sz, "%.2f KB", (double)bytes / 1024.0);
+    else
+        snprintf(buf, buf_sz, "%zu B", bytes);
+    return buf;
+}
+
+static void print_result(const BenchResult &r) {
+    char buf1[64], buf2[64];
+
+    printf("┌─────────────────────────────────────────────────────────────────┐\n");
+    printf("│ %-63s │\n", r.filename.c_str());
+    printf("├─────────────────────────────────────────────────────────────────┤\n");
+    printf("│ File size:      %-47s │\n", human_bytes((size_t)r.file_size, buf1, sizeof(buf1)));
+    printf("│ Iterations:     %-47d │\n", r.iterations);
+    printf("│                                                                 │\n");
+    printf("│ Parse time (ms):                                                │\n");
+    printf("│   min:    %10.3f                                            │\n", r.parse_min);
+    printf("│   max:    %10.3f                                            │\n", r.parse_max);
+    printf("│   avg:    %10.3f                                            │\n", r.parse_avg);
+    printf("│   median: %10.3f                                            │\n", r.parse_median);
+    printf("│                                                                 │\n");
+    printf("│ Throughput:     %-47s │\n",
+           (snprintf(buf1, sizeof(buf1), "%.2f MB/s", r.throughput_mbs), buf1));
+    printf("│ Arena peak:     %-47s │\n", human_bytes(r.arena_peak, buf1, sizeof(buf1)));
+    if (r.rss_before > 0) {
+        printf("│ RSS before:     %-47s │\n", human_bytes(r.rss_before, buf1, sizeof(buf1)));
+        printf("│ RSS after:      %-47s │\n", human_bytes(r.rss_after, buf2, sizeof(buf2)));
+    }
+    printf("│                                                                 │\n");
+    printf("│ Model: %u meshes, %u nodes, %u accessors, %u materials",
+           r.meshes, r.nodes, r.accessors, r.materials);
+    printf("        │\n");
+    printf("│        %u animations, %u buffers, %u images",
+           r.animations, r.buffers, r.images);
+    printf("                       │\n");
+    printf("└─────────────────────────────────────────────────────────────────┘\n");
+}
+
+static void print_csv_header() {
+    printf("file,size_bytes,iterations,parse_min_ms,parse_max_ms,parse_avg_ms,"
+           "parse_median_ms,throughput_mbs,arena_peak_bytes,"
+           "meshes,nodes,accessors,materials,animations\n");
+}
+
+static void print_csv_row(const BenchResult &r) {
+    printf("%s,%lu,%d,%.3f,%.3f,%.3f,%.3f,%.2f,%zu,%u,%u,%u,%u,%u\n",
+           r.filename.c_str(), (unsigned long)r.file_size, r.iterations,
+           r.parse_min, r.parse_max, r.parse_avg, r.parse_median,
+           r.throughput_mbs, r.arena_peak,
+           r.meshes, r.nodes, r.accessors, r.materials, r.animations);
+}
+
+/* ------------------------------------------------------------------ */
+/* Main                                                               */
+/* ------------------------------------------------------------------ */
+
+static void usage() {
+    fprintf(stderr,
+        "Usage:\n"
+        "  bench_v3 <file> [--iterations N] [--warmup N] [--csv] [--quiet]\n"
+        "  bench_v3 --batch <file1> [file2] ... [--iterations N] [--csv]\n"
+        "\n"
+        "Options:\n"
+        "  --iterations N   Number of timed parse iterations (default: 10)\n"
+        "  --warmup N       Number of warmup iterations (default: 2)\n"
+        "  --csv            Output in CSV format\n"
+        "  --quiet          Suppress per-iteration error messages\n"
+        "  --batch          Benchmark multiple files\n"
+        "  --float32        Parse JSON floats as float32 (faster, less precise)\n"
+        "  --skip-extras-values\n"
+        "                   Skip materializing extras/unknown extension values\n"
+        "  --borrow-input-buffers\n"
+        "                   Let GLB buffers reference caller-owned input bytes\n");
+}
+
+int main(int argc, char **argv) {
+    if (argc < 2) { usage(); return 1; }
+
+    int iterations = 10;
+    int warmup = 2;
+    bool csv = false;
+    bool quiet = false;
+    int float32_mode = 0;
+    int skip_extras_values = 0;
+    int borrow_input_buffers = 0;
+    std::vector<std::string> files;
+
+    for (int i = 1; i < argc; ++i) {
+        if (strcmp(argv[i], "--iterations") == 0 && i + 1 < argc) {
+            iterations = atoi(argv[++i]);
+        } else if (strcmp(argv[i], "--warmup") == 0 && i + 1 < argc) {
+            warmup = atoi(argv[++i]);
+        } else if (strcmp(argv[i], "--csv") == 0) {
+            csv = true;
+        } else if (strcmp(argv[i], "--quiet") == 0) {
+            quiet = true;
+        } else if (strcmp(argv[i], "--float32") == 0) {
+            float32_mode = 1;
+        } else if (strcmp(argv[i], "--skip-extras-values") == 0) {
+            skip_extras_values = 1;
+        } else if (strcmp(argv[i], "--borrow-input-buffers") == 0) {
+            borrow_input_buffers = 1;
+        } else if (strcmp(argv[i], "--batch") == 0) {
+            /* batch mode: just collect files */
+        } else if (argv[i][0] != '-') {
+            files.push_back(argv[i]);
+        }
+    }
+
+    if (files.empty()) { usage(); return 1; }
+
+    if (csv) print_csv_header();
+
+    for (const auto &file : files) {
+        if (!csv && !quiet) {
+            printf("Benchmarking: %s (%d iterations, %d warmup%s)\n",
+                   file.c_str(), iterations, warmup,
+                   float32_mode ? ", float32" :
+                   skip_extras_values ? ", skip extras" :
+                   borrow_input_buffers ? ", borrow buffers" : "");
+        }
+
+        BenchResult r = bench_file(file.c_str(), iterations, warmup, quiet,
+                                   float32_mode, skip_extras_values,
+                                   borrow_input_buffers);
+
+        if (csv) {
+            print_csv_row(r);
+        } else {
+            print_result(r);
+            printf("\n");
+        }
+    }
+
+    return 0;
+}

benchmark/gen_synthetic.cpp

@@ -0,0 +1,740 @@
+/*
+ * gen_synthetic.cpp — Generate synthetic glTF 2.0 scenes for benchmarking.
+ *
+ * Produces .gltf (ASCII) and .glb (binary) files with configurable:
+ *   - Number of meshes, each with N vertices/triangles
+ *   - Number of nodes (flat hierarchy)
+ *   - Number of materials
+ *   - Number of animations with M keyframes
+ *
+ * Usage:
+ *   gen_synthetic [--meshes N] [--verts-per-mesh N] [--nodes N]
+ *                 [--materials N] [--animations N] [--keyframes N]
+ *                 [--prefix NAME]
+ *
+ * Outputs: <prefix>_<label>.gltf and <prefix>_<label>.glb
+ */
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <cmath>
+#include <string>
+#include <vector>
+#include <cstdint>
+
+/* ------------------------------------------------------------------ */
+/* Tiny JSON writer (no dependencies)                                 */
+/* ------------------------------------------------------------------ */
+
+struct JsonWriter {
+    std::string buf;
+    int indent;
+    bool need_comma;
+    std::vector<bool> stack; /* true = array context */
+
+    JsonWriter() : indent(0), need_comma(false) {}
+
+    void comma() {
+        if (need_comma) buf += ",";
+        buf += "\n";
+        for (int i = 0; i < indent; ++i) buf += "  ";
+    }
+
+    void begin_obj() {
+        if (!stack.empty()) comma();
+        buf += "{";
+        indent++;
+        need_comma = false;
+        stack.push_back(false);
+    }
+    void end_obj() {
+        indent--;
+        buf += "\n";
+        for (int i = 0; i < indent; ++i) buf += "  ";
+        buf += "}";
+        stack.pop_back();
+        need_comma = true;
+    }
+
+    void begin_arr() {
+        if (!stack.empty() && !need_comma) { /* first elem */ }
+        buf += "[";
+        indent++;
+        need_comma = false;
+        stack.push_back(true);
+    }
+    void end_arr() {
+        indent--;
+        buf += "\n";
+        for (int i = 0; i < indent; ++i) buf += "  ";
+        buf += "]";
+        stack.pop_back();
+        need_comma = true;
+    }
+
+    void key(const char *k) {
+        comma();
+        buf += "\"";
+        buf += k;
+        buf += "\": ";
+        need_comma = false;
+    }
+
+    void val_str(const char *v) {
+        if (stack.back()) comma();
+        buf += "\"";
+        buf += v;
+        buf += "\"";
+        need_comma = true;
+    }
+    void val_int(int64_t v) {
+        if (stack.back()) comma();
+        buf += std::to_string(v);
+        need_comma = true;
+    }
+    void val_double(double v) {
+        if (stack.back()) comma();
+        char tmp[64];
+        snprintf(tmp, sizeof(tmp), "%.6g", v);
+        buf += tmp;
+        need_comma = true;
+    }
+    void val_bool(bool v) {
+        if (stack.back()) comma();
+        buf += v ? "true" : "false";
+        need_comma = true;
+    }
+
+    void kv_str(const char *k, const char *v) { key(k); val_str(v); need_comma = true; }
+    void kv_int(const char *k, int64_t v) { key(k); val_int(v); need_comma = true; }
+    void kv_double(const char *k, double v) { key(k); val_double(v); need_comma = true; }
+    void kv_bool(const char *k, bool v) { key(k); val_bool(v); need_comma = true; }
+};
+
+/* ------------------------------------------------------------------ */
+/* Binary buffer builder                                              */
+/* ------------------------------------------------------------------ */
+
+struct BinBuffer {
+    std::vector<uint8_t> data;
+
+    size_t offset() const { return data.size(); }
+
+    void push_float(float v) {
+        const uint8_t *p = reinterpret_cast<const uint8_t*>(&v);
+        data.insert(data.end(), p, p + 4);
+    }
+    void push_u16(uint16_t v) {
+        const uint8_t *p = reinterpret_cast<const uint8_t*>(&v);
+        data.insert(data.end(), p, p + 2);
+    }
+    void push_u32(uint32_t v) {
+        const uint8_t *p = reinterpret_cast<const uint8_t*>(&v);
+        data.insert(data.end(), p, p + 4);
+    }
+    void align4() {
+        while (data.size() % 4 != 0) data.push_back(0);
+    }
+};
+
+/* ------------------------------------------------------------------ */
+/* Scene config                                                       */
+/* ------------------------------------------------------------------ */
+
+struct SceneConfig {
+    int num_meshes;
+    int verts_per_mesh;
+    int num_nodes;
+    int num_materials;
+    int num_animations;
+    int keyframes;
+};
+
+/* ------------------------------------------------------------------ */
+/* Generate the scene                                                 */
+/* ------------------------------------------------------------------ */
+
+struct AccessorInfo {
+    int buffer_view;
+    int component_type;
+    int count;
+    const char *type;
+    float min_vals[3];
+    float max_vals[3];
+    int min_max_components; /* 0 = none, 1 = scalar, 3 = vec3 */
+};
+
+static void generate_scene(const SceneConfig &cfg,
+                            std::string &out_json,
+                            std::vector<uint8_t> &out_bin) {
+    BinBuffer bin;
+
+    /* Pre-compute sizes */
+    int tris_per_mesh = cfg.verts_per_mesh / 3;
+    if (tris_per_mesh < 1) tris_per_mesh = 1;
+    int actual_verts = tris_per_mesh * 3;
+
+    /*
+     * For each mesh:
+     *   - positions: actual_verts * 3 floats
+     *   - normals:   actual_verts * 3 floats
+     *   - indices:   tris_per_mesh * 3 uint16 (or uint32 if >65535)
+     *
+     * For each animation:
+     *   - time keys:  keyframes floats
+     *   - translation values: keyframes * 3 floats
+     */
+
+    /* Track buffer views and accessors */
+    std::vector<size_t> bv_offsets;
+    std::vector<size_t> bv_lengths;
+    std::vector<AccessorInfo> accessors;
+    int bv_idx = 0;
+
+    bool use_u32_indices = (actual_verts > 65535);
+
+    /* === Mesh data === */
+    for (int m = 0; m < cfg.num_meshes; ++m) {
+        float mesh_offset_x = (float)m * 5.0f;
+
+        /* Positions */
+        size_t pos_off = bin.offset();
+        float pmin[3] = {1e30f, 1e30f, 1e30f};
+        float pmax[3] = {-1e30f, -1e30f, -1e30f};
+        for (int v = 0; v < actual_verts; ++v) {
+            float angle = (float)v / (float)actual_verts * 6.2831853f;
+            float r = 1.0f + 0.3f * sinf(angle * 5.0f);
+            float x = mesh_offset_x + r * cosf(angle);
+            float y = r * sinf(angle);
+            float z = 0.5f * sinf(angle * 3.0f + (float)m);
+            bin.push_float(x); bin.push_float(y); bin.push_float(z);
+            if (x < pmin[0]) pmin[0] = x;
+            if (x > pmax[0]) pmax[0] = x;
+            if (y < pmin[1]) pmin[1] = y;
+            if (y > pmax[1]) pmax[1] = y;
+            if (z < pmin[2]) pmin[2] = z;
+            if (z > pmax[2]) pmax[2] = z;
+        }
+        size_t pos_len = bin.offset() - pos_off;
+        bin.align4();
+        bv_offsets.push_back(pos_off); bv_lengths.push_back(pos_len);
+        int pos_bv = bv_idx++;
+
+        AccessorInfo pos_acc;
+        pos_acc.buffer_view = pos_bv;
+        pos_acc.component_type = 5126; /* FLOAT */
+        pos_acc.count = actual_verts;
+        pos_acc.type = "VEC3";
+        memcpy(pos_acc.min_vals, pmin, sizeof(pmin));
+        memcpy(pos_acc.max_vals, pmax, sizeof(pmax));
+        pos_acc.min_max_components = 3;
+        accessors.push_back(pos_acc);
+
+        /* Normals */
+        size_t norm_off = bin.offset();
+        for (int v = 0; v < actual_verts; ++v) {
+            float angle = (float)v / (float)actual_verts * 6.2831853f;
+            float nx = cosf(angle), ny = sinf(angle), nz = 0.0f;
+            float len = sqrtf(nx*nx + ny*ny + nz*nz);
+            if (len > 0) { nx /= len; ny /= len; nz /= len; }
+            bin.push_float(nx); bin.push_float(ny); bin.push_float(nz);
+        }
+        size_t norm_len = bin.offset() - norm_off;
+        bin.align4();
+        bv_offsets.push_back(norm_off); bv_lengths.push_back(norm_len);
+        int norm_bv = bv_idx++;
+
+        AccessorInfo norm_acc;
+        norm_acc.buffer_view = norm_bv;
+        norm_acc.component_type = 5126;
+        norm_acc.count = actual_verts;
+        norm_acc.type = "VEC3";
+        norm_acc.min_max_components = 0;
+        accessors.push_back(norm_acc);
+
+        /* Indices */
+        size_t idx_off = bin.offset();
+        for (int t = 0; t < tris_per_mesh; ++t) {
+            if (use_u32_indices) {
+                bin.push_u32((uint32_t)(t * 3));
+                bin.push_u32((uint32_t)(t * 3 + 1));
+                bin.push_u32((uint32_t)(t * 3 + 2));
+            } else {
+                bin.push_u16((uint16_t)(t * 3));
+                bin.push_u16((uint16_t)(t * 3 + 1));
+                bin.push_u16((uint16_t)(t * 3 + 2));
+            }
+        }
+        size_t idx_len = bin.offset() - idx_off;
+        bin.align4();
+        bv_offsets.push_back(idx_off); bv_lengths.push_back(idx_len);
+        int idx_bv = bv_idx++;
+
+        AccessorInfo idx_acc;
+        idx_acc.buffer_view = idx_bv;
+        idx_acc.component_type = use_u32_indices ? 5125 : 5123; /* UINT or USHORT */
+        idx_acc.count = tris_per_mesh * 3;
+        idx_acc.type = "SCALAR";
+        idx_acc.min_max_components = 0;
+        accessors.push_back(idx_acc);
+    }
+
+    /* === Animation data === */
+    int anim_time_accessor_start = (int)accessors.size();
+    for (int a = 0; a < cfg.num_animations; ++a) {
+        /* Time keys */
+        size_t time_off = bin.offset();
+        float tmin = 0.0f, tmax = 0.0f;
+        for (int k = 0; k < cfg.keyframes; ++k) {
+            float t = (float)k / (float)(cfg.keyframes - 1) * 10.0f;
+            bin.push_float(t);
+            if (k == 0) tmin = t;
+            tmax = t;
+        }
+        size_t time_len = bin.offset() - time_off;
+        bin.align4();
+        bv_offsets.push_back(time_off); bv_lengths.push_back(time_len);
+        int time_bv = bv_idx++;
+
+        AccessorInfo time_acc;
+        time_acc.buffer_view = time_bv;
+        time_acc.component_type = 5126;
+        time_acc.count = cfg.keyframes;
+        time_acc.type = "SCALAR";
+        time_acc.min_vals[0] = tmin;
+        time_acc.max_vals[0] = tmax;
+        time_acc.min_max_components = 1;
+        accessors.push_back(time_acc);
+
+        /* Translation values */
+        size_t val_off = bin.offset();
+        for (int k = 0; k < cfg.keyframes; ++k) {
+            float t = (float)k / (float)(cfg.keyframes - 1) * 10.0f;
+            float x = sinf(t * 0.5f + (float)a) * 2.0f;
+            float y = cosf(t * 0.3f) * 1.5f;
+            float z = sinf(t * 0.7f + (float)a * 0.5f);
+            bin.push_float(x); bin.push_float(y); bin.push_float(z);
+        }
+        size_t val_len = bin.offset() - val_off;
+        bin.align4();
+        bv_offsets.push_back(val_off); bv_lengths.push_back(val_len);
+        int val_bv = bv_idx++;
+
+        AccessorInfo val_acc;
+        val_acc.buffer_view = val_bv;
+        val_acc.component_type = 5126;
+        val_acc.count = cfg.keyframes;
+        val_acc.type = "VEC3";
+        val_acc.min_max_components = 0;
+        accessors.push_back(val_acc);
+    }
+
+    size_t total_bin = bin.data.size();
+
+    /* === Build JSON === */
+    JsonWriter w;
+    w.begin_obj();
+
+    /* asset */
+    w.key("asset"); w.begin_obj();
+    w.kv_str("version", "2.0");
+    w.kv_str("generator", "tinygltf_benchmark_gen");
+    w.end_obj();
+
+    /* scene */
+    w.kv_int("scene", 0);
+
+    /* scenes */
+    w.key("scenes"); w.begin_arr();
+    w.begin_obj();
+    w.kv_str("name", "BenchmarkScene");
+    w.key("nodes"); w.begin_arr();
+    for (int n = 0; n < cfg.num_nodes; ++n) w.val_int(n);
+    w.end_arr();
+    w.end_obj();
+    w.end_arr();
+
+    /* nodes */
+    w.key("nodes"); w.begin_arr();
+    for (int n = 0; n < cfg.num_nodes; ++n) {
+        w.begin_obj();
+        w.kv_str("name", ("Node_" + std::to_string(n)).c_str());
+        if (n < cfg.num_meshes) {
+            w.kv_int("mesh", n);
+        }
+        w.key("translation"); w.begin_arr();
+        w.val_double((double)n * 3.0);
+        w.val_double(0.0);
+        w.val_double(0.0);
+        w.end_arr();
+        w.end_obj();
+    }
+    w.end_arr();
+
+    /* meshes */
+    w.key("meshes"); w.begin_arr();
+    for (int m = 0; m < cfg.num_meshes; ++m) {
+        int base_acc = m * 3; /* pos, norm, idx per mesh */
+        w.begin_obj();
+        w.kv_str("name", ("Mesh_" + std::to_string(m)).c_str());
+        w.key("primitives"); w.begin_arr();
+        w.begin_obj();
+        w.key("attributes"); w.begin_obj();
+        w.kv_int("POSITION", base_acc);
+        w.kv_int("NORMAL", base_acc + 1);
+        w.end_obj();
+        w.kv_int("indices", base_acc + 2);
+        w.kv_int("material", m % cfg.num_materials);
+        w.kv_int("mode", 4);
+        w.end_obj();
+        w.end_arr();
+        w.end_obj();
+    }
+    w.end_arr();
+
+    /* materials */
+    w.key("materials"); w.begin_arr();
+    for (int m = 0; m < cfg.num_materials; ++m) {
+        w.begin_obj();
+        w.kv_str("name", ("Material_" + std::to_string(m)).c_str());
+        w.key("pbrMetallicRoughness"); w.begin_obj();
+        w.key("baseColorFactor"); w.begin_arr();
+        float hue = (float)m / (float)cfg.num_materials;
+        w.val_double(0.5 + 0.5 * sin(hue * 6.28));
+        w.val_double(0.5 + 0.5 * sin(hue * 6.28 + 2.09));
+        w.val_double(0.5 + 0.5 * sin(hue * 6.28 + 4.19));
+        w.val_double(1.0);
+        w.end_arr();
+        w.kv_double("metallicFactor", 0.2 + 0.6 * ((double)m / cfg.num_materials));
+        w.kv_double("roughnessFactor", 0.3 + 0.5 * ((double)(cfg.num_materials - m) / cfg.num_materials));
+        w.end_obj();
+        w.end_obj();
+    }
+    w.end_arr();
+
+    /* accessors */
+    w.key("accessors"); w.begin_arr();
+    for (size_t i = 0; i < accessors.size(); ++i) {
+        const AccessorInfo &a = accessors[i];
+        w.begin_obj();
+        w.kv_int("bufferView", a.buffer_view);
+        w.kv_int("componentType", a.component_type);
+        w.kv_int("count", a.count);
+        w.kv_str("type", a.type);
+        if (a.min_max_components == 1) {
+            w.key("min"); w.begin_arr(); w.val_double(a.min_vals[0]); w.end_arr();
+            w.key("max"); w.begin_arr(); w.val_double(a.max_vals[0]); w.end_arr();
+        } else if (a.min_max_components == 3) {
+            w.key("min"); w.begin_arr();
+            w.val_double(a.min_vals[0]); w.val_double(a.min_vals[1]); w.val_double(a.min_vals[2]);
+            w.end_arr();
+            w.key("max"); w.begin_arr();
+            w.val_double(a.max_vals[0]); w.val_double(a.max_vals[1]); w.val_double(a.max_vals[2]);
+            w.end_arr();
+        }
+        w.end_obj();
+    }
+    w.end_arr();
+
+    /* bufferViews */
+    w.key("bufferViews"); w.begin_arr();
+    for (int i = 0; i < bv_idx; ++i) {
+        w.begin_obj();
+        w.kv_int("buffer", 0);
+        w.kv_int("byteOffset", (int64_t)bv_offsets[i]);
+        w.kv_int("byteLength", (int64_t)bv_lengths[i]);
+        w.end_obj();
+    }
+    w.end_arr();
+
+    /* buffers */
+    w.key("buffers"); w.begin_arr();
+    w.begin_obj();
+    w.kv_int("byteLength", (int64_t)total_bin);
+    /* URI will be set by caller for .gltf, omitted for .glb */
+    w.end_obj();
+    w.end_arr();
+
+    /* animations */
+    if (cfg.num_animations > 0) {
+        w.key("animations"); w.begin_arr();
+        for (int a = 0; a < cfg.num_animations; ++a) {
+            int time_acc = anim_time_accessor_start + a * 2;
+            int val_acc = time_acc + 1;
+            /* Target node: cycle through available nodes */
+            int target_node = a % cfg.num_nodes;
+
+            w.begin_obj();
+            w.kv_str("name", ("Anim_" + std::to_string(a)).c_str());
+
+            w.key("channels"); w.begin_arr();
+            w.begin_obj();
+            w.kv_int("sampler", 0);
+            w.key("target"); w.begin_obj();
+            w.kv_int("node", target_node);
+            w.kv_str("path", "translation");
+            w.end_obj();
+            w.end_obj();
+            w.end_arr();
+
+            w.key("samplers"); w.begin_arr();
+            w.begin_obj();
+            w.kv_int("input", time_acc);
+            w.kv_int("output", val_acc);
+            w.kv_str("interpolation", "LINEAR");
+            w.end_obj();
+            w.end_arr();
+
+            w.end_obj();
+        }
+        w.end_arr();
+    }
+
+    w.end_obj();
+
+    out_json = w.buf;
+    out_bin = bin.data;
+}
+
+/* ------------------------------------------------------------------ */
+/* Write .gltf + .bin                                                 */
+/* ------------------------------------------------------------------ */
+
+static void write_gltf(const std::string &prefix, const std::string &label,
+                        const std::string &json_str,
+                        const std::vector<uint8_t> &bin_data) {
+    std::string bin_name = prefix + "_" + label + ".bin";
+    std::string gltf_name = prefix + "_" + label + ".gltf";
+
+    /* Inject "uri" into the buffer object in JSON */
+    std::string json_patched = json_str;
+    /* Find the buffers array and add uri before the closing } of the buffer */
+    size_t pos = json_patched.find("\"byteLength\"");
+    if (pos != std::string::npos) {
+        /* Find the line end after byteLength value */
+        size_t line_end = json_patched.find('\n', pos);
+        if (line_end != std::string::npos) {
+            /* Extract just the filename for uri */
+            std::string bin_filename = prefix + "_" + label + ".bin";
+            std::string uri_line = ",\n      \"uri\": \"" + bin_filename + "\"";
+            json_patched.insert(line_end, uri_line);
+        }
+    }
+
+    /* Write .bin */
+    FILE *f = fopen(bin_name.c_str(), "wb");
+    if (f) {
+        fwrite(bin_data.data(), 1, bin_data.size(), f);
+        fclose(f);
+    }
+
+    /* Write .gltf */
+    f = fopen(gltf_name.c_str(), "w");
+    if (f) {
+        fwrite(json_patched.c_str(), 1, json_patched.size(), f);
+        fclose(f);
+    }
+
+    printf("  Written: %s (%zu bytes JSON) + %s (%zu bytes binary)\n",
+           gltf_name.c_str(), json_patched.size(),
+           bin_name.c_str(), bin_data.size());
+}
+
+/* ------------------------------------------------------------------ */
+/* Write .glb                                                         */
+/* ------------------------------------------------------------------ */
+
+static void write_glb(const std::string &prefix, const std::string &label,
+                       const std::string &json_str,
+                       const std::vector<uint8_t> &bin_data) {
+    std::string glb_name = prefix + "_" + label + ".glb";
+
+    uint32_t json_len = (uint32_t)json_str.size();
+    uint32_t json_padded = (json_len + 3) & ~3u;
+    uint32_t bin_len = (uint32_t)bin_data.size();
+    uint32_t bin_padded = (bin_len + 3) & ~3u;
+
+    uint32_t total = 12 + 8 + json_padded + 8 + bin_padded;
+
+    FILE *f = fopen(glb_name.c_str(), "wb");
+    if (!f) return;
+
+    /* Header */
+    fwrite("glTF", 1, 4, f);
+    uint32_t version = 2;
+    fwrite(&version, 4, 1, f);
+    fwrite(&total, 4, 1, f);
+
+    /* JSON chunk */
+    uint32_t json_type = 0x4E4F534A;
+    fwrite(&json_padded, 4, 1, f);
+    fwrite(&json_type, 4, 1, f);
+    fwrite(json_str.c_str(), 1, json_len, f);
+    for (uint32_t i = json_len; i < json_padded; ++i) {
+        char sp = ' ';
+        fwrite(&sp, 1, 1, f);
+    }
+
+    /* BIN chunk */
+    uint32_t bin_type = 0x004E4942;
+    fwrite(&bin_padded, 4, 1, f);
+    fwrite(&bin_type, 4, 1, f);
+    fwrite(bin_data.data(), 1, bin_len, f);
+    for (uint32_t i = bin_len; i < bin_padded; ++i) {
+        char z = 0;
+        fwrite(&z, 1, 1, f);
+    }
+
+    fclose(f);
+    printf("  Written: %s (%u bytes)\n", glb_name.c_str(), total);
+}
+
+/* ------------------------------------------------------------------ */
+/* Preset configurations                                              */
+/* ------------------------------------------------------------------ */
+
+struct Preset {
+    const char *label;
+    SceneConfig cfg;
+};
+
+static Preset presets[] = {
+    {"tiny",   {1,   100,    2,  1, 0,   0}},
+    {"small",  {5,   1000,  10,  3, 2,  50}},
+    {"medium", {20,  5000,  50, 10, 5, 200}},
+    {"large",  {100, 10000, 200, 20, 10, 500}},
+    {"huge",   {500, 50000, 1000, 50, 50, 1000}},
+};
+
+static const int num_presets = (int)(sizeof(presets) / sizeof(presets[0]));
+
+/* ------------------------------------------------------------------ */
+/* Generate float-heavy scene (~500MB of ASCII float values in JSON)  */
+/* ------------------------------------------------------------------ */
+
+static void generate_float_heavy(const std::string &prefix, size_t target_mb) {
+    std::string gltf_name = prefix + "_float_heavy.gltf";
+    FILE *f = fopen(gltf_name.c_str(), "w");
+    if (!f) {
+        fprintf(stderr, "Cannot open %s\n", gltf_name.c_str());
+        return;
+    }
+
+    /* Write minimal valid glTF with massive extras float array */
+    fprintf(f, "{\n");
+    fprintf(f, "  \"asset\": {\"version\": \"2.0\", \"generator\": \"tinygltf_benchmark_gen\"},\n");
+    fprintf(f, "  \"scene\": 0,\n");
+    fprintf(f, "  \"scenes\": [{\"name\": \"FloatHeavy\", \"nodes\": [0]}],\n");
+    fprintf(f, "  \"nodes\": [{\"name\": \"Root\"}],\n");
+    fprintf(f, "  \"extras\": {\n");
+
+    size_t target_bytes = target_mb * 1024ULL * 1024ULL;
+    size_t total_written = 0;
+    int num_channels = 10;
+    size_t per_channel = target_bytes / (size_t)num_channels;
+
+    for (int ch = 0; ch < num_channels; ++ch) {
+        fprintf(f, "    \"channel_%d\": [\n      ", ch);
+        size_t ch_written = 0;
+        size_t count = 0;
+        uint64_t seed = (uint64_t)ch * 7919ULL + 1;
+        bool first = true;
+
+        while (ch_written < per_channel) {
+            /* Comma before every value except the first */
+            if (!first) {
+                fwrite(",\n      ", 1, 8, f);
+                ch_written += 8;
+            }
+            first = false;
+
+            /* Generate varied float values: mix of magnitudes and precisions */
+            seed = seed * 6364136223846793005ULL + 1442695040888963407ULL;
+            double raw = (double)(int64_t)seed / (double)INT64_MAX;
+
+            double val;
+            int kind = (int)(count % 5);
+            switch (kind) {
+                case 0: val = raw * 1000.0; break;           /* large: -999.xxx */
+                case 1: val = raw * 0.001; break;            /* small: 0.000xxx */
+                case 2: val = raw * 3.14159265358979; break; /* medium: -3.14..3.14 */
+                case 3: val = raw * 1e6; break;              /* very large */
+                case 4: val = raw * 1e-6; break;             /* very small */
+                default: val = raw; break;
+            }
+
+            char buf[64];
+            int len = snprintf(buf, sizeof(buf), "%.8g", val);
+            fwrite(buf, 1, (size_t)len, f);
+            ch_written += (size_t)len;
+            count++;
+        }
+
+        total_written += ch_written;
+
+        if (ch < num_channels - 1) {
+            fprintf(f, "\n    ],\n");
+        } else {
+            fprintf(f, "\n    ]\n");
+        }
+    }
+
+    fprintf(f, "  }\n");
+    fprintf(f, "}\n");
+    fclose(f);
+
+    /* Report actual file size */
+    f = fopen(gltf_name.c_str(), "rb");
+    if (f) {
+        fseek(f, 0, SEEK_END);
+        long sz = ftell(f);
+        fclose(f);
+        printf("  Written: %s (%.1f MB, ~%zu float values across %d channels)\n",
+               gltf_name.c_str(), (double)sz / (1024.0 * 1024.0),
+               total_written / 12, num_channels);
+    }
+}
+
+/* ------------------------------------------------------------------ */
+/* Main                                                               */
+/* ------------------------------------------------------------------ */
+
+int main(int argc, char **argv) {
+    std::string prefix = "synthetic";
+
+    /* Parse args */
+    for (int i = 1; i < argc; ++i) {
+        if (strcmp(argv[i], "--prefix") == 0 && i + 1 < argc) {
+            prefix = argv[++i];
+        }
+    }
+
+    printf("Generating synthetic glTF benchmark scenes...\n\n");
+
+    for (int p = 0; p < num_presets; ++p) {
+        const Preset &pr = presets[p];
+
+        printf("[%s] meshes=%d verts/mesh=%d nodes=%d materials=%d "
+               "animations=%d keyframes=%d\n",
+               pr.label, pr.cfg.num_meshes, pr.cfg.verts_per_mesh,
+               pr.cfg.num_nodes, pr.cfg.num_materials,
+               pr.cfg.num_animations, pr.cfg.keyframes);
+
+        std::string json;
+        std::vector<uint8_t> bin;
+        generate_scene(pr.cfg, json, bin);
+
+        write_gltf(prefix, pr.label, json, bin);
+        write_glb(prefix, pr.label, json, bin);
+        printf("\n");
+    }
+
+    /* Float-heavy scene: ~500MB of ASCII floats in JSON */
+    printf("[float_heavy] ~500MB of ASCII float values in JSON extras\n");
+    generate_float_heavy(prefix, 500);
+    printf("\n");
+
+    printf("Done.\n");
+    return 0;
+}

examples/glview/glview.cc

@@ -788,8 +788,10 @@ static void QuatToAngleAxis(const std::vector<double> quaternion,
     return;
   }
 
+  constexpr double pi = 3.14159265358979323846;
+
   double denom = sqrt(1-qw*qw);
-  outAngleDegrees = angleRadians * 180.0 / M_PI;
+  outAngleDegrees = angleRadians * 180.0 / pi;
   axis[0] = qx / denom;
   axis[1] = qy / denom;
   axis[2] = qz / denom;

loader_example.cc

@@ -6,7 +6,10 @@
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #include "tiny_gltf.h"
 
+#include <algorithm>
+#include <cstdint>
 #include <cstdio>
+#include <cstring>
 #include <fstream>
 #include <iostream>
 
@@ -852,6 +855,206 @@ static void Dump(const tinygltf::Model &model) {
   }
 }
 
+/* ===== Digest helpers (used to compare v1 vs v3 parses) ===================== */
+
+static uint64_t fnv64(const unsigned char *data, size_t n) {
+  uint64_t h = 0xcbf29ce484222325ULL;
+  for (size_t i = 0; i < n; ++i) { h ^= data[i]; h *= 0x100000001b3ULL; }
+  return h;
+}
+
+static void d_str(const std::string &s) {
+  putchar('"');
+  for (unsigned char c : s) {
+    if (c == '"' || c == '\\') { putchar('\\'); putchar((char)c); }
+    else if (c < 0x20 || c >= 0x7f) putchar('?');
+    else putchar((char)c);
+  }
+  putchar('"');
+}
+
+static void d_dbl(double v) { printf("%.7g", v); }
+
+static void d_dbl_arr(const double *v, size_t n) {
+  putchar('[');
+  for (size_t i = 0; i < n; ++i) { if (i) putchar(','); d_dbl(v[i]); }
+  putchar(']');
+}
+
+static void d_dbl_vec(const std::vector<double> &v) {
+  d_dbl_arr(v.data(), v.size());
+}
+
+static void PrintDigest(const tinygltf::Model &m) {
+  printf("DIGEST_BEGIN\n");
+
+  printf("asset version=");
+  d_str(m.asset.version);
+  printf(" generator=");
+  d_str(m.asset.generator);
+  printf("\n");
+
+  for (size_t i = 0; i < m.buffers.size(); ++i) {
+    const auto &b = m.buffers[i];
+    uint64_t h = b.data.empty() ? 0 : fnv64(b.data.data(), b.data.size());
+    printf("buffer %zu byte_length=%llu fnv64=0x%016llx\n",
+           i, (unsigned long long)b.data.size(), (unsigned long long)h);
+  }
+  for (size_t i = 0; i < m.bufferViews.size(); ++i) {
+    const auto &bv = m.bufferViews[i];
+    printf("buffer_view %zu buffer=%d byte_offset=%llu byte_length=%llu byte_stride=%u\n",
+           i, bv.buffer, (unsigned long long)bv.byteOffset,
+           (unsigned long long)bv.byteLength, (unsigned)bv.byteStride);
+  }
+  for (size_t i = 0; i < m.accessors.size(); ++i) {
+    const auto &a = m.accessors[i];
+    printf("accessor %zu buffer_view=%d byte_offset=%llu component_type=%d count=%llu type=%d normalized=%d min=",
+           i, a.bufferView, (unsigned long long)a.byteOffset, a.componentType,
+           (unsigned long long)a.count, a.type, a.normalized ? 1 : 0);
+    d_dbl_vec(a.minValues);
+    printf(" max=");
+    d_dbl_vec(a.maxValues);
+    printf(" sparse=%d\n", a.sparse.isSparse ? 1 : 0);
+  }
+  for (size_t i = 0; i < m.meshes.size(); ++i) {
+    const auto &me = m.meshes[i];
+    printf("mesh %zu primitives_count=%zu weights_count=%zu\n",
+           i, me.primitives.size(), me.weights.size());
+    for (size_t j = 0; j < me.primitives.size(); ++j) {
+      const auto &p = me.primitives[j];
+      printf("prim %zu %zu indices=%d material=%d mode=%d attrs=[",
+             i, j, p.indices, p.material, p.mode);
+      // attributes is std::map → already sorted by key
+      bool first = true;
+      for (const auto &kv : p.attributes) {
+        if (!first) putchar(',');
+        printf("%s:%d", kv.first.c_str(), kv.second);
+        first = false;
+      }
+      printf("] targets_count=%zu\n", p.targets.size());
+    }
+  }
+  for (size_t i = 0; i < m.nodes.size(); ++i) {
+    const auto &n = m.nodes[i];
+    double t[3] = {0, 0, 0};
+    double r[4] = {0, 0, 0, 1};
+    double s[3] = {1, 1, 1};
+    double mat[16] = {1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1};
+    int has_matrix = (n.matrix.size() == 16) ? 1 : 0;
+    if (n.translation.size() == 3) std::copy(n.translation.begin(), n.translation.end(), t);
+    if (n.rotation.size() == 4)    std::copy(n.rotation.begin(),    n.rotation.end(),    r);
+    if (n.scale.size() == 3)       std::copy(n.scale.begin(),       n.scale.end(),       s);
+    if (has_matrix) std::copy(n.matrix.begin(), n.matrix.end(), mat);
+    printf("node %zu mesh=%d skin=%d camera=%d light=%d children_count=%zu has_matrix=%d t=",
+           i, n.mesh, n.skin, n.camera, n.light, n.children.size(), has_matrix);
+    d_dbl_arr(t, 3);
+    printf(" r=");
+    d_dbl_arr(r, 4);
+    printf(" s=");
+    d_dbl_arr(s, 3);
+    printf(" matrix=");
+    d_dbl_arr(mat, 16);
+    printf(" weights_count=%zu\n", n.weights.size());
+  }
+  for (size_t i = 0; i < m.materials.size(); ++i) {
+    const auto &mat = m.materials[i];
+    double ef[3] = {0, 0, 0};
+    double bcf[4] = {1, 1, 1, 1};
+    if (mat.emissiveFactor.size() == 3)
+      std::copy(mat.emissiveFactor.begin(), mat.emissiveFactor.end(), ef);
+    if (mat.pbrMetallicRoughness.baseColorFactor.size() == 4)
+      std::copy(mat.pbrMetallicRoughness.baseColorFactor.begin(),
+                mat.pbrMetallicRoughness.baseColorFactor.end(), bcf);
+    printf("material %zu alpha_mode=", i);
+    d_str(mat.alphaMode);
+    printf(" alpha_cutoff=");
+    d_dbl(mat.alphaCutoff);
+    printf(" double_sided=%d emissive=", mat.doubleSided ? 1 : 0);
+    d_dbl_arr(ef, 3);
+    printf(" base_color_factor=");
+    d_dbl_arr(bcf, 4);
+    printf(" metallic=");
+    d_dbl(mat.pbrMetallicRoughness.metallicFactor);
+    printf(" roughness=");
+    d_dbl(mat.pbrMetallicRoughness.roughnessFactor);
+    printf(" base_color_tex=%d normal_tex=%d occlusion_tex=%d emissive_tex=%d\n",
+           mat.pbrMetallicRoughness.baseColorTexture.index,
+           mat.normalTexture.index,
+           mat.occlusionTexture.index,
+           mat.emissiveTexture.index);
+  }
+  for (size_t i = 0; i < m.textures.size(); ++i) {
+    const auto &t = m.textures[i];
+    printf("texture %zu source=%d sampler=%d\n", i, t.source, t.sampler);
+  }
+  for (size_t i = 0; i < m.samplers.size(); ++i) {
+    const auto &s = m.samplers[i];
+    printf("sampler %zu min_filter=%d mag_filter=%d wrap_s=%d wrap_t=%d\n",
+           i, s.minFilter, s.magFilter, s.wrapS, s.wrapT);
+  }
+  for (size_t i = 0; i < m.images.size(); ++i) {
+    const auto &im = m.images[i];
+    /* mime_type and uri normalization differ between v1/v3 (data URIs,
+       extension inference); buffer_view reference is the parse-fidelity bit. */
+    printf("image %zu buffer_view=%d\n", i, im.bufferView);
+  }
+  for (size_t i = 0; i < m.skins.size(); ++i) {
+    const auto &s = m.skins[i];
+    printf("skin %zu inverse_bind_matrices=%d skeleton=%d joints_count=%zu\n",
+           i, s.inverseBindMatrices, s.skeleton, s.joints.size());
+  }
+  for (size_t i = 0; i < m.animations.size(); ++i) {
+    const auto &a = m.animations[i];
+    printf("animation %zu channels_count=%zu samplers_count=%zu\n",
+           i, a.channels.size(), a.samplers.size());
+    for (size_t j = 0; j < a.channels.size(); ++j) {
+      const auto &c = a.channels[j];
+      printf("chan %zu %zu sampler=%d target_node=%d target_path=", i, j,
+             c.sampler, c.target_node);
+      d_str(c.target_path);
+      printf("\n");
+    }
+    for (size_t j = 0; j < a.samplers.size(); ++j) {
+      const auto &as = a.samplers[j];
+      printf("samp %zu %zu input=%d output=%d interpolation=", i, j,
+             as.input, as.output);
+      d_str(as.interpolation);
+      printf("\n");
+    }
+  }
+  for (size_t i = 0; i < m.cameras.size(); ++i) {
+    const auto &c = m.cameras[i];
+    bool is_persp = (c.type == "perspective");
+    printf("camera %zu type=", i);
+    d_str(c.type);
+    if (is_persp) {
+      printf(" yfov=");
+      d_dbl(c.perspective.yfov);
+      printf(" znear=");
+      d_dbl(c.perspective.znear);
+      printf(" zfar=");
+      d_dbl(c.perspective.zfar);
+      printf(" aspect=");
+      d_dbl(c.perspective.aspectRatio);
+    } else {
+      printf(" xmag=");
+      d_dbl(c.orthographic.xmag);
+      printf(" ymag=");
+      d_dbl(c.orthographic.ymag);
+      printf(" znear=");
+      d_dbl(c.orthographic.znear);
+      printf(" zfar=");
+      d_dbl(c.orthographic.zfar);
+    }
+    printf("\n");
+  }
+  for (size_t i = 0; i < m.scenes.size(); ++i) {
+    const auto &s = m.scenes[i];
+    printf("scene %zu nodes_count=%zu\n", i, s.nodes.size());
+  }
+  printf("DIGEST_END\n");
+}
+
 int main(int argc, char **argv) {
   if (argc < 2) {
     printf("Needs input.gltf\n");
@@ -900,6 +1103,20 @@ int main(int argc, char **argv) {
     return -1;
   }
 
+  printf("COUNTS"
+         " accessors=%zu animations=%zu buffers=%zu bufferViews=%zu"
+         " cameras=%zu images=%zu materials=%zu meshes=%zu nodes=%zu"
+         " samplers=%zu scenes=%zu skins=%zu textures=%zu lights=%zu\n",
+         model.accessors.size(), model.animations.size(),
+         model.buffers.size(), model.bufferViews.size(),
+         model.cameras.size(), model.images.size(),
+         model.materials.size(), model.meshes.size(),
+         model.nodes.size(), model.samplers.size(),
+         model.scenes.size(), model.skins.size(),
+         model.textures.size(), model.lights.size());
+
+  PrintDigest(model);
+
   Dump(model);
 
   return 0;

meson.build

@@ -0,0 +1,52 @@
+project(
+  'tinygltf',
+  'c',
+  default_options: ['c_std=c11'],
+  meson_version: '>=0.55.0',
+)
+
+tinygltf_inc = include_directories('.', 'tests')
+
+if get_option('tests')
+  tests_workdir = join_paths(meson.current_source_dir(), 'tests')
+  cc = meson.get_compiler('c')
+
+  tester_v3_c = executable(
+    'tester_v3_c',
+    ['tests/tester_v3_c.c', 'tiny_gltf_v3.c'],
+    include_directories: tinygltf_inc,
+    c_args: ['-DTINYGLTF3_ENABLE_FS'],
+    install: false,
+  )
+  test('tester_v3_c', tester_v3_c, workdir: tests_workdir)
+
+  tester_v3_c_v1port = executable(
+    'tester_v3_c_v1port',
+    ['tests/tester_v3_c_v1port.c', 'tiny_gltf_v3.c'],
+    include_directories: tinygltf_inc,
+    c_args: ['-DTINYGLTF3_ENABLE_FS'],
+    install: false,
+  )
+  test('tester_v3_c_v1port', tester_v3_c_v1port, workdir: tests_workdir)
+
+  tester_v3_json_c = executable(
+    'tester_v3_json_c',
+    'tests/tester_v3_json_c.c',
+    include_directories: tinygltf_inc,
+    install: false,
+  )
+  test('tester_v3_json_c', tester_v3_json_c, workdir: tests_workdir)
+
+  freestanding_args = []
+  if cc.get_id() in ['clang', 'gcc']
+    freestanding_args += ['-ffreestanding']
+  endif
+  tester_v3_freestanding = executable(
+    'tester_v3_freestanding',
+    'tests/tester_v3_freestanding.c',
+    include_directories: tinygltf_inc,
+    c_args: freestanding_args,
+    install: false,
+  )
+  test('tester_v3_freestanding', tester_v3_freestanding, workdir: tests_workdir)
+endif

meson_options.txt

@@ -0,0 +1 @@
+option('tests', type: 'boolean', value: true, description: 'Build and run tinygltf tests')

stb_image_write.h

@@ -773,7 +773,7 @@ static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, f
 #ifdef __STDC_LIB_EXT1__
       len = sprintf_s(buffer, sizeof(buffer), "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
 #else
-      len = sprintf(buffer, "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
+      len = snprintf(buffer, sizeof(buffer), "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
 #endif
       s->func(s->context, buffer, len);
 

test_runner.py

@@ -2,63 +2,167 @@
 
 import glob
 import os
+import re
 import subprocess
+import sys
 
-## Simple test runner.
+## Cross-version verifier: parses each sample model with the mature v1
+## (loader_example) and the new v3 C tester, then compares both the COUNTS
+## summary line and the structured DIGEST block both binaries emit.
+## v1 is the ground truth.
 
 # -- config -----------------------
 
-# Absolute path pointing to your cloned git repo of https://github.com/KhronosGroup/glTF-Sample-Models
-sample_model_dir = "/home/syoyo/work/glTF-Sample-Models"
+sample_model_dir = "/mnt/nfs/syoyo/glTF-Sample-Models"
 base_model_dir = os.path.join(sample_model_dir, "2.0")
 
-# Include `glTF-Draco` when you build `loader_example` with draco support.
-kinds = [ "glTF", "glTF-Binary", "glTF-Embedded", "glTF-MaterialsCommon"]
+v1_bin = "./loader_example"
+v3_bin = "./tests/tester_v3_c"
+
+kinds = ["glTF", "glTF-Binary", "glTF-Embedded", "glTF-MaterialsCommon"]
 # ---------------------------------
 
-failed = []
-success = []
+COUNTS_RE = re.compile(r"^COUNTS\s+(.*)$", re.MULTILINE)
+DIGEST_RE = re.compile(r"^DIGEST_BEGIN\n(.*?)^DIGEST_END$", re.MULTILINE | re.DOTALL)
 
-def run(filename):
 
+def parse_counts(output):
+    m = COUNTS_RE.search(output)
+    if not m:
+        return None
+    counts = {}
+    for tok in m.group(1).split():
+        if "=" not in tok:
+            continue
+        k, v = tok.split("=", 1)
+        counts[k] = int(v)
+    return counts
+
+
+def parse_digest(output):
+    m = DIGEST_RE.search(output)
+    if not m:
+        return None
+    return [line for line in m.group(1).splitlines() if line]
+
+
+def run_binary(binary, filename):
+    p = subprocess.Popen(
+        [binary, filename], stdout=subprocess.PIPE, stderr=subprocess.PIPE
+    )
+    out, err = p.communicate()
+    return p.returncode, out.decode("utf-8", "replace"), err.decode("utf-8", "replace")
+
+
+def diff_digests(v1, v3, max_lines=20):
+    """Return a short summary of differences between two digest line lists."""
+    diffs = []
+    n = max(len(v1), len(v3))
+    for i in range(n):
+        a = v1[i] if i < len(v1) else "<missing>"
+        b = v3[i] if i < len(v3) else "<missing>"
+        if a != b:
+            diffs.append("  v1[{0}]: {1}".format(i, a))
+            diffs.append("  v3[{0}]: {1}".format(i, b))
+            if len(diffs) >= max_lines * 2:
+                diffs.append("  ... (truncated)")
+                break
+    return diffs
+
+
+parse_failed = []     # v3 returned non-zero or no COUNTS/DIGEST
+v1_skipped = []       # v1 returned non-zero or no COUNTS/DIGEST
+counts_diff = []      # counts disagree
+digest_diff = []      # digest disagrees
+ok = []
+
+
+def verify(filename):
     print("Testing: " + filename)
-    cmd = ["./loader_example", filename]
-    try:
-        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        (stdout, stderr) = p.communicate()
-    except:
-        print("Failed to execute: ", cmd)
-        raise
 
-    if p.returncode != 0:
-        failed.append(filename)
-        print(stdout)
-        print(stderr)
-    else:
-        success.append(filename)
+    rc1, out1, err1 = run_binary(v1_bin, filename)
+    c1 = parse_counts(out1) if rc1 == 0 else None
+    d1 = parse_digest(out1) if rc1 == 0 else None
+    if c1 is None or d1 is None:
+        v1_skipped.append(filename)
+        print("  v1 ground truth unavailable (rc={0}); skipping".format(rc1))
+        return
+
+    rc3, out3, err3 = run_binary(v3_bin, filename)
+    c3 = parse_counts(out3) if rc3 == 0 else None
+    d3 = parse_digest(out3) if rc3 == 0 else None
+    if c3 is None or d3 is None:
+        parse_failed.append((filename, rc3, err3.strip()))
+        print("  v3 FAILED (rc={0}): {1}".format(rc3, err3.strip()[:200]))
+        return
+
+    cdiffs = []
+    for k in sorted(set(c1) | set(c3)):
+        if c1.get(k) != c3.get(k):
+            cdiffs.append((k, c1.get(k), c3.get(k)))
+    if cdiffs:
+        counts_diff.append((filename, cdiffs))
+        print("  COUNTS MISMATCH:")
+        for k, a, b in cdiffs:
+            print("    {0}: v1={1} v3={2}".format(k, a, b))
+        return
+
+    if d1 != d3:
+        diffs = diff_digests(d1, d3)
+        digest_diff.append((filename, diffs))
+        print("  DIGEST MISMATCH ({0} v1 lines, {1} v3 lines):".format(len(d1), len(d3)))
+        for line in diffs[:8]:
+            print(line)
+        return
+
+    ok.append(filename)
 
 
 def test():
-
-    for d in os.listdir(base_model_dir):
+    for d in sorted(os.listdir(base_model_dir)):
         p = os.path.join(base_model_dir, d)
-        if os.path.isdir(p):
-            for k in kinds:
-                targetDir = os.path.join(p, k)
-                g = glob.glob(targetDir + "/*.gltf") + glob.glob(targetDir + "/*.glb")
-                for gltf in g:
-                    run(gltf)
+        if not os.path.isdir(p):
+            continue
+        for k in kinds:
+            targetDir = os.path.join(p, k)
+            g = sorted(
+                glob.glob(targetDir + "/*.gltf")
+                + glob.glob(targetDir + "/*.glb")
+            )
+            for gltf in g:
+                verify(gltf)
 
 
 def main():
+    if not os.path.exists(v1_bin):
+        sys.exit("error: v1 binary not found at {0}".format(v1_bin))
+    if not os.path.exists(v3_bin):
+        sys.exit("error: v3 binary not found at {0}".format(v3_bin))
 
     test()
 
-    print("Success : {0}".format(len(success)))
-    print("Failed  : {0}".format(len(failed)))
+    print("")
+    print("=== Summary ===")
+    print("OK            : {0}".format(len(ok)))
+    print("Counts diff   : {0}".format(len(counts_diff)))
+    print("Digest diff   : {0}".format(len(digest_diff)))
+    print("v3 failed     : {0}".format(len(parse_failed)))
+    print("v1 skipped    : {0}".format(len(v1_skipped)))
 
-    for fail in failed:
-        print("FAIL: " + fail)
+    for f, diffs in counts_diff:
+        print("COUNTS DIFF: " + f)
+        for k, a, b in diffs:
+            print("  {0}: v1={1} v3={2}".format(k, a, b))
+    for f, diffs in digest_diff:
+        print("DIGEST DIFF: " + f)
+        for line in diffs:
+            print(line)
+    for f, rc, err in parse_failed:
+        print("V3 FAIL: {0} (rc={1}) {2}".format(f, rc, err[:200]))
 
-if __name__ == '__main__':
+    if counts_diff or digest_diff or parse_failed:
+        sys.exit(1)
+
+
+if __name__ == "__main__":
     main()

tests/Makefile

@@ -1,6 +1,19 @@
 # Use this for strict compilation check(will work on clang 3.8+)
 #EXTRA_CXXFLAGS := -fsanitize=address -Wall -Werror -Weverything -Wno-c++11-long-long -DTINYGLTF_APPLY_CLANG_WEVERYTHING
 
-all: ../tiny_gltf.h
+all: ../tiny_gltf.h tester_v3_c tester_v3_c_v1port tester_v3_json_c tester_v3_freestanding
 	clang++  -I../ $(EXTRA_CXXFLAGS) -std=c++11 -g -O0 -o tester tester.cc
 	clang++ -DTINYGLTF_NOEXCEPTION -I../ $(EXTRA_CXXFLAGS) -std=c++11 -g -O0 -o tester_noexcept tester.cc
+	clang++ -DTINYGLTF_USE_CUSTOM_JSON -I../ $(EXTRA_CXXFLAGS) -std=c++11 -g -O0 -o tester_intensive_customjson tester_intensive_customjson.cc
+
+tester_v3_c: tester_v3_c.c ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_c.h
+	clang -I../ -std=c11 -g -O0 -DTINYGLTF3_ENABLE_FS -o tester_v3_c tester_v3_c.c ../tiny_gltf_v3.c
+
+tester_v3_c_v1port: tester_v3_c_v1port.c ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_c.h
+	clang -I../ -std=c11 -g -O0 -DTINYGLTF3_ENABLE_FS -o tester_v3_c_v1port tester_v3_c_v1port.c ../tiny_gltf_v3.c
+
+tester_v3_json_c: tester_v3_json_c.c ../tinygltf_json_c.h
+	clang -I../ -std=c11 -g -O0 -o tester_v3_json_c tester_v3_json_c.c
+
+tester_v3_freestanding: tester_v3_freestanding.c ../tiny_gltf_v3.h ../tiny_gltf_v3.c ../tinygltf_json_c.h
+	clang -I../ -std=c11 -ffreestanding -g -O0 -o tester_v3_freestanding tester_v3_freestanding.c

tests/fuzzer/README.md

@@ -4,9 +4,14 @@ Do fuzzing test for TinyGLTF API.
 
 ## Supported API
 
-* [x] LoadASCIIFromMemory
+* [x] LoadASCIIFromString
 * [ ] LoadBinaryFromMemory
 
+### Custom JSON backend (`tinygltf_json.h`)
+
+* [x] LoadASCIIFromString
+* [x] LoadBinaryFromMemory
+
 ## Requirements
 
 * meson
@@ -36,11 +41,17 @@ $ cd build
 $ ninja
 ```
 
+This builds two fuzzers:
+
+* `fuzz_gltf` – default nlohmann/json backend
+* `fuzz_gltf_customjson` – custom `tinygltf_json.h` backend (tests both ASCII and binary parsing paths)
+
 ## How to run
 
 Increase memory limit. e.g. `-rss_limit_mb=50000`
 
 ```
 $ ./fuzz_gltf -rss_limit_mb=20000 -jobs 4
+$ ./fuzz_gltf_customjson -rss_limit_mb=20000 -jobs 4
 ```
 

tests/fuzzer/fuzz_gltf_customjson.cc

@@ -0,0 +1,76 @@
+/*
+ * LLVM libFuzzer harness for tinygltf with the custom JSON backend
+ * (tinygltf_json.h).
+ *
+ * Exercises:
+ *   1. LoadASCIIFromString  – glTF JSON parsing
+ *   2. LoadBinaryFromMemory – GLB binary parsing
+ *
+ * Build (clang with libFuzzer):
+ *   clang++ -std=c++11 -fsanitize=address,fuzzer \
+ *           -DTINYGLTF_USE_CUSTOM_JSON           \
+ *           -I../../ fuzz_gltf_customjson.cc      \
+ *           -o fuzz_gltf_customjson
+ *
+ * Run:
+ *   ./fuzz_gltf_customjson -rss_limit_mb=20000 -jobs 4
+ */
+
+#include <cstdint>
+#include <cstring>
+
+#define STB_IMAGE_IMPLEMENTATION
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#define TINYGLTF_IMPLEMENTATION
+#ifndef TINYGLTF_USE_CUSTOM_JSON
+#define TINYGLTF_USE_CUSTOM_JSON
+#endif
+#include "tiny_gltf.h"
+
+/* Fuzz the ASCII (JSON) parser path */
+static void fuzz_ascii(const uint8_t *data, size_t size) {
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  const char *str = reinterpret_cast<const char *>(data);
+
+  bool ret =
+      ctx.LoadASCIIFromString(&model, &err, &warn, str,
+                              static_cast<unsigned int>(size), /* base_dir */ "");
+  (void)ret;
+}
+
+/* Fuzz the binary (GLB) parser path */
+static void fuzz_binary(const uint8_t *data, size_t size) {
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  bool ret = ctx.LoadBinaryFromMemory(&model, &err, &warn, data,
+                                      static_cast<unsigned int>(size),
+                                      /* base_dir */ "");
+  (void)ret;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size == 0) return 0;
+
+  /* Use the lowest bit of the first byte to select the parse path.
+   * The remaining bits are left for the fuzzer engine to explore;
+   * additional paths (e.g. LoadASCIIFromFile, check_sections flags)
+   * can be added here in the future using more selector bits. */
+  uint8_t selector = data[0];
+  const uint8_t *payload = data + 1;
+  size_t payload_size = size - 1;
+
+  if (selector & 1) {
+    fuzz_binary(payload, payload_size);
+  } else {
+    fuzz_ascii(payload, payload_size);
+  }
+
+  return 0;
+}

tests/fuzzer/meson.build

@@ -7,3 +7,9 @@ executable('fuzz_gltf',
   cpp_args : '-fsanitize=address,fuzzer',
   link_args : '-fsanitize=address,fuzzer' )
 
+executable('fuzz_gltf_customjson',
+  'fuzz_gltf_customjson.cc',
+  include_directories : incdirs,
+  cpp_args : ['-fsanitize=address,fuzzer', '-DTINYGLTF_USE_CUSTOM_JSON'],
+  link_args : '-fsanitize=address,fuzzer' )
+

tests/tester.cc

@@ -474,7 +474,7 @@ TEST_CASE("image-uri-spaces", "[issue-236]") {
     }
     REQUIRE(true == ret);
     REQUIRE(err.empty());
-    REQUIRE(!warn.empty());  // relative image path won't exist in tests/
+    REQUIRE(warn.empty());
     REQUIRE(saved.images.size() == model.images.size());
 
     // The image uri in CubeImageUriMultipleSpaces.gltf is not encoded and
@@ -494,25 +494,23 @@ TEST_CASE("image-uri-spaces", "[issue-236]") {
 }
 
 TEST_CASE("serialize-empty-material", "[issue-294]") {
-
   tinygltf::Model m;
-
-  tinygltf::Material mat;
-  mat.pbrMetallicRoughness.baseColorFactor = {1.0f, 1.0f, 1.0f, 1.0f}; // default baseColorFactor
-  m.materials.push_back(mat);
-
+  // Add default constructed material to model
+  m.materials.push_back({});
+  // Serialize model to output stream
   std::stringstream os;
-
   tinygltf::TinyGLTF ctx;
   bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
   REQUIRE(true == ret);
-
-  // use nlohmann json
+  // Parse serialized model
   nlohmann::json j = nlohmann::json::parse(os.str());
-
+  // Serialized materials shall hold an empty object that
+  // represents the default constructed material
+  REQUIRE(j.find("materials") != j.end());
+  REQUIRE(j["materials"].is_array());
   REQUIRE(1 == j["materials"].size());
-  REQUIRE(j["materials"][0].is_object());
-
+  CHECK(j["materials"][0].is_object());
+  CHECK(j["materials"][0].empty());
 }
 
 TEST_CASE("empty-skeleton-id", "[issue-321]") {
@@ -664,10 +662,11 @@ TEST_CASE("serialize-image-callback", "[issue-394]") {
 
   auto writer = [](const std::string *basepath, const std::string *filename,
                    const tinygltf::Image *image, bool embedImages,
-                   const tinygltf::URICallbacks *uri_cb, std::string *out_uri,
-                   void *user_pointer) -> bool {
+                   const tinygltf::FsCallbacks* fs, const tinygltf::URICallbacks *uri_cb,
+                   std::string *out_uri, void *user_pointer) -> bool {
     (void)basepath;
     (void)image;
+    (void)fs;
     (void)uri_cb;
     REQUIRE(*filename == "foo");
     REQUIRE(embedImages == true);
@@ -701,12 +700,13 @@ TEST_CASE("serialize-image-failure", "[issue-394]") {
 
   auto writer = [](const std::string *basepath, const std::string *filename,
                    const tinygltf::Image *image, bool embedImages,
-                   const tinygltf::URICallbacks *uri_cb, std::string *out_uri,
-                   void *user_pointer) -> bool {
+                   const tinygltf::FsCallbacks* fs, const tinygltf::URICallbacks *uri_cb,
+                   std::string *out_uri, void *user_pointer) -> bool {
     (void)basepath;
     (void)filename;
     (void)image;
     (void)embedImages;
+    (void)fs;
     (void)uri_cb;
     (void)out_uri;
     (void)user_pointer;
@@ -757,3 +757,529 @@ TEST_CASE("load-issue-416-model", "[issue-416]") {
   // external file load fails, but reading glTF itself is ok.
   REQUIRE(true == ret);
 }
+
+TEST_CASE("serialize-empty-node", "[issue-457]") {
+  tinygltf::Model m;
+  // Add default constructed node to model
+  m.nodes.push_back({});
+  // Add scene to model
+  m.scenes.push_back({});
+  // The scene's only node is the empty node
+  m.scenes.front().nodes.push_back(0);
+
+  // Serialize model to output stream
+  std::stringstream os;
+  tinygltf::TinyGLTF ctx;
+  bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
+  REQUIRE(true == ret);
+
+  // Parse serialized model
+  nlohmann::json j = nlohmann::json::parse(os.str());
+
+  // Serialized nodes shall hold an empty object that
+  // represents the default constructed node
+  REQUIRE(j.find("nodes") != j.end());
+  REQUIRE(j["nodes"].is_array());
+  REQUIRE(1 == j["nodes"].size());
+  CHECK(j["nodes"][0].is_object());
+  CHECK(j["nodes"][0].empty());
+
+  // We also want to make sure that the serialized scene
+  // is referencing the empty node.
+
+  // There shall be a single serialized scene
+  auto scenes = j.find("scenes");
+  REQUIRE(scenes != j.end());
+  REQUIRE(scenes->is_array());
+  REQUIRE(1 == scenes->size());
+  auto scene = scenes->at(0);
+  REQUIRE(scene.is_object());
+  // The scene's nodes array shall hold a reference
+  // to the single node
+  auto nodes = scene.find("nodes");
+  REQUIRE(nodes != scene.end());
+  REQUIRE(nodes->is_array());
+  REQUIRE(1 == nodes->size());
+  auto node = nodes->at(0);
+  CHECK(node.is_number_integer());
+  int idx = -1;
+  node.get_to(idx);
+  CHECK(0 == idx);
+}
+
+TEST_CASE("serialize-light-index", "[issue-458]") {
+
+  // Create the light
+  tinygltf::Light light;
+  light.type = "point";
+  light.intensity = 0.75;
+  light.color = std::vector<double>{1.0, 0.8, 0.95};
+
+  // Stream to serialize to
+  std::stringstream os;
+
+  {
+    tinygltf::Model m;
+    tinygltf::Scene scene;
+    // Add the light to the model
+    m.lights.push_back(light);
+    // Create a node that uses the light
+    tinygltf::Node node;
+    node.light = 0;
+    // Add the node to the model
+    m.nodes.push_back(node);
+    // Add the node to the scene
+    scene.nodes.push_back(0);
+    // Add the scene to the model
+    m.scenes.push_back(scene);
+    // Serialize model to output stream
+    tinygltf::TinyGLTF ctx;
+    bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
+    REQUIRE(true == ret);
+  }
+
+  {
+    tinygltf::Model m;
+    tinygltf::TinyGLTF ctx;
+    // Parse the serialized model
+    bool ok = ctx.LoadASCIIFromString(&m, nullptr, nullptr, os.str().c_str(), os.str().size(), "");
+    REQUIRE(true == ok);
+    // Check if the light was correctly serialized
+    REQUIRE(1 == m.lights.size());
+    CHECK(m.lights[0] == light);
+    // Check that the node properly references the light
+    REQUIRE(1 == m.nodes.size());
+    CHECK(m.nodes[0].light == 0);
+  }
+}
+
+TEST_CASE("default-material", "[issue-459]") {
+  const std::vector<double> default_emissive_factor{ 0.0, 0.0, 0.0 };
+  const std::vector<double> default_base_color_factor{ 1.0, 1.0, 1.0, 1.0 };
+  const std::string default_alpha_mode = "OPAQUE";
+  const double default_alpha_cutoff = 0.5;
+  const bool default_double_sided = false;
+  const double default_metallic_factor = 1.0;
+  const double default_roughness_factor = 1.0;
+  // Check that default constructed material
+  // holds actual default GLTF material properties
+  tinygltf::Material mat;
+  CHECK(mat.alphaMode == default_alpha_mode);
+  CHECK(mat.alphaCutoff == default_alpha_cutoff);
+  CHECK(mat.doubleSided == default_double_sided);
+  CHECK(mat.emissiveFactor == default_emissive_factor);
+  CHECK(mat.pbrMetallicRoughness.baseColorFactor == default_base_color_factor);
+  CHECK(mat.pbrMetallicRoughness.metallicFactor == default_metallic_factor);
+  CHECK(mat.pbrMetallicRoughness.roughnessFactor == default_roughness_factor);
+  // None of the textures should be set
+  CHECK(mat.normalTexture.index == -1);
+  CHECK(mat.occlusionTexture.index == -1);
+  CHECK(mat.emissiveTexture.index == -1);
+}
+
+TEST_CASE("serialize-empty-scene", "[issue-464]") {
+  // Stream to serialize to
+  std::stringstream os;
+
+  {
+    tinygltf::Model m;
+    // Add empty scene to the model
+    m.scenes.push_back({});
+    // Serialize model to output stream
+    tinygltf::TinyGLTF ctx;
+    bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
+    REQUIRE(true == ret);
+  }
+
+  {
+    tinygltf::Model m;
+    tinygltf::TinyGLTF ctx;
+    // Parse the serialized model
+    bool ok = ctx.LoadASCIIFromString(&m, nullptr, nullptr, os.str().c_str(), os.str().size(), "");
+    REQUIRE(true == ok);
+    // Make sure the empty scene is there
+    REQUIRE(1 == m.scenes.size());
+    tinygltf::Scene scene{};
+    // Check that the scene is empty
+    CHECK(m.scenes[0] == scene);
+  }
+}
+
+TEST_CASE("zero-sized-bin-chunk-glb", "[issue-440]") {
+
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  // Input glb has zero-sized data in bin chunk(8 bytes for BIN chunk, and chunksize == 0)
+  // The spec https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#binary-buffer says
+  //
+  // When the binary buffer is empty or when it is stored by other means, this chunk SHOULD be omitted.
+  //
+  // 'SHOULD' mean 'RECOMMENDED', so we'll need to allow such zero-sized bin chunk is NOT omitted.
+  bool ret = ctx.LoadBinaryFromFile(&model, &err, &warn, "../models/regression/zero-sized-bin-chunk-issue-440.glb");
+  if (!warn.empty()) {
+    std::cout << "WARN: " << warn << "\n";
+  }
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+
+  REQUIRE(true == ret);
+}
+
+TEST_CASE("serialize-node-emitter", "[KHR_audio]") {
+  // Stream to serialize to
+  std::stringstream os;
+
+  {
+    tinygltf::Model m;
+    // Create a default audio emitter
+    m.audioEmitters.resize(1);
+    // Create a single node
+    m.nodes.resize(1);
+    // The node references the single emitter
+    m.nodes[0].emitter = 0;
+    // Create a single scene
+    m.scenes.resize(1);
+    // Make the scene reference the single node
+    m.scenes[0].nodes.push_back(0);
+
+    // Serialize model to output stream
+    tinygltf::TinyGLTF ctx;
+    bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
+    REQUIRE(true == ret);
+  }
+
+  {
+    tinygltf::Model m;
+    tinygltf::TinyGLTF ctx;
+    // Parse the serialized model
+    bool ok = ctx.LoadASCIIFromString(&m, nullptr, nullptr, os.str().c_str(), os.str().size(), "");
+    REQUIRE(true == ok);
+
+    // Make sure the single scene is there
+    REQUIRE(1 == m.scenes.size());
+    // Make sure all three nodes are there
+    REQUIRE(1 == m.nodes.size());
+    // Make sure the single root node of the scene is there
+    REQUIRE(1 == m.scenes[0].nodes.size());
+    REQUIRE(0 == m.scenes[0].nodes[0]);
+    // Retrieve the scene root node
+    const tinygltf::Node& node = m.nodes[m.scenes[0].nodes[0]];
+    // Make sure the single root node has both lod nodes
+    REQUIRE(0 == node.emitter);
+  }
+}
+
+TEST_CASE("serialize-lods", "[lods]") {
+  // Stream to serialize to
+  std::stringstream os;
+
+  {
+    tinygltf::Model m;
+
+    m.nodes.resize(4);
+    // Add Node 1 and Node 2 as lods to Node 0
+    m.nodes[0].lods.push_back(1);
+    m.nodes[0].lods.push_back(2);
+
+    // Add Material 1 and Material 2 as lods to Material 0
+    m.materials.resize(4);
+    m.materials[0].lods.push_back(1);
+    m.materials[0].lods.push_back(2);
+
+    tinygltf::Scene scene;
+    // Scene uses Node 0 and 3 as root node
+    scene.nodes.push_back(0);
+    scene.nodes.push_back(3);
+    // Add scene to the model
+    m.scenes.push_back(scene);
+
+    // Serialize model to output stream
+    tinygltf::TinyGLTF ctx;
+    bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
+    REQUIRE(true == ret);
+  }
+
+  {
+    tinygltf::Model m;
+    tinygltf::TinyGLTF ctx;
+    // Parse the serialized model
+    bool ok = ctx.LoadASCIIFromString(&m, nullptr, nullptr, os.str().c_str(), os.str().size(), "");
+    REQUIRE(true == ok);
+    // Make sure the model's used extensions hold MSFT_lod
+    CHECK(m.extensionsUsed.size() == 1);
+    CHECK(m.extensionsUsed[0].compare("MSFT_lod") == 0);
+    // MSFT_lod is not a required extension
+    CHECK(m.extensionsRequired.size() == 0);
+
+    // Make sure all four materials are there
+    REQUIRE(4 == m.materials.size());
+    // Make sure the first material has both lod materials
+    REQUIRE(2 == m.materials[0].lods.size());
+    // Make sure the order is still the same after serialization and deserialization
+    CHECK(1 == m.materials[0].lods[0]);
+    CHECK(2 == m.materials[0].lods[1]);
+    // Make sure the material with lods exposes the MSFT_lod extension
+    CHECK(m.materials[0].extensions.size() == 1);
+    CHECK(m.materials[0].extensions.count("MSFT_lod") == 1);
+    // Make sure the last material has no lod materials
+    CHECK(0 == m.materials[3].lods.size());
+    // Make sure the material without lods does not exposes the MSFT_lod extension
+    CHECK(m.materials[3].extensions.size() == 0);
+    CHECK(m.materials[3].extensions.count("MSFT_lod") == 0);
+
+    // Make sure the single scene is there
+    REQUIRE(1 == m.scenes.size());
+    // Make sure all four nodes are there
+    REQUIRE(4 == m.nodes.size());
+    // Make sure the two root nodes of the scene are there
+    REQUIRE(2 == m.scenes[0].nodes.size());
+    REQUIRE(0 == m.scenes[0].nodes[0]);
+    REQUIRE(3 == m.scenes[0].nodes[1]);
+    // Retrieve the node with lods
+    const tinygltf::Node& nodeWithLods = m.nodes[m.scenes[0].nodes[0]];
+    // Make sure the node has both lod nodes
+    REQUIRE(2 == nodeWithLods.lods.size());
+    // Make sure the order is still the same after serialization and deserialization
+    CHECK(1 == nodeWithLods.lods[0]);
+    CHECK(2 == nodeWithLods.lods[1]);
+    // Make sure the node with lods exposes the MSFT_lod extension
+    CHECK(nodeWithLods.extensions.size() == 1);
+    CHECK(nodeWithLods.extensions.count("MSFT_lod") == 1);
+    // Retrieve the node without lods
+    const tinygltf::Node& nodeWithoutLods = m.nodes[m.scenes[0].nodes[1]];
+    // Make sure the node has no lod nodes
+    CHECK(0 == nodeWithoutLods.lods.size());
+    // Make sure the node without lods does not exposes the MSFT_lod extension
+    CHECK(nodeWithoutLods.extensions.size() == 0);
+    CHECK(nodeWithoutLods.extensions.count("MSFT_lod") == 0);
+  }
+}
+
+TEST_CASE("write-image-issue", "[issue-473]") {
+  std::string err;
+  std::string warn;
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  bool ok = ctx.LoadASCIIFromFile(&model, &err, &warn, "../models/Cube/Cube.gltf");
+  REQUIRE(ok);
+  REQUIRE(err.empty());
+  REQUIRE(warn.empty());
+
+  REQUIRE(model.images.size() == 2);
+  REQUIRE(model.images[0].uri == "Cube_BaseColor.png");
+  REQUIRE(model.images[1].uri == "Cube_MetallicRoughness.png");
+
+  REQUIRE_FALSE(model.images[0].image.empty());
+  REQUIRE_FALSE(model.images[1].image.empty());
+
+  ok = ctx.WriteGltfSceneToFile(&model, "Cube.gltf");
+  REQUIRE(ok);
+
+  for (const auto& image : model.images) {
+    std::fstream file(image.uri);
+    CHECK(file.good());
+  }
+}
+
+TEST_CASE("images-as-is", "[issue-487]") {
+  std::string err;
+  std::string warn;
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  ctx.SetImagesAsIs(true);
+  bool ok = ctx.LoadASCIIFromFile(&model, &err, &warn, "../models/Cube/Cube.gltf");
+  REQUIRE(ok);
+  REQUIRE(err.empty());
+  REQUIRE(warn.empty());
+
+  for (const auto& image : model.images) {
+    CHECK(image.as_is == true);
+    CHECK_FALSE(image.uri.empty());
+    CHECK_FALSE(image.image.empty());
+
+#ifndef TINYGLTF_NO_STB_IMAGE
+    // Make sure we can decode the images
+    int w = -1, h = -1, component = -1;
+    unsigned char *data = stbi_load_from_memory(image.image.data(), static_cast<int>(image.image.size()), &w, &h, &component, 0);
+    CHECK(data != nullptr);
+    CHECK(w == 512);
+    CHECK(h == 512);
+    CHECK(component >= 3);
+    stbi_image_free(data);
+#endif
+  }
+
+  // Write glTF model to disk, and images as separate files
+  {
+    ok = ctx.WriteGltfSceneToFile(&model, "Cube_with_image_files.gltf");
+    REQUIRE(ok);
+
+    // All the images should have been written to disk with their original data
+    for (const auto& image : model.images)  {
+      // Make sure the image files exist
+      {
+        std::fstream file(image.uri);
+        CHECK(file.good());
+      } // Close file before stbi_load (Windows sharing violation fix)
+#ifndef TINYGLTF_NO_STB_IMAGE
+      // Make sure we can load the images
+      int w = -1, h = -1, component = -1;
+      unsigned char *data = stbi_load(image.uri.c_str(), &w, &h, &component, 0);
+      CHECK(data != nullptr);
+      CHECK(w == 512);
+      CHECK(h == 512);
+      CHECK(component >= 3);
+      stbi_image_free(data);
+#endif
+    }
+  }
+
+  // Write glTF model to disk, and embed images as data URIs
+  {
+    ok = ctx.WriteGltfSceneToFile(&model, "Cube_with_embedded_images.gltf", true, false);
+    REQUIRE(ok);
+
+    // Load above model again, and check if the images are loaded properly
+    tinygltf::Model embeddedImages;
+    ctx.SetImagesAsIs(false);
+    bool ok = ctx.LoadASCIIFromFile(&embeddedImages, &err, &warn, "Cube_with_embedded_images.gltf");
+    REQUIRE(ok);
+    REQUIRE(err.empty());
+    REQUIRE(warn.empty());
+
+    for (const auto& image : embeddedImages.images) {
+      CHECK(image.as_is == false);
+      CHECK_FALSE(image.mimeType.empty());
+      CHECK_FALSE(image.image.empty());
+      CHECK(image.width == 512);
+      CHECK(image.height == 512);
+      CHECK(image.component >= 3);
+    }
+  }
+
+  // Write glTF model to disk, as GLB
+  {
+    ok = ctx.WriteGltfSceneToFile(&model, "Cube.glb", true, true, true, true);
+    REQUIRE(ok);
+
+    // Load above model again, and check if the images are loaded properly
+    tinygltf::Model glbModel;
+    ctx.SetImagesAsIs(false);
+    bool ok = ctx.LoadBinaryFromFile(&glbModel, &err, &warn, "Cube.glb");
+    REQUIRE(ok);
+    REQUIRE(err.empty());
+    REQUIRE(warn.empty());
+
+    for (const auto& image : glbModel.images) {
+      CHECK(image.as_is == false);
+      CHECK_FALSE(image.mimeType.empty());
+      CHECK_FALSE(image.image.empty());
+      CHECK(image.width == 512);
+      CHECK(image.height == 512);
+      CHECK(image.component >= 3);
+    }
+  }
+}
+
+TEST_CASE("inverse-bind-matrices-optional", "[issue-492]") {
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  bool ret = ctx.LoadBinaryFromFile(&model, &err, &warn, "issue-492.glb");
+  if (!warn.empty()) {
+    std::cout << "WARN:" << warn << std::endl;
+  }
+  if (!err.empty()) {
+    std::cerr << "ERR:" << err << std::endl;
+  }
+
+  REQUIRE(true == ret);
+  REQUIRE(err.empty());
+}
+
+bool LoadImageData(tinygltf::Image * /* image */, const int /* image_idx */, std::string * /* err */,
+                   std::string * /* warn */, int /* req_width */, int /* req_height */,
+                   const unsigned char * /* bytes */, int /* size */, void * /*user_data */) {
+    return true;
+}
+
+bool WriteImageData(const std::string * /* basepath */, const std::string * /* filename */,
+                    const tinygltf::Image *image, bool /* embedImages */,
+                    const tinygltf::FsCallbacks * /* fs_cb */, const tinygltf::URICallbacks * /* uri_cb */,
+                    std::string * /* out_uri */, void * user_pointer) {
+    REQUIRE(user_pointer != nullptr);
+    auto counter = static_cast<int*>(user_pointer);
+    *counter = *counter + 1;
+    return true;
+}
+
+TEST_CASE("empty-images-not-written", "[issue-495]") {
+  std::string err;
+  std::string warn;
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+
+  ctx.SetImageLoader(LoadImageData, nullptr);
+  bool ok = ctx.LoadASCIIFromFile(&model, &err, &warn, "../models/Cube/Cube.gltf");
+  REQUIRE(ok);
+  REQUIRE(err.empty());
+  REQUIRE(warn.empty());
+
+  CHECK(model.images.size() == 2);
+  for (const auto& image : model.images) {
+    // No data loaded or decoded
+    CHECK(image.image.empty());
+    // The URI is kept
+    CHECK_FALSE(image.uri.empty());
+    // The URI should not be a data URI
+    CHECK(image.uri.find("data:") != 0);
+  }
+
+  // Now write the loaded model
+  int counter = 0;
+  ctx.SetImageWriter(WriteImageData, &counter);
+  ok = ctx.WriteGltfSceneToFile(&model, "issue-495-external.gltf");
+  CHECK(ok);
+  // WriteImageData should be invoked for both images
+  CHECK(counter == 2);
+}
+
+#ifdef TINYGLTF_USE_CUSTOM_JSON
+/* Regression test: in float32_mode, integer-only tokens with more than 9
+ * digits must still be parsed as integers (is_int == 1), not floats.
+ * Previously, max_sig=9 was applied to the integer part too, causing excess
+ * digits to bump exp10, which broke the exp10==0 guard in the integer
+ * fast-path and mis-classified the value as a float. */
+TEST_CASE("cj-float32-long-integer", "[customjson]") {
+    // Values chosen to cover exactly-at, just-over, and near int64 boundaries.
+    struct {
+        const char *text;
+        int64_t     expected;
+    } cases[] = {
+        { "1234567890",           1234567890LL        }, /* 10 digits */
+        { "12345678901",          12345678901LL       }, /* 11 digits */
+        { "1000000000000",        1000000000000LL     }, /* 13 digits */
+        { "9223372036854775807",  INT64_MAX           }, /* max int64 (19 digits) */
+        { "-1234567890",         -1234567890LL        }, /* negative 10 digits */
+        { "-9223372036854775808", INT64_MIN           }, /* min int64 */
+    };
+
+    for (auto &tc : cases) {
+        int      is_int = 0;
+        int64_t  ival   = 0;
+        double   dval   = 0.0;
+        const char *end = tc.text + strlen(tc.text);
+        const char *ret = cj_parse_number(tc.text, end, &is_int, &ival, &dval, /*float32_mode=*/1);
+        CAPTURE(tc.text);
+        REQUIRE(ret != nullptr);
+        CHECK(is_int == 1);
+        CHECK(ival == tc.expected);
+    }
+}
+#endif /* TINYGLTF_USE_CUSTOM_JSON */

tests/tester_v3_c_v1port.c

@@ -0,0 +1,559 @@
+/*
+ * tester_v3_c_v1port.c — Parse/load tests ported from tester.cc (v1) to the
+ * pure-C v3 runtime. Each PORT_CASE corresponds to a TEST_CASE in tester.cc;
+ * the comment marks the original test name.
+ *
+ * Skipped from tester.cc (require v3 writer or v1-internal helpers, out of
+ * scope for this port):
+ *   serialize-empty-material, serialize-empty-node, serialize-light-index,
+ *   serialize-empty-scene, serialize-node-emitter, serialize-lods,
+ *   serialize-const-image, serialize-image-callback, serialize-image-failure,
+ *   write-image-issue, empty-images-not-written, empty-bin-buffer,
+ *   parse-integer, parse-unsigned, parse-integer-array,
+ *   expandpath-utf-8, cj-float32-long-integer
+ *
+ * Build (run from tests/):
+ *   make tester_v3_c_v1port
+ * Run:
+ *   ./tester_v3_c_v1port
+ */
+
+#include "tiny_gltf_v3.h"
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* --- thin helpers ---------------------------------------------------------- */
+
+static int tg3_str_eq(const tg3_str *s, const char *cstr) {
+  size_t n = strlen(cstr);
+  return s->data && s->len == (uint32_t)n &&
+         memcmp(s->data, cstr, n) == 0;
+}
+
+static int tg3_str_contains(const tg3_str *s, char ch) {
+  uint32_t i;
+  if (!s->data) return 0;
+  for (i = 0; i < s->len; ++i) {
+    if (s->data[i] == ch) return 1;
+  }
+  return 0;
+}
+
+static int has_extension(const tg3_extras_ext *e, const char *name) {
+  uint32_t i;
+  if (!e || !e->extensions) return 0;
+  for (i = 0; i < e->extensions_count; ++i) {
+    if (tg3_str_eq(&e->extensions[i].name, name)) return 1;
+  }
+  return 0;
+}
+
+static const tg3_extension *find_extension(const tg3_extras_ext *e, const char *name) {
+  uint32_t i;
+  if (!e || !e->extensions) return NULL;
+  for (i = 0; i < e->extensions_count; ++i) {
+    if (tg3_str_eq(&e->extensions[i].name, name)) return &e->extensions[i];
+  }
+  return NULL;
+}
+
+static const tg3_value *value_get(const tg3_value *v, const char *key) {
+  uint32_t i;
+  if (!v || v->type != TG3_VALUE_OBJECT || !v->object_data) return NULL;
+  for (i = 0; i < v->object_count; ++i) {
+    if (tg3_str_eq(&v->object_data[i].key, key)) {
+      return &v->object_data[i].value;
+    }
+  }
+  return NULL;
+}
+
+/* Read a glTF/GLB file into a heap buffer; returns 1 on success. */
+static int slurp(const char *path, uint8_t **out, size_t *out_len) {
+  FILE *fp = fopen(path, "rb");
+  long sz;
+  size_t got;
+  uint8_t *buf;
+  if (!fp) return 0;
+  if (fseek(fp, 0, SEEK_END) != 0 || (sz = ftell(fp)) < 0 ||
+      fseek(fp, 0, SEEK_SET) != 0) { fclose(fp); return 0; }
+  buf = (uint8_t *)malloc((size_t)sz);
+  if (!buf) { fclose(fp); return 0; }
+  got = fread(buf, 1, (size_t)sz, fp);
+  fclose(fp);
+  if (got != (size_t)sz) { free(buf); return 0; }
+  *out = buf;
+  *out_len = (size_t)sz;
+  return 1;
+}
+
+static const char *base_dir_of(const char *path, uint32_t *out_len) {
+  const char *slash = strrchr(path, '/');
+  if (slash) {
+    *out_len = (uint32_t)(slash - path);
+  } else {
+    *out_len = 0;
+  }
+  return path;
+}
+
+static int parse_path(tg3_model *m, tg3_error_stack *e,
+                      tg3_parse_options *opts,
+                      const char *path, tg3_error_code *err_out) {
+  uint8_t *buf = NULL;
+  size_t sz = 0;
+  uint32_t base_len = 0;
+  const char *base_dir;
+  if (!slurp(path, &buf, &sz)) {
+    fprintf(stderr, "  slurp failed: %s\n", path);
+    return 0;
+  }
+  base_dir = base_dir_of(path, &base_len);
+  *err_out = tg3_parse_auto(m, e, buf, (uint64_t)sz,
+                            base_dir, base_len, opts);
+  free(buf);
+  return 1;
+}
+
+static int errstack_contains(const tg3_error_stack *e, const char *needle) {
+  uint32_t i;
+  size_t nl = strlen(needle);
+  for (i = 0; i < e->count; ++i) {
+    const char *m = e->entries[i].message;
+    if (m && strstr(m, needle) != NULL) return 1;
+    (void)nl;
+  }
+  return 0;
+}
+
+/* --- test cases ------------------------------------------------------------ */
+
+#define PASS_OR_RET(label) do { \
+  fprintf(stdout, "  [PASS] %s\n", label); \
+  return 1; \
+} while (0)
+#define FAIL(...) do { \
+  fprintf(stderr, "  [FAIL] "); \
+  fprintf(stderr, __VA_ARGS__); \
+  fprintf(stderr, "\n"); \
+  goto fail; \
+} while (0)
+
+/* TEST_CASE("parse-error", "[parse]") */
+static int t_parse_error(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  static const uint8_t bad[] = "bora";
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  err = tg3_parse(&m, &e, bad, (uint64_t)(sizeof(bad) - 1), "", 0, &opts);
+  if (err == TG3_OK) FAIL("expected parse failure on garbage input");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("parse-error");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("datauri-in-glb", "[issue-79]") */
+static int t_datauri_in_glb(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts, "../models/box01.glb", &err)) goto fail;
+  if (err != TG3_OK) FAIL("box01.glb load failed err=%d", (int)err);
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("datauri-in-glb");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("extension-with-empty-object", "[issue-97]") */
+static int t_extension_empty_object(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts, "../models/Extensions-issue97/test.gltf", &err)) goto fail;
+  if (err != TG3_OK) FAIL("load failed err=%d", (int)err);
+  if (m.extensions_used_count != 1)
+    FAIL("extensionsUsed.size %u != 1", m.extensions_used_count);
+  if (!tg3_str_eq(&m.extensions_used[0], "VENDOR_material_some_ext"))
+    FAIL("unexpected extensionsUsed[0]");
+  if (m.materials_count != 1) FAIL("materials.size %u != 1", m.materials_count);
+  if (!has_extension(&m.materials[0].ext, "VENDOR_material_some_ext"))
+    FAIL("material missing VENDOR_material_some_ext extension");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("extension-with-empty-object");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("extension-overwrite", "[issue-261]") */
+static int t_extension_overwrite(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  uint32_t i;
+  int has_lights = 0;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/Extensions-overwrite-issue261/issue-261.gltf",
+                  &err)) goto fail;
+  if (err != TG3_OK) FAIL("load failed err=%d", (int)err);
+  if (m.extensions_used_count != 3)
+    FAIL("extensionsUsed.size %u != 3", m.extensions_used_count);
+  for (i = 0; i < m.extensions_used_count; ++i) {
+    if (tg3_str_eq(&m.extensions_used[i], "KHR_lights_punctual")) {
+      has_lights = 1; break;
+    }
+  }
+  if (!has_lights) FAIL("KHR_lights_punctual missing in extensionsUsed");
+  if (!has_extension(&m.ext, "NV_MDL")) FAIL("model.extensions missing NV_MDL");
+  if (!has_extension(&m.ext, "KHR_lights_punctual"))
+    FAIL("model.extensions missing KHR_lights_punctual");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("extension-overwrite");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("invalid-primitive-indices", "[bounds-checking]") */
+static int t_invalid_primitive_indices(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/BoundsChecking/invalid-primitive-indices.gltf",
+                  &err)) goto fail;
+  if (err == TG3_OK)
+    FAIL("invalid-primitive-indices unexpectedly succeeded");
+  /* v3 reports TG3_ERR_INVALID_INDEX from validate_indices. v1 reports
+   * "primitive indices accessor out of bounds" at parse time; either is
+   * acceptable as long as the parser does not crash and rejects the model. */
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("invalid-primitive-indices");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("invalid-buffer-view-index", "[bounds-checking]") */
+static int t_invalid_buffer_view_index(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/BoundsChecking/invalid-buffer-view-index.gltf",
+                  &err)) goto fail;
+  if (err == TG3_OK) FAIL("invalid-buffer-view-index unexpectedly succeeded");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("invalid-buffer-view-index");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("invalid-buffer-index", "[bounds-checking]") */
+static int t_invalid_buffer_index(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/BoundsChecking/invalid-buffer-index.gltf",
+                  &err)) goto fail;
+  if (err == TG3_OK) FAIL("invalid-buffer-index unexpectedly succeeded");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("invalid-buffer-index");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("glb-invalid-length", "[bounds-checking]") */
+static int t_glb_invalid_length(void) {
+  /* 'glTF' magic, version=2, length=0x0000666c (way larger than provided
+   * data), JSON chunk with empty {}. */
+  static const unsigned char glb[] = "glTF"
+      "\x02\x00\x00\x00" "\x6c\x66\x00\x00"
+      "\x02\x00\x00\x00" "\x4a\x53\x4f\x4e{}";
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  err = tg3_parse_glb(&m, &e, glb, (uint64_t)(sizeof(glb) - 1), "", 0, &opts);
+  if (err == TG3_OK) FAIL("invalid-length GLB unexpectedly accepted");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("glb-invalid-length");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("integer-out-of-bounds", "[bounds-checking]") */
+static int t_integer_out_of_bounds(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/BoundsChecking/integer-out-of-bounds.gltf",
+                  &err)) goto fail;
+  if (err == TG3_OK) FAIL("integer-out-of-bounds unexpectedly succeeded");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("integer-out-of-bounds");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("pbr-khr-texture-transform", "[material]") */
+static int t_pbr_khr_texture_transform(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  const tg3_extension *ext;
+  const tg3_value *scale, *s0, *s1;
+  double v0, v1;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/Cube-texture-ext/Cube-textransform.gltf",
+                  &err)) goto fail;
+  if (err != TG3_OK) FAIL("load failed err=%d", (int)err);
+  if (m.materials_count != 2) FAIL("materials.size %u != 2", m.materials_count);
+  ext = find_extension(&m.materials[0].emissive_texture.ext,
+                       "KHR_texture_transform");
+  if (!ext) FAIL("KHR_texture_transform missing on emissiveTexture");
+  if (ext->value.type != TG3_VALUE_OBJECT)
+    FAIL("KHR_texture_transform value not an object");
+  scale = value_get(&ext->value, "scale");
+  if (!scale || scale->type != TG3_VALUE_ARRAY || scale->array_count != 2)
+    FAIL("scale not an array of 2");
+  s0 = &scale->array_data[0];
+  s1 = &scale->array_data[1];
+  v0 = (s0->type == TG3_VALUE_INT) ? (double)s0->int_val : s0->real_val;
+  v1 = (s1->type == TG3_VALUE_INT) ? (double)s1->int_val : s1->real_val;
+  if (v0 != 1.0)  FAIL("scale[0] %g != 1.0", v0);
+  if (v1 != -1.0) FAIL("scale[1] %g != -1.0", v1);
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("pbr-khr-texture-transform");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("image-uri-spaces", "[issue-236]") */
+static int t_image_uri_spaces(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+
+  /* Single-spaces variant. */
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/CubeImageUriSpaces/CubeImageUriSpaces.gltf",
+                  &err)) goto fail;
+  if (err != TG3_OK) FAIL("CubeImageUriSpaces load failed err=%d", (int)err);
+  if (m.images_count != 1) FAIL("images.size %u != 1", m.images_count);
+  if (!tg3_str_contains(&m.images[0].uri, ' '))
+    FAIL("image.uri does not contain a space");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+
+  /* Multiple-spaces variant. */
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/CubeImageUriSpaces/CubeImageUriMultipleSpaces.gltf",
+                  &err)) goto fail2;
+  if (err != TG3_OK) FAIL("MultipleSpaces load failed err=%d", (int)err);
+  if (m.images_count != 1) FAIL("images.size %u != 1", m.images_count);
+  if (m.images[0].uri.len < 2 || m.images[0].uri.data[0] != ' ')
+    FAIL("image.uri does not start with a space");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("image-uri-spaces");
+fail2:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("empty-skeleton-id", "[issue-321]") */
+static int t_empty_skeleton_id(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/regression/unassigned-skeleton.gltf",
+                  &err)) goto fail;
+  if (err != TG3_OK) FAIL("load failed err=%d", (int)err);
+  if (m.skins_count != 1) FAIL("skins.size %u != 1", m.skins_count);
+  if (m.skins[0].skeleton != -1)
+    FAIL("skin.skeleton %d != -1", m.skins[0].skeleton);
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("empty-skeleton-id");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("filesize-check", "[issue-416]") */
+static int t_filesize_check(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  opts.max_external_file_size = 10; /* 10 bytes — texture image will exceed */
+  if (!parse_path(&m, &e, &opts, "../models/Cube/Cube.gltf", &err)) goto fail;
+  if (err == TG3_OK)
+    FAIL("expected load failure due to oversized external file");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("filesize-check");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("load-issue-416-model", "[issue-416]") */
+static int t_load_issue_416_model(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts, "issue-416.gltf", &err)) goto fail;
+  /* External file is missing, but the parser should still accept the glTF
+   * structurally. v1 returns true; v3 returns TG3_OK or a non-fatal error
+   * about the missing file. */
+  (void)err; /* tolerate either outcome */
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("load-issue-416-model");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("zero-sized-bin-chunk-glb", "[issue-440]") */
+static int t_zero_sized_bin_chunk_glb(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts,
+                  "../models/regression/zero-sized-bin-chunk-issue-440.glb",
+                  &err)) goto fail;
+  if (err != TG3_OK) FAIL("zero-sized-bin-chunk failed err=%d", (int)err);
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("zero-sized-bin-chunk-glb");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("images-as-is", "[issue-487]") */
+static int t_images_as_is(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  uint32_t i;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  opts.images_as_is = 1;
+  if (!parse_path(&m, &e, &opts, "../models/Cube/Cube.gltf", &err)) goto fail;
+  if (err != TG3_OK) FAIL("Cube load failed err=%d", (int)err);
+  if (m.images_count == 0) FAIL("no images parsed");
+  for (i = 0; i < m.images_count; ++i) {
+    if (m.images[i].as_is != 1) FAIL("image[%u].as_is != 1", i);
+    if (m.images[i].uri.len == 0) FAIL("image[%u].uri empty", i);
+  }
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("images-as-is");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("inverse-bind-matrices-optional", "[issue-492]") */
+static int t_ibm_optional(void) {
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  if (!parse_path(&m, &e, &opts, "issue-492.glb", &err)) goto fail;
+  if (err != TG3_OK) FAIL("issue-492.glb load failed err=%d", (int)err);
+  /* No "error" entries (warnings are not errors). */
+  if (errstack_contains(&e, "error"))
+    FAIL("unexpected error message present");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("inverse-bind-matrices-optional");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* TEST_CASE("default-material", "[issue-459]") — black-box parse of a
+ * minimal model with a default material; verify v3 populates the same
+ * default-PBR field values v1 documents. */
+static int t_default_material(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"materials\":[{}]}";
+  tg3_model m; tg3_error_stack e; tg3_parse_options opts;
+  tg3_error_code err;
+  const tg3_material *mat;
+  tg3_error_stack_init(&e); tg3_parse_options_init(&opts);
+  err = tg3_parse(&m, &e, json, (uint64_t)(sizeof(json) - 1), "", 0, &opts);
+  if (err != TG3_OK) FAIL("minimal default-material parse failed err=%d", (int)err);
+  if (m.materials_count != 1) FAIL("materials.size %u != 1", m.materials_count);
+  mat = &m.materials[0];
+  if (!tg3_str_eq(&mat->alpha_mode, "OPAQUE")) FAIL("alpha_mode default mismatch");
+  if (mat->alpha_cutoff != 0.5) FAIL("alpha_cutoff default %g != 0.5", mat->alpha_cutoff);
+  if (mat->double_sided != 0)   FAIL("double_sided default != 0");
+  if (mat->emissive_factor[0] != 0.0 ||
+      mat->emissive_factor[1] != 0.0 ||
+      mat->emissive_factor[2] != 0.0) FAIL("emissive_factor default mismatch");
+  if (mat->pbr_metallic_roughness.base_color_factor[0] != 1.0 ||
+      mat->pbr_metallic_roughness.base_color_factor[1] != 1.0 ||
+      mat->pbr_metallic_roughness.base_color_factor[2] != 1.0 ||
+      mat->pbr_metallic_roughness.base_color_factor[3] != 1.0)
+    FAIL("base_color_factor default mismatch");
+  if (mat->pbr_metallic_roughness.metallic_factor != 1.0)
+    FAIL("metallic_factor default %g != 1.0",
+         mat->pbr_metallic_roughness.metallic_factor);
+  if (mat->pbr_metallic_roughness.roughness_factor != 1.0)
+    FAIL("roughness_factor default %g != 1.0",
+         mat->pbr_metallic_roughness.roughness_factor);
+  if (mat->normal_texture.index != -1)    FAIL("normal_texture.index != -1");
+  if (mat->occlusion_texture.index != -1) FAIL("occlusion_texture.index != -1");
+  if (mat->emissive_texture.index != -1)  FAIL("emissive_texture.index != -1");
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  PASS_OR_RET("default-material");
+fail:
+  tg3_model_free(&m); tg3_error_stack_free(&e);
+  return 0;
+}
+
+/* --- main ------------------------------------------------------------------ */
+
+int main(void) {
+  struct { const char *name; int (*fn)(void); } cases[] = {
+    {"parse-error",                    t_parse_error},
+    {"datauri-in-glb",                 t_datauri_in_glb},
+    {"extension-with-empty-object",    t_extension_empty_object},
+    {"extension-overwrite",            t_extension_overwrite},
+    {"invalid-primitive-indices",      t_invalid_primitive_indices},
+    {"invalid-buffer-view-index",      t_invalid_buffer_view_index},
+    {"invalid-buffer-index",           t_invalid_buffer_index},
+    {"glb-invalid-length",             t_glb_invalid_length},
+    {"integer-out-of-bounds",          t_integer_out_of_bounds},
+    {"pbr-khr-texture-transform",      t_pbr_khr_texture_transform},
+    {"image-uri-spaces",               t_image_uri_spaces},
+    {"empty-skeleton-id",              t_empty_skeleton_id},
+    {"filesize-check",                 t_filesize_check},
+    {"load-issue-416-model",           t_load_issue_416_model},
+    {"zero-sized-bin-chunk-glb",       t_zero_sized_bin_chunk_glb},
+    {"images-as-is",                   t_images_as_is},
+    {"inverse-bind-matrices-optional", t_ibm_optional},
+    {"default-material",               t_default_material},
+  };
+  size_t total = sizeof(cases) / sizeof(cases[0]);
+  size_t passed = 0;
+  size_t i;
+  for (i = 0; i < total; ++i) {
+    fprintf(stdout, "RUN  %s\n", cases[i].name);
+    if (cases[i].fn()) ++passed;
+  }
+  fprintf(stdout, "\n=== v1 port: %zu/%zu passed ===\n", passed, total);
+  return passed == total ? 0 : 1;
+}

tests/tester_v3_freestanding.c

@@ -0,0 +1,75 @@
+#include <stddef.h>
+#include <stdint.h>
+
+static union {
+  uint64_t align;
+  unsigned char bytes[512 * 1024];
+} test_heap;
+static size_t test_heap_used;
+
+static void *test_malloc(size_t size) {
+  size_t total = (size + sizeof(size_t) + 7u) & ~(size_t)7u;
+  if (test_heap_used + total > sizeof(test_heap.bytes)) return 0;
+  {
+    unsigned char *base = test_heap.bytes + test_heap_used;
+    *((size_t *)base) = size;
+    test_heap_used += total;
+    return base + sizeof(size_t);
+  }
+}
+
+static void *test_realloc(void *ptr, size_t size) {
+  unsigned char *old_base;
+  size_t old_size;
+  unsigned char *new_ptr;
+  size_t n;
+  size_t i;
+  if (!ptr) return test_malloc(size);
+  old_base = (unsigned char *)ptr - sizeof(size_t);
+  old_size = *((size_t *)old_base);
+  new_ptr = (unsigned char *)test_malloc(size);
+  if (!new_ptr) return 0;
+  n = old_size < size ? old_size : size;
+  for (i = 0; i < n; ++i) new_ptr[i] = ((unsigned char *)ptr)[i];
+  return new_ptr;
+}
+
+static void test_free(void *ptr) {
+  (void)ptr;
+}
+
+#define TINYGLTF3_NO_STDLIB
+#define TINYGLTF3_MALLOC(sz) test_malloc(sz)
+#define TINYGLTF3_REALLOC(ptr, sz) test_realloc((ptr), (sz))
+#define TINYGLTF3_FREE(ptr) test_free(ptr)
+#define TINYGLTF3_IMPLEMENTATION
+#include "tiny_gltf_v3.h"
+
+static int streq(tg3_str s, const char *lit, uint32_t len) {
+  uint32_t i;
+  if (!s.data || s.len != len) return 0;
+  for (i = 0; i < len; ++i) {
+    if (s.data[i] != lit[i]) return 0;
+  }
+  return 1;
+}
+
+int main(void) {
+  static const uint8_t json[] =
+      "{\"asset\":{\"version\":\"2.0\"},\"nodes\":[{\"name\":\"free\"}]}";
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+  tg3_error_code err;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  err = tg3_parse_auto(&model, &errors, json, (uint64_t)(sizeof(json) - 1),
+                       "", 0, &opts);
+  if (err != TG3_OK) return 1;
+  if (model.nodes_count != 1) return 3;
+  if (!streq(model.nodes[0].name, "free", 4)) return 4;
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+  return 0;
+}

tests/tester_v3_json_c.c

@@ -0,0 +1,165 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#define TINYGLTF_JSON_C_IMPLEMENTATION
+#include "tinygltf_json_c.h"
+
+static uint64_t dbl_bits(double v) {
+  uint64_t bits;
+  memcpy(&bits, &v, sizeof(bits));
+  return bits;
+}
+
+static double dbl_from_bits(uint64_t bits) {
+  double v;
+  memcpy(&v, &bits, sizeof(v));
+  return v;
+}
+
+static int check_stringify(const char *json, const char *expected) {
+  tg3json_value v;
+  const char *err = NULL;
+  char *out;
+  size_t out_len = 0;
+  int ok = 1;
+  if (!tg3json_parse(json, json + strlen(json), 128, &v, &err)) {
+    fprintf(stderr, "parse failed for %s at %td\n", json, err ? err - json : -1);
+    return 0;
+  }
+  out = tg3json_stringify(&v, &out_len);
+  if (!out || strcmp(out, expected) != 0) {
+    fprintf(stderr, "stringify(%s) = %s, expected %s\n",
+            json, out ? out : "(null)", expected);
+    ok = 0;
+  }
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&v);
+  return ok;
+}
+
+static int check_parse_rejects(const char *json) {
+  tg3json_value v;
+  const char *err = NULL;
+  if (tg3json_parse(json, json + strlen(json), 128, &v, &err)) {
+    fprintf(stderr, "parse unexpectedly accepted %s\n", json);
+    tg3json_value_free(&v);
+    return 0;
+  }
+  return 1;
+}
+
+static int check_roundtrip(const char *json) {
+  tg3json_value a;
+  tg3json_value b;
+  const char *err = NULL;
+  char *out;
+  size_t out_len = 0;
+  int ok = 1;
+  if (!tg3json_parse(json, json + strlen(json), 128, &a, &err)) return 0;
+  out = tg3json_stringify(&a, &out_len);
+  if (!out || !tg3json_parse(out, out + out_len, 128, &b, &err)) {
+    ok = 0;
+  } else if (a.type != TG3JSON_REAL ||
+             !((b.type == TG3JSON_REAL && dbl_bits(a.u.real) == dbl_bits(b.u.real)) ||
+               (b.type == TG3JSON_INT && dbl_bits(a.u.real) == dbl_bits((double)b.u.integer)))) {
+    fprintf(stderr, "roundtrip changed bits: %s -> %s\n", json, out);
+    ok = 0;
+  }
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&a);
+  tg3json_value_free(&b);
+  return ok;
+}
+
+static int check_parse_bits(const char *json, uint64_t expected_bits) {
+  tg3json_value v;
+  const char *err = NULL;
+  if (!tg3json_parse(json, json + strlen(json), 128, &v, &err)) {
+    fprintf(stderr, "parse failed for %s at %td\n", json, err ? err - json : -1);
+    return 0;
+  }
+  if (v.type != TG3JSON_REAL || dbl_bits(v.u.real) != expected_bits) {
+    fprintf(stderr, "parse bits mismatch: %s -> 0x%llx, expected 0x%llx\n",
+            json, (unsigned long long)(v.type == TG3JSON_REAL ? dbl_bits(v.u.real) : 0),
+            (unsigned long long)expected_bits);
+    tg3json_value_free(&v);
+    return 0;
+  }
+  tg3json_value_free(&v);
+  return 1;
+}
+
+static int check_parse_float32(void) {
+  static const char json[] = "0.10000000149011612";
+  tg3json_parse_options opts;
+  tg3json_value v;
+  const char *err = NULL;
+  double expected = (double)(float)0.10000000149011612;
+  memset(&opts, 0, sizeof(opts));
+  opts.parse_float32 = 1;
+  if (!tg3json_parse_n_opts(json, strlen(json), &opts, &v, &err)) {
+    fprintf(stderr, "parse_float32 parse failed\n");
+    return 0;
+  }
+  if (v.type != TG3JSON_REAL || dbl_bits(v.u.real) != dbl_bits(expected)) {
+    fprintf(stderr, "parse_float32 did not round through float\n");
+    tg3json_value_free(&v);
+    return 0;
+  }
+  tg3json_value_free(&v);
+  return 1;
+}
+
+static int check_nonfinite_stringifies_to_null(void) {
+  tg3json_value v;
+  char *out;
+  size_t len = 0;
+  int ok;
+  tg3json_value_init_real(&v, dbl_from_bits(0x7ff0000000000000ULL));
+  out = tg3json_stringify(&v, &len);
+  ok = out && strcmp(out, "null") == 0;
+  if (!ok) fprintf(stderr, "inf stringify = %s\n", out ? out : "(null)");
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&v);
+  if (!ok) return 0;
+
+  tg3json_value_init_real(&v, dbl_from_bits(0x7ff8000000000001ULL));
+  out = tg3json_stringify(&v, &len);
+  ok = out && strcmp(out, "null") == 0;
+  if (!ok) fprintf(stderr, "nan stringify = %s\n", out ? out : "(null)");
+  if (out) TINYGLTF_JSON_FREE(out);
+  tg3json_value_free(&v);
+  return ok;
+}
+
+int main(void) {
+  int ok = 1;
+  ok = check_stringify("1.0", "1") && ok;
+  ok = check_stringify("-1.0", "-1") && ok;
+  ok = check_stringify("0.1", "0.1") && ok;
+  ok = check_stringify("0.0001", "0.0001") && ok;
+  ok = check_stringify("0.00001", "1e-5") && ok;
+  ok = check_stringify("1000000000000000.0", "1000000000000000") && ok;
+  ok = check_stringify("10000000000000000.0", "1e16") && ok;
+  ok = check_roundtrip("1.2345678901234567") && ok;
+  ok = check_roundtrip("2.2250738585072014e-308") && ok;
+  ok = check_roundtrip("5e-324") && ok;
+  ok = check_roundtrip("-5e-324") && ok;
+  ok = check_roundtrip("9007199254740993.0") && ok;
+  ok = check_parse_bits("1.23456789012345678901", 0x3ff3c0ca428c59fbULL) && ok;
+  ok = check_parse_bits("1.234567890123456789012345678901234567890e-100",
+                        0x2b31482fe620c5d2ULL) && ok;
+  ok = check_parse_bits("1.7976931348623157e308", 0x7fefffffffffffffULL) && ok;
+  ok = check_parse_float32() && ok;
+  ok = check_nonfinite_stringifies_to_null() && ok;
+  ok = check_parse_rejects("+1") && ok;
+  ok = check_parse_rejects("01") && ok;
+  ok = check_parse_rejects("1.") && ok;
+  ok = check_parse_rejects("1e") && ok;
+  ok = check_parse_rejects("1e400") && ok;
+  ok = check_parse_rejects("-1e400") && ok;
+  ok = check_parse_rejects("1.7976931348623159e308") && ok;
+  ok = check_parse_rejects("[1,]") && ok;
+  return ok ? 0 : 1;
+}

tests/v3/fuzzer/Makefile

@@ -0,0 +1,83 @@
+# tests/v3/fuzzer/Makefile — Build libFuzzer harnesses for tinygltf v3
+#
+# Requires: clang/clang++ with libFuzzer support
+#
+# Targets:
+#   make             — build both harnesses with ASan + UBSan
+#   make run         — run the dedicated pure-C v3 harness
+#   make run-cpp     — run the legacy header-implementation harness
+#   make seed        — generate seed corpus from test models
+#   make clean       — remove binaries and corpus
+
+CC        = clang
+CXX       = clang++
+CCFLAGS   = -g -O1 -std=c11
+CXXFLAGS  = -g -O1 -std=c++17 -fno-rtti -fno-exceptions
+SANITIZE  = -fsanitize=fuzzer,address,undefined
+INCLUDES  = -I../../..
+
+FUZZER    = fuzz_gltf_v3
+FUZZER_C  = fuzz_gltf_v3_c
+CORPUS    = corpus
+ARTIFACTS = artifacts
+
+# Fuzzer runtime options
+MAX_LEN   ?= 65536
+JOBS      ?= $(shell nproc 2>/dev/null || echo 4)
+MAX_TIME  ?= 0
+FUZZ_ENV  ?= LSAN_OPTIONS=detect_leaks=0
+
+.PHONY: all run run-cpp seed clean
+
+all: $(FUZZER) $(FUZZER_C)
+
+$(FUZZER): fuzz_gltf_v3.cc ../../../tiny_gltf_v3.h ../../../tiny_gltf_v3.c ../../../tinygltf_json_c.h
+	$(CXX) $(CXXFLAGS) $(SANITIZE) $(INCLUDES) -o $@ $<
+
+$(FUZZER_C): fuzz_gltf_v3_c.c ../../../tiny_gltf_v3.h ../../../tiny_gltf_v3.c ../../../tinygltf_json_c.h
+	$(CC) $(CCFLAGS) $(SANITIZE) $(INCLUDES) -o $@ $< ../../../tiny_gltf_v3.c
+
+run: $(FUZZER_C) | $(CORPUS) $(ARTIFACTS)
+	$(FUZZ_ENV) ./$(FUZZER_C) $(CORPUS) \
+		-artifact_prefix=$(ARTIFACTS)/ \
+		-max_len=$(MAX_LEN) \
+		-jobs=$(JOBS) \
+		-workers=$(JOBS) \
+		$(if $(filter-out 0,$(MAX_TIME)),-max_total_time=$(MAX_TIME))
+
+run-cpp: $(FUZZER) | $(CORPUS) $(ARTIFACTS)
+	$(FUZZ_ENV) ./$(FUZZER) $(CORPUS) \
+		-artifact_prefix=$(ARTIFACTS)/ \
+		-max_len=$(MAX_LEN) \
+		-jobs=$(JOBS) \
+		-workers=$(JOBS) \
+		$(if $(filter-out 0,$(MAX_TIME)),-max_total_time=$(MAX_TIME))
+
+# Generate seed corpus from existing test models
+seed: | $(CORPUS)
+	@echo "Seeding corpus from test models..."
+	@for f in ../../../models/Cube/Cube.gltf \
+	          ../../../models/Cube/Cube.glb; do \
+		if [ -f "$$f" ]; then \
+			cp "$$f" $(CORPUS)/; \
+			echo "  Added: $$f"; \
+		fi; \
+	done
+	@# Add a minimal valid glTF JSON
+	@echo '{"asset":{"version":"2.0"},"scene":0,"scenes":[{"nodes":[0]}],"nodes":[{"name":"n"}]}' > $(CORPUS)/minimal.gltf
+	@# Add a minimal valid GLB (header + empty JSON chunk)
+	@printf 'glTF\x02\x00\x00\x00\x1c\x00\x00\x00\x04\x00\x00\x00JSON{}  ' > $(CORPUS)/minimal.glb
+	@# Add edge cases
+	@echo '{}' > $(CORPUS)/empty_object.gltf
+	@echo '{"asset":{"version":"2.0"}}' > $(CORPUS)/asset_only.gltf
+	@echo "Corpus: $$(ls $(CORPUS) | wc -l) files"
+
+$(CORPUS):
+	mkdir -p $(CORPUS)
+
+$(ARTIFACTS):
+	mkdir -p $(ARTIFACTS)
+
+clean:
+	rm -f $(FUZZER) $(FUZZER_C)
+	rm -rf $(CORPUS) $(ARTIFACTS)

tests/v3/fuzzer/fuzz_gltf_v3.cc

@@ -0,0 +1,110 @@
+/*
+ * fuzz_gltf_v3.cc — libFuzzer harness for tinygltf v3 parser.
+ *
+ * Fuzz targets:
+ *   - Auto-detect (GLB or JSON) parse from arbitrary bytes
+ *   - Exercises JSON parser, GLB header parsing, arena allocator,
+ *     error stack, and all glTF entity parsing paths.
+ *
+ * Build (clang with libFuzzer):
+ *   clang++ -g -O1 -fsanitize=fuzzer,address,undefined \
+ *       -std=c++17 -fno-rtti -fno-exceptions \
+ *       -I../../.. -o fuzz_gltf_v3 fuzz_gltf_v3.cc
+ *
+ * Run:
+ *   ./fuzz_gltf_v3 corpus/ -max_len=65536
+ *
+ * Seed corpus: place valid .gltf and .glb files in corpus/
+ */
+
+#define TINYGLTF3_IMPLEMENTATION
+#include "tiny_gltf_v3.h"
+
+#include <cstdint>
+#include <cstddef>
+
+/* Memory budget to prevent OOM during fuzzing */
+static const uint64_t FUZZ_MEMORY_BUDGET = 64ULL * 1024 * 1024; /* 64 MB */
+
+static void fuzz_parse_auto(const uint8_t *data, size_t size) {
+    tg3_model model;
+    tg3_error_stack errors;
+    tg3_error_stack_init(&errors);
+
+    tg3_parse_options opts;
+    tg3_parse_options_init(&opts);
+    opts.memory.memory_budget = FUZZ_MEMORY_BUDGET;
+
+    tg3_parse_auto(&model, &errors, data, (uint64_t)size,
+                   "", 0, &opts);
+
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+}
+
+static void fuzz_parse_json(const uint8_t *data, size_t size) {
+    tg3_model model;
+    tg3_error_stack errors;
+    tg3_error_stack_init(&errors);
+
+    tg3_parse_options opts;
+    tg3_parse_options_init(&opts);
+    opts.memory.memory_budget = FUZZ_MEMORY_BUDGET;
+
+    tg3_parse(&model, &errors, data, (uint64_t)size,
+              "", 0, &opts);
+
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+}
+
+static void fuzz_parse_glb(const uint8_t *data, size_t size) {
+    tg3_model model;
+    tg3_error_stack errors;
+    tg3_error_stack_init(&errors);
+
+    tg3_parse_options opts;
+    tg3_parse_options_init(&opts);
+    opts.memory.memory_budget = FUZZ_MEMORY_BUDGET;
+
+    tg3_parse_glb(&model, &errors, data, (uint64_t)size,
+                  "", 0, &opts);
+
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+}
+
+static void fuzz_parse_float32(const uint8_t *data, size_t size) {
+    tg3_model model;
+    tg3_error_stack errors;
+    tg3_error_stack_init(&errors);
+
+    tg3_parse_options opts;
+    tg3_parse_options_init(&opts);
+    opts.memory.memory_budget = FUZZ_MEMORY_BUDGET;
+    opts.parse_float32 = 1;
+
+    tg3_parse_auto(&model, &errors, data, (uint64_t)size,
+                   "", 0, &opts);
+
+    tg3_model_free(&model);
+    tg3_error_stack_free(&errors);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    if (size == 0) return 0;
+
+    /* Use first byte to select parse path, rest is the payload */
+    uint8_t selector = data[0] % 4;
+    const uint8_t *payload = data + 1;
+    size_t payload_size = size - 1;
+
+    switch (selector) {
+    case 0: fuzz_parse_auto(payload, payload_size);    break;
+    case 1: fuzz_parse_json(payload, payload_size);    break;
+    case 2: fuzz_parse_glb(payload, payload_size);     break;
+    case 3: fuzz_parse_float32(payload, payload_size); break;
+    }
+
+    return 0;
+}

tests/v3/fuzzer/fuzz_gltf_v3_c.c

@@ -0,0 +1,39 @@
+#include "tiny_gltf_v3.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+static const uint64_t FUZZ_MEMORY_BUDGET = 64ULL * 1024 * 1024;
+
+typedef tg3_error_code (*tg3_fuzz_parse_fn)(tg3_model *, tg3_error_stack *,
+    const uint8_t *, uint64_t, const char *, uint32_t, const tg3_parse_options *);
+
+static void tg3_fuzz_run(tg3_fuzz_parse_fn fn, int parse_float32,
+                         const uint8_t *data, size_t size) {
+  tg3_model model;
+  tg3_error_stack errors;
+  tg3_parse_options opts;
+
+  tg3_error_stack_init(&errors);
+  tg3_parse_options_init(&opts);
+  opts.memory.memory_budget = FUZZ_MEMORY_BUDGET;
+  opts.parse_float32 = parse_float32;
+
+  fn(&model, &errors, data, (uint64_t)size, "", 0, &opts);
+
+  tg3_model_free(&model);
+  tg3_error_stack_free(&errors);
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size == 0) return 0;
+
+  switch (data[0] % 4) {
+    case 0: tg3_fuzz_run(tg3_parse_auto, 0, data + 1, size - 1); break;
+    case 1: tg3_fuzz_run(tg3_parse,      0, data + 1, size - 1); break;
+    case 2: tg3_fuzz_run(tg3_parse_glb,  0, data + 1, size - 1); break;
+    case 3: tg3_fuzz_run(tg3_parse_auto, 1, data + 1, size - 1); break;
+  }
+
+  return 0;
+}

tests/v3/security/negstride.gltf

@@ -0,0 +1,8 @@
+{
+  "asset": {"version": "2.0"},
+  "buffers": [{"byteLength": 4}],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 4, "byteStride": -1}
+  ],
+  "scenes": [{"nodes": []}]
+}

tests/v3/security/oob_buffer_view.gltf

@@ -0,0 +1,9 @@
+{
+  "asset": {"version": "2.0"},
+  "buffers": [{"byteLength": 4}],
+  "bufferViews": [{"buffer": 0, "byteOffset": 0, "byteLength": 4}],
+  "accessors": [
+    {"bufferView": 1000000, "byteOffset": 0, "componentType": 5121, "count": 1, "type": "SCALAR"}
+  ],
+  "scenes": [{"nodes": []}]
+}

tests/v3/security/oob_extension_indices.gltf

@@ -0,0 +1,19 @@
+{
+  "asset": {"version": "2.0"},
+  "nodes": [
+    {"extensions": {"KHR_audio": {"emitter": 2147483647},
+                    "MSFT_lod": {"ids": [-1, 9999]}}}
+  ],
+  "materials": [
+    {"extensions": {"MSFT_lod": {"ids": [-5]}}}
+  ],
+  "scenes": [
+    {"extensions": {"KHR_audio": {"emitters": [12345]}}}
+  ],
+  "extensions": {
+    "KHR_audio": {
+      "sources":  [{"bufferView": -1}],
+      "emitters": [{"source": 99999}]
+    }
+  }
+}

tests/v3/security/traversal_relative.gltf

@@ -0,0 +1,14 @@
+{
+  "asset": {"version": "2.0"},
+  "buffers": [
+    {"uri": "../../../../../../../../tmp/tg3-poc-secret.txt", "byteLength": 32}
+  ],
+  "bufferViews": [
+    {"buffer": 0, "byteOffset": 0, "byteLength": 32}
+  ],
+  "accessors": [
+    {"bufferView": 0, "byteOffset": 0, "componentType": 5121, "count": 32, "type": "SCALAR"}
+  ],
+  "scenes": [{"nodes": []}],
+  "scene": 0
+}