Fix tg3_writer allocation: use new/delete instead of calloc/free

Co-authored-by: syoyo <18676+syoyo@users.noreply.github.com>
Agent-Logs-Url: https://github.com/syoyo/tinygltf/sessions/c2a9ce6c-1c60-4925-b67b-e5ad2ffe1cd2

.github/instructions/copilot-instructions.md

@@ -0,0 +1,92 @@
+# Copilot Review Instructions for TinyGLTF
+
+This document provides guidelines for reviewing code changes in the TinyGLTF repository.
+
+## Memory Safety
+
+- **Buffer Overflows**: Check for proper bounds checking when accessing arrays, vectors, and buffers. Verify that buffer sizes are validated before read/write operations.
+- **Null Pointer Dereferences**: Ensure all pointers are checked for null before dereferencing, especially when handling optional glTF fields.
+- **Memory Leaks**: Verify proper resource management, including RAII patterns for file handles, image data, and dynamically allocated memory.
+- **Use-After-Free**: Check for proper lifetime management of objects, especially when dealing with callbacks and asynchronous operations.
+
+## Error Handling
+
+- **File I/O**: Verify that all file operations have proper error checking and meaningful error messages.
+- **JSON Parsing**: Ensure JSON parsing errors are caught and reported with helpful context about the location and nature of the error.
+- **Resource Loading**: Check that failures in loading images, buffers, and other resources are properly handled and don't cause crashes.
+- **Error Propagation**: Verify that errors are properly propagated through the call stack with appropriate error messages.
+
+## glTF 2.0 Specification Compliance
+
+- **Required Fields**: Ensure all required glTF fields are validated and present.
+- **Data Types**: Verify that data types match the glTF specification (e.g., component types, accessor types).
+- **Constraints**: Check that glTF constraints are enforced (e.g., valid ranges for enums, buffer stride requirements).
+- **Extensions**: Verify proper handling of glTF extensions and that unknown extensions are handled gracefully.
+- **Validation**: Ensure new features align with the glTF 2.0 specification from the Khronos Group.
+
+## Cross-Platform Compatibility
+
+- **Windows**: Check for proper handling of Windows-specific issues (path separators, line endings, file operations).
+- **Linux**: Verify compatibility with various Linux distributions and compilers (GCC, Clang).
+- **macOS**: Ensure macOS-specific considerations are addressed (case-sensitive filesystems, Clang compatibility).
+- **Mobile Platforms**: Consider Android and iOS compatibility where applicable.
+- **Endianness**: Verify proper handling of byte order when reading binary data.
+- **Compiler Compatibility**: Ensure code compiles with C++11 standard and supported compilers (MSVC, GCC, Clang).
+
+## Edge Cases in glTF Parsing
+
+- **Empty/Minimal Files**: Verify handling of minimal valid glTF files.
+- **Large Files**: Check for proper handling of large glTF files and buffers without memory exhaustion.
+- **Malformed Data**: Ensure graceful handling of malformed or invalid glTF data.
+- **Missing Optional Fields**: Verify correct behavior when optional glTF fields are absent.
+- **Edge Values**: Check handling of boundary values (e.g., maximum buffer sizes, extreme floating-point values).
+- **Base64 Encoding**: Verify proper handling of base64-encoded data URIs and invalid encodings.
+
+## Backwards Compatibility
+
+- **API Changes**: Ensure public API changes maintain backwards compatibility or are properly deprecated.
+- **Breaking Changes**: Flag any breaking changes for major version updates and document migration paths.
+- **Binary Compatibility**: Consider ABI stability for header-only library changes.
+- **Default Behavior**: Verify that default behavior of existing functionality remains unchanged.
+
+## Performance Considerations
+
+- **Parsing Performance**: Check for unnecessary copies, redundant allocations, and inefficient algorithms in parsing logic.
+- **Memory Usage**: Verify efficient memory usage, especially when loading large glTF files.
+- **I/O Operations**: Ensure efficient file reading and minimize unnecessary disk access.
+- **String Operations**: Check for efficient string handling (use of string_view, move semantics).
+- **STL Usage**: Verify appropriate use of STL containers and algorithms.
+
+## Documentation
+
+- **Public API**: Ensure all public functions, classes, and methods have clear documentation comments.
+- **Parameters**: Verify that function parameters are documented, including expected ranges and constraints.
+- **Return Values**: Document return values and possible error conditions.
+- **Examples**: Check that complex features include usage examples.
+- **Changelog**: Verify that significant changes are documented in release notes or changelog.
+
+## Testing
+
+- **Test Coverage**: Ensure new features include appropriate unit tests or integration tests.
+- **Edge Cases**: Verify that tests cover edge cases and error conditions.
+- **Cross-Platform Tests**: Check that tests run on all supported platforms.
+- **Regression Tests**: Ensure bug fixes include regression tests to prevent recurrence.
+- **Sample Files**: Verify that changes are tested with various valid and invalid glTF sample files.
+
+## Code Style Consistency
+
+- **Header-Only Pattern**: Maintain the header-only library structure.
+- **Naming Conventions**: Follow existing naming conventions (CamelCase for types, snake_case for functions where applicable).
+- **Formatting**: Adhere to the existing code formatting style (check `.clang-format` if available).
+- **Include Guards**: Verify proper include guards and header organization.
+- **Namespace Usage**: Ensure proper use of the `tinygltf` namespace.
+- **Comments**: Maintain consistent comment style with existing code.
+- **C++11 Compliance**: Verify that code uses C++11 features appropriately and doesn't require newer standards unless specified.
+
+## Additional Considerations
+
+- **Third-Party Dependencies**: Minimize new dependencies; prefer existing dependencies (json.hpp, stb_image).
+- **Warnings**: Ensure code compiles without warnings on supported compilers.
+- **const Correctness**: Verify proper use of const for parameters and methods.
+- **RAII**: Prefer RAII patterns for resource management over manual cleanup.
+- **noexcept**: Use noexcept appropriately for move constructors and move assignment operators.

.github/workflows/ci.yml

@@ -0,0 +1,330 @@
+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@v4
+
+      - name: Configure
+        run: cmake -B build -DTINYGLTF_BUILD_LOADER_EXAMPLE=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@v4
+
+      - 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
+
+      - 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@v4
+
+      - name: Configure
+        run: cmake -B build -DTINYGLTF_BUILD_LOADER_EXAMPLE=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@v4
+
+      - name: Configure
+        run: cmake -B build -DTINYGLTF_BUILD_LOADER_EXAMPLE=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@v4
+
+      - 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 ..
+
+      - 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@v4
+
+      - 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 ..
+
+      - 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@v4
+
+      - 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@v4
+
+      - 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
+          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@v4
+
+      - 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@v4
+
+      - 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@v4
+
+      - name: Build with CMake Header-Only
+        run: |
+          mkdir build
+          cmake -B build -DTINYGLTF_HEADER_ONLY=ON -DTINYGLTF_BUILD_LOADER_EXAMPLE=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
+
+  # Special Configuration: RapidJSON Backend
+  linux-rapidjson:
+    runs-on: ubuntu-latest
+    name: Linux x64 (GCC) - RapidJSON Backend
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - 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 -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@v4
+
+      - 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@v4
+
+      - 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

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

@@ -0,0 +1,45 @@
+name: MSYS2 MinGW-w64 Windows 64bit Build
+
+on:
+  push:
+    branches:
+      - release
+      - devel
+    paths:
+    - 'tiny_gltf.*'
+    - 'CMakeLists.txt'
+    - '.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@v3
+
+      - 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
+
+      - name: Build
+        run: |
+          cmake --build build
+

.gitignore

@@ -21,6 +21,9 @@ premake5.tar.gz
 *.vcxproj*
 .vs
 
+# default cmake build dir
+build/
+
 #binary directories
 bin/
 obj/
@@ -70,6 +73,19 @@ tests/tester
 tests/tester_noexcept
 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 +39,25 @@ if (TINYGLTF_BUILD_BUILDER_EXAMPLE)
   add_subdirectory ( examples/build-gltf )
 endif (TINYGLTF_BUILD_BUILDER_EXAMPLE)
 
+if (TINYGLTF_BUILD_TESTS)
+  enable_testing()
+  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)
+endif (TINYGLTF_BUILD_TESTS)
+
 #
 # for add_subdirectory and standalone build
 #
@@ -59,21 +81,37 @@ 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
+    tinygltf_json.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

@@ -9,7 +9,7 @@ If you are looking for old, C++03 version, please use `devel-picojson` branch (b
 ## Status
 
 Currently TinyGLTF is stable and 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 +26,6 @@ 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
@@ -109,6 +105,7 @@ WASI build example is located in [wasm](wasm) .
 * [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
@@ -160,9 +157,10 @@ 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());
@@ -173,8 +171,7 @@ if (!err.empty()) {
 }
 
 if (!ret) {
-  printf("Failed to parse glTF\n");
-  return -1;
+  printf("Failed to parse glTF: %s\n", filename.c_str());
 }
 ```
 
@@ -195,7 +192,6 @@ 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
@@ -212,6 +208,11 @@ 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
 

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 ../tinygltf_json.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 +1,396 @@
+/*
+ * 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) {
+    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;
+
+        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");
+}
+
+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;
+    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], "--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" : "");
+        }
+
+        BenchResult r = bench_file(file.c_str(), iterations, warmup, quiet, float32_mode);
+
+        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;

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);
 

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 +757,495 @@ 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);
+}

tests/v3/fuzzer/Makefile

@@ -0,0 +1,67 @@
+# tests/v3/fuzzer/Makefile — Build libFuzzer harness for tinygltf v3
+#
+# Requires: clang++ with libFuzzer support
+#
+# Targets:
+#   make             — build fuzzer with ASan + UBSan
+#   make run         — run fuzzer with default settings
+#   make seed        — generate seed corpus from test models
+#   make clean       — remove binaries and corpus
+
+CXX       = clang++
+CXXFLAGS  = -g -O1 -std=c++17 -fno-rtti -fno-exceptions
+SANITIZE  = -fsanitize=fuzzer,address,undefined
+INCLUDES  = -I../../..
+
+FUZZER    = fuzz_gltf_v3
+CORPUS    = corpus
+ARTIFACTS = artifacts
+
+# Fuzzer runtime options
+MAX_LEN   ?= 65536
+JOBS      ?= $(shell nproc 2>/dev/null || echo 4)
+MAX_TIME  ?= 0
+
+.PHONY: all run seed clean
+
+all: $(FUZZER)
+
+$(FUZZER): fuzz_gltf_v3.cc ../../../tiny_gltf_v3.h ../../../tinygltf_json.h
+	$(CXX) $(CXXFLAGS) $(SANITIZE) $(INCLUDES) -o $@ $<
+
+run: $(FUZZER) | $(CORPUS) $(ARTIFACTS)
+	./$(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)
+	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;
+}