Add regression test for issue 321

Also ensure `inverseBindMatrices` should not be -2 or other negative values.

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1 @@
+blank_issues_enabled: false

.github/ISSUE_TEMPLATE/issue-report.md

@@ -0,0 +1,30 @@
+---
+name: Issue report
+about: Create a report
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Describe the issue**
+
+A clear and concise description of what the issue is.
+
+**To Reproduce**
+
+- OS
+- Compiler, compiler version, compile options
+- Please attach minimal and reproducible .glTF file if you got an issue related to .glTF data
+
+**Expected behaviour**
+
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+
+If applicable, add screenshots to help explain your problem.
+
+
+**Additional context**
+Add any other context about the problem here.

.github/workflows/c-cpp.yml

@@ -0,0 +1,165 @@
+name: C/C++ CI
+
+on: [push, pull_request]
+
+jobs:
+
+  # compile with older gcc4.8
+  build-gcc48:
+
+    runs-on: ubuntu-18.04
+    name: Build with gcc 4.8
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+
+      - name: Build
+        run: |
+            sudo apt-get update
+            sudo apt-get install -y build-essential
+            sudo apt-get install -y gcc-4.8 g++-4.8
+            g++-4.8 -std=c++11 -o loader_example loader_example.cc
+
+      - name: NoexceptBuild
+        run: |
+            g++-4.8 -DTINYGLTF_NOEXCEPTION -std=c++11 -o loader_example loader_example.cc
+
+      - name: RapidjsonBuild
+        run: |
+            git clone https://github.com/Tencent/rapidjson
+            g++-4.8 -DTINYGLTF_USE_RAPIDJSON -I./rapidjson/include/rapidjson -std=c++11 -o loader_example loader_example.cc
+
+  # compile with mingw gcc cross
+  build-mingw-cross:
+
+    runs-on: ubuntu-18.04
+    name: Build with MinGW gcc cross
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+
+      - name: Build
+        run: |
+            sudo apt-get update
+            sudo apt-get install -y build-essential
+            sudo apt-get install -y mingw-w64
+            x86_64-w64-mingw32-g++ -std=c++11 -o loader_example loader_example.cc
+
+  # Windows(x64) + Visual Studio 2019 build
+  build-windows-msvc:
+
+    runs-on: windows-latest
+    name: Build for Windows(x64, MSVC)
+
+    # Use system installed cmake
+    # https://help.github.com/en/actions/reference/software-installed-on-github-hosted-runners
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Configure
+        run: |
+          mkdir build
+          cd build
+          cmake -G "Visual Studio 16 2019" -DTINYGLTF_BUILD_LOADER_EXAMPLE=On -DTINYGLTF_BUILD_GL_EXAMPLES=Off -DTINYGLTF_BUILD_VALIDATOR_EXAMPLE=On ..
+          cd ..
+      - name: Build
+        run: cmake --build build --config Release
+
+
+  build-linux:
+
+    runs-on: ubuntu-latest
+    name: Buld with gcc
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: build
+      run: |
+        g++ -std=c++11 -o loader_example loader_example.cc
+    - name: test
+      run: |
+        ./loader_example models/Cube/Cube.gltf
+
+    - name: tests
+      run: |
+        cd tests
+        g++ -I../  -std=c++11 -g -O0 -o tester tester.cc
+        ./tester
+        cd ..
+
+    - name: noexcept_tests
+      run: |
+        cd tests
+        g++ -DTINYGLTF_NOEXCEPTION -I../  -std=c++11 -g -O0 -o tester_noexcept tester.cc
+        ./tester_noexcept
+        cd ..
+
+
+  build-rapidjson-linux:
+
+    runs-on: ubuntu-latest
+    name: Buld with gcc + rapidjson
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: build
+      run: |
+        git clone https://github.com/Tencent/rapidjson
+        g++ -v
+        g++ -DTINYGLTF_USE_RAPIDJSON -I./rapidjson/include/rapidjson -std=c++11 -o loader_example loader_example.cc
+
+    - name: loader_example_test
+      run: |
+        ./loader_example models/Cube/Cube.gltf
+
+    - name: tests
+      run: |
+        cd tests
+        g++ -DTINYGLTF_USE_RAPIDJSON -I../rapidjson/include/rapidjson -I../  -std=c++11 -g -O0 -o tester tester.cc
+        ./tester
+        cd ..
+
+    - name: noexcept_tests
+      run: |
+        cd tests
+        g++ -DTINYGLTF_USE_RAPIDJSON -I../rapidjson/include/rapidjson -DTINYGLTF_NOEXCEPTION -I../  -std=c++11 -g -O0 -o tester_noexcept tester.cc
+        ./tester_noexcept
+        cd ..
+
+  # Cross-compile for aarch64 linux target
+  build-cross-aarch64:
+
+    runs-on: ubuntu-18.04
+    name: Build on cross aarch64
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Build
+        run: |
+            sudo apt-get update
+            sudo apt-get install -y build-essential
+            sudo apt-get install -y gcc-8-aarch64-linux-gnu g++-8-aarch64-linux-gnu
+
+            git clone https://github.com/Tencent/rapidjson
+            aarch64-linux-gnu-g++-8 -DTINYGLTF_USE_RAPIDJSON -I./rapidjson/include/rapidjson -std=c++11 -g -O0 -o loader_example loader_example.cc
+
+  # macOS clang
+  build-macos:
+
+    runs-on: macos-latest
+    name: Build on macOS
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Build
+        run: |
+            clang++ -std=c++11 -g -O0 -o loader_example loader_example.cc
+            ./loader_example models/Cube/Cube.gltf
+
+            git clone https://github.com/Tencent/rapidjson
+            clang++ -DTINYGLTF_USE_RAPIDJSON -I./rapidjson/include/rapidjson -std=c++11 -g -O0 -o loader_example loader_example.cc
+

CMakeLists.txt

@@ -4,17 +4,29 @@ PROJECT (tinygltf)
 
 SET(CMAKE_CXX_STANDARD 11)
 
-option(TINYGLTF_BUILD_EXAMPLES "Build examples" ON)
+option(TINYGLTF_BUILD_LOADER_EXAMPLE "Build loader_example" ON)
+option(TINYGLTF_BUILD_GL_EXAMPLES "Build GL exampels(requires glfw, OpenGL, etc)" OFF)
+option(TINYGLTF_BUILD_VALIDATOR_EXAMPLE "Build validator example" OFF)
+option(TINYGLTF_BUILD_BUILDER_EXAMPLE "Build glTF builder example" OFF)
 
-if (TINYGLTF_BUILD_EXAMPLES)
+if (TINYGLTF_BUILD_LOADER_EXAMPLE)
   ADD_EXECUTABLE ( loader_example
     loader_example.cc
     )
+endif (TINYGLTF_BUILD_LOADER_EXAMPLE)
 
+if (TINYGLTF_BUILD_GL_EXAMPLES)
   ADD_SUBDIRECTORY ( examples/gltfutil )
   ADD_SUBDIRECTORY ( examples/glview )
+endif (TINYGLTF_BUILD_GL_EXAMPLES)
+
+if (TINYGLTF_BUILD_VALIDATOR_EXAMPLE)
   ADD_SUBDIRECTORY ( examples/validator )
-endif (TINYGLTF_BUILD_EXAMPLES)
+endif (TINYGLTF_BUILD_VALIDATOR_EXAMPLE)
+
+if (TINYGLTF_BUILD_BUILDER_EXAMPLE)
+  ADD_SUBDIRECTORY ( examples/build-gltf )
+endif (TINYGLTF_BUILD_BUILDER_EXAMPLE)
 
 #
 # TinuGLTF is a header-only library, so no library build. just install header files.

README.md

@@ -3,7 +3,7 @@
 `TinyGLTF` is a header only C++11 glTF 2.0 https://github.com/KhronosGroup/glTF library.
 
 `TinyGLTF` uses Niels Lohmann's json library(https://github.com/nlohmann/json), so now it requires C++11 compiler.
-If you are looking for old, C++03 version, please use `devel-picojson` branch.
+If you are looking for old, C++03 version, please use `devel-picojson` branch(but not maintained anymore).
 
 ## Status
 
@@ -13,12 +13,18 @@ If you are looking for old, C++03 version, please use `devel-picojson` branch.
  - v2.1.0 release(Draco support)
  - v2.0.0 release(22 Aug, 2018)!
 
+### Branches
+
+* `sajson` : Use sajson to parse JSON. Parsing only but faster compile time(2x reduction compared to json.hpp and RapidJson)
+
 ## 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
 
 * Written in portable C++. C++-11 with STL dependency only.
@@ -71,6 +77,7 @@ In extension(`ExtensionMap`), JSON number value is parsed as int or float(number
 * [glview](examples/glview) : Simple glTF geometry viewer.
 * [validator](examples/validator) : Simple glTF validator with JSON schema.
 * [basic](examples/basic) : Basic glTF viewer with texturing support.
+* [build-gltf](examples/build-gltf) : Build simple glTF scene from a scratch.
 
 ## Projects using TinyGLTF
 
@@ -83,6 +90,8 @@ In extension(`ExtensionMap`), JSON number value is parsed as int or float(number
 * [QuickLook GLTF](https://github.com/toshiks/glTF-quicklook) - quicklook plugin for macos. Also SceneKit wrapper for tinygltf.
 * [GlslViewer](https://github.com/patriciogonzalezvivo/glslViewer) - live GLSL coding for MacOS and Linux
 * [Vulkan-Samples](https://github.com/KhronosGroup/Vulkan-Samples) - The Vulkan Samples is collection of resources to help you develop optimized Vulkan applications.
+* [TDME2](https://github.com/andreasdr/tdme2) - TDME2 - ThreeDeeMiniEngine2 is a lightweight 3D engine including tools suited for 3D game development using C++11
+* [SanityEngine](https://github.com/DethRaid/SanityEngine) - A C++/D3D12 renderer focused on the personal and proessional development of its developer
 * Your projects here! (Please send PR)
 
 ## TODOs
@@ -148,6 +157,10 @@ if (!ret) {
 }
 ```
 
+#### Loader options
+
+* `TinyGLTF::SetPreserveimageChannels(bool onoff)`. `true` to preserve image channels as stored in image file for loaded image. `false` by default for backward compatibility(image channels are widen to `RGBA` 4 channels). Effective only when using builtin image loader(STB image loader).
+
 ## Compile options
 
 * `TINYGLTF_NOEXCEPTION` : Disable C++ exception in JSON parsing. You can use `-fno-exceptions` or by defining the symbol `JSON_NOEXCEPTION` and `TINYGLTF_NOEXCEPTION`  to fully remove C++ exception codes when compiling TinyGLTF.
@@ -157,6 +170,7 @@ if (!ret) {
 * `TINYGLTF_ANDROID_LOAD_FROM_ASSETS`: Load all files from packaged app assets instead of the regular file system. **Note:** You must pass a valid asset manager from your android app to `tinygltf::asset_manager` beforehand.
 * `TINYGLTF_ENABLE_DRACO`: Enable Draco compression. User must provide include path and link correspnding libraries in your project file.
 * `TINYGLTF_NO_INCLUDE_JSON `: Disable including `json.hpp` 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_RAPIDJSON `: Disable including RapidJson's header files 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 `: 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 featrure.

examples/basic/.gitignore

@@ -1,5 +1,6 @@
 .vs
 Debug
+Release
 x64
 packages
 

examples/basic/README.md

@@ -19,3 +19,7 @@ $ make
 Plese use solution file located at `basic` folder.
 
 
+## Limitation
+
+There are so many limitations in this example(e.g. no PBR shader. the shader only shows texture of textures[0] if available).
+

examples/basic/basic/basic.vcxproj

@@ -22,32 +22,32 @@
     <VCProjectVersion>15.0</VCProjectVersion>
     <ProjectGuid>{0589AC44-0CF3-40D8-8D89-68393CFD40F3}</ProjectGuid>
     <RootNamespace>basic</RootNamespace>
-    <WindowsTargetPlatformVersion>10.0.17134.0</WindowsTargetPlatformVersion>
+    <WindowsTargetPlatformVersion>10.0</WindowsTargetPlatformVersion>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v142</PlatformToolset>
     <CharacterSet>MultiByte</CharacterSet>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v142</PlatformToolset>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v142</PlatformToolset>
     <CharacterSet>MultiByte</CharacterSet>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
-    <PlatformToolset>v141</PlatformToolset>
+    <PlatformToolset>v142</PlatformToolset>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>MultiByte</CharacterSet>
   </PropertyGroup>

examples/basic/main.cpp

@@ -100,42 +100,49 @@ std::map<int, GLuint> bindMesh(std::map<int, GLuint> vbos,
         std::cout << "vaa missing: " << attrib.first << std::endl;
     }
 
-    GLuint texid;
-    glGenTextures(1, &texid);
+    if (model.textures.size() > 0) {
+      // fixme: Use material's baseColor
+      tinygltf::Texture &tex = model.textures[0];
 
-    tinygltf::Texture &tex = model.textures[0];
-    tinygltf::Image &image = model.images[tex.source];
+      if (tex.source > -1) {
 
-    glBindTexture(GL_TEXTURE_2D, texid);
-    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
-    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+        GLuint texid;
+        glGenTextures(1, &texid);
 
-    GLenum format = GL_RGBA;
+        tinygltf::Image &image = model.images[tex.source];
 
-    if (image.component == 1) {
-      format = GL_RED;
-    } else if (image.component == 2) {
-      format = GL_RG;
-    } else if (image.component == 3) {
-      format = GL_RGB;
-    } else {
-      // ???
+        glBindTexture(GL_TEXTURE_2D, texid);
+        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+        GLenum format = GL_RGBA;
+
+        if (image.component == 1) {
+          format = GL_RED;
+        } else if (image.component == 2) {
+          format = GL_RG;
+        } else if (image.component == 3) {
+          format = GL_RGB;
+        } else {
+          // ???
+        }
+
+        GLenum type = GL_UNSIGNED_BYTE;
+        if (image.bits == 8) {
+          // ok
+        } else if (image.bits == 16) {
+          type = GL_UNSIGNED_SHORT;
+        } else {
+          // ???
+        }
+
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0,
+                     format, type, &image.image.at(0));
+      }
     }
-
-    GLenum type = GL_UNSIGNED_BYTE;
-    if (image.bits == 8) {
-      // ok
-    } else if (image.bits == 16) {
-      type = GL_UNSIGNED_SHORT;
-    } else {
-      // ???
-    }
-
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0,
-                 format, type, &image.image.at(0));
   }
 
   return vbos;
@@ -144,8 +151,12 @@ std::map<int, GLuint> bindMesh(std::map<int, GLuint> vbos,
 // bind models
 void bindModelNodes(std::map<int, GLuint> vbos, tinygltf::Model &model,
                     tinygltf::Node &node) {
-  bindMesh(vbos, model, model.meshes[node.mesh]);
+  if ((node.mesh >= 0) && (node.mesh < model.meshes.size())) {
+    bindMesh(vbos, model, model.meshes[node.mesh]);
+  }
+
   for (size_t i = 0; i < node.children.size(); i++) {
+    assert((node.children[i] >= 0) && (node.children[i] < model.nodes.size()));
     bindModelNodes(vbos, model, model.nodes[node.children[i]]);
   }
 }
@@ -157,6 +168,7 @@ GLuint bindModel(tinygltf::Model &model) {
 
   const tinygltf::Scene &scene = model.scenes[model.defaultScene];
   for (size_t i = 0; i < scene.nodes.size(); ++i) {
+    assert((scene.nodes[i] >= 0) && (scene.nodes[i] < model.nodes.size()));
     bindModelNodes(vbos, model, model.nodes[scene.nodes[i]]);
   }
 
@@ -182,7 +194,9 @@ void drawMesh(tinygltf::Model &model, tinygltf::Mesh &mesh) {
 
 // recursively draw node and children nodes of model
 void drawModelNodes(tinygltf::Model &model, tinygltf::Node &node) {
-  drawMesh(model, model.meshes[node.mesh]);
+  if ((node.mesh >= 0) && (node.mesh < model.meshes.size())) {
+    drawMesh(model, model.meshes[node.mesh]);
+  }
   for (size_t i = 0; i < node.children.size(); i++) {
     drawModelNodes(model, model.nodes[node.children[i]]);
   }
@@ -315,7 +329,7 @@ static void error_callback(int error, const char *description) {
 }
 
 int main(int argc, char **argv) {
-  std::string filename = "../../models/Cube/Cube.gltf";
+  std::string filename = "../../../models/Cube/Cube.gltf";
 
   if (argc > 1) {
     filename = argv[1];
@@ -327,9 +341,12 @@ int main(int argc, char **argv) {
 
   // Force create OpenGL 3.3
   // NOTE(syoyo): Linux + NVIDIA driver segfaults for some reason? commenting out glfwWindowHint will work.
+  // Note (PE): On laptops with intel hd graphics card you can overcome the segfault by enabling experimental, see below (tested on lenovo thinkpad)
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
   glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+  glewExperimental = GL_TRUE;
+
 #ifdef __APPLE__
   glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
 #endif

examples/build-gltf/Makefile

@@ -0,0 +1,2 @@
+all:
+	$(CXX) -o create_triangle_gltf -I../../ create_triangle_gltf.cpp

examples/build-gltf/create_triangle_gltf.cpp

@@ -0,0 +1,121 @@
+// An example of how to generate a gltf file from scratch. This example
+// was translated from the pygltlib documentation in the pypi project page,
+// which in turn is based on the Khronos Sample Models at:
+//
+// https://github.com/KhronosGroup/glTF-Sample-Models
+//
+// This example is released under the MIT license. 
+//
+// 2021-02-25 Thu
+// Dov Grobgeld <dov.grobgeld@gmail.com>
+
+
+// Define these only in *one* .cc file.
+#define TINYGLTF_IMPLEMENTATION
+#define STB_IMAGE_IMPLEMENTATION
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+
+// #define TINYGLTF_NOEXCEPTION // optional. disable exception handling.
+#include "tiny_gltf.h"
+
+int main(int argc, char **argv)
+{
+  // Create a model with a single mesh and save it as a gltf file
+  tinygltf::Model m;
+  tinygltf::Scene scene;
+  tinygltf::Mesh mesh;
+  tinygltf::Primitive primitive;
+  tinygltf::Node node;
+  tinygltf::Buffer buffer;
+  tinygltf::BufferView bufferView1;
+  tinygltf::BufferView bufferView2;
+  tinygltf::Accessor accessor1;
+  tinygltf::Accessor accessor2;
+  tinygltf::Asset asset;
+
+  // This is the raw data buffer. 
+  buffer.data = {
+    // 6 bytes of indices and two bytes of padding
+    0x00,0x00,0x01,0x00,0x02,0x00,0x00,0x00,
+    // 36 bytes of floating point numbers
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x3f,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+    0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x3f,
+    0x00,0x00,0x00,0x00};
+
+  // "The indices of the vertices (ELEMENT_ARRAY_BUFFER) take up 6 bytes in the
+  // start of the buffer.
+  bufferView1.buffer = 0;
+  bufferView1.byteOffset=0;
+  bufferView1.byteLength=6;
+  bufferView1.target = TINYGLTF_TARGET_ELEMENT_ARRAY_BUFFER;
+
+  // The vertices take up 36 bytes (3 vertices * 3 floating points * 4 bytes)
+  // at position 8 in the buffer and are of type ARRAY_BUFFER
+  bufferView2.buffer = 0;
+  bufferView2.byteOffset=8;
+  bufferView2.byteLength=36;
+  bufferView2.target = TINYGLTF_TARGET_ARRAY_BUFFER;
+
+  // Describe the layout of bufferView1, the indices of the vertices
+  accessor1.bufferView = 0;
+  accessor1.byteOffset = 0;
+  accessor1.componentType = TINYGLTF_COMPONENT_TYPE_UNSIGNED_SHORT;
+  accessor1.count = 3;
+  accessor1.type = TINYGLTF_TYPE_SCALAR;
+  accessor1.maxValues.push_back(2);
+  accessor1.minValues.push_back(0);
+
+  // Describe the layout of bufferView2, the vertices themself
+  accessor2.bufferView = 1;
+  accessor2.byteOffset = 0;
+  accessor2.componentType = TINYGLTF_COMPONENT_TYPE_FLOAT;
+  accessor2.count = 3;
+  accessor2.type = TINYGLTF_TYPE_VEC3;
+  accessor2.maxValues = {1.0, 1.0, 0.0};
+  accessor2.minValues = {0.0, 0.0, 0.0};
+
+  // Build the mesh primitive and add it to the mesh
+  primitive.indices = 0;                 // The index of the accessor for the vertex indices
+  primitive.attributes["POSITION"] = 1;  // The index of the accessor for positions
+  primitive.material = 0;
+  primitive.mode = TINYGLTF_MODE_TRIANGLES;
+  mesh.primitives.push_back(primitive);
+
+  // Other tie ups
+  node.mesh = 0;
+  scene.nodes.push_back(0); // Default scene
+
+  // Define the asset. The version is required
+  asset.version = "2.0";
+  asset.generator = "tinygltf";
+
+  // Now all that remains is to tie back all the loose objects into the
+  // our single model.
+  m.scenes.push_back(scene);
+  m.meshes.push_back(mesh);
+  m.nodes.push_back(node);
+  m.buffers.push_back(buffer);
+  m.bufferViews.push_back(bufferView1);
+  m.bufferViews.push_back(bufferView2);
+  m.accessors.push_back(accessor1);
+  m.accessors.push_back(accessor2);
+  m.asset = asset;
+
+  // Create a simple material
+  tinygltf::Material mat;
+  mat.pbrMetallicRoughness.baseColorFactor = {1.0f, 0.9f, 0.9f, 1.0f};  
+  mat.doubleSided = true;
+  m.materials.push_back(mat);
+
+  // Save it to a file
+  tinygltf::TinyGLTF gltf;
+  gltf.WriteGltfSceneToFile(&m, "triangle.gltf",
+                           true, // embedImages
+                           true, // embedBuffers
+                           true, // pretty print
+                           false); // write binary
+  
+  exit(0);
+}

examples/dxview/CMakeLists.txt

@@ -0,0 +1,36 @@
+cmake_minimum_required(VERSION 3.5)
+project(dxview)
+
+find_package(glfw3 CONFIG REQUIRED)
+find_package(spdlog CONFIG REQUIRED)
+
+add_executable(dxview
+    src/Viewer.h
+    src/Viewer.cc
+    src/dxview.cc
+)
+
+target_include_directories(dxview
+PRIVATE
+    ../../
+)
+
+target_compile_definitions(dxview
+PRIVATE
+    DXVIEW_SWAP_CHAIN_BUFFER_COUNT=3
+    DXVIEW_RES_DIR=L"${PROJECT_SOURCE_DIR}/res"
+)
+
+target_link_libraries(dxview
+PRIVATE
+    dxgi
+    d3dcompiler
+    d3d12
+    glfw
+    spdlog::spdlog
+)
+
+set_target_properties(dxview
+PROPERTIES
+    CXX_STANDARD 17
+)

examples/dxview/README.md

@@ -0,0 +1,37 @@
+# DirectX glTF Viewer
+
+## Overview
+
+This project was motivated by a lack of sample code demonstrating the graphics API agnostic nature of the glTF specification. The sample code is written using modern C++ and DirectX 12 for the client application.
+
+## Features
+
+* [x] DirectX 12
+* [ ] Loader
+* [ ] Animation
+* [ ] Morph Target
+* [ ] Physical Base Rendering
+* [ ] Environment Map
+
+## Dependencies
+
+* [CMake](https://github.com/Kitware/CMake)
+* [Vcpkg](https://github.com/Microsoft/vcpkg)
+* [GLFW](https://github.com/glfw/glfw)
+* [spdlog](https://github.com/gabime/spdlog)
+
+## Building
+
+### Install dependencies
+
+```
+vcpkg install glfw3:x64-windows
+vcpkg install spdlog:x64-windows
+```
+
+### Generate Project Files
+
+```
+mkdir build
+cmake . -B build -DCMAKE_TOOLCHAIN_FILE=${VCPKG_DIR}/script/buildsystem/vcpkg.cmake
+```

examples/dxview/res/gray.hlsl

@@ -0,0 +1,3 @@
+float4 main() : SV_Target {
+    return float4(0.5, 0.5, 0.5, 1.0);
+}

examples/dxview/res/lighting.hlsl

@@ -0,0 +1,52 @@
+struct RS2PS {
+    float4 position : SV_POSITION;
+
+#ifdef HAS_TEXCOORD_0
+    float2 texcoord_0: TEXCOORD_0;
+#endif
+};
+
+struct TextureInfo {
+    uint textureIndex;
+    uint samplerIndex;
+};
+
+struct PBRMetallicRoughness {
+    float4 baseColorFactor;
+    TextureInfo baseColorTexture;
+    float metallicFactor;
+    float roughnessFactor;
+    TextureInfo metallicRoughnessTexture;
+};
+
+cbuffer Material : register(b2) {
+    PBRMetallicRoughness pbrMetallicRoughness;
+};
+
+Texture2D textures[5] : register(t0);
+SamplerState samplerState[5] : register(s0);
+
+float4 getBaseColor(float2 uv) {
+    float4 baseColor = pbrMetallicRoughness.baseColorFactor;
+
+#ifdef HAS_TEXCOORD_0
+    TextureInfo baseColorTexture = pbrMetallicRoughness.baseColorTexture;
+    if (baseColorTexture.textureIndex >= 0) {
+        baseColor *= textures[baseColorTexture.textureIndex].Sample(samplerState[baseColorTexture.samplerIndex], uv);
+    }
+#endif
+
+    return baseColor;
+}
+
+float4 main(RS2PS input) : SV_Target {
+    float2 uv = float2(0.0, 0.0);
+
+#ifdef HAS_TEXCOORD_0
+    uv = input.texcoord_0;
+#endif
+
+    float4 color = getBaseColor(uv);
+
+    return color;
+}

examples/dxview/res/primitive.hlsl

@@ -0,0 +1,46 @@
+struct IA2VS {
+    float3 position  : POSITION;
+
+#ifdef HAS_NORMAL
+    float3 normal : NORMAL;
+#endif
+
+#ifdef HAS_TANGENT
+    float4 tangent : TANGENT;
+#endif
+
+#ifdef HAS_TEXCOORD_0
+    float2 texcoord_0: TEXCOORD_0;
+#endif
+};
+
+struct VS2RS {
+    float4 position : SV_POSITION;
+
+#ifdef HAS_TEXCOORD_0
+    float2 texcoord_0: TEXCOORD_0;
+#endif
+};
+
+cbuffer Camera : register(b0) {
+    float4x4 V;
+    float4x4 P;
+    float4x4 VP;
+};
+
+cbuffer Node : register(b1) {
+    float4x4 M;
+};
+
+VS2RS main(IA2VS input) {
+    VS2RS output;
+    output.position = mul(float4(input.position, 1.0), M);
+    output.position = mul(output.position, V);
+    output.position = mul(output.position, P);
+
+#ifdef HAS_TEXCOORD_0
+    output.texcoord_0 = input.texcoord_0;
+#endif
+
+    return output;
+}

examples/dxview/src/Viewer.h

@@ -0,0 +1,130 @@
+#ifndef DXVIEW_VIEWER_GUARD
+#define DXVIEW_VIEWER_GUARD
+
+#include <DirectXMath.h>
+#include <d3d12.h>
+#include <dxgi1_6.h>
+#include <tiny_gltf.h>
+#include <wrl.h>
+
+#include <filesystem>
+#include <map>
+#include <string>
+#include <vector>
+
+using Microsoft::WRL::ComPtr;
+
+enum RenderPassType { RENDER_PASS_TYPE_PRESENT = 0, RENDER_PASS_TYPE_COUNT };
+
+struct RenderTarget {
+  ComPtr<ID3D12Resource> pTexture;
+  D3D12_CPU_DESCRIPTOR_HANDLE viewDescriptor;
+};
+
+struct TextureInfo {
+  int32_t textureIndex;
+  int32_t samplerIndex;
+};
+
+struct PBRMetallicRoughness {
+  DirectX::XMFLOAT4 baseColorFactor;
+  TextureInfo baseColorTexture;
+  float metallicFactor;
+  float roughnessFactor;
+  TextureInfo metallicRoughnessTexture;
+};
+
+struct Material {
+  std::string name;
+  D3D12_BLEND_DESC blendDesc;
+  D3D12_RASTERIZER_DESC rasterizerDesc;
+  ComPtr<ID3D12Resource> pBuffer;
+  void* pBufferData;
+  ComPtr<ID3D12DescriptorHeap> pSRVDescriptorHeap;
+  ComPtr<ID3D12DescriptorHeap> pSamplerDescriptorHeap;
+};
+
+struct Attribute {
+  std::string name;
+  DXGI_FORMAT format;
+  D3D12_VERTEX_BUFFER_VIEW vertexBufferView;
+};
+
+struct Primitive {
+  std::vector<Attribute> attributes;
+  uint32_t vertexCount;
+  D3D12_PRIMITIVE_TOPOLOGY primitiveTopology;
+  D3D12_INDEX_BUFFER_VIEW indexBufferView;
+  uint32_t indexCount;
+  Material* pMaterial;
+  ComPtr<ID3D12RootSignature> pRootSignature;
+  ComPtr<ID3D12PipelineState> pPipelineState;
+};
+
+struct Mesh {
+  std::string name;
+  std::vector<Primitive> primitives;
+};
+
+struct Node {
+  DirectX::XMFLOAT4X4 M;
+};
+
+struct Camera {
+  DirectX::XMFLOAT4X4 V;
+  DirectX::XMFLOAT4X4 P;
+  DirectX::XMFLOAT4X4 VP;
+};
+
+class Viewer {
+ public:
+  Viewer(HWND window, tinygltf::Model* pModel);
+
+  void update(double deltaTime);
+  void render(double deltaTime);
+
+ private:
+  void initDirectX(HWND window);
+  void buildRenderTargets();
+  void buildResources();
+  void buildBuffers(std::vector<ComPtr<ID3D12Resource> >* pStagingResources);
+  void buildImages(std::vector<ComPtr<ID3D12Resource> >* pStagingResources);
+  void buildSamplerDescs();
+  void buildMaterials();
+  void buildMeshes();
+  void buildNodes();
+
+  void drawNode(uint64_t nodeIndex);
+
+ private:
+  tinygltf::Model* pModel_;
+  ComPtr<IDXGIFactory1> pFactory_;
+  ComPtr<IDXGIAdapter1> pAdapter_;
+  ComPtr<ID3D12Device> pDevice_;
+  ComPtr<ID3D12CommandQueue> pDirectCommandQueue_;
+  UINT64 directFenceValue_;
+  ComPtr<ID3D12Fence> pDirectFence_;
+  ComPtr<ID3D12CommandQueue> pCopyCommandQueue_;
+  UINT64 copyFenceValue_;
+  ComPtr<ID3D12Fence> pCopyFence_;
+  ComPtr<IDXGISwapChain3> pSwapChain_;
+  ComPtr<ID3D12Resource> pSwapChainBuffers_[DXVIEW_SWAP_CHAIN_BUFFER_COUNT];
+  ComPtr<ID3D12CommandAllocator>
+      pDirectCommandAllocators_[DXVIEW_SWAP_CHAIN_BUFFER_COUNT];
+  ComPtr<ID3D12GraphicsCommandList> pDirectCommandList_;
+  ComPtr<ID3D12CommandAllocator> pCopyCommandAllocator_;
+  ComPtr<ID3D12GraphicsCommandList> pCopyCommandList_;
+  UINT descriptorIncrementSize_[D3D12_DESCRIPTOR_HEAP_TYPE_NUM_TYPES];
+  ComPtr<ID3D12DescriptorHeap>
+      pRTVDescriptorHeaps_[DXVIEW_SWAP_CHAIN_BUFFER_COUNT];
+  std::vector<RenderTarget> renderTargets_[DXVIEW_SWAP_CHAIN_BUFFER_COUNT];
+  std::vector<ComPtr<ID3D12Resource> > pBuffers_;
+  std::vector<ComPtr<ID3D12Resource> > pTextures_;
+  std::vector<D3D12_SAMPLER_DESC> samplerDescs_;
+  std::vector<Material> materials_;
+  std::vector<Mesh> meshes_;
+  std::vector<ComPtr<ID3D12Resource> > pNodeBuffers_;
+  ComPtr<ID3D12Resource> pCameraBuffer_;
+};
+
+#endif

examples/dxview/src/dxview.cc

@@ -0,0 +1,90 @@
+#define GLFW_EXPOSE_NATIVE_WIN32
+#define TINYGLTF_IMPLEMENTATION
+#define STBI_MSC_SECURE_CRT
+#define STB_IMAGE_IMPLEMENTATION
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+
+#include <GLFW/glfw3.h>
+#include <GLFW/glfw3native.h>
+#include <spdlog/spdlog.h>
+#include <tiny_gltf.h>
+
+#undef GLFW_EXPOSE_NATIVE_WIN32
+#undef TINYGLTF_IMPLEMENTATION
+#undef STBI_MSC_SECURE_CRT
+#undef STB_IMAGE_IMPLEMENTATION
+#undef STB_IMAGE_WRITE_IMPLEMENTATION
+
+#include <iostream>
+#include <string>
+
+#include "Viewer.h"
+
+static void onError(int error, const char* message) {
+  spdlog::error("[{}] {}", error, message);
+}
+
+static void onRender(Viewer* pViewer, double deltaTime) {
+  pViewer->update(deltaTime);
+  pViewer->render(deltaTime);
+}
+
+int main(int argc, char* argv[]) {
+  tinygltf::TinyGLTF context;
+
+  tinygltf::Model model;
+  std::string error;
+  std::string warning;
+  if (!context.LoadASCIIFromFile(&model, &error, &warning, argv[1])) {
+    if (!error.empty()) {
+      spdlog::error("{}", error);
+    }
+
+    if (!warning.empty()) {
+      spdlog::warn("{}", warning);
+    }
+
+    exit(EXIT_FAILURE);
+  }
+
+  GLFWwindow* pWindow;
+
+  glfwSetErrorCallback(onError);
+
+  if (!glfwInit()) {
+    spdlog::error("Fail to initialize GLFW!!!");
+    exit(EXIT_FAILURE);
+  }
+
+  glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
+  glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
+
+  pWindow = glfwCreateWindow(512, 512, "dxview", nullptr, nullptr);
+  if (!pWindow) {
+    spdlog::error("Fail to create GLFWwindow!!!");
+    glfwTerminate();
+    exit(EXIT_FAILURE);
+  }
+
+  auto pViewer = std::make_unique<Viewer>(glfwGetWin32Window(pWindow), &model);
+  if (!pViewer) {
+    spdlog::error("Fail to create Viewer");
+    glfwDestroyWindow(pWindow);
+    glfwTerminate();
+    exit(EXIT_FAILURE);
+  }
+
+  auto prevTimeStamp = glfwGetTime();
+  while (!glfwWindowShouldClose(pWindow)) {
+    auto currTimeStamp = glfwGetTime();
+
+    onRender(pViewer.get(), currTimeStamp - prevTimeStamp);
+    prevTimeStamp = currTimeStamp;
+
+    glfwPollEvents();
+  }
+
+  glfwDestroyWindow(pWindow);
+  glfwTerminate();
+  exit(EXIT_SUCCESS);
+}

models/Extensions-overwrite-issue261/issue-261.gltf

@@ -0,0 +1,376 @@
+{
+  "accessors": [
+    {
+      "bufferView": 0,
+      "componentType": 5126,
+      "count": 8,
+      "max": [
+        0.5,
+        0.5,
+        0.5
+      ],
+      "min": [
+        -0.5,
+        -0.5,
+        -0.5
+      ],
+      "type": "VEC3"
+    },
+    {
+      "bufferView": 1,
+      "componentType": 5125,
+      "count": 36,
+      "type": "SCALAR"
+    }
+  ],
+  "asset": {
+    "copyright": "NVIDIA Corporation",
+    "generator": "Iray glTF plugin",
+    "version": "2.0"
+  },
+  "bufferViews": [
+    {
+      "buffer": 0,
+      "byteLength": 96,
+      "byteStride": 12
+    },
+    {
+      "buffer": 0,
+      "byteLength": 144,
+      "byteOffset": 96
+    }
+  ],
+  "buffers": [
+    {
+      "byteLength": 240,
+      "uri": "issue-261.bin"
+    }
+  ],
+  "cameras": [
+    {
+      "extensions": {
+        "NV_Iray": {
+          "mip_burn_highlights": 0.699999988079071,
+          "mip_burn_highlights_per_component": false,
+          "mip_camera_shutter": 4.0,
+          "mip_cm2_factor": 1.0,
+          "mip_crush_blacks": 0.5,
+          "mip_f_number": 1.0,
+          "mip_film_iso": 100.0,
+          "mip_gamma": 2.200000047683716,
+          "mip_saturation": 1.0,
+          "mip_vignetting": 0.00019999999494757503,
+          "mip_whitepoint": [
+            1.0,
+            1.0,
+            1.0,
+            1.0
+          ],
+          "tm_enable_tonemapper": true,
+          "tm_tonemapper": "mia_exposure_photographic"
+        }
+      },
+      "extras": {
+        "resolution": [
+          640,
+          480
+        ]
+      },
+      "name": "default",
+      "perspective": {
+        "aspectRatio": 1.3333333730697632,
+        "yfov": 0.9272952079772949,
+        "zfar": 1000.0,
+        "znear": 0.1
+      },
+      "type": "perspective"
+    }
+  ],
+  "extensions": {
+    "KHR_lights_punctual": {
+      "lights": [
+        {
+          "color": [
+            1.0,
+            1.0,
+            1.0
+          ],
+          "intensity": 1000.0,
+          "name": "light",
+          "type": "point"
+        }
+      ]
+    },
+    "NV_MDL": {
+      "modules": [
+        "mdl::base",
+        "mdl::nvidia::core_definitions",
+        "mdl::state"
+      ],
+      "shaders": [
+        {
+          "definition": "mdl::base::environment_spherical(texture_2d)",
+          "name": "env_shd"
+        },
+        {
+          "arguments": {
+            "base_color": [
+              0.0055217444896698,
+              0.36859095096588135,
+              0.0041161770932376385
+            ],
+            "normal=": 2
+          },
+          "definition": "mdl::nvidia::core_definitions::flex_material",
+          "name": "cube_instance_material"
+        },
+        {
+          "definition": "mdl::state::normal()",
+          "name": "mdl::state::normal_341"
+        },
+        {
+          "arguments": {
+            "base_color": [
+              0.0055217444896698,
+              0.36859095096588135,
+              0.0041161770932376385
+            ],
+            "normal=": 4
+          },
+          "definition": "mdl::nvidia::core_definitions::flex_material",
+          "name": "cube_instance_material"
+        },
+        {
+          "definition": "mdl::state::normal()",
+          "name": "mdl::state::normal_341"
+        }
+      ]
+    }
+  },
+  "extensionsUsed": [
+    "NV_MDL",
+    "NV_Iray",
+    "KHR_lights_punctual"
+  ],
+  "materials": [
+    {
+      "doubleSided": true,
+      "extras": {
+        "mdl_shader": 1
+      },
+      "name": "cube_instance_material",
+      "pbrMetallicRoughness": {
+        "baseColorFactor": [
+          0.0055217444896698,
+          0.36859095096588135,
+          0.0041161770932376385,
+          1.0
+        ]
+      }
+    }
+  ],
+  "meshes": [
+    {
+      "name": "cube",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 0
+          },
+          "indices": 1,
+          "material": 0,
+          "mode": 4
+        }
+      ]
+    }
+  ],
+  "nodes": [
+    {
+      "camera": 0,
+      "extensions": {
+        "NV_Iray": {
+          "iview:fkey": -1,
+          "iview:fov": 53.130104064941406,
+          "iview:interest": [
+            0.1342654824256897,
+            -0.14356137812137604,
+            0.037264324724674225
+          ],
+          "iview:position": [
+            0.9729073643684387,
+            1.2592438459396362,
+            2.4199187755584717
+          ],
+          "iview:roll": 0.0,
+          "iview:up": [
+            0.0,
+            1.0,
+            0.0
+          ]
+        }
+      },
+      "matrix": [
+        0.9432751389105357,
+        -1.1769874756875739e-16,
+        -0.3320120665176343,
+        0.0,
+        -0.16119596696756341,
+        0.8742297945345237,
+        -0.45797175303889276,
+        0.0,
+        0.290254840694694,
+        0.48551237507207207,
+        0.8246392308792816,
+        0.0,
+        0.9729073377709113,
+        1.2592438262175363,
+        2.419918748461627,
+        1.0
+      ],
+      "name": "CamInst"
+    },
+    {
+      "extensions": {
+        "NV_Iray": {
+          "caustic": true,
+          "caustic_cast": true,
+          "caustic_recv": true,
+          "face_back": true,
+          "face_front": true,
+          "finalgather": true,
+          "finalgather_cast": true,
+          "finalgather_recv": true,
+          "globillum": true,
+          "globillum_cast": true,
+          "globillum_recv": true,
+          "material=": 3,
+          "pickable": true,
+          "reflection_cast": true,
+          "reflection_recv": true,
+          "refraction_cast": true,
+          "refraction_recv": true,
+          "shadow_cast": true,
+          "shadow_recv": true,
+          "transparency_cast": true,
+          "transparency_recv": true,
+          "visible": true
+        }
+      },
+      "mesh": 0,
+      "name": "cube_instance"
+    },
+    {
+      "extensions": {
+        "KHR_lights_punctual": {
+          "light": 0
+        },
+        "NV_Iray": {
+          "shadow_cast": true,
+          "visible": false
+        }
+      },
+      "matrix": [
+        0.6988062355563571,
+        -7.76042172309776e-17,
+        -0.7153110128800992,
+        -0.0,
+        -0.4276881690736487,
+        0.8015668284138362,
+        -0.41781987700564616,
+        -0.0,
+        0.57336957992379,
+        0.5979051928078428,
+        0.5601398979107212,
+        0.0,
+        2.3640632834071384,
+        2.465226204472449,
+        2.309515908392224,
+        1.0
+      ],
+      "name": "light_inst"
+    }
+  ],
+  "scene": 0,
+  "scenes": [
+    {
+      "extensions": {
+        "NV_Iray": {
+          "CP_canny_threshold1": 40,
+          "CP_canny_threshold2": 120,
+          "CP_color_quantization": 8,
+          "IVP_color": [
+            1.0,
+            0.0,
+            0.0,
+            1.0
+          ],
+          "TM_drago_bias": 0.8500000238418579,
+          "TM_drago_gamma2": 2.200000047683716,
+          "TM_drago_saturation": 1.0,
+          "TM_durand_contrast": 4.0,
+          "TM_durand_gamma": 2.200000047683716,
+          "TM_durand_saturation": 1.0,
+          "TM_durand_sigma_color": 2.0,
+          "TM_durand_sigma_space": 2.0,
+          "TM_linear_gamma": 2.200000047683716,
+          "TM_reinhard_color_adapt": 0.8999999761581421,
+          "TM_reinhard_gamma": 1.0,
+          "TM_reinhard_intensity": 0.0,
+          "TM_reinhard_light_adapt": 1.0,
+          "TM_reye_Ywhite": 1000000.0,
+          "TM_reye_bsize": 2,
+          "TM_reye_bthres": 3.0,
+          "TM_reye_gamma": 2.200000047683716,
+          "TM_reye_key": 0.5,
+          "TM_reye_saturation": 1.0,
+          "TM_reye_whitebalance": [
+            1.0,
+            0.9965101480484009,
+            0.9805564880371094,
+            0.0
+          ],
+          "environment_dome_depth": 200.0,
+          "environment_dome_height": 200.0,
+          "environment_dome_mode": "infinite",
+          "environment_dome_position": [
+            0.0,
+            0.0,
+            0.0
+          ],
+          "environment_dome_radius": 100.0,
+          "environment_dome_rotation_angle": 0.0,
+          "environment_dome_width": 200.0,
+          "environment_function=": 0,
+          "environment_function_intensity": 1.9900000095367432,
+          "iray_instancing": "off",
+          "iview::inline_color": [
+            1.0,
+            0.0,
+            0.0,
+            1.0
+          ],
+          "iview::inline_width": 1.0,
+          "iview::magnifier_size": 300,
+          "iview::offset": 10.0,
+          "iview::outline_color": [
+            0.0,
+            0.0,
+            0.0,
+            1.0
+          ],
+          "iview::outline_width": 2.0,
+          "iview::overview": true,
+          "iview::zoom_factor": 1.0,
+          "samples": 4.0,
+          "shadow_cast": true,
+          "shadow_recv": true
+        }
+      },
+      "nodes": [
+        0,
+        1,
+        2
+      ]
+    }
+  ]
+}

tests/tester.cc

@@ -3,6 +3,9 @@
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #include "tiny_gltf.h"
 
+// Nlohmann json(include ../json.hpp)
+#include "json.hpp"
+
 #define CATCH_CONFIG_MAIN  // This tells Catch to provide a main() - only do this in one cpp file
 #include "catch.hpp"
 
@@ -93,6 +96,59 @@ TEST_CASE("extension-with-empty-object", "[issue-97]") {
 
 }
 
+TEST_CASE("extension-overwrite", "[issue-261]") {
+
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  bool ret = ctx.LoadASCIIFromFile(&model, &err, &warn, "../models/Extensions-overwrite-issue261/issue-261.gltf");
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+  REQUIRE(true == ret);
+
+  REQUIRE(model.extensionsUsed.size() == 3);
+  {
+    bool has_ext_lights = false;
+    has_ext_lights |= (model.extensionsUsed[0].compare("KHR_lights_punctual") == 0);
+    has_ext_lights |= (model.extensionsUsed[1].compare("KHR_lights_punctual") == 0);
+    has_ext_lights |= (model.extensionsUsed[2].compare("KHR_lights_punctual") == 0);
+
+    REQUIRE(true == has_ext_lights);
+  }
+
+  {
+    REQUIRE(model.extensions.size() == 2);
+    REQUIRE(model.extensions.count("NV_MDL"));
+    REQUIRE(model.extensions.count("KHR_lights_punctual"));
+  }
+
+  // TODO(syoyo): create temp directory.
+  {
+    ret = ctx.WriteGltfSceneToFile(&model, "issue-261.gltf", true, true);
+    REQUIRE(true == ret);
+
+    tinygltf::Model m;
+
+    // read back serialized glTF
+    bool ret = ctx.LoadASCIIFromFile(&m, &err, &warn, "issue-261.gltf");
+    if (!err.empty()) {
+      std::cerr << err << std::endl;
+    }
+    REQUIRE(true == ret);
+
+    REQUIRE(m.extensionsUsed.size() == 3);
+
+    REQUIRE(m.extensions.size() == 2);
+    REQUIRE(m.extensions.count("NV_MDL"));
+    REQUIRE(m.extensions.count("KHR_lights_punctual"));
+
+  }
+
+}
+
 TEST_CASE("invalid-primitive-indices", "[bounds-checking]") {
   tinygltf::Model model;
   tinygltf::TinyGLTF ctx;
@@ -359,3 +415,70 @@ TEST_CASE("image-uri-spaces", "[issue-236]") {
   REQUIRE(true == ret);
 }
 
+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);
+
+  std::stringstream os;
+
+  tinygltf::TinyGLTF ctx;
+  ctx.WriteGltfSceneToStream(&m, os, false, false);
+
+  // use nlohmann json
+  nlohmann::json j = nlohmann::json::parse(os.str());
+
+  REQUIRE(1 == j["materials"].size());
+  REQUIRE(j["materials"][0].is_object());
+
+}
+
+TEST_CASE("empty-skeleton-id", "[issue-321]") {
+
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  bool ret = ctx.LoadASCIIFromFile(&model, &err, &warn, "../models/regression/unassigned-skeleton.gltf");
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+  REQUIRE(true == ret);
+
+  REQUIRE(model.skins.size() == 1);
+  REQUIRE(model.skins[0].skeleton == -1); // unassigned
+
+  std::stringstream os;
+
+  ctx.WriteGltfSceneToStream(&model, os, false, false);
+
+  // use nlohmann json
+  nlohmann::json j = nlohmann::json::parse(os.str());
+
+  // Ensure `skeleton` property is not written to .gltf(was serialized as -1)
+  REQUIRE(1 == j["skins"].size());
+  REQUIRE(j["skins"][0].is_object());
+  REQUIRE(j["skins"][0].count("skeleton") == 0);
+
+}
+
+#ifndef TINYGLTF_NO_FS
+TEST_CASE("expandpath-utf-8", "[pr-226]") {
+
+  std::string s1 = "\xe5\xaf\xb9"; // utf-8 string
+
+  std::string ret = tinygltf::ExpandFilePath(s1, /* userdata */nullptr);
+
+  // expected: E5 AF B9
+  REQUIRE(3 == ret.size());
+
+  REQUIRE(0xe5 == static_cast<uint8_t>(ret[0]));
+  REQUIRE(0xaf == static_cast<uint8_t>(ret[1]));
+  REQUIRE(0xb9 == static_cast<uint8_t>(ret[2]));
+
+}
+#endif

tiny_gltf.h

@@ -4,7 +4,7 @@
 //
 // The MIT License (MIT)
 //
-// Copyright (c) 2015 - 2020 Syoyo Fujita, Aurélien Chatelain and many
+// Copyright (c) 2015 - Present Syoyo Fujita, Aurélien Chatelain and many
 // contributors.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -26,6 +26,9 @@
 // THE SOFTWARE.
 
 // Version:
+//  - v2.5.0 Add SetPreserveImageChannels() option to load image data as is.
+//  - v2.4.3 Fix null object output when when material has all default
+//  parameters.
 //  - v2.4.2 Decode percent-encoded URI.
 //  - v2.4.1 Fix some glTF object class does not have `extensions` and/or
 //  `extras` property.
@@ -52,6 +55,7 @@
 
 #include <array>
 #include <cassert>
+#include <cmath>  // std::fabs
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
@@ -294,7 +298,7 @@ class Value {
 
   DEFAULT_METHODS(Value)
 
-  char Type() const { return static_cast<const char>(type_); }
+  char Type() const { return static_cast<char>(type_); }
 
   bool IsBool() const { return (type_ == BOOL_TYPE); }
 
@@ -322,7 +326,8 @@ class Value {
   }
 
   // Use this function if you want to have number value as int.
-  double GetNumberAsInt() const {
+  // TODO(syoyo): Support int value larger than 32 bits
+  int GetNumberAsInt() const {
     if (type_ == REAL_TYPE) {
       return int(real_value_);
     } else {
@@ -609,7 +614,7 @@ struct Sampler {
   int wrapT =
       TINYGLTF_TEXTURE_WRAP_REPEAT;  // ["CLAMP_TO_EDGE", "MIRRORED_REPEAT",
                                      // "REPEAT"], default "REPEAT"
-  int wrapR = TINYGLTF_TEXTURE_WRAP_REPEAT;  // TinyGLTF extension
+  //int wrapR = TINYGLTF_TEXTURE_WRAP_REPEAT;  // TinyGLTF extension. currently not used.
 
   Value extras;
   ExtensionMap extensions;
@@ -622,8 +627,7 @@ struct Sampler {
       : minFilter(-1),
         magFilter(-1),
         wrapS(TINYGLTF_TEXTURE_WRAP_REPEAT),
-        wrapT(TINYGLTF_TEXTURE_WRAP_REPEAT),
-        wrapR(TINYGLTF_TEXTURE_WRAP_REPEAT) {}
+        wrapT(TINYGLTF_TEXTURE_WRAP_REPEAT) {}
   DEFAULT_METHODS(Sampler)
   bool operator==(const Sampler &) const;
 };
@@ -662,6 +666,8 @@ struct Image {
     width = -1;
     height = -1;
     component = -1;
+    bits = -1;
+    pixel_type = -1;
   }
   DEFAULT_METHODS(Image)
 
@@ -844,8 +850,10 @@ struct Accessor {
   std::string extras_json_string;
   std::string extensions_json_string;
 
-  std::vector<double> minValues;  // optional
-  std::vector<double> maxValues;  // optional
+  std::vector<double>
+      minValues;  // optional. integer value is promoted to double
+  std::vector<double>
+      maxValues;  // optional. integer value is promoted to double
 
   struct {
     int count;
@@ -994,6 +1002,7 @@ struct Primitive {
   Primitive() {
     material = -1;
     indices = -1;
+    mode = -1;
   }
   DEFAULT_METHODS(Primitive)
   bool operator==(const Primitive &) const;
@@ -1062,7 +1071,7 @@ struct Buffer {
 };
 
 struct Asset {
-  std::string version;  // required
+  std::string version = "2.0";  // required
   std::string generator;
   std::string minVersion;
   std::string copyright;
@@ -1113,9 +1122,9 @@ struct SpotLight {
 struct Light {
   std::string name;
   std::vector<double> color;
-  double intensity;
+  double intensity{1.0};
   std::string type;
-  double range;
+  double range{0.0};  // 0.0 = inifinite
   SpotLight spot;
 
   Light() : intensity(1.0), range(0.0) {}
@@ -1184,7 +1193,8 @@ enum SectionCheck {
 ///
 typedef bool (*LoadImageDataFunction)(Image *, const int, std::string *,
                                       std::string *, int, int,
-                                      const unsigned char *, int, void *);
+                                      const unsigned char *, int,
+                                      void *user_pointer);
 
 ///
 /// WriteImageDataFunction type. Signature for custom image writing callbacks.
@@ -1247,7 +1257,14 @@ struct FsCallbacks {
 
 bool FileExists(const std::string &abs_filename, void *);
 
-std::string ExpandFilePath(const std::string &filepath, void *);
+///
+/// Expand file path(e.g. `~` to home directory on posix, `%APPDATA%` to
+/// `C:\\Users\\tinygltf\\AppData`)
+///
+/// @param[in] filepath File path string. Assume UTF-8
+/// @param[in] userdata User data. Set to `nullptr` if you don't need it.
+///
+std::string ExpandFilePath(const std::string &filepath, void *userdata);
 
 bool ReadWholeFile(std::vector<unsigned char> *out, std::string *err,
                    const std::string &filepath, void *);
@@ -1333,6 +1350,11 @@ class TinyGLTF {
   ///
   void SetImageLoader(LoadImageDataFunction LoadImageData, void *user_data);
 
+  ///
+  /// Unset(remove) callback of loading image data
+  ///
+  void RemoveImageLoader();
+
   ///
   /// Set callback to use for writing image data
   ///
@@ -1371,6 +1393,16 @@ class TinyGLTF {
     return store_original_json_for_extras_and_extensions_;
   }
 
+  ///
+  /// Specify whether preserve image channales when loading images or not.
+  /// (Not effective when the user suppy their own LoadImageData callbacks)
+  ///
+  void SetPreserveImageChannels(bool onoff) {
+    preserve_image_channels_ = onoff;
+  }
+
+  bool GetPreserveImageChannels() const { return preserve_image_channels_; }
+
  private:
   ///
   /// Loads glTF asset from string(memory).
@@ -1390,6 +1422,9 @@ class TinyGLTF {
 
   bool store_original_json_for_extras_and_extensions_ = false;
 
+  bool preserve_image_channels_ = false;  /// Default false(expand channels to
+                                          /// RGBA) for backward compatibility.
+
   FsCallbacks fs = {
 #ifndef TINYGLTF_NO_FS
       &tinygltf::FileExists, &tinygltf::ExpandFilePath,
@@ -1409,7 +1444,8 @@ class TinyGLTF {
 #else
       nullptr;
 #endif
-  void *load_image_user_data_ = reinterpret_cast<void *>(&fs);
+  void *load_image_user_data_{nullptr};
+  bool user_image_loader_{false};
 
   WriteImageDataFunction WriteImageData =
 #ifndef TINYGLTF_NO_STB_IMAGE_WRITE
@@ -1417,7 +1453,7 @@ class TinyGLTF {
 #else
       nullptr;
 #endif
-  void *write_image_user_data_ = reinterpret_cast<void *>(&fs);
+  void *write_image_user_data_{nullptr};
 };
 
 #ifdef __clang__
@@ -1502,6 +1538,7 @@ class TinyGLTF {
 #ifndef TINYGLTF_USE_RAPIDJSON
 #include "json.hpp"
 #else
+#ifndef TINYGLTF_NO_INCLUDE_RAPIDJSON
 #include "document.h"
 #include "prettywriter.h"
 #include "rapidjson.h"
@@ -1509,6 +1546,7 @@ class TinyGLTF {
 #include "writer.h"
 #endif
 #endif
+#endif
 
 #ifdef TINYGLTF_ENABLE_DRACO
 #include "draco/compression/decode.h"
@@ -1671,6 +1709,19 @@ void JsonParse(JsonDocument &doc, const char *str, size_t length,
 
 namespace tinygltf {
 
+///
+/// Internal LoadImageDataOption struct.
+/// This struct is passed through `user_pointer` in LoadImageData.
+/// The struct is not passed when the user supply their own LoadImageData
+/// callbacks.
+///
+struct LoadImageDataOption {
+  // true: preserve image channels(e.g. load as RGB image if the image has RGB
+  // channels) default `false`(channels are expanded to RGBA for backward
+  // compatiblity).
+  bool preserve_channels{false};
+};
+
 // Equals function for Value, for recursivity
 static bool Equals(const tinygltf::Value &one, const tinygltf::Value &other) {
   if (one.Type() != other.Type()) return false;
@@ -1883,8 +1934,9 @@ bool Sampler::operator==(const Sampler &other) const {
   return this->extensions == other.extensions && this->extras == other.extras &&
          this->magFilter == other.magFilter &&
          this->minFilter == other.minFilter && this->name == other.name &&
-         this->wrapR == other.wrapR && this->wrapS == other.wrapS &&
          this->wrapT == other.wrapT;
+
+         //this->wrapR == other.wrapR && this->wrapS == other.wrapS &&
 }
 bool Scene::operator==(const Scene &other) const {
   return this->extensions == other.extensions && this->extras == other.extras &&
@@ -2285,22 +2337,40 @@ static bool LoadExternalFile(std::vector<unsigned char> *out, std::string *err,
 void TinyGLTF::SetImageLoader(LoadImageDataFunction func, void *user_data) {
   LoadImageData = func;
   load_image_user_data_ = user_data;
+  user_image_loader_ = true;
+}
+
+void TinyGLTF::RemoveImageLoader() {
+  LoadImageData =
+#ifndef TINYGLTF_NO_STB_IMAGE
+      &tinygltf::LoadImageData;
+#else
+      nullptr;
+#endif
+
+  load_image_user_data_ = nullptr;
+  user_image_loader_ = false;
 }
 
 #ifndef TINYGLTF_NO_STB_IMAGE
 bool LoadImageData(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) {
-  (void)user_data;
   (void)warn;
 
+  LoadImageDataOption option;
+  if (user_data) {
+    option = *reinterpret_cast<LoadImageDataOption *>(user_data);
+  }
+
   int w = 0, h = 0, comp = 0, req_comp = 0;
 
   unsigned char *data = nullptr;
 
-  // force 32-bit textures for common Vulkan compatibility. It appears that
-  // some GPU drivers do not support 24-bit images for Vulkan
-  req_comp = 4;
+  // preserve_channels true: Use channels stored in the image file.
+  // false: force 32-bit textures for common Vulkan compatibility. It appears
+  // that some GPU drivers do not support 24-bit images for Vulkan
+  req_comp = option.preserve_channels ? 0 : 4;
   int bits = 8;
   int pixel_type = TINYGLTF_COMPONENT_TYPE_UNSIGNED_BYTE;
 
@@ -2372,13 +2442,18 @@ bool LoadImageData(Image *image, const int image_idx, std::string *err,
     }
   }
 
+  if (req_comp != 0) {
+    // loaded data has `req_comp` channels(components)
+    comp = req_comp;
+  }
+
   image->width = w;
   image->height = h;
-  image->component = req_comp;
+  image->component = comp;
   image->bits = bits;
   image->pixel_type = pixel_type;
-  image->image.resize(static_cast<size_t>(w * h * req_comp) * size_t(bits / 8));
-  std::copy(data, data + w * h * req_comp * (bits / 8), image->image.begin());
+  image->image.resize(static_cast<size_t>(w * h * comp) * size_t(bits / 8));
+  std::copy(data, data + w * h * comp * (bits / 8), image->image.begin());
   stbi_image_free(data);
 
   return true;
@@ -2481,6 +2556,15 @@ static inline std::wstring UTF8ToWchar(const std::string &str) {
                       (int)wstr.size());
   return wstr;
 }
+
+static inline std::string WcharToUTF8(const std::wstring &wstr) {
+  int str_size = WideCharToMultiByte(CP_UTF8, 0, wstr.data(), (int)wstr.size(),
+                                     nullptr, 0, NULL, NULL);
+  std::string str(str_size, 0);
+  WideCharToMultiByte(CP_UTF8, 0, wstr.data(), (int)wstr.size(), &str[0],
+                      (int)str.size(), NULL, NULL);
+  return str;
+}
 #endif
 
 #ifndef TINYGLTF_NO_FS
@@ -2532,15 +2616,16 @@ bool FileExists(const std::string &abs_filename, void *) {
 
 std::string ExpandFilePath(const std::string &filepath, void *) {
 #ifdef _WIN32
-  DWORD len = ExpandEnvironmentStringsA(filepath.c_str(), NULL, 0);
-  char *str = new char[len];
-  ExpandEnvironmentStringsA(filepath.c_str(), str, len);
+  // Assume input `filepath` is encoded in UTF-8
+  std::wstring wfilepath = UTF8ToWchar(filepath);
+  DWORD wlen = ExpandEnvironmentStringsW(wfilepath.c_str(), nullptr, 0);
+  wchar_t *wstr = new wchar_t[wlen];
+  ExpandEnvironmentStringsW(wfilepath.c_str(), wstr, wlen);
 
-  std::string s(str);
+  std::wstring ws(wstr);
+  delete[] wstr;
+  return WcharToUTF8(ws);
 
-  delete[] str;
-
-  return s;
 #else
 
 #if defined(TARGET_OS_IPHONE) || defined(TARGET_IPHONE_SIMULATOR) || \
@@ -2592,11 +2677,12 @@ bool ReadWholeFile(std::vector<unsigned char> *out, std::string *err,
       return false;
     }
     size_t size = AAsset_getLength(asset);
-    if (size <= 0) {
+    if (size == 0) {
       if (err) {
         (*err) += "Invalid file size : " + filepath +
                   " (does the path point to a directory?)";
       }
+      return false;
     }
     out->resize(size);
     AAsset_read(asset, reinterpret_cast<char *>(&out->at(0)), size);
@@ -2615,9 +2701,12 @@ bool ReadWholeFile(std::vector<unsigned char> *out, std::string *err,
       _wopen(UTF8ToWchar(filepath).c_str(), _O_RDONLY | _O_BINARY);
   __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
   std::istream f(&wfile_buf);
-#elif defined(_MSC_VER)
+#elif defined(_MSC_VER) || defined(_LIBCPP_VERSION)
+  // For libcxx, assume _LIBCPP_HAS_OPEN_WITH_WCHAR is defined to accept
+  // `wchar_t *`
   std::ifstream f(UTF8ToWchar(filepath).c_str(), std::ifstream::binary);
-#else  // clang?
+#else
+  // Unknown compiler/runtime
   std::ifstream f(filepath.c_str(), std::ifstream::binary);
 #endif
 #else
@@ -2659,9 +2748,10 @@ bool WriteWholeFile(std::string *err, const std::string &filepath,
                     const std::vector<unsigned char> &contents, void *) {
 #ifdef _WIN32
 #if defined(__GLIBCXX__)  // mingw
-  int file_descriptor =
-      _wopen(UTF8ToWchar(filepath).c_str(), _O_WRONLY | _O_BINARY);
-  __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
+  int file_descriptor = _wopen(UTF8ToWchar(filepath).c_str(),
+                               _O_CREAT | _O_WRONLY | _O_TRUNC | _O_BINARY);
+  __gnu_cxx::stdio_filebuf<char> wfile_buf(
+      file_descriptor, std::ios_base::out | std::ios_base::binary);
   std::ostream f(&wfile_buf);
 #elif defined(_MSC_VER)
   std::ofstream f(UTF8ToWchar(filepath).c_str(), std::ofstream::binary);
@@ -2712,12 +2802,13 @@ static void UpdateImageObject(Image &image, std::string &baseDir, int index,
                               void *user_data = nullptr) {
   std::string filename;
   std::string ext;
-
-  // If image have uri. Use it it as a filename
+  // If image has uri, use it it as a filename
   if (image.uri.size()) {
     filename = GetBaseFilename(image.uri);
     ext = GetFilePathExtension(filename);
-
+  } else if (image.bufferView != -1) {
+    // If there's no URI and the data exists in a buffer,
+    // don't change properties or write images
   } else if (image.name.size()) {
     ext = MimeToExt(image.mimeType);
     // Otherwise use name as filename
@@ -2729,7 +2820,7 @@ static void UpdateImageObject(Image &image, std::string &baseDir, int index,
   }
 
   // If callback is set, modify image data object
-  if (*WriteImageData != nullptr) {
+  if (*WriteImageData != nullptr && !filename.empty()) {
     std::string uri;
     (*WriteImageData)(&baseDir, &filename, &image, embedImages, user_data);
   }
@@ -2974,7 +3065,9 @@ json_const_iterator ObjectEnd(const json &o) {
 #endif
 }
 
-const char *GetKey(json_const_iterator &it) {
+// Making this a const char* results in a pointer to a temporary when
+// TINYGLTF_USE_RAPIDJSON is off.
+std::string GetKey(json_const_iterator &it) {
 #ifdef TINYGLTF_USE_RAPIDJSON
   return it->name.GetString();
 #else
@@ -4379,6 +4472,7 @@ static bool GetAttributeForAllPoints(uint32_t componentType, draco::Mesh *mesh,
 static bool ParseDracoExtension(Primitive *primitive, Model *model,
                                 std::string *err,
                                 const Value &dracoExtensionValue) {
+  (void)err;
   auto bufferViewValue = dracoExtensionValue.Get("bufferView");
   if (!bufferViewValue.IsInt()) return false;
   auto attributesValue = dracoExtensionValue.Get("attributes");
@@ -4439,7 +4533,6 @@ static bool ParseDracoExtension(Primitive *primitive, Model *model,
 
     int dracoAttributeIndex = attribute.second.Get<int>();
     const auto pAttribute = mesh->GetAttributeByUniqueId(dracoAttributeIndex);
-    const auto pBuffer = pAttribute->buffer();
     const auto componentType =
         model->accessors[primitiveAttribute->second].componentType;
 
@@ -4860,13 +4953,13 @@ static bool ParseAnimationChannel(
       }
       return false;
     }
-	ParseExtensionsProperty(&channel->target_extensions, err, target_object);
-	if (store_original_json_for_extras_and_extensions) {
+    ParseExtensionsProperty(&channel->target_extensions, err, target_object);
+    if (store_original_json_for_extras_and_extensions) {
       json_const_iterator it;
       if (FindMember(target_object, "extensions", it)) {
         channel->target_extensions_json_string = JsonToString(GetValue(it));
       }
-	}
+    }
   }
 
   channel->sampler = samplerIndex;
@@ -4998,12 +5091,12 @@ static bool ParseSampler(Sampler *sampler, std::string *err, const json &o,
   int magFilter = -1;
   int wrapS = TINYGLTF_TEXTURE_WRAP_REPEAT;
   int wrapT = TINYGLTF_TEXTURE_WRAP_REPEAT;
-  int wrapR = TINYGLTF_TEXTURE_WRAP_REPEAT;
+  //int wrapR = TINYGLTF_TEXTURE_WRAP_REPEAT;
   ParseIntegerProperty(&minFilter, err, o, "minFilter", false);
   ParseIntegerProperty(&magFilter, err, o, "magFilter", false);
   ParseIntegerProperty(&wrapS, err, o, "wrapS", false);
   ParseIntegerProperty(&wrapT, err, o, "wrapT", false);
-  ParseIntegerProperty(&wrapR, err, o, "wrapR", false);  // tinygltf extension
+  //ParseIntegerProperty(&wrapR, err, o, "wrapR", false);  // tinygltf extension
 
   // TODO(syoyo): Check the value is alloed one.
   // (e.g. we allow 9728(NEAREST), but don't allow 9727)
@@ -5012,7 +5105,7 @@ static bool ParseSampler(Sampler *sampler, std::string *err, const json &o,
   sampler->magFilter = magFilter;
   sampler->wrapS = wrapS;
   sampler->wrapT = wrapT;
-  sampler->wrapR = wrapR;
+  //sampler->wrapR = wrapR;
 
   ParseExtensionsProperty(&(sampler->extensions), err, o);
   ParseExtrasProperty(&(sampler->extras), o);
@@ -5677,10 +5770,15 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
             .target = TINYGLTF_TARGET_ARRAY_BUFFER;
       }
 
-      for(auto &target : primitive.targets) {
-        for(auto &attribute : target) {
-          model->bufferViews[size_t(model->accessors[size_t(attribute.second)].bufferView)]
-              .target = TINYGLTF_TARGET_ARRAY_BUFFER;
+      for (auto &target : primitive.targets) {
+        for (auto &attribute : target) {
+          auto bufferView =
+              model->accessors[size_t(attribute.second)].bufferView;
+          // bufferView could be null(-1) for sparse morph target
+          if (bufferView >= 0) {
+            model->bufferViews[size_t(bufferView)].target =
+                TINYGLTF_TARGET_ARRAY_BUFFER;
+          }
         }
       }
     }
@@ -5790,6 +5888,18 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
   }
 
   // 11. Parse Image
+  void *load_image_user_data{nullptr};
+
+  LoadImageDataOption load_image_option;
+
+  if (user_image_loader_) {
+    // Use user supplied pointer
+    load_image_user_data = load_image_user_data_;
+  } else {
+    load_image_option.preserve_channels = preserve_image_channels_;
+    load_image_user_data = reinterpret_cast<void *>(&load_image_option);
+  }
+
   {
     int idx = 0;
     bool success = ForEachInArray(v, "images", [&](const json &o) {
@@ -5802,7 +5912,7 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
       Image image;
       if (!ParseImage(&image, idx, err, warn, o,
                       store_original_json_for_extras_and_extensions_, base_dir,
-                      &fs, &this->LoadImageData, load_image_user_data_)) {
+                      &fs, &this->LoadImageData, load_image_user_data)) {
         return false;
       }
 
@@ -5840,7 +5950,7 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
         bool ret = LoadImageData(
             &image, idx, err, warn, image.width, image.height,
             &buffer.data[bufferView.byteOffset],
-            static_cast<int>(bufferView.byteLength), load_image_user_data_);
+            static_cast<int>(bufferView.byteLength), load_image_user_data);
         if (!ret) {
           return false;
         }
@@ -6265,6 +6375,13 @@ static void SerializeNumberProperty(const std::string &key, T number,
   JsonAddMember(obj, key.c_str(), json(number));
 }
 
+#ifdef TINYGLTF_USE_RAPIDJSON
+template <>
+void SerializeNumberProperty(const std::string &key, size_t number, json &obj) {
+  JsonAddMember(obj, key.c_str(), json(static_cast<uint64_t>(number)));
+}
+#endif
+
 template <typename T>
 static void SerializeNumberArrayProperty(const std::string &key,
                                          const std::vector<T> &value,
@@ -6415,9 +6532,10 @@ static bool SerializeGltfBufferData(const std::vector<unsigned char> &data,
                                     const std::string &binFilename) {
 #ifdef _WIN32
 #if defined(__GLIBCXX__)  // mingw
-  int file_descriptor =
-      _wopen(UTF8ToWchar(binFilename).c_str(), _O_WRONLY | _O_BINARY);
-  __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
+  int file_descriptor = _wopen(UTF8ToWchar(binFilename).c_str(),
+                               _O_CREAT | _O_WRONLY | _O_TRUNC | _O_BINARY);
+  __gnu_cxx::stdio_filebuf<char> wfile_buf(
+      file_descriptor, std::ios_base::out | std::ios_base::binary);
   std::ostream output(&wfile_buf);
   if (!wfile_buf.is_open()) return false;
 #elif defined(_MSC_VER)
@@ -6500,15 +6618,41 @@ static void SerializeExtensionMap(const ExtensionMap &extensions, json &o) {
 }
 
 static void SerializeGltfAccessor(Accessor &accessor, json &o) {
-  SerializeNumberProperty<int>("bufferView", accessor.bufferView, o);
+  if (accessor.bufferView >= 0)
+    SerializeNumberProperty<int>("bufferView", accessor.bufferView, o);
 
-  if (accessor.byteOffset != 0.0)
+  if (accessor.byteOffset != 0)
     SerializeNumberProperty<int>("byteOffset", int(accessor.byteOffset), o);
 
   SerializeNumberProperty<int>("componentType", accessor.componentType, o);
   SerializeNumberProperty<size_t>("count", accessor.count, o);
-  SerializeNumberArrayProperty<double>("min", accessor.minValues, o);
-  SerializeNumberArrayProperty<double>("max", accessor.maxValues, o);
+
+  if ((accessor.componentType == TINYGLTF_COMPONENT_TYPE_FLOAT) ||
+      (accessor.componentType == TINYGLTF_COMPONENT_TYPE_DOUBLE)) {
+    SerializeNumberArrayProperty<double>("min", accessor.minValues, o);
+    SerializeNumberArrayProperty<double>("max", accessor.maxValues, o);
+  } else {
+    // Issue #301. Serialize as integer.
+    // Assume int value is within [-2**31-1, 2**31-1]
+    {
+      std::vector<int> values;
+      std::transform(accessor.minValues.begin(), accessor.minValues.end(),
+                     std::back_inserter(values),
+                     [](double v) { return static_cast<int>(v); });
+
+      SerializeNumberArrayProperty<int>("min", values, o);
+    }
+
+    {
+      std::vector<int> values;
+      std::transform(accessor.maxValues.begin(), accessor.maxValues.end(),
+                     std::back_inserter(values),
+                     [](double v) { return static_cast<int>(v); });
+
+      SerializeNumberArrayProperty<int>("max", values, o);
+    }
+  }
+
   if (accessor.normalized)
     SerializeValue("normalized", Value(accessor.normalized), o);
   std::string type;
@@ -6551,7 +6695,7 @@ static void SerializeGltfAnimationChannel(AnimationChannel &channel, json &o) {
     SerializeNumberProperty("node", channel.target_node, target);
     SerializeStringProperty("path", channel.target_path, target);
 
-	SerializeExtensionMap(channel.target_extensions, target);
+    SerializeExtensionMap(channel.target_extensions, target);
 
     JsonAddMember(o, "target", std::move(target));
   }
@@ -6618,10 +6762,15 @@ static void SerializeGltfAsset(Asset &asset, json &o) {
     SerializeStringProperty("copyright", asset.copyright, o);
   }
 
-  if (!asset.version.empty()) {
-    SerializeStringProperty("version", asset.version, o);
+  if (asset.version.empty()) {
+    // Just in case
+    // `version` must be defined
+    asset.version = "2.0";
   }
 
+  // TODO(syoyo): Do we need to check if `version` is greater or equal to 2.0?
+  SerializeStringProperty("version", asset.version, o);
+
   if (asset.extras.Keys().size()) {
     SerializeValue("extras", asset.extras, o);
   }
@@ -6958,7 +7107,9 @@ static void SerializeSpotLight(SpotLight &spot, json &o) {
 static void SerializeGltfLight(Light &light, json &o) {
   if (!light.name.empty()) SerializeStringProperty("name", light.name, o);
   SerializeNumberProperty("intensity", light.intensity, o);
-  SerializeNumberProperty("range", light.range, o);
+  if (light.range > 0.0) {
+    SerializeNumberProperty("range", light.range, o);
+  }
   SerializeNumberArrayProperty("color", light.color, o);
   SerializeStringProperty("type", light.type, o);
   if (light.type == "spot") {
@@ -7017,7 +7168,7 @@ static void SerializeGltfSampler(Sampler &sampler, json &o) {
   if (sampler.minFilter != -1) {
     SerializeNumberProperty("minFilter", sampler.minFilter, o);
   }
-  SerializeNumberProperty("wrapR", sampler.wrapR, o);
+  //SerializeNumberProperty("wrapR", sampler.wrapR, o);
   SerializeNumberProperty("wrapS", sampler.wrapS, o);
   SerializeNumberProperty("wrapT", sampler.wrapT, o);
 
@@ -7072,6 +7223,11 @@ static void SerializeGltfCamera(const Camera &camera, json &o) {
   } else {
     // ???
   }
+
+  if (camera.extras.Type() != NULL_TYPE) {
+    SerializeValue("extras", camera.extras, o);
+  }
+  SerializeExtensionMap(camera.extensions, o);
 }
 
 static void SerializeGltfScene(Scene &scene, json &o) {
@@ -7087,11 +7243,17 @@ static void SerializeGltfScene(Scene &scene, json &o) {
 }
 
 static void SerializeGltfSkin(Skin &skin, json &o) {
-  if (skin.inverseBindMatrices != -1)
-    SerializeNumberProperty("inverseBindMatrices", skin.inverseBindMatrices, o);
-
+  // required
   SerializeNumberArrayProperty<int>("joints", skin.joints, o);
-  SerializeNumberProperty("skeleton", skin.skeleton, o);
+
+  if (skin.inverseBindMatrices >= 0) {
+    SerializeNumberProperty("inverseBindMatrices", skin.inverseBindMatrices, o);
+  }
+
+  if (skin.skeleton >= 0) {
+    SerializeNumberProperty("skeleton", skin.skeleton, o);
+  }
+
   if (skin.name.size()) {
     SerializeStringProperty("name", skin.name, o);
   }
@@ -7150,7 +7312,7 @@ static void SerializeGltfModel(Model *model, json &o) {
   JsonAddMember(o, "asset", std::move(asset));
 
   // BUFFERVIEWS
-  if(model->bufferViews.size()) {
+  if (model->bufferViews.size()) {
     json bufferViews;
     JsonReserveArray(bufferViews, model->bufferViews.size());
     for (unsigned int i = 0; i < model->bufferViews.size(); ++i) {
@@ -7161,11 +7323,6 @@ static void SerializeGltfModel(Model *model, json &o) {
     JsonAddMember(o, "bufferViews", std::move(bufferViews));
   }
 
-  // Extensions used
-  if (model->extensionsUsed.size()) {
-    SerializeStringArrayProperty("extensionsUsed", model->extensionsUsed, o);
-  }
-
   // Extensions required
   if (model->extensionsRequired.size()) {
     SerializeStringArrayProperty("extensionsRequired",
@@ -7179,6 +7336,16 @@ static void SerializeGltfModel(Model *model, json &o) {
     for (unsigned int i = 0; i < model->materials.size(); ++i) {
       json material;
       SerializeGltfMaterial(model->materials[i], material);
+
+      if (JsonIsNull(material)) {
+        // Issue 294.
+        // `material` does not have any required parameters
+        // so the result may be null(unmodified) when all material parameters
+        // have default value.
+        //
+        // null is not allowed thus we create an empty JSON object.
+        JsonSetObject(material);
+      }
       JsonPushBack(materials, std::move(material));
     }
     JsonAddMember(o, "materials", std::move(materials));
@@ -7276,7 +7443,9 @@ static void SerializeGltfModel(Model *model, json &o) {
   // EXTENSIONS
   SerializeExtensionMap(model->extensions, o);
 
-  // LIGHTS as KHR_lights_cmn
+  auto extensionsUsed = model->extensionsUsed;
+
+  // LIGHTS as KHR_lights_punctual
   if (model->lights.size()) {
     json lights;
     JsonReserveArray(lights, model->lights.size());
@@ -7291,7 +7460,7 @@ static void SerializeGltfModel(Model *model, json &o) {
 
     {
       json_const_iterator it;
-      if (!FindMember(o, "extensions", it)) {
+      if (FindMember(o, "extensions", it)) {
         JsonAssign(ext_j, GetValue(it));
       }
     }
@@ -7299,6 +7468,24 @@ static void SerializeGltfModel(Model *model, json &o) {
     JsonAddMember(ext_j, "KHR_lights_punctual", std::move(khr_lights_cmn));
 
     JsonAddMember(o, "extensions", std::move(ext_j));
+
+    // Also add "KHR_lights_punctual" to `extensionsUsed`
+    {
+      auto has_khr_lights_punctual =
+          std::find_if(extensionsUsed.begin(), extensionsUsed.end(),
+                       [](const std::string &s) {
+                         return (s.compare("KHR_lights_punctual") == 0);
+                       });
+
+      if (has_khr_lights_punctual == extensionsUsed.end()) {
+        extensionsUsed.push_back("KHR_lights_punctual");
+      }
+    }
+  }
+
+  // Extensions used
+  if (extensionsUsed.size()) {
+    SerializeStringArrayProperty("extensionsUsed", extensionsUsed, o);
   }
 
   // EXTRAS
@@ -7318,9 +7505,10 @@ static bool WriteGltfFile(const std::string &output,
 #if defined(_MSC_VER)
   std::ofstream gltfFile(UTF8ToWchar(output).c_str());
 #elif defined(__GLIBCXX__)
-  int file_descriptor =
-      _wopen(UTF8ToWchar(output).c_str(), _O_WRONLY | _O_BINARY);
-  __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
+  int file_descriptor = _wopen(UTF8ToWchar(output).c_str(),
+                               _O_CREAT | _O_WRONLY | _O_TRUNC | _O_BINARY);
+  __gnu_cxx::stdio_filebuf<char> wfile_buf(
+      file_descriptor, std::ios_base::out | std::ios_base::binary);
   std::ostream gltfFile(&wfile_buf);
   if (!wfile_buf.is_open()) return false;
 #else
@@ -7406,9 +7594,10 @@ static void WriteBinaryGltfFile(const std::string &output,
 #if defined(_MSC_VER)
   std::ofstream gltfFile(UTF8ToWchar(output).c_str(), std::ios::binary);
 #elif defined(__GLIBCXX__)
-  int file_descriptor =
-      _wopen(UTF8ToWchar(output).c_str(), _O_WRONLY | _O_BINARY);
-  __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
+  int file_descriptor = _wopen(UTF8ToWchar(output).c_str(),
+                               _O_CREAT | _O_WRONLY | _O_TRUNC | _O_BINARY);
+  __gnu_cxx::stdio_filebuf<char> wfile_buf(
+      file_descriptor, std::ios_base::out | std::ios_base::binary);
   std::ostream gltfFile(&wfile_buf);
 #else
   std::ofstream gltfFile(output.c_str(), std::ios::binary);
@@ -7429,13 +7618,13 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
 
   // BUFFERS
   std::vector<unsigned char> binBuffer;
-  if(model->buffers.size()) {
+  if (model->buffers.size()) {
     json buffers;
     JsonReserveArray(buffers, model->buffers.size());
     for (unsigned int i = 0; i < model->buffers.size(); ++i) {
       json buffer;
-      if (writeBinary && i==0 && model->buffers[i].uri.empty()){
-        SerializeGltfBufferBin(model->buffers[i], buffer,binBuffer);
+      if (writeBinary && i == 0 && model->buffers[i].uri.empty()) {
+        SerializeGltfBufferBin(model->buffers[i], buffer, binBuffer);
       } else {
         SerializeGltfBuffer(model->buffers[i], buffer);
       }
@@ -7452,9 +7641,9 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
       json image;
 
       std::string dummystring = "";
-      // UpdateImageObject need baseDir but only uses it if embededImages is
-      // enable, since we won't write separte images when writing to a stream we
-      // use a dummystring
+      // UpdateImageObject need baseDir but only uses it if embeddedImages is
+      // enabled, since we won't write separate images when writing to a stream
+      // we
       UpdateImageObject(model->images[i], dummystring, int(i), false,
                         &this->WriteImageData, this->write_image_user_data_);
       SerializeGltfImage(model->images[i], image);
@@ -7501,14 +7690,15 @@ bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
     JsonReserveArray(buffers, model->buffers.size());
     for (unsigned int i = 0; i < model->buffers.size(); ++i) {
       json buffer;
-      if (writeBinary && i==0 && model->buffers[i].uri.empty()){
-        SerializeGltfBufferBin(model->buffers[i], buffer,binBuffer);
+      if (writeBinary && i == 0 && model->buffers[i].uri.empty()) {
+        SerializeGltfBufferBin(model->buffers[i], buffer, binBuffer);
       } else if (embedBuffers) {
         SerializeGltfBuffer(model->buffers[i], buffer);
       } else {
         std::string binSavePath;
         std::string binUri;
-        if (!model->buffers[i].uri.empty() && !IsDataURI(model->buffers[i].uri)) {
+        if (!model->buffers[i].uri.empty() &&
+            !IsDataURI(model->buffers[i].uri)) {
           binUri = model->buffers[i].uri;
         } else {
           binUri = defaultBinFilename + defaultBinFileExt;
@@ -7534,7 +7724,7 @@ bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
       }
       JsonPushBack(buffers, std::move(buffer));
     }
-  JsonAddMember(output, "buffers", std::move(buffers));
+    JsonAddMember(output, "buffers", std::move(buffers));
   }
 
   // IMAGES