Merge pull request #512 from ctrlaltf2/oob-fix

Add bounds check to images loaded from bufferviews
2026-06-08 11:13:50 +00:00 · 2025-01-22 22:45:07 +09:00 · 2025-01-20 23:43:07 -05:00 · 2024-12-30 22:11:09 +09:00 · 2024-12-30 03:12:20 +08:00 · 2024-12-21 19:59:42 +09:00
17 changed files with 3846 additions and 2036 deletions
--- a/.github/workflows/c-cpp.yml
+++ b/.github/workflows/c-cpp.yml
@@ -4,41 +4,43 @@ on: [push, pull_request]

 jobs:

-  # compile with older gcc4.8
-  build-gcc48:
+  # gcc4.8 is too old and ubuntu-18.04 image is not supported in GitHub Actions anymore,
+  # so disable this build.
+  ## compile with older gcc4.8
+  #build-gcc48:

-    runs-on: ubuntu-18.04
-    name: Build with gcc 4.8
+  #  runs-on: ubuntu-18.04
+  #  name: Build with gcc 4.8

-    steps:
-      - name: Checkout
-        uses: actions/checkout@v1
+  #  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: 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: 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
+  #    - 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
+    runs-on: ubuntu-latest
    name: Build with MinGW gcc cross

    steps:
      - name: Checkout
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2

      - name: Build
        run: |
@@ -133,20 +135,20 @@ jobs:
  # Cross-compile for aarch64 linux target
  build-cross-aarch64:

-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
    name: Build on cross aarch64

    steps:
      - name: Checkout
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2
      - 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
+            sudo apt-get install -y gcc-aarch64-linux-gnu g++-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
+            aarch64-linux-gnu-g++ -DTINYGLTF_USE_RAPIDJSON -I./rapidjson/include/rapidjson -std=c++11 -g -O0 -o loader_example loader_example.cc

  # macOS clang
  build-macos:
--- a/.github/workflows/mingw-w64-msys2.yml
+++ b/.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
+
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,7 @@ premake5.tar.gz
 #binary directories
 bin/
 obj/
+out/

 #runtime gui config
 imgui.ini
--- a/.travis-before-install.sh
+++ b/.travis-before-install.sh
@@ -1,10 +0,0 @@
-#!/bin/bash
-
-if [[ "$TRAVIS_OS_NAME" == "osx" ]]
-then
-    brew upgrade
-    curl -o premake5.tar.gz https://github.com/premake/premake-core/releases/download/v5.0.0-alpha12/premake-5.0.0-alpha12-macosx.tar.gz
-else
-    wget https://github.com/premake/premake-core/releases/download/v5.0.0-alpha12/premake-5.0.0-alpha12-linux.tar.gz -O premake5.tar.gz
-fi
-tar xzf premake5.tar.gz
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,63 +0,0 @@
-language: cpp
-sudo: false
-matrix:
-  include:
-  - addons: &1
-      apt:
-        sources:
-        - george-edison55-precise-backports
-        - ubuntu-toolchain-r-test
-        - llvm-toolchain-trusty-3.9
-        packages:
-        - g++-4.9
-        - clang-3.9
-    compiler: clang
-    env: COMPILER_VERSION=3.9 BUILD_TYPE=Debug
-  - addons: *1
-    compiler: clang
-    env: COMPILER_VERSION=3.9 BUILD_TYPE=Release
-  - addons: &2
-      apt:
-        sources:
-        - george-edison55-precise-backports
-        - ubuntu-toolchain-r-test
-        packages:
-        - g++-4.9
-    compiler: gcc
-    env: COMPILER_VERSION=4.9 BUILD_TYPE=Debug EXTRA_CXXFLAGS="-fsanitize=address"
-  - addons: *2
-    compiler: gcc
-    env: COMPILER_VERSION=4.9 BUILD_TYPE=Release EXTRA_CXXFLAGS="-fsanitize=address"
-  - addons: *1
-    compiler: clang
-    env: COMPILER_VERSION=3.9 BUILD_TYPE=Debug CFLAGS="-O0" CXXFLAGS="-O0"
-  - addons: &3
-      apt:
-        sources:
-        - ubuntu-toolchain-r-test
-        packages:
-        - g++-4.8
-    compiler: gcc
-    env: COMPILER_VERSION=4.8 BUILD_TYPE=Debug
-  - addons: *3
-    compiler: gcc
-    env: COMPILER_VERSION=4.8 BUILD_TYPE=Release
-
-before_install:
-  - ./.travis-before-install.sh
-
-
-script:
-  - export CC="${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
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,11 +1,14 @@
 cmake_minimum_required(VERSION 3.6)

-PROJECT (tinygltf)
+project(tinygltf)

 include(GNUInstallDirs)
 include(CMakePackageConfigHelpers)

-SET(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED On)
+set(CMAKE_CXX_EXTENSIONS Off)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

 option(TINYGLTF_BUILD_LOADER_EXAMPLE "Build loader_example(load glTF and dump infos)" ON)
 option(TINYGLTF_BUILD_GL_EXAMPLES "Build GL exampels(requires glfw, OpenGL, etc)" OFF)
@@ -13,24 +16,25 @@ option(TINYGLTF_BUILD_VALIDATOR_EXAMPLE "Build validator exampe" OFF)
 option(TINYGLTF_BUILD_BUILDER_EXAMPLE "Build glTF builder example" 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)

 if (TINYGLTF_BUILD_LOADER_EXAMPLE)
-  ADD_EXECUTABLE ( 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 )
+  add_subdirectory( examples/gltfutil )
+  add_subdirectory( examples/glview )
 endif (TINYGLTF_BUILD_GL_EXAMPLES)

 if (TINYGLTF_BUILD_VALIDATOR_EXAMPLE)
-  ADD_SUBDIRECTORY ( examples/validator )
+  add_subdirectory( examples/validator )
 endif (TINYGLTF_BUILD_VALIDATOR_EXAMPLE)

 if (TINYGLTF_BUILD_BUILDER_EXAMPLE)
-  ADD_SUBDIRECTORY ( examples/build-gltf )
+  add_subdirectory ( examples/build-gltf )
 endif (TINYGLTF_BUILD_BUILDER_EXAMPLE)

 #
@@ -58,19 +62,26 @@ endif (TINYGLTF_HEADER_ONLY)

 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_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)
--- a/README.md
+++ b/README.md
@@ -2,14 +2,14 @@

 `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.
+`TinyGLTF` uses Niels Lohmann's json library (https://github.com/nlohmann/json), so now it requires C++11 compiler.
 (Also, you can use RadpidJSON as an JSON backend)
-If you are looking for old, C++03 version, please use `devel-picojson` branch(but not maintained anymore).
+If you are looking for old, C++03 version, please use `devel-picojson` branch (but not maintained anymore).

 ## Status

-Currently TinyGLTF is stable and maintainance mode. No drastic changes and feature additions planned.
-
+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).
@@ -26,8 +26,6 @@ Currently TinyGLTF is stable and maintainance mode. No drastic changes and featu

 ## 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)
@@ -106,9 +104,10 @@ WASI build example is located in [wasm](wasm) .
 * [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
+* [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
@@ -197,6 +196,7 @@ if (!ret) {
 * `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

 You can add tinygltf using `add_subdirectory` feature.
@@ -211,6 +211,11 @@ 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

--- a/examples/build-gltf/CMakeLists.txt
+++ b/examples/build-gltf/CMakeLists.txt
@@ -0,0 +1,5 @@
+
+include_directories(${CMAKE_SOURCE_DIR})
+add_executable(create_triangle_gltf create_triangle_gltf.cpp)
+target_compile_options(create_triangle_gltf PUBLIC -Wall)
+target_link_libraries(create_triangle_gltf )
--- a/examples/glview/glview.cc
+++ b/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;
--- a/models/regression/zero-sized-bin-chunk-issue-440.glb
+++ b/models/regression/zero-sized-bin-chunk-issue-440.glb
--- a/stb_image.h
+++ b/stb_image.h
--- a/stb_image_write.h
+++ b/stb_image_write.h
@@ -1,4 +1,4 @@
-/* stb_image_write - v1.11 - public domain - http://nothings.org/stb/stb_image_write.h
+/* stb_image_write - v1.16 - public domain - http://nothings.org/stb
   writes out PNG/BMP/TGA/JPEG/HDR images to C stdio - Sean Barrett 2010-2015
                                     no warranty implied; use at your own risk

@@ -10,11 +10,6 @@

   Will probably not work correctly with strict-aliasing optimizations.

-   If using a modern Microsoft Compiler, non-safe versions of CRT calls may cause 
-   compilation warnings or even errors. To avoid this, also before #including,
-
-       #define STBI_MSC_SECURE_CRT
-
 ABOUT:

   This header file is a library for writing images to C stdio or a callback.
@@ -110,7 +105,7 @@ USAGE:

   TGA supports RLE or non-RLE compressed data. To use non-RLE-compressed
   data, set the global variable 'stbi_write_tga_with_rle' to 0.
-   
+
   JPEG does ignore alpha channels in input data; quality is between 1 and 100.
   Higher quality looks better but results in a bigger image.
   JPEG baseline (no JPEG progressive).
@@ -118,7 +113,7 @@ USAGE:
 CREDITS:


-   Sean Barrett           -    PNG/BMP/TGA 
+   Sean Barrett           -    PNG/BMP/TGA
   Baldur Karlsson        -    HDR
   Jean-Sebastien Guay    -    TGA monochrome
   Tim Kelsey             -    misc enhancements
@@ -145,6 +140,7 @@ CREDITS:
      Ivan Tikhonov
      github:ignotion
      Adam Schackart
+      Andrew Kensler

 LICENSE

@@ -171,9 +167,9 @@ LICENSE
 #endif

 #ifndef STB_IMAGE_WRITE_STATIC  // C++ forbids static forward declarations
-extern int stbi_write_tga_with_rle;
-extern int stbi_write_png_compression_level;
-extern int stbi_write_force_png_filter;
+STBIWDEF int stbi_write_tga_with_rle;
+STBIWDEF int stbi_write_png_compression_level;
+STBIWDEF int stbi_write_force_png_filter;
 #endif

 #ifndef STBI_WRITE_NO_STDIO
@@ -183,7 +179,7 @@ STBIWDEF int stbi_write_tga(char const *filename, int w, int h, int comp, const
 STBIWDEF int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
 STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void  *data, int quality);

-#ifdef STBI_WINDOWS_UTF8
+#ifdef STBIW_WINDOWS_UTF8
 STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input);
 #endif
 #endif
@@ -252,17 +248,17 @@ STBIWDEF void stbi_flip_vertically_on_write(int flip_boolean);
 #define STBIW_UCHAR(x) (unsigned char) ((x) & 0xff)

 #ifdef STB_IMAGE_WRITE_STATIC
-static int stbi__flip_vertically_on_write=0;
 static int stbi_write_png_compression_level = 8;
 static int stbi_write_tga_with_rle = 1;
 static int stbi_write_force_png_filter = -1;
 #else
 int stbi_write_png_compression_level = 8;
-int stbi__flip_vertically_on_write=0;
 int stbi_write_tga_with_rle = 1;
 int stbi_write_force_png_filter = -1;
 #endif

+static int stbi__flip_vertically_on_write = 0;
+
 STBIWDEF void stbi_flip_vertically_on_write(int flag)
 {
   stbi__flip_vertically_on_write = flag;
@@ -272,6 +268,8 @@ typedef struct
 {
   stbi_write_func *func;
   void *context;
+   unsigned char buffer[64];
+   int buf_used;
 } stbi__write_context;

 // initialize a callback-based context
@@ -288,7 +286,7 @@ static void stbi__stdio_write(void *context, void *data, int size)
   fwrite(data,1,size,(FILE*) context);
 }

-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBIW_WINDOWS_UTF8)
 #ifdef __cplusplus
 #define STBIW_EXTERN extern "C"
 #else
@@ -299,25 +297,25 @@ STBIW_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned in

 STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
 {
-	return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, bufferlen, NULL, NULL);
+   return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
 }
 #endif

 static FILE *stbiw__fopen(char const *filename, char const *mode)
 {
   FILE *f;
-#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#if defined(_WIN32) && defined(STBIW_WINDOWS_UTF8)
   wchar_t wMode[64];
   wchar_t wFilename[1024];
-	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
-      return 0;
-	
-	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
+   if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)/sizeof(*wFilename)))
      return 0;

-#if _MSC_VER >= 1400
-	if (0 != _wfopen_s(&f, wFilename, wMode))
-		f = 0;
+   if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)/sizeof(*wMode)))
+      return 0;
+
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+   if (0 != _wfopen_s(&f, wFilename, wMode))
+      f = 0;
 #else
   f = _wfopen(wFilename, wMode);
 #endif
@@ -385,16 +383,36 @@ static void stbiw__writef(stbi__write_context *s, const char *fmt, ...)
   va_end(v);
 }

+static void stbiw__write_flush(stbi__write_context *s)
+{
+   if (s->buf_used) {
+      s->func(s->context, &s->buffer, s->buf_used);
+      s->buf_used = 0;
+   }
+}
+
 static void stbiw__putc(stbi__write_context *s, unsigned char c)
 {
   s->func(s->context, &c, 1);
 }

+static void stbiw__write1(stbi__write_context *s, unsigned char a)
+{
+   if ((size_t)s->buf_used + 1 > sizeof(s->buffer))
+      stbiw__write_flush(s);
+   s->buffer[s->buf_used++] = a;
+}
+
 static void stbiw__write3(stbi__write_context *s, unsigned char a, unsigned char b, unsigned char c)
 {
-   unsigned char arr[3];
-   arr[0] = a, arr[1] = b, arr[2] = c;
-   s->func(s->context, arr, 3);
+   int n;
+   if ((size_t)s->buf_used + 3 > sizeof(s->buffer))
+      stbiw__write_flush(s);
+   n = s->buf_used;
+   s->buf_used = n+3;
+   s->buffer[n+0] = a;
+   s->buffer[n+1] = b;
+   s->buffer[n+2] = c;
 }

 static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, int write_alpha, int expand_mono, unsigned char *d)
@@ -403,7 +421,7 @@ static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, in
   int k;

   if (write_alpha < 0)
-      s->func(s->context, &d[comp - 1], 1);
+      stbiw__write1(s, d[comp - 1]);

   switch (comp) {
      case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as 1-channel case
@@ -411,7 +429,7 @@ static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, in
         if (expand_mono)
            stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
         else
-            s->func(s->context, d, 1);  // monochrome TGA
+            stbiw__write1(s, d[0]);  // monochrome TGA
         break;
      case 4:
         if (!write_alpha) {
@@ -427,7 +445,7 @@ static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, in
         break;
   }
   if (write_alpha > 0)
-      s->func(s->context, &d[comp - 1], 1);
+      stbiw__write1(s, d[comp - 1]);
 }

 static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad, int expand_mono)
@@ -441,16 +459,18 @@ static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, i
   if (stbi__flip_vertically_on_write)
      vdir *= -1;

-   if (vdir < 0)
-      j_end = -1, j = y-1;
-   else
-      j_end =  y, j = 0;
+   if (vdir < 0) {
+      j_end = -1; j = y-1;
+   } else {
+      j_end =  y; j = 0;
+   }

   for (; j != j_end; j += vdir) {
      for (i=0; i < x; ++i) {
         unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
         stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
      }
+      stbiw__write_flush(s);
      s->func(s->context, &zero, scanline_pad);
   }
 }
@@ -471,16 +491,27 @@ static int stbiw__outfile(stbi__write_context *s, int rgb_dir, int vdir, int x,

 static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp, const void *data)
 {
-   int pad = (-x*3) & 3;
-   return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
-           "11 4 22 4" "4 44 22 444444",
-           'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40,  // file header
-            40, x,y, 1,24, 0,0,0,0,0,0);             // bitmap header
+   if (comp != 4) {
+      // write RGB bitmap
+      int pad = (-x*3) & 3;
+      return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
+              "11 4 22 4" "4 44 22 444444",
+              'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40,  // file header
+               40, x,y, 1,24, 0,0,0,0,0,0);             // bitmap header
+   } else {
+      // RGBA bitmaps need a v4 header
+      // use BI_BITFIELDS mode with 32bpp and alpha mask
+      // (straight BI_RGB with alpha mask doesn't work in most readers)
+      return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *)data,1,0,
+         "11 4 22 4" "4 44 22 444444 4444 4 444 444 444 444",
+         'B', 'M', 14+108+x*y*4, 0, 0, 14+108, // file header
+         108, x,y, 1,32, 3,0,0,0,0,0, 0xff0000,0xff00,0xff,0xff000000u, 0, 0,0,0, 0,0,0, 0,0,0, 0,0,0); // bitmap V4 header
+   }
 }

 STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   stbi__start_write_callbacks(&s, func, context);
   return stbi_write_bmp_core(&s, x, y, comp, data);
 }
@@ -488,7 +519,7 @@ STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x,
 #ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   if (stbi__start_write_file(&s,filename)) {
      int r = stbi_write_bmp_core(&s, x, y, comp, data);
      stbi__end_write_file(&s);
@@ -561,24 +592,25 @@ static int stbi_write_tga_core(stbi__write_context *s, int x, int y, int comp, v

            if (diff) {
               unsigned char header = STBIW_UCHAR(len - 1);
-               s->func(s->context, &header, 1);
+               stbiw__write1(s, header);
               for (k = 0; k < len; ++k) {
                  stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
               }
            } else {
               unsigned char header = STBIW_UCHAR(len - 129);
-               s->func(s->context, &header, 1);
+               stbiw__write1(s, header);
               stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
            }
         }
      }
+      stbiw__write_flush(s);
   }
   return 1;
 }

 STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   stbi__start_write_callbacks(&s, func, context);
   return stbi_write_tga_core(&s, x, y, comp, (void *) data);
 }
@@ -586,7 +618,7 @@ STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x,
 #ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   if (stbi__start_write_file(&s,filename)) {
      int r = stbi_write_tga_core(&s, x, y, comp, (void *) data);
      stbi__end_write_file(&s);
@@ -602,6 +634,8 @@ STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const

 #define stbiw__max(a, b)  ((a) > (b) ? (a) : (b))

+#ifndef STBI_WRITE_NO_STDIO
+
 static void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear)
 {
   int exponent;
@@ -736,10 +770,10 @@ static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, f
      char header[] = "#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
      s->func(s->context, header, sizeof(header)-1);

-#ifdef STBI_MSC_SECURE_CRT
-      len = sprintf_s(buffer, "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
+#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);

@@ -752,15 +786,14 @@ static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, f

 STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const float *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   stbi__start_write_callbacks(&s, func, context);
   return stbi_write_hdr_core(&s, x, y, comp, (float *) data);
 }

-#ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const float *data)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   if (stbi__start_write_file(&s,filename)) {
      int r = stbi_write_hdr_core(&s, x, y, comp, (float *) data);
      stbi__end_write_file(&s);
@@ -778,7 +811,7 @@ STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const

 #ifndef STBIW_ZLIB_COMPRESS
 // stretchy buffer; stbiw__sbpush() == vector<>::push_back() -- stbiw__sbcount() == vector<>::size()
-#define stbiw__sbraw(a) ((int *) (a) - 2)
+#define stbiw__sbraw(a) ((int *) (void *) (a) - 2)
 #define stbiw__sbm(a)   stbiw__sbraw(a)[0]
 #define stbiw__sbn(a)   stbiw__sbraw(a)[1]

@@ -872,7 +905,7 @@ STBIWDEF unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, i
   unsigned int bitbuf=0;
   int i,j, bitcount=0;
   unsigned char *out = NULL;
-   unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(char**));
+   unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(unsigned char**));
   if (hash_table == NULL)
      return NULL;
   if (quality < 5) quality = 5;
@@ -895,7 +928,7 @@ STBIWDEF unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, i
      for (j=0; j < n; ++j) {
         if (hlist[j]-data > i-32768) { // if entry lies within window
            int d = stbiw__zlib_countm(hlist[j], data+i, data_len-i);
-            if (d >= best) best=d,bestloc=hlist[j];
+            if (d >= best) { best=d; bestloc=hlist[j]; }
         }
      }
      // when hash table entry is too long, delete half the entries
@@ -948,14 +981,31 @@ STBIWDEF unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, i
      (void) stbiw__sbfree(hash_table[i]);
   STBIW_FREE(hash_table);

+   // store uncompressed instead if compression was worse
+   if (stbiw__sbn(out) > data_len + 2 + ((data_len+32766)/32767)*5) {
+      stbiw__sbn(out) = 2;  // truncate to DEFLATE 32K window and FLEVEL = 1
+      for (j = 0; j < data_len;) {
+         int blocklen = data_len - j;
+         if (blocklen > 32767) blocklen = 32767;
+         stbiw__sbpush(out, data_len - j == blocklen); // BFINAL = ?, BTYPE = 0 -- no compression
+         stbiw__sbpush(out, STBIW_UCHAR(blocklen)); // LEN
+         stbiw__sbpush(out, STBIW_UCHAR(blocklen >> 8));
+         stbiw__sbpush(out, STBIW_UCHAR(~blocklen)); // NLEN
+         stbiw__sbpush(out, STBIW_UCHAR(~blocklen >> 8));
+         memcpy(out+stbiw__sbn(out), data+j, blocklen);
+         stbiw__sbn(out) += blocklen;
+         j += blocklen;
+      }
+   }
+
   {
      // compute adler32 on input
      unsigned int s1=1, s2=0;
      int blocklen = (int) (data_len % 5552);
      j=0;
      while (j < data_len) {
-         for (i=0; i < blocklen; ++i) s1 += data[j+i], s2 += s1;
-         s1 %= 65521, s2 %= 65521;
+         for (i=0; i < blocklen; ++i) { s1 += data[j+i]; s2 += s1; }
+         s1 %= 65521; s2 %= 65521;
         j += blocklen;
         blocklen = 5552;
      }
@@ -1048,13 +1098,13 @@ static void stbiw__encode_png_line(unsigned char *pixels, int stride_bytes, int
   int type = mymap[filter_type];
   unsigned char *z = pixels + stride_bytes * (stbi__flip_vertically_on_write ? height-1-y : y);
   int signed_stride = stbi__flip_vertically_on_write ? -stride_bytes : stride_bytes;
-    
+
   if (type==0) {
      memcpy(line_buffer, z, width*n);
      return;
   }

-   // first loop isn't optimized since it's just one pixel    
+   // first loop isn't optimized since it's just one pixel
   for (i = 0; i < n; ++i) {
      switch (type) {
         case 1: line_buffer[i] = z[i]; break;
@@ -1275,26 +1325,31 @@ static void stbiw__jpg_calcBits(int val, unsigned short bits[2]) {
   bits[0] = val & ((1<<bits[1])-1);
 }

-static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
+static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, int du_stride, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
   const unsigned short EOB[2] = { HTAC[0x00][0], HTAC[0x00][1] };
   const unsigned short M16zeroes[2] = { HTAC[0xF0][0], HTAC[0xF0][1] };
-   int dataOff, i, diff, end0pos;
+   int dataOff, i, j, n, diff, end0pos, x, y;
   int DU[64];

   // DCT rows
-   for(dataOff=0; dataOff<64; dataOff+=8) {
+   for(dataOff=0, n=du_stride*8; dataOff<n; dataOff+=du_stride) {
      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+1], &CDU[dataOff+2], &CDU[dataOff+3], &CDU[dataOff+4], &CDU[dataOff+5], &CDU[dataOff+6], &CDU[dataOff+7]);
   }
   // DCT columns
   for(dataOff=0; dataOff<8; ++dataOff) {
-      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+8], &CDU[dataOff+16], &CDU[dataOff+24], &CDU[dataOff+32], &CDU[dataOff+40], &CDU[dataOff+48], &CDU[dataOff+56]);
+      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+du_stride], &CDU[dataOff+du_stride*2], &CDU[dataOff+du_stride*3], &CDU[dataOff+du_stride*4],
+                     &CDU[dataOff+du_stride*5], &CDU[dataOff+du_stride*6], &CDU[dataOff+du_stride*7]);
   }
   // Quantize/descale/zigzag the coefficients
-   for(i=0; i<64; ++i) {
-      float v = CDU[i]*fdtbl[i];
-      // DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
-      // ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
-      DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
+   for(y = 0, j=0; y < 8; ++y) {
+      for(x = 0; x < 8; ++x,++j) {
+         float v;
+         i = y*du_stride+x;
+         v = CDU[i]*fdtbl[j];
+         // DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
+         // ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
+         DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
+      }
   }

   // Encode DC
@@ -1409,10 +1464,10 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
                             37,56,68,109,103,77,24,35,55,64,81,104,113,92,49,64,78,87,103,121,120,101,72,92,95,98,112,100,103,99};
   static const int UVQT[] = {17,18,24,47,99,99,99,99,18,21,26,66,99,99,99,99,24,26,56,99,99,99,99,99,47,66,99,99,99,99,99,99,
                              99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99};
-   static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f, 
+   static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f,
                                 1.0f * 2.828427125f, 0.785694958f * 2.828427125f, 0.541196100f * 2.828427125f, 0.275899379f * 2.828427125f };

-   int row, col, i, k;
+   int row, col, i, k, subsample;
   float fdtbl_Y[64], fdtbl_UV[64];
   unsigned char YTable[64], UVTable[64];

@@ -1421,6 +1476,7 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
   }

   quality = quality ? quality : 90;
+   subsample = quality <= 90 ? 1 : 0;
   quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
   quality = quality < 50 ? 5000 / quality : 200 - quality * 2;

@@ -1443,7 +1499,7 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
      static const unsigned char head0[] = { 0xFF,0xD8,0xFF,0xE0,0,0x10,'J','F','I','F',0,1,1,0,0,1,0,1,0,0,0xFF,0xDB,0,0x84,0 };
      static const unsigned char head2[] = { 0xFF,0xDA,0,0xC,3,1,0,2,0x11,3,0x11,0,0x3F,0 };
      const unsigned char head1[] = { 0xFF,0xC0,0,0x11,8,(unsigned char)(height>>8),STBIW_UCHAR(height),(unsigned char)(width>>8),STBIW_UCHAR(width),
-                                      3,1,0x11,0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
+                                      3,1,(unsigned char)(subsample?0x22:0x11),0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
      s->func(s->context, (void*)head0, sizeof(head0));
      s->func(s->context, (void*)YTable, sizeof(YTable));
      stbiw__putc(s, 1);
@@ -1466,36 +1522,74 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
   // Encode 8x8 macroblocks
   {
      static const unsigned short fillBits[] = {0x7F, 7};
-      const unsigned char *imageData = (const unsigned char *)data;
      int DCY=0, DCU=0, DCV=0;
      int bitBuf=0, bitCnt=0;
      // comp == 2 is grey+alpha (alpha is ignored)
      int ofsG = comp > 2 ? 1 : 0, ofsB = comp > 2 ? 2 : 0;
+      const unsigned char *dataR = (const unsigned char *)data;
+      const unsigned char *dataG = dataR + ofsG;
+      const unsigned char *dataB = dataR + ofsB;
      int x, y, pos;
-      for(y = 0; y < height; y += 8) {
-         for(x = 0; x < width; x += 8) {
-            float YDU[64], UDU[64], VDU[64];
-            for(row = y, pos = 0; row < y+8; ++row) {
-               // row >= height => use last input row
-               int clamped_row = (row < height) ? row : height - 1;
-               int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
-               for(col = x; col < x+8; ++col, ++pos) {
-                  float r, g, b;
-                  // if col >= width => use pixel from last input column
-                  int p = base_p + ((col < width) ? col : (width-1))*comp;
+      if(subsample) {
+         for(y = 0; y < height; y += 16) {
+            for(x = 0; x < width; x += 16) {
+               float Y[256], U[256], V[256];
+               for(row = y, pos = 0; row < y+16; ++row) {
+                  // row >= height => use last input row
+                  int clamped_row = (row < height) ? row : height - 1;
+                  int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
+                  for(col = x; col < x+16; ++col, ++pos) {
+                     // if col >= width => use pixel from last input column
+                     int p = base_p + ((col < width) ? col : (width-1))*comp;
+                     float r = dataR[p], g = dataG[p], b = dataB[p];
+                     Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
+                     U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
+                     V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
+                  }
+               }
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+0,   16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+8,   16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+128, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+136, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);

-                  r = imageData[p+0];
-                  g = imageData[p+ofsG];
-                  b = imageData[p+ofsB];
-                  YDU[pos]=+0.29900f*r+0.58700f*g+0.11400f*b-128;
-                  UDU[pos]=-0.16874f*r-0.33126f*g+0.50000f*b;
-                  VDU[pos]=+0.50000f*r-0.41869f*g-0.08131f*b;
+               // subsample U,V
+               {
+                  float subU[64], subV[64];
+                  int yy, xx;
+                  for(yy = 0, pos = 0; yy < 8; ++yy) {
+                     for(xx = 0; xx < 8; ++xx, ++pos) {
+                        int j = yy*32+xx*2;
+                        subU[pos] = (U[j+0] + U[j+1] + U[j+16] + U[j+17]) * 0.25f;
+                        subV[pos] = (V[j+0] + V[j+1] + V[j+16] + V[j+17]) * 0.25f;
+                     }
+                  }
+                  DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subU, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
+                  DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subV, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
               }
            }
+         }
+      } else {
+         for(y = 0; y < height; y += 8) {
+            for(x = 0; x < width; x += 8) {
+               float Y[64], U[64], V[64];
+               for(row = y, pos = 0; row < y+8; ++row) {
+                  // row >= height => use last input row
+                  int clamped_row = (row < height) ? row : height - 1;
+                  int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
+                  for(col = x; col < x+8; ++col, ++pos) {
+                     // if col >= width => use pixel from last input column
+                     int p = base_p + ((col < width) ? col : (width-1))*comp;
+                     float r = dataR[p], g = dataG[p], b = dataB[p];
+                     Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
+                     U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
+                     V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
+                  }
+               }

-            DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
-            DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
-            DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y, 8, fdtbl_Y,  DCY, YDC_HT, YAC_HT);
+               DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, U, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
+               DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, V, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
+            }
         }
      }

@@ -1512,7 +1606,7 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in

 STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   stbi__start_write_callbacks(&s, func, context);
   return stbi_write_jpg_core(&s, x, y, comp, (void *) data, quality);
 }
@@ -1521,7 +1615,7 @@ STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x,
 #ifndef STBI_WRITE_NO_STDIO
 STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality)
 {
-   stbi__write_context s;
+   stbi__write_context s = { 0 };
   if (stbi__start_write_file(&s,filename)) {
      int r = stbi_write_jpg_core(&s, x, y, comp, data, quality);
      stbi__end_write_file(&s);
@@ -1534,8 +1628,17 @@ STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const
 #endif // STB_IMAGE_WRITE_IMPLEMENTATION

 /* Revision history
+      1.16  (2021-07-11)
+             make Deflate code emit uncompressed blocks when it would otherwise expand
+             support writing BMPs with alpha channel
+      1.15  (2020-07-13) unknown
+      1.14  (2020-02-02) updated JPEG writer to downsample chroma channels
+      1.13
+      1.12
+      1.11  (2019-08-11)
+
      1.10  (2019-02-07)
-             support utf8 filenames in Windows; fix warnings and platform ifdefs 
+             support utf8 filenames in Windows; fix warnings and platform ifdefs
      1.09  (2018-02-11)
             fix typo in zlib quality API, improve STB_I_W_STATIC in C++
      1.08  (2018-01-29)
@@ -1566,7 +1669,7 @@ STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const
             add HDR output
             fix monochrome BMP
      0.95 (2014-08-17)
-		       add monochrome TGA output
+             add monochrome TGA output
      0.94 (2014-05-31)
             rename private functions to avoid conflicts with stb_image.h
      0.93 (2014-05-27)
@@ -1584,38 +1687,38 @@ This software is available under 2 licenses -- choose whichever you prefer.
 ------------------------------------------------------------------------------
 ALTERNATIVE A - MIT License
 Copyright (c) 2017 Sean Barrett
-Permission is hereby granted, free of charge, to any person obtaining a copy of 
-this software and associated documentation files (the "Software"), to deal in 
-the Software without restriction, including without limitation the rights to 
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
-of the Software, and to permit persons to whom the Software is furnished to do 
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
 so, subject to the following conditions:
-The above copyright notice and this permission notice shall be included in all 
+The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 ------------------------------------------------------------------------------
 ALTERNATIVE B - Public Domain (www.unlicense.org)
 This is free and unencumbered software released into the public domain.
-Anyone is free to copy, modify, publish, use, compile, sell, or distribute this 
-software, either in source code form or as a compiled binary, for any purpose, 
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
 commercial or non-commercial, and by any means.
-In jurisdictions that recognize copyright laws, the author or authors of this 
-software dedicate any and all copyright interest in the software to the public 
-domain. We make this dedication for the benefit of the public at large and to 
-the detriment of our heirs and successors. We intend this dedication to be an 
-overt act of relinquishment in perpetuity of all present and future rights to 
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
 this software under copyright law.
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
-AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
-ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ------------------------------------------------------------------------------
 */
--- a/tests/issue-416.gltf
+++ b/tests/issue-416.gltf
@@ -0,0 +1 @@
+{"images":[{"uri":"%!QAAAQAAA5"}],"asset":{"version":""}}
--- a/tests/issue-492.glb
+++ b/tests/issue-492.glb
--- a/tests/tester.cc
+++ b/tests/tester.cc
@@ -16,10 +16,10 @@
 #include <sstream>
 #include <fstream>

-static JsonDocument JsonConstruct(const char* str)
+static tinygltf::detail::JsonDocument JsonConstruct(const char* str)
 {
-  JsonDocument doc;
-  JsonParse(doc, str, strlen(str));
+  tinygltf::detail::JsonDocument doc;
+  tinygltf::detail::JsonParse(doc, str, strlen(str));
  return doc;
 }

@@ -275,9 +275,9 @@ TEST_CASE("parse-integer", "[bounds-checking]") {

    err.clear();
    {
-      JsonDocument o;
+      tinygltf::detail::JsonDocument o;
      double nan = std::numeric_limits<double>::quiet_NaN();
-      tinygltf::JsonAddMember(o, "int", json(nan));
+      tinygltf::detail::JsonAddMember(o, "int", tinygltf::detail::json(nan));
      CHECK_FALSE(tinygltf::ParseIntegerProperty(
        &result, &err, o,
        "int", true));
@@ -321,9 +321,9 @@ TEST_CASE("parse-unsigned", "[bounds-checking]") {

    err.clear();
    {
-      JsonDocument o;
+      tinygltf::detail::JsonDocument o;
      double nan = std::numeric_limits<double>::quiet_NaN();
-      tinygltf::JsonAddMember(o, "int", json(nan));
+      tinygltf::detail::JsonAddMember(o, "int", tinygltf::detail::json(nan));
      CHECK_FALSE(tinygltf::ParseUnsignedProperty(
        &result, &err, o,
        "int", true));
@@ -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
@@ -494,24 +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;
-  ctx.WriteGltfSceneToStream(&m, os, false, false);
-
-  // use nlohmann json
+  bool ret = ctx.WriteGltfSceneToStream(&m, os, false, false);
+  REQUIRE(true == ret);
+  // 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]") {
@@ -532,7 +531,8 @@ TEST_CASE("empty-skeleton-id", "[issue-321]") {

  std::stringstream os;

-  ctx.WriteGltfSceneToStream(&model, os, false, false);
+  ret = ctx.WriteGltfSceneToStream(&model, os, false, false);
+  REQUIRE(true == ret);

  // use nlohmann json
  nlohmann::json j = nlohmann::json::parse(os.str());
@@ -634,8 +634,9 @@ TEST_CASE("serialize-const-image", "[issue-394]") {
  std::stringstream os;

  tinygltf::TinyGLTF ctx;
-  ctx.WriteGltfSceneToStream(const_cast<const tinygltf::Model *>(&m), os, false,
+  bool ret = ctx.WriteGltfSceneToStream(const_cast<const tinygltf::Model *>(&m), os, false,
                             false);
+  REQUIRE(true == ret);
  REQUIRE(m.images[0].uri == i.uri);

  // use nlohmann json
@@ -661,10 +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);
@@ -698,12 +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;
@@ -718,3 +721,529 @@ TEST_CASE("serialize-image-failure", "[issue-394]") {
  REQUIRE(false == result);
  REQUIRE(os.str().size() == 0);
 }
+
+TEST_CASE("filesize-check", "[issue-416]") {
+
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  ctx.SetMaxExternalFileSize(10); // 10 bytes. will fail to load texture image.
+
+  bool ret = ctx.LoadASCIIFromFile(&model, &err, &warn, "../models/Cube/Cube.gltf");
+  if (!err.empty()) {
+    std::cerr << err << std::endl;
+  }
+
+  REQUIRE(false == ret);
+}
+
+TEST_CASE("load-issue-416-model", "[issue-416]") {
+
+  tinygltf::Model model;
+  tinygltf::TinyGLTF ctx;
+  std::string err;
+  std::string warn;
+
+  bool ret = ctx.LoadASCIIFromFile(&model, &err, &warn, "issue-416.gltf");
+  if (!warn.empty()) {
+    std::cout << "WARN:" << warn << std::endl;
+  }
+  if (!err.empty()) {
+    std::cerr << "ERR:" << err << std::endl;
+  }
+
+  // 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());
+#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);
+}
--- a/tiny_gltf.h
+++ b/tiny_gltf.h
--- a/wasm/README.md
+++ b/wasm/README.md
@@ -4,7 +4,7 @@ Experimental WASI/WASM build

 Download wasi-sdk https://github.com/WebAssembly/wasi-sdk

-Compile tinygltf with C++ exceptions and threads off. See `Makefile` for details
+Compile tinygltf without C++ exceptions and threads. See `Makefile` for details
 (NOTE: TinyGLTF itself does not use RTTI and threading feature(C++ threads, posix, win32 thread))

 ## Build examples and Run
				`@@ -0,0 +1 @@`
				`{"images":[{"uri":"%!QAAAQAAA5"}],"asset":{"version":""}}`