GLB: Fix interger-overflow when calculating JSON Chunk size.

GLB: Check BIN Chunk size.
GLB: Chenk byte alignment of each chunk.

README.md

@@ -3,12 +3,15 @@
 `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.
+(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).
 
 ## Status
 
-Currently TinyGLTF is stable and maintainance mode. No drastic changes and feature addition planned.
+Currently TinyGLTF is stable and maintainance mode. No drastic changes and feature additions planned.
 
+ - v2.6.0 Support serializing sparse accessor(Thanks to @fynv).
+ - v2.5.0 Add SetPreserveImageChannels() option to load image data as is.
  - v2.4.0 Experimental RapidJSON support. Experimental C++14 support(C++14 may give better performance)
  - v2.3.0 Modified Material representation according to glTF 2.0 schema(and introduced TextureInfo class)
  - v2.2.0 release(Support loading 16bit PNG. Sparse accessor support)
@@ -17,7 +20,7 @@ Currently TinyGLTF is stable and maintainance mode. No drastic changes and featu
 
 ### Branches
 
-* `sajson` : Use sajson to parse JSON. Parsing only but faster compile time(2x reduction compared to json.hpp and RapidJson)
+* `sajson` : Use sajson to parse JSON. Parsing only but faster compile time(2x reduction compared to json.hpp and RapidJson), but not well maintained.
 
 ## Builds
 
@@ -29,6 +32,8 @@ Currently TinyGLTF is stable and maintainance mode. No drastic changes and featu
 
 ## Features
 
+Probably mostly feature-complete. Last missing feature is Draco encoding: https://github.com/syoyo/tinygltf/issues/207
+
 * Written in portable C++. C++-11 with STL dependency only.
   * [x] macOS + clang(LLVM)
   * [x] iOS + clang
@@ -94,11 +99,12 @@ In extension(`ExtensionMap`), JSON number value is parsed as int or float(number
 * [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
+* [Open3D](http://www.open3d.org/) - A Modern Library for 3D Data Processing
 * Your projects here! (Please send PR)
 
 ## TODOs
 
-* [ ] Write C++ code generator which emits C++ code from JSON schema for robust parsing.
+* [ ] Robust URI decoding/encoding. https://github.com/syoyo/tinygltf/issues/369
 * [ ] Mesh Compression/decompression(Open3DGC, etc)
   * [x] Load Draco compressed mesh
   * [ ] Save Draco compressed mesh
@@ -109,6 +115,10 @@ In extension(`ExtensionMap`), JSON number value is parsed as int or float(number
 * [ ] 16bit PNG support in Serialization
 * [ ] Write example and tests for `animation` and `skin`
 
+### Optional
+
+* [ ] Write C++ code generator which emits C++ code from JSON schema for robust parsing?
+
 ## Licenses
 
 TinyGLTF is licensed under MIT license.

examples/basic/main.cpp

@@ -39,8 +39,8 @@ bool loadModel(tinygltf::Model &model, const char *filename) {
   return res;
 }
 
-std::map<int, GLuint> bindMesh(std::map<int, GLuint> vbos,
-                               tinygltf::Model &model, tinygltf::Mesh &mesh) {
+void bindMesh(std::map<int, GLuint>& vbos,
+              tinygltf::Model &model, tinygltf::Mesh &mesh) {
   for (size_t i = 0; i < model.bufferViews.size(); ++i) {
     const tinygltf::BufferView &bufferView = model.bufferViews[i];
     if (bufferView.target == 0) {  // TODO impl drawarrays
@@ -144,12 +144,10 @@ std::map<int, GLuint> bindMesh(std::map<int, GLuint> vbos,
       }
     }
   }
-
-  return vbos;
 }
 
 // bind models
-void bindModelNodes(std::map<int, GLuint> vbos, tinygltf::Model &model,
+void bindModelNodes(std::map<int, GLuint>& vbos, tinygltf::Model &model,
                     tinygltf::Node &node) {
   if ((node.mesh >= 0) && (node.mesh < model.meshes.size())) {
     bindMesh(vbos, model, model.meshes[node.mesh]);
@@ -160,7 +158,8 @@ void bindModelNodes(std::map<int, GLuint> vbos, tinygltf::Model &model,
     bindModelNodes(vbos, model, model.nodes[node.children[i]]);
   }
 }
-GLuint bindModel(tinygltf::Model &model) {
+
+std::pair<GLuint, std::map<int, GLuint>> bindModel(tinygltf::Model &model) {
   std::map<int, GLuint> vbos;
   GLuint vao;
   glGenVertexArrays(1, &vao);
@@ -173,19 +172,29 @@ GLuint bindModel(tinygltf::Model &model) {
   }
 
   glBindVertexArray(0);
-  // cleanup vbos
-  for (size_t i = 0; i < vbos.size(); ++i) {
-    glDeleteBuffers(1, &vbos[i]);
+  // cleanup vbos but do not delete index buffers yet
+  for (auto it = vbos.cbegin(); it != vbos.cend();) {
+    tinygltf::BufferView bufferView = model.bufferViews[it->first];
+    if (bufferView.target != GL_ELEMENT_ARRAY_BUFFER) {
+      glDeleteBuffers(1, &vbos[it->first]);
+      vbos.erase(it++);
+    }
+    else {
+      ++it;
+    }
   }
 
-  return vao;
+  return {vao, vbos};
 }
 
-void drawMesh(tinygltf::Model &model, tinygltf::Mesh &mesh) {
+void drawMesh(const std::map<int, GLuint>& vbos,
+              tinygltf::Model &model, tinygltf::Mesh &mesh) {
   for (size_t i = 0; i < mesh.primitives.size(); ++i) {
     tinygltf::Primitive primitive = mesh.primitives[i];
     tinygltf::Accessor indexAccessor = model.accessors[primitive.indices];
 
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vbos.at(indexAccessor.bufferView));
+
     glDrawElements(primitive.mode, indexAccessor.count,
                    indexAccessor.componentType,
                    BUFFER_OFFSET(indexAccessor.byteOffset));
@@ -193,20 +202,22 @@ void drawMesh(tinygltf::Model &model, tinygltf::Mesh &mesh) {
 }
 
 // recursively draw node and children nodes of model
-void drawModelNodes(tinygltf::Model &model, tinygltf::Node &node) {
+void drawModelNodes(const std::pair<GLuint, std::map<int, GLuint>>& vaoAndEbos,
+                    tinygltf::Model &model, tinygltf::Node &node) {
   if ((node.mesh >= 0) && (node.mesh < model.meshes.size())) {
-    drawMesh(model, model.meshes[node.mesh]);
+    drawMesh(vaoAndEbos.second, model, model.meshes[node.mesh]);
   }
   for (size_t i = 0; i < node.children.size(); i++) {
-    drawModelNodes(model, model.nodes[node.children[i]]);
+    drawModelNodes(vaoAndEbos, model, model.nodes[node.children[i]]);
   }
 }
-void drawModel(GLuint vao, tinygltf::Model &model) {
-  glBindVertexArray(vao);
+void drawModel(const std::pair<GLuint, std::map<int, GLuint>>& vaoAndEbos,
+               tinygltf::Model &model) {
+  glBindVertexArray(vaoAndEbos.first);
 
   const tinygltf::Scene &scene = model.scenes[model.defaultScene];
   for (size_t i = 0; i < scene.nodes.size(); ++i) {
-    drawModelNodes(model, model.nodes[scene.nodes[i]]);
+    drawModelNodes(vaoAndEbos, model, model.nodes[scene.nodes[i]]);
   }
 
   glBindVertexArray(0);
@@ -282,7 +293,7 @@ void displayLoop(Window &window, const std::string &filename) {
   tinygltf::Model model;
   if (!loadModel(model, filename.c_str())) return;
 
-  GLuint vao = bindModel(model);
+  std::pair<GLuint, std::map<int, GLuint>> vaoAndEbos = bindModel(model);
   // dbgModel(model); return;
 
   // Model matrix : an identity matrix (model will be at the origin)
@@ -317,10 +328,12 @@ void displayLoop(Window &window, const std::string &filename) {
     glUniform3fv(sun_position_u, 1, &sun_position[0]);
     glUniform3fv(sun_color_u, 1, &sun_color[0]);
 
-    drawModel(vao, model);
+    drawModel(vaoAndEbos, model);
     glfwSwapBuffers(window.window);
     glfwPollEvents();
   }
+
+  glDeleteVertexArrays(1, &vaoAndEbos.first);
 }
 
 static void error_callback(int error, const char *description) {

examples/glview/glview.cc

@@ -771,6 +771,30 @@ static void DrawCurves(tinygltf::Scene &scene, const tinygltf::Mesh &mesh) {
 }
 #endif
 
+static void QuatToAngleAxis(const std::vector<double> quaternion,
+			    double &outAngleDegrees,
+			    double *axis) {
+  double qx = quaternion[0];
+  double qy = quaternion[1];
+  double qz = quaternion[2];
+  double qw = quaternion[3];
+  
+  double angleRadians = 2 * acos(qw);
+  if (angleRadians == 0.0) {
+    outAngleDegrees = 0.0;
+    axis[0] = 0.0;
+    axis[1] = 0.0;
+    axis[2] = 1.0;
+    return;
+  }
+
+  double denom = sqrt(1-qw*qw);
+  outAngleDegrees = angleRadians * 180.0 / M_PI;
+  axis[0] = qx / denom;
+  axis[1] = qy / denom;
+  axis[2] = qz / denom;
+}
+
 // Hierarchically draw nodes
 static void DrawNode(tinygltf::Model &model, const tinygltf::Node &node) {
   // Apply xform
@@ -781,18 +805,22 @@ static void DrawNode(tinygltf::Model &model, const tinygltf::Node &node) {
     glMultMatrixd(node.matrix.data());
   } else {
     // Assume Trans x Rotate x Scale order
-    if (node.scale.size() == 3) {
-      glScaled(node.scale[0], node.scale[1], node.scale[2]);
-    }
-
-    if (node.rotation.size() == 4) {
-      glRotated(node.rotation[0], node.rotation[1], node.rotation[2],
-                node.rotation[3]);
-    }
-
     if (node.translation.size() == 3) {
       glTranslated(node.translation[0], node.translation[1],
                    node.translation[2]);
+    }    
+
+    if (node.rotation.size() == 4) {
+      double angleDegrees;
+      double axis[3];
+
+      QuatToAngleAxis(node.rotation, angleDegrees, axis);
+      
+      glRotated(angleDegrees, axis[0], axis[1], axis[2]);
+    }
+
+    if (node.scale.size() == 3) {
+      glScaled(node.scale[0], node.scale[1], node.scale[2]);
     }
   }
 

tiny_gltf.h

@@ -26,6 +26,8 @@
 // THE SOFTWARE.
 
 // Version:
+//  - v2.6.0 Support serializing sparse accessor(Thanks to @fynv).
+//           Disable expanding file path for security(no use of awkward `wordexp` anymore).
 //  - 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.
@@ -108,7 +110,11 @@ namespace tinygltf {
 #define TINYGLTF_COMPONENT_TYPE_INT (5124)
 #define TINYGLTF_COMPONENT_TYPE_UNSIGNED_INT (5125)
 #define TINYGLTF_COMPONENT_TYPE_FLOAT (5126)
-#define TINYGLTF_COMPONENT_TYPE_DOUBLE (5130)
+#define TINYGLTF_COMPONENT_TYPE_DOUBLE \
+  (5130)  // OpenGL double type. Note that some of glTF 2.0 validator does not
+          // support double type even the schema seems allow any value of
+          // integer:
+          // https://github.com/KhronosGroup/glTF/blob/b9884a2fd45130b4d673dd6c8a706ee21ee5c5f7/specification/2.0/schema/accessor.schema.json#L22
 
 #define TINYGLTF_TEXTURE_FILTER_NEAREST (9728)
 #define TINYGLTF_TEXTURE_FILTER_LINEAR (9729)
@@ -613,7 +619,8 @@ struct Sampler {
   int wrapT =
       TINYGLTF_TEXTURE_WRAP_REPEAT;  // ["CLAMP_TO_EDGE", "MIRRORED_REPEAT",
                                      // "REPEAT"], default "REPEAT"
-  //int wrapR = TINYGLTF_TEXTURE_WRAP_REPEAT;  // TinyGLTF extension. currently not used.
+  // int wrapR = TINYGLTF_TEXTURE_WRAP_REPEAT;  // TinyGLTF extension. currently
+  // not used.
 
   Value extras;
   ExtensionMap extensions;
@@ -1302,8 +1309,10 @@ class TinyGLTF {
   ///
   /// Loads glTF ASCII asset from string(memory).
   /// `length` = strlen(str);
-  /// Set warning message to `warn` for example it fails to load asserts.
-  /// Returns false and set error string to `err` if there's an error.
+  /// `base_dir` is a search path of glTF asset(e.g. images). Path Must be an
+  /// expanded path (e.g. no tilde(`~`), no environment variables). Set warning
+  /// message to `warn` for example it fails to load asserts. Returns false and
+  /// set error string to `err` if there's an error.
   ///
   bool LoadASCIIFromString(Model *model, std::string *err, std::string *warn,
                            const char *str, const unsigned int length,
@@ -1322,6 +1331,8 @@ class TinyGLTF {
   ///
   /// Loads glTF binary asset from memory.
   /// `length` = strlen(str);
+  /// `base_dir` is a search path of glTF asset(e.g. images). Path Must be an
+  /// expanded path (e.g. no tilde(`~`), no environment variables).
   /// Set warning message to `warn` for example it fails to load asserts.
   /// Returns false and set error string to `err` if there's an error.
   ///
@@ -1424,6 +1435,10 @@ class TinyGLTF {
   bool preserve_image_channels_ = false;  /// Default false(expand channels to
                                           /// RGBA) for backward compatibility.
 
+  // Warning & error messages
+  std::string warn_;
+  std::string err_;
+
   FsCallbacks fs = {
 #ifndef TINYGLTF_NO_FS
       &tinygltf::FileExists, &tinygltf::ExpandFilePath,
@@ -1605,10 +1620,10 @@ class TinyGLTF {
 #endif
 
 #elif !defined(__ANDROID__) && !defined(__OpenBSD__)
-#include <wordexp.h>
+//#include <wordexp.h>
 #endif
 
-#if defined(__sparcv9)
+#if defined(__sparcv9) || defined(__powerpc__)
 // Big endian
 #else
 #if (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) || MINIZ_X86_OR_X64_CPU
@@ -1933,10 +1948,9 @@ 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->wrapS == other.wrapS &&
-         this->wrapT == other.wrapT;
+         this->wrapS == other.wrapS && this->wrapT == other.wrapT;
 
-         //this->wrapR == other.wrapR
+  // this->wrapR == other.wrapR
 }
 bool Scene::operator==(const Scene &other) const {
   return this->extensions == other.extensions && this->extras == other.extras &&
@@ -2041,10 +2055,8 @@ static std::string GetBaseDir(const std::string &filepath) {
 }
 
 static std::string GetBaseFilename(const std::string &filepath) {
-  constexpr char path_separators[2] = { '/', '\\' };
-  auto idx = filepath.find_last_of(path_separators);
-  if (idx != std::string::npos)
-    return filepath.substr(idx + 1);
+  auto idx = filepath.find_last_of("/\\");
+  if (idx != std::string::npos) return filepath.substr(idx + 1);
   return filepath;
 }
 
@@ -2606,6 +2618,18 @@ bool FileExists(const std::string &abs_filename, void *) {
 }
 
 std::string ExpandFilePath(const std::string &filepath, void *) {
+  // https://github.com/syoyo/tinygltf/issues/368
+  //
+  // No file path expansion in built-in FS function anymore, since glTF URI
+  // should not contain tilde('~') and environment variables, and for security
+  // reason(`wordexp`).
+  //
+  // Users need to supply `base_dir`(in `LoadASCIIFromString`,
+  // `LoadBinaryFromMemory`) in expanded absolute path.
+
+  return filepath;
+
+#if 0
 #ifdef _WIN32
   // Assume input `filepath` is encoded in UTF-8
   std::wstring wfilepath = UTF8ToWchar(filepath);
@@ -2653,6 +2677,7 @@ std::string ExpandFilePath(const std::string &filepath, void *) {
 
   return s;
 #endif
+#endif
 }
 
 bool ReadWholeFile(std::vector<unsigned char> *out, std::string *err,
@@ -3093,11 +3118,17 @@ std::string JsonToString(const json &o, int spacing = -1) {
   StringBuffer buffer;
   if (spacing == -1) {
     Writer<StringBuffer> writer(buffer);
-    o.Accept(writer);
+    // TODO: Better error handling.
+    // https://github.com/syoyo/tinygltf/issues/332
+    if (!o.Accept(writer)) {
+      return "tiny_gltf::JsonToString() failed rapidjson conversion";
+    }
   } else {
     PrettyWriter<StringBuffer> writer(buffer);
     writer.SetIndent(' ', uint32_t(spacing));
-    o.Accept(writer);
+    if (!o.Accept(writer)) {
+      return "tiny_gltf::JsonToString() failed rapidjson conversion";
+    }
   }
   return buffer.GetString();
 #else
@@ -4237,20 +4268,20 @@ static bool ParseSparseAccessor(Accessor *accessor, std::string *err,
   const json &values_obj = GetValue(values_iterator);
 
   int indices_buffer_view = 0, indices_byte_offset = 0, component_type = 0;
-  if (!ParseIntegerProperty(&indices_buffer_view, err, indices_obj, "bufferView",
-                       true, "SparseAccessor")) {
+  if (!ParseIntegerProperty(&indices_buffer_view, err, indices_obj,
+                            "bufferView", true, "SparseAccessor")) {
     return false;
   }
   ParseIntegerProperty(&indices_byte_offset, err, indices_obj, "byteOffset",
                        false);
   if (!ParseIntegerProperty(&component_type, err, indices_obj, "componentType",
-                       true, "SparseAccessor")) {
+                            true, "SparseAccessor")) {
     return false;
   }
 
   int values_buffer_view = 0, values_byte_offset = 0;
   if (!ParseIntegerProperty(&values_buffer_view, err, values_obj, "bufferView",
-                       true, "SparseAccessor")) {
+                            true, "SparseAccessor")) {
     return false;
   }
   ParseIntegerProperty(&values_byte_offset, err, values_obj, "byteOffset",
@@ -5089,12 +5120,13 @@ 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)
@@ -5103,7 +5135,7 @@ 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);
@@ -6216,44 +6248,109 @@ bool TinyGLTF::LoadBinaryFromMemory(Model *model, std::string *err,
 
   unsigned int version;       // 4 bytes
   unsigned int length;        // 4 bytes
-  unsigned int model_length;  // 4 bytes
-  unsigned int model_format;  // 4 bytes;
+  unsigned int chunk0_length;  // 4 bytes
+  unsigned int chunk0_format;  // 4 bytes;
 
-  // @todo { Endian swap for big endian machine. }
   memcpy(&version, bytes + 4, 4);
   swap4(&version);
   memcpy(&length, bytes + 8, 4);
   swap4(&length);
-  memcpy(&model_length, bytes + 12, 4);
-  swap4(&model_length);
-  memcpy(&model_format, bytes + 16, 4);
-  swap4(&model_format);
+  memcpy(&chunk0_length, bytes + 12, 4); // JSON data length
+  swap4(&chunk0_length);
+  memcpy(&chunk0_format, bytes + 16, 4);
+  swap4(&chunk0_format);
 
+  // https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#binary-gltf-layout
+  //
   // In case the Bin buffer is not present, the size is exactly 20 + size of
   // JSON contents,
   // so use "greater than" operator.
-  if ((20 + model_length > size) || (model_length < 1) || (length > size) ||
-      (20 + model_length > length) ||
-      (model_format != 0x4E4F534A)) {  // 0x4E4F534A = JSON format.
+  //
+  // https://github.com/syoyo/tinygltf/issues/372
+  // Use 64bit uint to avoid integer overflow.
+  uint64_t json_size = 20ull + uint64_t(chunk0_length);
+
+  if (json_size > std::numeric_limits<uint32_t>::max()) {
+    // Do not allow 4GB or more GLB data.
+   (*err) = "Invalid glTF binary. GLB data exceeds 4GB.";
+  }
+
+  if ((json_size > uint64_t(size)) || (chunk0_length < 1) || (length > size) ||
+      (json_size > uint64_t(length)) ||
+      (chunk0_format != 0x4E4F534A)) {  // 0x4E4F534A = JSON format.
     if (err) {
       (*err) = "Invalid glTF binary.";
     }
     return false;
   }
 
+  // Padding check
+  // The start and the end of each chunk must be aligned to a 4-byte boundary.
+  // No padding check for chunk0 start since its 4byte-boundary is ensured.
+  if ((json_size % 4) != 0) {
+    if (err) {
+      (*err) = "JSON Chunk end does not aligned to a 4-byte boundary.";
+    }
+  }
+
+  // Read Chunk1 info(BIN data)
+  if ((json_size + 8ull) > uint64_t(length)) {
+    if (err) {
+      (*err) = "Insufficient storage space for Chunk1(BIN data).";
+    }
+    return false;
+  }
+
+  unsigned int chunk1_length;  // 4 bytes
+  unsigned int chunk1_format;  // 4 bytes;
+  memcpy(&chunk1_length, bytes + json_size, 4); // JSON data length
+  swap4(&chunk1_length);
+  memcpy(&chunk1_format, bytes + json_size + 4, 4);
+  swap4(&chunk1_format);
+
+  if (chunk1_length < 4) {
+    // TODO: Do we allow 0byte BIN data?
+    if (err) {
+      (*err) = "Insufficient Chunk1(BIN) data size.";
+    }
+    return false;
+  }
+
+  if ((chunk1_length % 4) != 0) {
+    if (err) {
+      (*err) = "BIN Chunk end does not aligned to a 4-byte boundary.";
+    }
+    return false;
+  }
+
+  if (uint64_t(chunk1_length) + json_size > uint64_t(length)) {
+    if (err) {
+      (*err) = "BIN Chunk data length exceeds the GLB size.";
+    }
+    return false;
+  }
+
+  if (chunk1_format != 0x004e4942) {
+    if (err) {
+      (*err) = "Invlid type for chunk1 data.";
+    }
+    return false;
+  }
+
+  bin_data_ = bytes + json_size +
+              8;  // 4 bytes (bin_buffer_length) + 4 bytes(bin_buffer_format)
+
+  bin_size_ = size_t(chunk1_length);
+
   // Extract JSON string.
   std::string jsonString(reinterpret_cast<const char *>(&bytes[20]),
-                         model_length);
+                         chunk0_length);
 
   is_binary_ = true;
-  bin_data_ = bytes + 20 + model_length +
-              8;  // 4 bytes (buffer_length) + 4 bytes(buffer_format)
-  bin_size_ =
-      length - (20 + model_length);  // extract header + JSON scene data.
 
   bool ret = LoadFromString(model, err, warn,
                             reinterpret_cast<const char *>(&bytes[20]),
-                            model_length, base_dir, check_sections);
+                            chunk0_length, base_dir, check_sections);
   if (!ret) {
     return ret;
   }
@@ -6684,6 +6781,27 @@ static void SerializeGltfAccessor(Accessor &accessor, json &o) {
   if (accessor.extras.Type() != NULL_TYPE) {
     SerializeValue("extras", accessor.extras, o);
   }
+
+  // sparse
+  if (accessor.sparse.isSparse)
+  {
+      json sparse;
+      SerializeNumberProperty<int>("count", accessor.sparse.count, sparse);
+      {
+          json indices;
+          SerializeNumberProperty<int>("bufferView", accessor.sparse.indices.bufferView, indices);
+          SerializeNumberProperty<int>("byteOffset", accessor.sparse.indices.byteOffset, indices);
+          SerializeNumberProperty<int>("componentType", accessor.sparse.indices.componentType, indices);
+          JsonAddMember(sparse, "indices", std::move(indices));
+      }
+      {
+          json values;
+          SerializeNumberProperty<int>("bufferView", accessor.sparse.values.bufferView, values);
+          SerializeNumberProperty<int>("byteOffset", accessor.sparse.values.byteOffset, values);
+          JsonAddMember(sparse, "values", std::move(values));
+      }
+      JsonAddMember(o, "sparse", std::move(sparse));
+  }
 }
 
 static void SerializeGltfAnimationChannel(AnimationChannel &channel, json &o) {
@@ -7166,7 +7284,7 @@ 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);
 
@@ -7520,7 +7638,7 @@ static bool WriteGltfFile(const std::string &output,
   return WriteGltfStream(gltfFile, content);
 }
 
-static void WriteBinaryGltfStream(std::ostream &stream,
+static bool WriteBinaryGltfStream(std::ostream &stream,
                                   const std::string &content,
                                   const std::vector<unsigned char> &binBuffer) {
   const std::string header = "glTF";
@@ -7529,8 +7647,10 @@ static void WriteBinaryGltfStream(std::ostream &stream,
   const uint32_t content_size = uint32_t(content.size());
   const uint32_t binBuffer_size = uint32_t(binBuffer.size());
   // determine number of padding bytes required to ensure 4 byte alignment
-  const uint32_t content_padding_size = content_size % 4 == 0 ? 0 : 4 - content_size % 4;
-  const uint32_t bin_padding_size = binBuffer_size % 4 == 0 ? 0 : 4 - binBuffer_size % 4;
+  const uint32_t content_padding_size =
+      content_size % 4 == 0 ? 0 : 4 - content_size % 4;
+  const uint32_t bin_padding_size =
+      binBuffer_size % 4 == 0 ? 0 : 4 - binBuffer_size % 4;
 
   // 12 bytes for header, JSON content length, 8 bytes for JSON chunk info.
   // Chunk data must be located at 4-byte boundary, which may require padding
@@ -7574,9 +7694,12 @@ static void WriteBinaryGltfStream(std::ostream &stream,
                    std::streamsize(padding.size()));
     }
   }
+
+  // TODO: Check error on stream.write
+  return true;
 }
 
-static void WriteBinaryGltfFile(const std::string &output,
+static bool WriteBinaryGltfFile(const std::string &output,
                                 const std::string &content,
                                 const std::vector<unsigned char> &binBuffer) {
 #ifdef _WIN32
@@ -7594,7 +7717,7 @@ static void WriteBinaryGltfFile(const std::string &output,
 #else
   std::ofstream gltfFile(output.c_str(), std::ios::binary);
 #endif
-  WriteBinaryGltfStream(gltfFile, content, binBuffer);
+  return WriteBinaryGltfStream(gltfFile, content, binBuffer);
 }
 
 bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
@@ -7633,7 +7756,7 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
       // 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,
+      UpdateImageObject(model->images[i], dummystring, int(i), true,
                         &this->WriteImageData, this->write_image_user_data_);
       SerializeGltfImage(model->images[i], image);
       JsonPushBack(images, std::move(image));
@@ -7642,12 +7765,11 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
   }
 
   if (writeBinary) {
-    WriteBinaryGltfStream(stream, JsonToString(output), binBuffer);
+    return WriteBinaryGltfStream(stream, JsonToString(output), binBuffer);
   } else {
-    WriteGltfStream(stream, JsonToString(output, prettyPrint ? 2 : -1));
+    return WriteGltfStream(stream, JsonToString(output, prettyPrint ? 2 : -1));
   }
 
-  return true;
 }
 
 bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
@@ -7732,12 +7854,11 @@ bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
   }
 
   if (writeBinary) {
-    WriteBinaryGltfFile(filename, JsonToString(output), binBuffer);
+    return WriteBinaryGltfFile(filename, JsonToString(output), binBuffer);
   } else {
-    WriteGltfFile(filename, JsonToString(output, (prettyPrint ? 2 : -1)));
+    return WriteGltfFile(filename, JsonToString(output, (prettyPrint ? 2 : -1)));
   }
 
-  return true;
 }
 
 }  // namespace tinygltf