Add dlib license.

Do not set target on bufferView pointing to animation data

README.md

@@ -34,8 +34,11 @@ If you are looking for old, C++03 version, please use `devel-picojson` branch.
 * Moderate parsing time and memory consumption.
 * glTF specification v2.0.0
   * [x] ASCII glTF
+    * [x] Load
+    * [x] Save
   * [x] Binary glTF(GLB)
-  * [x] PBR material description
+    * [x] Load
+    * [x] Save(.bin embedded .glb)
 * Buffers
   * [x] Parse BASE64 encoded embedded buffer data(DataURI).
   * [x] Load `.bin` file.
@@ -55,6 +58,7 @@ If you are looking for old, C++03 version, please use `devel-picojson` branch.
   * [x] Image save
 * Extensions
   * [x] Draco mesh decoding
+  * [ ] Draco mesh encoding
 
 ## Note on extension property
 
@@ -160,14 +164,17 @@ if (!ret) {
 
 
 ### Saving gltTF 2.0 model
-* [ ] Buffers.
+
+* Buffers.
   * [x] To file
   * [x] Embedded
   * [ ] Draco compressed?
 * [x] Images
   * [x] To file
   * [x] Embedded
-* [ ] Binary(.glb)
+* Binary(.glb)
+  * [x] .bin embedded single .glb
+  * [ ] External .bin
 
 ## Running tests.
 
@@ -201,3 +208,4 @@ $ ./tester_noexcept
 * stb_image : Public domain.
 * catch : Copyright (c) 2012 Two Blue Cubes Ltd. All rights reserved. Distributed under the Boost Software License, Version 1.0.
 * RapidJSON : Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. http://rapidjson.org/
+* dlib(uridecode, uriencode) : Copyright (C) 2003  Davis E. King Boost Software License 1.0. http://dlib.net/dlib/server/server_http.cpp.html

tiny_gltf.h

@@ -26,6 +26,7 @@
 // THE SOFTWARE.
 
 // Version:
+//  - v2.4.2 Decode percent-encoded URI.
 //  - v2.4.1 Fix some glTF object class does not have `extensions` and/or
 //  `extras` property.
 //  - v2.4.0 Experimental RapidJSON and C++14 support(Thanks to @jrkoone).
@@ -637,7 +638,8 @@ struct Image {
   int bufferView;        // (required if no uri)
   std::string mimeType;  // (required if no uri) ["image/jpeg", "image/png",
                          // "image/bmp", "image/gif"]
-  std::string uri;       // (required if no mimeType)
+  std::string uri;       // (required if no mimeType) uri is not decoded(e.g.
+                         // whitespace may be represented as %20)
   Value extras;
   ExtensionMap extensions;
 
@@ -797,12 +799,13 @@ struct Material {
 
 struct BufferView {
   std::string name;
-  int buffer;         // Required
-  size_t byteOffset;  // minimum 0, default 0
-  size_t byteLength;  // required, minimum 1
-  size_t byteStride;  // minimum 4, maximum 252 (multiple of 4), default 0 =
-                      // understood to be tightly packed
-  int target;         // ["ARRAY_BUFFER", "ELEMENT_ARRAY_BUFFER"]
+  int buffer{-1};        // Required
+  size_t byteOffset{0};  // minimum 0, default 0
+  size_t byteLength{0};  // required, minimum 1. 0 = invalid
+  size_t byteStride{0};  // minimum 4, maximum 252 (multiple of 4), default 0 =
+                         // understood to be tightly packed
+  int target{0};  // ["ARRAY_BUFFER", "ELEMENT_ARRAY_BUFFER"] for vertex indices
+                  // or atttribs. Could be 0 for other data
   Value extras;
   ExtensionMap extensions;
 
@@ -810,9 +813,15 @@ struct BufferView {
   std::string extras_json_string;
   std::string extensions_json_string;
 
-  bool dracoDecoded;  // Flag indicating this has been draco decoded
+  bool dracoDecoded{false};  // Flag indicating this has been draco decoded
 
-  BufferView() : byteOffset(0), byteStride(0), dracoDecoded(false) {}
+  BufferView()
+      : buffer(-1),
+        byteOffset(0),
+        byteLength(0),
+        byteStride(0),
+        target(0),
+        dracoDecoded(false) {}
   DEFAULT_METHODS(BufferView)
   bool operator==(const BufferView &) const;
 };
@@ -887,8 +896,13 @@ struct Accessor {
     // unreachable return 0;
   }
 
-  Accessor() {
-    bufferView = -1;
+  Accessor()
+      : bufferView(-1),
+        byteOffset(0),
+        normalized(false),
+        componentType(-1),
+        count(0),
+        type(-1) {
     sparse.isSparse = false;
   }
   DEFAULT_METHODS(Accessor)
@@ -1032,6 +1046,7 @@ struct Buffer {
   std::vector<unsigned char> data;
   std::string
       uri;  // considered as required here but not in the spec (need to clarify)
+            // uri is not decoded(e.g. whitespace may be represented as %20)
   Value extras;
   ExtensionMap extensions;
 
@@ -1542,10 +1557,11 @@ class TinyGLTF {
 #undef NOMINMAX
 #endif
 
-#if defined(__GLIBCXX__) // mingw
+#if defined(__GLIBCXX__)  // mingw
 
-#include <ext/stdio_filebuf.h>	// fstream (all sorts of IO stuff) + stdio_filebuf (=streambuf)
-#include <fcntl.h>	// _O_RDONLY
+#include <fcntl.h>  // _O_RDONLY
+
+#include <ext/stdio_filebuf.h>  // fstream (all sorts of IO stuff) + stdio_filebuf (=streambuf)
 
 #endif
 
@@ -2114,6 +2130,88 @@ std::string base64_decode(std::string const &encoded_string) {
 #pragma clang diagnostic pop
 #endif
 
+// https://github.com/syoyo/tinygltf/issues/228
+// TODO(syoyo): Use uriparser https://uriparser.github.io/ for stricter Uri
+// decoding?
+//
+// https://stackoverflow.com/questions/18307429/encode-decode-url-in-c
+// http://dlib.net/dlib/server/server_http.cpp.html
+
+// --- dlib beign ------------------------------------------------------------
+// Copyright (C) 2003  Davis E. King (davis@dlib.net)
+// License: Boost Software License   See LICENSE.txt for the full license.
+
+namespace dlib {
+
+#if 0
+        inline unsigned char to_hex( unsigned char x )  
+        {
+            return x + (x > 9 ? ('A'-10) : '0');
+        }
+
+        const std::string urlencode( const std::string& s )  
+        {
+            std::ostringstream os;
+
+            for ( std::string::const_iterator ci = s.begin(); ci != s.end(); ++ci )
+            {
+                if ( (*ci >= 'a' && *ci <= 'z') ||
+                     (*ci >= 'A' && *ci <= 'Z') ||
+                     (*ci >= '0' && *ci <= '9') )
+                { // allowed
+                    os << *ci;
+                }
+                else if ( *ci == ' ')
+                {
+                    os << '+';
+                }
+                else
+                {
+                    os << '%' << to_hex(static_cast<unsigned char>(*ci >> 4)) << to_hex(static_cast<unsigned char>(*ci % 16));
+                }
+            }
+
+            return os.str();
+        }
+#endif
+
+inline unsigned char from_hex(unsigned char ch) {
+  if (ch <= '9' && ch >= '0')
+    ch -= '0';
+  else if (ch <= 'f' && ch >= 'a')
+    ch -= 'a' - 10;
+  else if (ch <= 'F' && ch >= 'A')
+    ch -= 'A' - 10;
+  else
+    ch = 0;
+  return ch;
+}
+
+static const std::string urldecode(const std::string &str) {
+  using namespace std;
+  string result;
+  string::size_type i;
+  for (i = 0; i < str.size(); ++i) {
+    if (str[i] == '+') {
+      result += ' ';
+    } else if (str[i] == '%' && str.size() > i + 2) {
+      const unsigned char ch1 =
+          from_hex(static_cast<unsigned char>(str[i + 1]));
+      const unsigned char ch2 =
+          from_hex(static_cast<unsigned char>(str[i + 2]));
+      const unsigned char ch = static_cast<unsigned char>((ch1 << 4) | ch2);
+      result += static_cast<char>(ch);
+      i += 2;
+    } else {
+      result += str[i];
+    }
+  }
+  return result;
+}
+
+}  // namespace dlib
+// --- dlib end --------------------------------------------------------------
+
 static bool LoadExternalFile(std::vector<unsigned char> *out, std::string *err,
                              std::string *warn, const std::string &filename,
                              const std::string &basedir, bool required,
@@ -2374,9 +2472,11 @@ void TinyGLTF::SetFsCallbacks(FsCallbacks callbacks) { fs = callbacks; }
 
 #ifdef _WIN32
 static inline std::wstring UTF8ToWchar(const std::string &str) {
-  int wstr_size = MultiByteToWideChar(CP_UTF8, 0, str.data(), (int)str.size(), nullptr, 0);
+  int wstr_size =
+      MultiByteToWideChar(CP_UTF8, 0, str.data(), (int)str.size(), nullptr, 0);
   std::wstring wstr(wstr_size, 0);
-  MultiByteToWideChar(CP_UTF8, 0, str.data(), (int)str.size(), &wstr[0], (int)wstr.size());
+  MultiByteToWideChar(CP_UTF8, 0, str.data(), (int)str.size(), &wstr[0],
+                      (int)wstr.size());
   return wstr;
 }
 #endif
@@ -2506,13 +2606,14 @@ bool ReadWholeFile(std::vector<unsigned char> *out, std::string *err,
   }
 #else
 #ifdef _WIN32
-#if defined(__GLIBCXX__) // mingw
-  int file_descriptor = _wopen(UTF8ToWchar(filepath).c_str(), _O_RDONLY | _O_BINARY);
+#if defined(__GLIBCXX__)  // mingw
+  int file_descriptor =
+      _wopen(UTF8ToWchar(filepath).c_str(), _O_RDONLY | _O_BINARY);
   __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
   std::istream f(&wfile_buf);
 #elif defined(_MSC_VER)
   std::ifstream f(UTF8ToWchar(filepath).c_str(), std::ifstream::binary);
-#else // clang?
+#else  // clang?
   std::ifstream f(filepath.c_str(), std::ifstream::binary);
 #endif
 #else
@@ -2553,13 +2654,14 @@ bool ReadWholeFile(std::vector<unsigned char> *out, std::string *err,
 bool WriteWholeFile(std::string *err, const std::string &filepath,
                     const std::vector<unsigned char> &contents, void *) {
 #ifdef _WIN32
-#if defined(__GLIBCXX__) // mingw
-  int file_descriptor = _wopen(UTF8ToWchar(filepath).c_str(), _O_WRONLY | _O_BINARY);
+#if defined(__GLIBCXX__)  // mingw
+  int file_descriptor =
+      _wopen(UTF8ToWchar(filepath).c_str(), _O_WRONLY | _O_BINARY);
   __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
   std::ostream f(&wfile_buf);
 #elif defined(_MSC_VER)
   std::ofstream f(UTF8ToWchar(filepath).c_str(), std::ofstream::binary);
-#else // clang?
+#else  // clang?
   std::ofstream f(filepath.c_str(), std::ofstream::binary);
 #endif
 #else
@@ -2723,6 +2825,7 @@ bool DecodeDataURI(std::vector<unsigned char> *out, std::string &mime_type,
     }
   }
 
+  // TODO(syoyo): Allow empty buffer? #229
   if (data.empty()) {
     return false;
   }
@@ -3641,7 +3744,10 @@ static bool ParseImage(Image *image, const int image_idx, std::string *err,
 #ifdef TINYGLTF_NO_EXTERNAL_IMAGE
     return true;
 #endif
-    if (!LoadExternalFile(&img, err, warn, uri, basedir, false, 0, false, fs)) {
+    std::string decoded_uri = dlib::urldecode(uri);
+    if (!LoadExternalFile(&img, err, warn, decoded_uri, basedir,
+                          /* required */ false, /* required bytes */ 0,
+                          /* checksize */ false, fs)) {
       if (warn) {
         (*warn) += "Failed to load external 'uri' for image[" +
                    std::to_string(image_idx) + "] name = [" + image->name +
@@ -3863,9 +3969,10 @@ static bool ParseBuffer(Buffer *buffer, std::string *err, const json &o,
         }
       } else {
         // External .bin file.
+        std::string decoded_uri = dlib::urldecode(buffer->uri);
         if (!LoadExternalFile(&buffer->data, err, /* warn */ nullptr,
-                              buffer->uri, basedir, true, byteLength, true,
-                              fs)) {
+                              decoded_uri, basedir, /* required */ true,
+                              byteLength, /* checkSize */ true, fs)) {
           return false;
         }
       }
@@ -3907,8 +4014,10 @@ static bool ParseBuffer(Buffer *buffer, std::string *err, const json &o,
       }
     } else {
       // Assume external .bin file.
-      if (!LoadExternalFile(&buffer->data, err, /* warn */ nullptr, buffer->uri,
-                            basedir, true, byteLength, true, fs)) {
+      std::string decoded_uri = dlib::urldecode(buffer->uri);
+      if (!LoadExternalFile(&buffer->data, err, /* warn */ nullptr, decoded_uri,
+                            basedir, /* required */ true, byteLength,
+                            /* checkSize */ true, fs)) {
         return false;
       }
     }
@@ -5247,7 +5356,7 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
 
 #if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || \
      defined(_CPPUNWIND)) &&                               \
-    not defined(TINYGLTF_NOEXCEPTION)
+    !defined(TINYGLTF_NOEXCEPTION)
   try {
     JsonParse(v, json_str, json_str_length, true);
 
@@ -5520,7 +5629,7 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
 
   // Assign missing bufferView target types
   // - Look for missing Mesh indices
-  // - Look for missing bufferView targets
+  // - Look for missing Mesh attributes
   for (auto &mesh : model->meshes) {
     for (auto &primitive : mesh.primitives) {
       if (primitive.indices >
@@ -5548,14 +5657,13 @@ bool TinyGLTF::LoadFromString(Model *model, std::string *err, std::string *warn,
         // we could optionally check if acessors' bufferView type is Scalar, as
         // it should be
       }
-    }
-  }
-  // find any missing targets, must be an array buffer type if not fulfilled
-  // from previous check
-  for (auto &bufferView : model->bufferViews) {
-    if (bufferView.target == 0)  // missing target type
-    {
-      bufferView.target = TINYGLTF_TARGET_ARRAY_BUFFER;
+
+      for (auto &attribute : primitive.attributes) {
+        model
+            ->bufferViews[size_t(
+                model->accessors[size_t(attribute.second)].bufferView)]
+            .target = TINYGLTF_TARGET_ARRAY_BUFFER;
+      }
     }
   }
 
@@ -6273,16 +6381,23 @@ static void SerializeValue(const std::string &key, const Value &value,
 static void SerializeGltfBufferData(const std::vector<unsigned char> &data,
                                     json &o) {
   std::string header = "data:application/octet-stream;base64,";
-  std::string encodedData =
-      base64_encode(&data[0], static_cast<unsigned int>(data.size()));
-  SerializeStringProperty("uri", header + encodedData, o);
+  if (data.size() > 0) {
+    std::string encodedData =
+        base64_encode(&data[0], static_cast<unsigned int>(data.size()));
+    SerializeStringProperty("uri", header + encodedData, o);
+  } else {
+    // Issue #229
+    // size 0 is allowd. Just emit mime header.
+    SerializeStringProperty("uri", header, o);
+  }
 }
 
 static bool SerializeGltfBufferData(const std::vector<unsigned char> &data,
                                     const std::string &binFilename) {
 #ifdef _WIN32
-#if defined(__GLIBCXX__) // mingw
- int file_descriptor = _wopen(UTF8ToWchar(binFilename).c_str(), _O_WRONLY | _O_BINARY);
+#if defined(__GLIBCXX__)  // mingw
+  int file_descriptor =
+      _wopen(UTF8ToWchar(binFilename).c_str(), _O_WRONLY | _O_BINARY);
   __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
   std::ostream output(&wfile_buf);
   if (!wfile_buf.is_open()) return false;
@@ -6297,8 +6412,14 @@ static bool SerializeGltfBufferData(const std::vector<unsigned char> &data,
   std::ofstream output(binFilename.c_str(), std::ofstream::binary);
   if (!output.is_open()) return false;
 #endif
-  output.write(reinterpret_cast<const char *>(&data[0]),
-               std::streamsize(data.size()));
+  if (data.size() > 0) {
+    output.write(reinterpret_cast<const char *>(&data[0]),
+                 std::streamsize(data.size()));
+  } else {
+    // Issue #229
+    // size 0 will be still valid buffer data.
+    // write empty file.
+  }
   return true;
 }
 
@@ -6369,7 +6490,8 @@ static void SerializeGltfAccessor(Accessor &accessor, json &o) {
   SerializeNumberProperty<size_t>("count", accessor.count, o);
   SerializeNumberArrayProperty<double>("min", accessor.minValues, o);
   SerializeNumberArrayProperty<double>("max", accessor.maxValues, o);
-  SerializeValue("normalized", Value(accessor.normalized), o);
+  if (accessor.normalized)
+    SerializeValue("normalized", Value(accessor.normalized), o);
   std::string type;
   switch (accessor.type) {
     case TINYGLTF_TYPE_SCALAR:
@@ -6485,6 +6607,18 @@ static void SerializeGltfAsset(Asset &asset, json &o) {
   SerializeExtensionMap(asset.extensions, o);
 }
 
+static void SerializeGltfBufferBin(Buffer &buffer, json &o,
+                                   std::vector<unsigned char> &binBuffer) {
+  SerializeNumberProperty("byteLength", buffer.data.size(), o);
+  binBuffer = buffer.data;
+
+  if (buffer.name.size()) SerializeStringProperty("name", buffer.name, o);
+
+  if (buffer.extras.Type() != NULL_TYPE) {
+    SerializeValue("extras", buffer.extras, o);
+  }
+}
+
 static void SerializeGltfBuffer(Buffer &buffer, json &o) {
   SerializeNumberProperty("byteLength", buffer.data.size(), o);
   SerializeGltfBufferData(buffer.data, o);
@@ -6543,6 +6677,7 @@ static void SerializeGltfImage(Image &image, json &o) {
     SerializeStringProperty("mimeType", image.mimeType, o);
     SerializeNumberProperty<int>("bufferView", image.bufferView, o);
   } else {
+    // TODO(syoyo): dlib::urilencode?
     SerializeStringProperty("uri", image.uri, o);
   }
 
@@ -6659,8 +6794,8 @@ static void SerializeGltfMaterial(Material &material, json &o) {
     SerializeStringProperty("alphaMode", material.alphaMode, o);
   }
 
-  if(material.doubleSided != false)
-	JsonAddMember(o, "doubleSided", json(material.doubleSided));
+  if (material.doubleSided != false)
+    JsonAddMember(o, "doubleSided", json(material.doubleSided));
 
   if (material.normalTexture.index > -1) {
     json texinfo;
@@ -6764,7 +6899,7 @@ static void SerializeGltfMesh(Mesh &mesh, json &o) {
       JsonAddMember(primitive, "targets", std::move(targets));
     }
 
-    SerializeExtensionMap(gltfPrimitive.extensions, o);
+    SerializeExtensionMap(gltfPrimitive.extensions, primitive);
 
     if (gltfPrimitive.extras.Type() != NULL_TYPE) {
       SerializeValue("extras", gltfPrimitive.extras, primitive);
@@ -7157,7 +7292,8 @@ static bool WriteGltfFile(const std::string &output,
 #if defined(_MSC_VER)
   std::ofstream gltfFile(UTF8ToWchar(output).c_str());
 #elif defined(__GLIBCXX__)
-  int file_descriptor = _wopen(UTF8ToWchar(output).c_str(), _O_WRONLY | _O_BINARY);
+  int file_descriptor =
+      _wopen(UTF8ToWchar(output).c_str(), _O_WRONLY | _O_BINARY);
   __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
   std::ostream gltfFile(&wfile_buf);
   if (!wfile_buf.is_open()) return false;
@@ -7173,22 +7309,37 @@ static bool WriteGltfFile(const std::string &output,
 }
 
 static void WriteBinaryGltfStream(std::ostream &stream,
-                                  const std::string &content) {
+                                  const std::string &content,
+                                  const std::vector<unsigned char> &binBuffer) {
   const std::string header = "glTF";
   const int version = 2;
-  const int padding_size = content.size() % 4;
 
-  // 12 bytes for header, JSON content length, 8 bytes for JSON chunk info,
-  // padding
-  const int length = 12 + 8 + int(content.size()) + padding_size;
+  // https://stackoverflow.com/questions/3407012/c-rounding-up-to-the-nearest-multiple-of-a-number
+  auto roundUp = [](uint32_t numToRound, uint32_t multiple) {
+    if (multiple == 0) return numToRound;
+
+    uint32_t remainder = numToRound % multiple;
+    if (remainder == 0) return numToRound;
+
+    return numToRound + multiple - remainder;
+  };
+
+  const uint32_t padding_size =
+      roundUp(uint32_t(content.size()), 4) - uint32_t(content.size());
+
+  // 12 bytes for header, JSON content length, 8 bytes for JSON chunk info.
+  // Chunk data must be located at 4-byte boundary.
+  const uint32_t length =
+      12 + 8 + roundUp(uint32_t(content.size()), 4) +
+      (binBuffer.size() ? (8 + roundUp(uint32_t(binBuffer.size()), 4)) : 0);
 
   stream.write(header.c_str(), std::streamsize(header.size()));
   stream.write(reinterpret_cast<const char *>(&version), sizeof(version));
   stream.write(reinterpret_cast<const char *>(&length), sizeof(length));
 
   // JSON chunk info, then JSON data
-  const int model_length = int(content.size()) + padding_size;
-  const int model_format = 0x4E4F534A;
+  const uint32_t model_length = uint32_t(content.size()) + padding_size;
+  const uint32_t model_format = 0x4E4F534A;
   stream.write(reinterpret_cast<const char *>(&model_length),
                sizeof(model_length));
   stream.write(reinterpret_cast<const char *>(&model_format),
@@ -7200,22 +7351,46 @@ static void WriteBinaryGltfStream(std::ostream &stream,
     const std::string padding = std::string(size_t(padding_size), ' ');
     stream.write(padding.c_str(), std::streamsize(padding.size()));
   }
+  if (binBuffer.size() > 0) {
+    const uint32_t bin_padding_size =
+        roundUp(uint32_t(binBuffer.size()), 4) - uint32_t(binBuffer.size());
+    // BIN chunk info, then BIN data
+    const uint32_t bin_length = uint32_t(binBuffer.size()) + bin_padding_size;
+    const uint32_t bin_format = 0x004e4942;
+    stream.write(reinterpret_cast<const char *>(&bin_length),
+                 sizeof(bin_length));
+    stream.write(reinterpret_cast<const char *>(&bin_format),
+                 sizeof(bin_format));
+    stream.write(reinterpret_cast<const char *>(binBuffer.data()),
+                 std::streamsize(binBuffer.size()));
+    // Chunksize must be multiplies of 4, so pad with zeroes
+    if (bin_padding_size > 0) {
+      const std::vector<unsigned char> padding =
+          std::vector<unsigned char>(size_t(bin_padding_size), 0);
+      stream.write(reinterpret_cast<const char *>(padding.data()),
+                   std::streamsize(padding.size()));
+    }
+  }
 }
 
 static void WriteBinaryGltfFile(const std::string &output,
-                                const std::string &content) {
+                                const std::string &content,
+                                const std::vector<unsigned char> &binBuffer) {
 #ifdef _WIN32
 #if defined(_MSC_VER)
   std::ofstream gltfFile(UTF8ToWchar(output).c_str(), std::ios::binary);
 #elif defined(__GLIBCXX__)
-  std::ofstream gltfFile(output.c_str(), std::ios::binary);
+  int file_descriptor =
+      _wopen(UTF8ToWchar(output).c_str(), _O_WRONLY | _O_BINARY);
+  __gnu_cxx::stdio_filebuf<char> wfile_buf(file_descriptor, std::ios_base::in);
+  std::ostream gltfFile(&wfile_buf);
 #else
   std::ofstream gltfFile(output.c_str(), std::ios::binary);
 #endif
 #else
   std::ofstream gltfFile(output.c_str(), std::ios::binary);
 #endif
-  WriteBinaryGltfStream(gltfFile, content);
+  WriteBinaryGltfStream(gltfFile, content, binBuffer);
 }
 
 bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
@@ -7228,11 +7403,16 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
 
   // BUFFERS
   std::vector<std::string> usedUris;
+  std::vector<unsigned char> binBuffer;
   json buffers;
   JsonReserveArray(buffers, model->buffers.size());
   for (unsigned int i = 0; i < model->buffers.size(); ++i) {
     json buffer;
-    SerializeGltfBuffer(model->buffers[i], buffer);
+    if (writeBinary && i == 0 && model->buffers[i].uri.empty()) {
+      SerializeGltfBufferBin(model->buffers[i], buffer, binBuffer);
+    } else {
+      SerializeGltfBuffer(model->buffers[i], buffer);
+    }
     JsonPushBack(buffers, std::move(buffer));
   }
   JsonAddMember(output, "buffers", std::move(buffers));
@@ -7257,7 +7437,7 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
   }
 
   if (writeBinary) {
-    WriteBinaryGltfStream(stream, JsonToString(output));
+    WriteBinaryGltfStream(stream, JsonToString(output), binBuffer);
   } else {
     WriteGltfStream(stream, JsonToString(output, prettyPrint ? 2 : -1));
   }
@@ -7288,11 +7468,14 @@ bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
 
   // BUFFERS
   std::vector<std::string> usedUris;
+  std::vector<unsigned char> binBuffer;
   json buffers;
   JsonReserveArray(buffers, model->buffers.size());
   for (unsigned int i = 0; i < model->buffers.size(); ++i) {
     json buffer;
-    if (embedBuffers) {
+    if (writeBinary && i == 0 && model->buffers[i].uri.empty()) {
+      SerializeGltfBufferBin(model->buffers[i], buffer, binBuffer);
+    } else if (embedBuffers) {
       SerializeGltfBuffer(model->buffers[i], buffer);
     } else {
       std::string binSavePath;
@@ -7341,7 +7524,7 @@ bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
   }
 
   if (writeBinary) {
-    WriteBinaryGltfFile(filename, JsonToString(output));
+    WriteBinaryGltfFile(filename, JsonToString(output), binBuffer);
   } else {
     WriteGltfFile(filename, JsonToString(output, (prettyPrint ? 2 : -1)));
   }