Update README.

Check bit depth when saving image as PNG.

README.md

@@ -3,11 +3,13 @@
 `TinyGLTF` is a header only C++11 glTF 2.0 https://github.com/KhronosGroup/glTF library.
 
 `TinyGLTF` uses Niels Lohmann's json library(https://github.com/nlohmann/json), so now it requires C++11 compiler.
-If you are looking for old, C++03 version, please use `devel-picojson` branch.  
+If you are looking for old, C++03 version, please use `devel-picojson` branch.
 
 ## Status
 
-v2.0.0 release(22 Aug, 2018)! 
+v2.2.0 release(Support loading 16bit PNG)
+v2.1.0 release(Draco support)
+v2.0.0 release(22 Aug, 2018)!
 
 ## Builds
 
@@ -38,14 +40,15 @@ v2.0.0 release(22 Aug, 2018)!
 * Image(Using stb_image)
   * [x] Parse BASE64 encoded embedded image data(DataURI).
   * [x] Load external image file.
-  * [x] PNG(8bit only)
-  * [x] JPEG(8bit only)
-  * [x] BMP
-  * [x] GIF
+  * [x] Load PNG(8bit and 16bit)
+  * [x] Load JPEG(8bit only)
+  * [x] Load BMP
+  * [x] Load GIF
   * [x] Custom Image decoder callback(e.g. for decoding OpenEXR image)
 * Load from memory
 * Custom callback handler
   * [x] Image load
+  * [x] Image save
 * Extensions
   * [x] Draco mesh decoding
 
@@ -69,10 +72,12 @@ v2.0.0 release(22 Aug, 2018)!
 * [ ] Mesh Compression/decompression(Open3DGC, etc)
   * [x] Load Draco compressed mesh
   * [x] Save Draco compressed mesh
+  * [ ] Open3DGC?
 * [ ] Support `extensions` and `extras` property
 * [ ] HDR image?
   * [ ] OpenEXR extension through TinyEXR.
-* [ ] Write example and tests for `animation` and `skin` 
+* [ ] 16bit PNG support in Serialization
+* [ ] Write example and tests for `animation` and `skin`
   * [ ] Skinning
   * [ ] Morph targets
 
@@ -104,13 +109,13 @@ Copy `stb_image.h`, `stb_image_write.h`, `json.hpp` and `tiny_gltf.h` to your pr
 
 using namespace tinygltf;
 
-Model model; 
+Model model;
 TinyGLTF loader;
 std::string err;
 std::string warn;
-  
+
 bool ret = loader.LoadASCIIFromFile(&model, &err, &warn, argv[1]);
-//bool ret = loader.LoadBinaryFromFile(&model, &err, &warn, argv[1]); // for binary glTF(.glb) 
+//bool ret = loader.LoadBinaryFromFile(&model, &err, &warn, argv[1]); // for binary glTF(.glb)
 
 if (!warn.empty()) {
   printf("Warn: %s\n", warn.c_str());

examples/basic/main.cpp

@@ -50,8 +50,9 @@ std::map<int, GLuint> bindMesh(std::map<int, GLuint> vbos,
                    From spec2.0 readme:
                    https://github.com/KhronosGroup/glTF/tree/master/specification/2.0
                             ... drawArrays function should be used with a count equal to
-                   the count            property of any of the accessors referenced by the attributes
-                   property            (they are all equal for a given primitive).
+                   the count            property of any of the accessors referenced by the
+                   attributes            property            (they are all equal for a given
+                   primitive).
                  */
     }
 
@@ -112,8 +113,29 @@ std::map<int, GLuint> bindMesh(std::map<int, GLuint> vbos,
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 
+    GLenum format = GL_RGBA;
+
+    if (image.component == 1) {
+      format = GL_RED;
+    } else if (image.component == 2) {
+      format = GL_RG;
+    } else if (image.component == 3) {
+      format = GL_RGB;
+    } else {
+      // ???
+    }
+
+    GLenum type = GL_UNSIGNED_BYTE;
+    if (image.bits == 8) {
+      // ok
+    } else if (image.bits == 16) {
+      type = GL_UNSIGNED_SHORT;
+    } else {
+      // ???
+    }
+
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0,
-                 GL_RGBA, GL_UNSIGNED_BYTE, &image.image.at(0));
+                 format, type, &image.image.at(0));
   }
 
   return vbos;
@@ -255,7 +277,7 @@ void displayLoop(Window &window, const std::string &filename) {
   glm::vec3 model_pos = glm::vec3(-3, 0, -3);
 
   // generate a camera view, based on eye-position and lookAt world-position
-  glm::mat4 view_mat = genView(glm::vec3(2, 2, 2), model_pos);
+  glm::mat4 view_mat = genView(glm::vec3(2, 2, 20), model_pos);
 
   glm::vec3 sun_position = glm::vec3(3.0, 10.0, -5.0);
   glm::vec3 sun_color = glm::vec3(1.0);
@@ -287,6 +309,11 @@ void displayLoop(Window &window, const std::string &filename) {
   }
 }
 
+static void error_callback(int error, const char *description) {
+  (void)error;
+  fprintf(stderr, "Error: %s\n", description);
+}
+
 int main(int argc, char **argv) {
   std::string filename = "../../models/Cube/Cube.gltf";
 
@@ -294,14 +321,18 @@ int main(int argc, char **argv) {
     filename = argv[1];
   }
 
+  glfwSetErrorCallback(error_callback);
+
   if (!glfwInit()) return -1;
 
-  // Force create 3.3 profile.
+  // Force create OpenGL 3.3
+  // NOTE(syoyo): Linux + NVIDIA driver segfaults for some reason? commenting out glfwWindowHint will work.
   glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
   glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 #ifdef __APPLE__
   glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
+#endif
 #endif
 
   Window window = Window(800, 600, "TinyGLTF basic example");

examples/common/LICENSE.lodepng

@@ -0,0 +1,21 @@
+Copyright (c) 2005-2018 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+    

examples/gltfutil/CMakeLists.txt

@@ -4,9 +4,10 @@ project(gltfutil)
 set(CMAKE_CXX_STANDARD 11)
 
 include_directories(../../)
+include_directories(../common/)
 
 file(GLOB gltfutil_sources *.cc *.h)
-add_executable(gltfutil ${gltfutil_sources})
+add_executable(gltfutil ${gltfutil_sources} ../common/lodepng.cpp)
 
 install ( TARGETS
   gltfutil

examples/gltfutil/gltfuilconfig.h

@@ -49,6 +49,7 @@ struct configuration {
   cli_action action = cli_action::not_set;
   texture_dumper::texture_output_format requested_format =
       texture_dumper::texture_output_format::not_specified;
+  bool use_exr = false;
 
   bool has_output_dir;
   bool is_valid() {

examples/gltfutil/main.cc

@@ -11,6 +11,9 @@
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #include "stb_image_write.h"
 
+#define TINYEXR_IMPLEMENTATION
+#include "tinyexr.h"
+
 namespace gltfutil {
 int usage(int ret = 0) {
   using std::cout;
@@ -20,8 +23,9 @@ int usage(int ret = 0) {
           "[path to output directory])\n\n"
        //<< "\t\t -i: start in interactive mode\n"
        << "\t\t -d: dump enclosed content (image assets)\n"
-       << "\t\t -f: file format for image output"
-       << "\t\t -o: ouptput directory path"
+       << "\t\t -f: file format for image output\n"
+       << "\t\t -o: ouptput directory path\n"
+       << "\t\t -e: Use OpenEXR format for 16bit image\n"
        << "\t\t -h: print this help\n";
   return ret;
 }
@@ -44,6 +48,9 @@ int parse_args(int argc, char** argv) {
           config.mode = ui_mode::cli;
           config.action = cli_action::dump;
           break;
+        case 'e':
+          config.use_exr = true;
+          break;
         case 'i':
           config.mode = ui_mode::interactive;
           break;
@@ -97,6 +104,11 @@ int parse_args(int argc, char** argv) {
 
         case cli_action::dump: {
           texture_dumper dumper(model);
+
+          if (config.use_exr) {
+            dumper.set_use_exr(true);
+          }
+
           if (config.requested_format !=
               texture_dumper::texture_output_format::not_specified)
             dumper.set_output_format(config.requested_format);

examples/gltfutil/texture_dumper.cc

@@ -1,15 +1,84 @@
-#include <iostream>
 #include <algorithm>
+#include <iostream>
 
 #include "stb_image_write.h"
 #include "texture_dumper.h"
 
+#include "lodepng.h"  // ../common
+
+#include "tinyexr.h"
+
 #include <tiny_gltf.h>
 
 using namespace gltfutil;
 using namespace tinygltf;
 using std::cout;
 
+static LodePNGColorType GetLodePNGColorType(int channels) {
+  if (channels == 1) {
+    return LodePNGColorType::LCT_GREY;
+  } else if (channels == 2) {
+    return LodePNGColorType::LCT_GREY_ALPHA;
+  } else if (channels == 3) {
+    return LodePNGColorType::LCT_RGB;
+  } else if (channels == 4) {
+    return LodePNGColorType::LCT_RGBA;
+  } else {
+    std::cerr << "??? unsupported channels " << channels << "\n";
+    return LodePNGColorType::LCT_RGB;  // FIXME(syoyo): Raise error
+  }
+}
+
+static void ToBigEndian(std::vector<uint8_t>* image) {
+
+  assert(image->size() % 2 == 0);
+
+  union {
+    unsigned int i;
+    char c[4];
+  } bint = {0x01020304};
+
+  bool is_big_endian = (bint.c[0] == 1);
+
+  if (is_big_endian) {
+    return;
+  }
+
+  uint16_t *ptr = reinterpret_cast<uint16_t *>(image->data());
+  size_t n = image->size() / 2;
+
+  for (size_t i = 0; i < n; i++) {
+    ptr[i] = ((0xFF00 & ptr[i]) >> 8) | ((0x00FF & ptr[i]) << 8);
+  }
+}
+
+static bool Save16bitImageAsEXR(const std::string& filename,
+                                const tinygltf::Image& image) {
+  assert(image.bits == 16);
+
+  std::vector<float> buf(image.width * image.height * image.component);
+
+  // widen to float image.
+  // Store as is(i.e, pixel value range is [0.0, 65535.0])
+  const unsigned short* ptr =
+      reinterpret_cast<const unsigned short*>(image.image.data());
+  for (size_t i = 0; i < image.width * image.height * image.component; i++) {
+    buf[i] = float(ptr[i]);
+  }
+
+  const char* err = nullptr;
+  int ret = SaveEXR(buf.data(), image.width, image.height, image.component,
+                    /* save_as_fp16 */ 0, filename.c_str(), &err);
+
+  if (err) {
+    std::cerr << "EXR err: " << err << std::endl;
+    FreeEXRErrorMessage(err);
+    return false;
+  }
+
+  return (ret == TINYEXR_SUCCESS);
+}
+
 texture_dumper::texture_dumper(const Model& input)
     : model(input), configured_format(texture_output_format::png) {
   cout << "Texture dumper\n";
@@ -26,26 +95,58 @@ void texture_dumper::dump_to_folder(const std::string& path) {
     cout << "image name is: \"" << image.name << "\"\n";
     cout << "image size is: " << image.width << 'x' << image.height << '\n';
     cout << "pixel channel count :" << image.component << '\n';
-    std::string name = image.name.empty() ? std::to_string(index) : image.name;
+    cout << "pixel bit depth :" << image.bits << '\n';
+    std::string basename =
+        image.name.empty() ? std::to_string(index) : image.name;
 
+    unsigned char* bytes_to_write =
+        const_cast<unsigned char*>(image.image.data());
+
+    std::string filename;
     switch (configured_format) {
       case texture_output_format::png:
-        name = path + "/" + name + ".png";
-        std::cout << "Image will be written to " << name << '\n';
-        stbi_write_png(name.c_str(), image.width, image.height, image.component,
-                       image.image.data(), 0);
+        filename = path + "/" + basename + ".png";
+
+        if (this->use_exr) {
+          if (image.pixel_type == TINYGLTF_COMPONENT_TYPE_UNSIGNED_SHORT) {
+            filename = path + "/" + basename + ".exr";
+          }
+        }
+
+        std::cout << "Image will be written to " << filename << '\n';
+
+        if (image.pixel_type == TINYGLTF_COMPONENT_TYPE_UNSIGNED_SHORT) {
+          if (this->use_exr) {
+            bool ret = Save16bitImageAsEXR(filename, image);
+            assert(ret);
+          } else {
+            // Use lodepng to save 16bit PNG.
+            // NOTE(syoyo): `loadpng::encode` requires image data must be stored in big endian.
+            std::vector<uint8_t> tmp = image.image; // copy
+            ToBigEndian(&tmp);
+
+            unsigned ret = lodepng::encode(
+                filename, tmp.data(), image.width, image.height,
+                GetLodePNGColorType(image.component), /* bits */ 16);
+            assert(ret == 0);  // 0 = no err.
+          }
+        } else {
+          // TODO(syoyo): check status
+          stbi_write_png(filename.c_str(), image.width, image.height,
+                         image.component, bytes_to_write, 0);
+        }
         break;
       case texture_output_format::bmp:
-        std::cout << "Image will be written to " << name << '\n';
-        name = path + "/" + name + ".bmp";
-        stbi_write_bmp(name.c_str(), image.width, image.height, image.component,
-                       image.image.data());
+        filename = path + "/" + basename + ".bmp";
+        std::cout << "Image will be written to " << filename << '\n';
+        stbi_write_bmp(filename.c_str(), image.width, image.height,
+                       image.component, bytes_to_write);
         break;
       case texture_output_format::tga:
-        std::cout << "Image will be written to " << name << '\n';
-        name = path + "/" + name + ".tga";
-        stbi_write_tga(name.c_str(), image.width, image.height, image.component,
-                       image.image.data());
+        filename = path + "/" + basename + ".tga";
+        std::cout << "Image will be written to " << filename << '\n';
+        stbi_write_tga(filename.c_str(), image.width, image.height,
+                       image.component, bytes_to_write);
         break;
     }
   }

examples/gltfutil/texture_dumper.h

@@ -12,11 +12,15 @@ class texture_dumper {
  private:
   const tinygltf::Model& model;
   texture_output_format configured_format;
+  bool use_exr = false; // Use EXR for 16bit image?
 
  public:
   texture_dumper(const tinygltf::Model& inputModel);
   void dump_to_folder(const std::string& path = "./");
   void set_output_format(texture_output_format format);
+  void set_use_exr(const bool value) {
+    use_exr = value;
+  }
 
   static texture_output_format get_fromat_from_string(const std::string& str);
 };

tiny_gltf.h

@@ -26,6 +26,7 @@
 // THE SOFTWARE.
 
 // Version:
+//  - v2.2.0 Add loading 16bit PNG support.
 //  - v2.1.0 Add draco compression.
 //  - v2.0.1 Add comparsion feature(Thanks to @Selmar).
 //  - v2.0.0 glTF 2.0!.
@@ -380,6 +381,17 @@ struct Parameter {
     return -1;
   }
 
+  /// Return the index of a texture coordinate set if this Parameter is a texture map.
+  /// Returned value is only valid if the parameter represent a texture from a
+  /// material
+  int TextureTexCoord() const {
+      const auto it = json_double_value.find("texCoord");
+      if (it != std::end(json_double_value)) {
+          return int(it->second);
+      }
+      return 0;
+  }
+
   /// Material factor, like the roughness or metalness of a material
   /// Returned value is only valid if the parameter represent a texture from a
   /// material
@@ -468,7 +480,9 @@ struct Sampler {
   Value extras;
 
   Sampler()
-      : wrapS(TINYGLTF_TEXTURE_WRAP_REPEAT),
+      : minFilter(TINYGLTF_TEXTURE_FILTER_LINEAR_MIPMAP_LINEAR),
+        magFilter(TINYGLTF_TEXTURE_FILTER_LINEAR),
+        wrapS(TINYGLTF_TEXTURE_WRAP_REPEAT),
         wrapT(TINYGLTF_TEXTURE_WRAP_REPEAT),
         wrapR(TINYGLTF_TEXTURE_WRAP_REPEAT){}
   bool operator==(const Sampler &) const;
@@ -479,6 +493,8 @@ struct Image {
   int width;
   int height;
   int component;
+  int bits; // bit depth per channel. 8(byte), 16 or 32.
+  int pixel_type; // pixel type(TINYGLTF_COMPONENT_TYPE_***). usually UBYTE(bits = 8) or USHORT(bits = 16)
   std::vector<unsigned char> image;
   int bufferView;        // (required if no uri)
   std::string mimeType;  // (required if no uri) ["image/jpeg", "image/png",
@@ -1062,7 +1078,19 @@ class TinyGLTF {
 #if __has_warning("-Wnewline-eof")
 #pragma clang diagnostic ignored "-Wnewline-eof"
 #endif
+#if __has_warning("-Wunused-parameter")
+#pragma clang diagnostic ignored "-Wunused-parameter"
 #endif
+#if __has_warning("-Wmismatched-tags")
+#pragma clang diagnostic ignored "-Wmismatched-tags"
+#endif
+#endif
+
+// Disable GCC warnigs
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wtype-limits"
+#endif // __GNUC__
 
 #include "json.hpp"
 
@@ -1083,8 +1111,34 @@ class TinyGLTF {
 #pragma clang diagnostic pop
 #endif
 
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
 #ifdef _WIN32
-#include <windows.h>
+
+// issue 143.
+// Define NOMINMAX to avoid min/max defines,
+// but undef it after included windows.h
+#ifndef NOMINMAX
+#define TINYGLTF_INTERNAL_NOMINMAX
+#define NOMINMAX
+#endif
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#define TINYGLTF_INTERNAL_WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h> // include API for expanding a file path
+
+#ifdef TINYGLTF_INTERNAL_WIN32_LEAN_AND_MEAN
+#undef WIN32_LEAN_AND_MEAN
+#endif
+
+#if defined(TINYGLTF_INTERNAL_NOMINMAX)
+#undef NOMINMAX
+#endif
+
 #elif !defined(__ANDROID__)
 #include <wordexp.h>
 #endif
@@ -1598,46 +1652,73 @@ void TinyGLTF::SetImageLoader(LoadImageDataFunction func, void *user_data) {
 }
 
 #ifndef TINYGLTF_NO_STB_IMAGE
-bool LoadImageData(Image *image, const int image_idx, std::string *err, std::string *warn,
-                   int req_width, int req_height, const unsigned char *bytes,
-                   int size, void *user_data) {
+bool LoadImageData(Image *image, const int image_idx, std::string *err,
+                   std::string *warn, int req_width, int req_height,
+                   const unsigned char *bytes, int size, void *user_data) {
+  (void)user_data;
   (void)warn;
 
   int w, h, comp, req_comp;
 
+  unsigned char *data = nullptr;
+
   // force 32-bit textures for common Vulkan compatibility. It appears that
   // some GPU drivers do not support 24-bit images for Vulkan
   req_comp = 4;
+  int bits = 8;
+  int pixel_type = TINYGLTF_COMPONENT_TYPE_UNSIGNED_BYTE;
 
+  // It is possible that the image we want to load is a 16bit per channel image
+  // We are going to attempt to load it as 16bit per channel, and if it worked,
+  // set the image data accodingly. We are casting the returned pointer into
+  // unsigned char, because we are representing "bytes". But we are updating
+  // the Image metadata to signal that this image uses 2 bytes (16bits) per
+  // channel:
+  if (stbi_is_16_bit_from_memory(bytes, size)) {
+    data = (unsigned char *)stbi_load_16_from_memory(bytes, size, &w, &h, &comp,
+                                                     req_comp);
+    if (data) {
+      bits = 16;
+      pixel_type = TINYGLTF_COMPONENT_TYPE_UNSIGNED_SHORT;
+    }
+  }
+
+  // at this point, if data is still NULL, it means that the image wasn't
+  // 16bit per channel, we are going to load it as a normal 8bit per channel
+  // mage as we used to do:
   // if image cannot be decoded, ignore parsing and keep it by its path
   // don't break in this case
   // FIXME we should only enter this function if the image is embedded. If
   // image->uri references
   // an image file, it should be left as it is. Image loading should not be
   // mandatory (to support other formats)
-  unsigned char *data =
-      stbi_load_from_memory(bytes, size, &w, &h, &comp, req_comp);
+  if (!data) data = stbi_load_from_memory(bytes, size, &w, &h, &comp, req_comp);
   if (!data) {
     // NOTE: you can use `warn` instead of `err`
     if (err) {
-      (*err) += "Unknown image format. STB cannot decode image data for image[" + std::to_string(image_idx) + "] name = \"" + image->name + "\". Proably 16bit PNG?\n";
+      (*err) +=
+          "Unknown image format. STB cannot decode image data for image[" +
+          std::to_string(image_idx) + "] name = \"" + image->name + "\".\n";
     }
     return false;
   }
 
   if (w < 1 || h < 1) {
-    free(data);
+    stbi_image_free(data);
     if (err) {
-      (*err) += "Invalid image data for image[" + std::to_string(image_idx) + "] name = \"" + image->name + "\"\n";
+      (*err) += "Invalid image data for image[" + std::to_string(image_idx) +
+                "] name = \"" + image->name + "\"\n";
     }
     return false;
   }
 
   if (req_width > 0) {
     if (req_width != w) {
-      free(data);
+      stbi_image_free(data);
       if (err) {
-        (*err) += "Image width mismatch for image[" + std::to_string(image_idx) + "] name = \"" + image->name + "\"\n";
+        (*err) += "Image width mismatch for image[" +
+                  std::to_string(image_idx) + "] name = \"" + image->name +
+                  "\"\n";
       }
       return false;
     }
@@ -1645,9 +1726,11 @@ bool LoadImageData(Image *image, const int image_idx, std::string *err, std::str
 
   if (req_height > 0) {
     if (req_height != h) {
-      free(data);
+      stbi_image_free(data);
       if (err) {
-        (*err) += "Image height mismatch. for image[" + std::to_string(image_idx) + "] name = \"" + image->name + "\"\n";
+        (*err) += "Image height mismatch. for image[" +
+                  std::to_string(image_idx) + "] name = \"" + image->name +
+                  "\"\n";
       }
       return false;
     }
@@ -1656,10 +1739,11 @@ bool LoadImageData(Image *image, const int image_idx, std::string *err, std::str
   image->width = w;
   image->height = h;
   image->component = req_comp;
-  image->image.resize(static_cast<size_t>(w * h * req_comp));
-  std::copy(data, data + w * h * req_comp, image->image.begin());
-
-  free(data);
+  image->bits = bits;
+  image->pixel_type = pixel_type;
+  image->image.resize(static_cast<size_t>(w * h * req_comp) * (bits / 8));
+  std::copy(data, data + w * h * req_comp * (bits / 8), image->image.begin());
+  stbi_image_free(data);
 
   return true;
 }
@@ -1689,6 +1773,11 @@ bool WriteImageData(const std::string *basepath, const std::string *filename,
   std::vector<unsigned char> data;
 
   if (ext == "png") {
+    if ((image->bits != 8) || (image->pixel_type != TINYGLTF_COMPONENT_TYPE_UNSIGNED_BYTE)) {
+      // Unsupported pixel format
+      return false;
+    }
+
     if (!stbi_write_png_to_func(WriteToMemory_stbi, &data, image->width,
                                 image->height, image->component,
                                 &image->image[0], 0)) {
@@ -3045,6 +3134,8 @@ static bool ParsePrimitive(Primitive *primitive, Model *model, std::string *err,
   {
       ParseDracoExtension(primitive, model, err, dracoExtension->second);
   }
+#else
+  (void)model;
 #endif
 
   return true;
@@ -3261,13 +3352,8 @@ static bool ParseAnimation(Animation *animation, std::string *err,
           }
           return false;
         }
-        if (!ParseStringProperty(&sampler.interpolation, err, s,
-                                 "interpolation", true)) {
-          if (err) {
-            (*err) += "`interpolation` field is missing in animation.sampler\n";
-          }
-          return false;
-        }
+        ParseStringProperty(&sampler.interpolation, err, s, "interpolation",
+                            false);
         if (!ParseNumberProperty(&outputIndex, err, s, "output", true)) {
           if (err) {
             (*err) += "`output` field is missing in animation.sampler\n";
@@ -4825,7 +4911,7 @@ static void WriteBinaryGltfFile(const std::string &output,
 
   // 12 bytes for header, JSON content length, 8 bytes for JSON chunk info, padding
   const int length = 12 + 8 + int(content.size()) + padding_size;
-  
+
   gltfFile.write(header.c_str(), header.size());
   gltfFile.write(reinterpret_cast<const char *>(&version), sizeof(version));
   gltfFile.write(reinterpret_cast<const char *>(&length), sizeof(length));