Serializer skips null values

tiny_gltf.h

@@ -3298,9 +3298,10 @@ static void SerializeNumberArrayProperty(const std::string &key,
   for (unsigned int i = 0; i < value.size(); ++i) {
     vals.push_back(static_cast<double>(value[i]));
   }
-
+  if (!vals.is_null()) {
     obj[key] = vals;
   }
+}
 
 static void SerializeStringProperty(const std::string &key,
                                     const std::string &value, json &obj) {
@@ -3477,10 +3478,20 @@ static void SerializeGltfBuffer(Buffer &buffer, json &o,
 static void SerializeGltfBufferView(BufferView &bufferView, json &o) {
   SerializeNumberProperty("buffer", bufferView.buffer, o);
   SerializeNumberProperty<size_t>("byteLength", bufferView.byteLength, o);
-  SerializeNumberProperty<size_t>("byteStride", bufferView.byteStride, o);
-  SerializeNumberProperty<size_t>("byteOffset", bufferView.byteOffset, o);
-  SerializeNumberProperty("target", bufferView.target, o);
 
+  // byteStride is optional, minimum allowed is 4
+  if (bufferView.byteStride >= 4) {
+    SerializeNumberProperty<size_t>("byteStride", bufferView.byteStride, o);
+  }
+  // byteOffset is optional, default is 0
+  if (bufferView.byteOffset > 0) {
+    SerializeNumberProperty<size_t>("byteOffset", bufferView.byteOffset, o);
+  }
+  // Target is optional, check if it contains a valid value
+  if (bufferView.target == TINYGLTF_TARGET_ARRAY_BUFFER ||
+      bufferView.target == TINYGLTF_TARGET_ELEMENT_ARRAY_BUFFER) {
+    SerializeNumberProperty("target", bufferView.target, o);
+  }
   if (bufferView.name.size()) {
     SerializeStringProperty("name", bufferView.name, o);
   }
@@ -3532,8 +3543,15 @@ static void SerializeGltfMesh(Mesh &mesh, json &o) {
     }
 
     primitive["attributes"] = attributes;
+
+    // Indicies is optional
+    if (gltfPrimitive.indices > -1) {
       SerializeNumberProperty<int>("indices", gltfPrimitive.indices, primitive);
+    }
+    // Material is optional
+    if (gltfPrimitive.material > -1) {
       SerializeNumberProperty<int>("material", gltfPrimitive.material, primitive);
+    }
     SerializeNumberProperty<int>("mode", gltfPrimitive.mode, primitive);
 
     // Morph targets
@@ -3773,6 +3791,7 @@ bool TinyGLTF::WriteGltfSceneToFile(
   }
 
   // IMAGES
+  if (model->images.size()) {
     json images;
     for (unsigned int i = 0; i < model->images.size(); ++i) {
       json image;
@@ -3780,8 +3799,10 @@ bool TinyGLTF::WriteGltfSceneToFile(
       images.push_back(image);
     }
     output["images"] = images;
+  }
 
   // MATERIALS
+  if (model->materials.size()) {
     json materials;
     for (unsigned int i = 0; i < model->materials.size(); ++i) {
       json material;
@@ -3789,8 +3810,10 @@ bool TinyGLTF::WriteGltfSceneToFile(
       materials.push_back(material);
     }
     output["materials"] = materials;
+  }
 
   // MESHES
+  if (model->meshes.size()) {
     json meshes;
     for (unsigned int i = 0; i < model->meshes.size(); ++i) {
       json mesh;
@@ -3798,8 +3821,10 @@ bool TinyGLTF::WriteGltfSceneToFile(
       meshes.push_back(mesh);
     }
     output["meshes"] = meshes;
+  }
 
   // NODES
+  if (model->nodes.size()) {
     json nodes;
     for (unsigned int i = 0; i < model->nodes.size(); ++i) {
       json node;
@@ -3807,11 +3832,15 @@ bool TinyGLTF::WriteGltfSceneToFile(
       nodes.push_back(node);
     }
     output["nodes"] = nodes;
+  }
 
   // SCENE
+  if (model->defaultScene > -1) {
     SerializeNumberProperty<int>("scene", model->defaultScene, output);
+  }
 
   // SCENES
+  if (model->scenes.size()) {
     json scenes;
     for (unsigned int i = 0; i < model->scenes.size(); ++i) {
       json currentScene;
@@ -3819,6 +3848,7 @@ bool TinyGLTF::WriteGltfSceneToFile(
       scenes.push_back(currentScene);
     }
     output["scenes"] = scenes;
+  }
 
   // SKINS
   if (model->skins.size()) {
@@ -3832,6 +3862,7 @@ bool TinyGLTF::WriteGltfSceneToFile(
   }
 
   // TEXTURES
+  if (model->textures.size()) {
     json textures;
     for (unsigned int i = 0; i < model->textures.size(); ++i) {
       json texture;
@@ -3839,8 +3870,10 @@ bool TinyGLTF::WriteGltfSceneToFile(
       textures.push_back(texture);
     }
     output["textures"] = textures;
+  }
 
   // SAMPLERS
+  if (model->samplers.size()) {
     json samplers;
     for (unsigned int i = 0; i < model->samplers.size(); ++i) {
       json sampler;
@@ -3848,8 +3881,10 @@ bool TinyGLTF::WriteGltfSceneToFile(
       samplers.push_back(sampler);
     }
     output["samplers"] = samplers;
+  }
 
   // CAMERAS
+  if (model->cameras.size()) {
     json cameras;
     for (unsigned int i = 0; i < model->cameras.size(); ++i) {
       json camera;
@@ -3857,8 +3892,10 @@ bool TinyGLTF::WriteGltfSceneToFile(
       cameras.push_back(camera);
     }
     output["cameras"] = cameras;
+  }
 
   // LIGHTS
+  if (model->lights.size()) {
     json lights;
     for (unsigned int i = 0; i < model->lights.size(); ++i) {
       json light;
@@ -3866,6 +3903,7 @@ bool TinyGLTF::WriteGltfSceneToFile(
       lights.push_back(light);
     }
     output["lights"] = lights;
+  }
 
   WriteGltfFile(filename, output.dump());
   return true;