Merge pull request #246 from zeux/master

Implement support for KHR_materials_dispersion

cgltf.h

@@ -505,6 +505,11 @@ typedef struct cgltf_anisotropy
 	cgltf_texture_view anisotropy_texture;
 } cgltf_anisotropy;
 
+typedef struct cgltf_dispersion
+{
+	cgltf_float dispersion;
+} cgltf_dispersion;
+
 typedef struct cgltf_material
 {
 	char* name;
@@ -519,6 +524,7 @@ typedef struct cgltf_material
 	cgltf_bool has_emissive_strength;
 	cgltf_bool has_iridescence;
 	cgltf_bool has_anisotropy;
+	cgltf_bool has_dispersion;
 	cgltf_pbr_metallic_roughness pbr_metallic_roughness;
 	cgltf_pbr_specular_glossiness pbr_specular_glossiness;
 	cgltf_clearcoat clearcoat;
@@ -530,6 +536,7 @@ typedef struct cgltf_material
 	cgltf_emissive_strength emissive_strength;
 	cgltf_iridescence iridescence;
 	cgltf_anisotropy anisotropy;
+	cgltf_dispersion dispersion;
 	cgltf_texture_view normal_texture;
 	cgltf_texture_view occlusion_texture;
 	cgltf_texture_view emissive_texture;
@@ -4297,6 +4304,37 @@ static int cgltf_parse_json_anisotropy(cgltf_options* options, jsmntok_t const*
 	return i;
 }
 
+static int cgltf_parse_json_dispersion(jsmntok_t const* tokens, int i, const uint8_t* json_chunk, cgltf_dispersion* out_dispersion)
+{
+	CGLTF_CHECK_TOKTYPE(tokens[i], JSMN_OBJECT);
+	int size = tokens[i].size;
+	++i;
+
+
+	for (int j = 0; j < size; ++j)
+	{
+		CGLTF_CHECK_KEY(tokens[i]);
+
+		if (cgltf_json_strcmp(tokens + i, json_chunk, "dispersion") == 0)
+		{
+			++i;
+			out_dispersion->dispersion = cgltf_json_to_float(tokens + i, json_chunk);
+			++i;
+		}
+		else
+		{
+			i = cgltf_skip_json(tokens, i + 1);
+		}
+
+		if (i < 0)
+		{
+			return i;
+		}
+	}
+
+	return i;
+}
+
 static int cgltf_parse_json_image(cgltf_options* options, jsmntok_t const* tokens, int i, const uint8_t* json_chunk, cgltf_image* out_image)
 {
 	CGLTF_CHECK_TOKTYPE(tokens[i], JSMN_OBJECT);
@@ -4690,6 +4728,11 @@ static int cgltf_parse_json_material(cgltf_options* options, jsmntok_t const* to
 					out_material->has_anisotropy = 1;
 					i = cgltf_parse_json_anisotropy(options, tokens, i + 1, json_chunk, &out_material->anisotropy);
 				}
+				else if (cgltf_json_strcmp(tokens + i, json_chunk, "KHR_materials_dispersion") == 0)
+				{
+					out_material->has_dispersion = 1;
+					i = cgltf_parse_json_dispersion(tokens, i + 1, json_chunk, &out_material->dispersion);
+				}
 				else
 				{
 					i = cgltf_parse_json_unprocessed_extension(options, tokens, i, json_chunk, &(out_material->extensions[out_material->extensions_count++]));

cgltf_write.h

@@ -86,6 +86,7 @@ cgltf_size cgltf_write(const cgltf_options* options, char* buffer, cgltf_size si
 #define CGLTF_EXTENSION_FLAG_MESH_GPU_INSTANCING (1 << 14)
 #define CGLTF_EXTENSION_FLAG_MATERIALS_IRIDESCENCE (1 << 15)
 #define CGLTF_EXTENSION_FLAG_MATERIALS_ANISOTROPY (1 << 16)
+#define CGLTF_EXTENSION_FLAG_MATERIALS_DISPERSION (1 << 17)
 
 typedef struct {
 	char* buffer;
@@ -659,6 +660,11 @@ static void cgltf_write_material(cgltf_write_context* context, const cgltf_mater
 		context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_ANISOTROPY;
 	}
 
+	if (material->has_dispersion)
+	{
+		context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_DISPERSION;
+	}
+
 	if (material->has_pbr_metallic_roughness)
 	{
 		const cgltf_pbr_metallic_roughness* params = &material->pbr_metallic_roughness;
@@ -674,7 +680,7 @@ static void cgltf_write_material(cgltf_write_context* context, const cgltf_mater
 		cgltf_write_line(context, "}");
 	}
 
-	if (material->unlit || material->has_pbr_specular_glossiness || material->has_clearcoat || material->has_ior || material->has_specular || material->has_transmission || material->has_sheen || material->has_volume || material->has_emissive_strength || material->has_iridescence || material->has_anisotropy)
+	if (material->unlit || material->has_pbr_specular_glossiness || material->has_clearcoat || material->has_ior || material->has_specular || material->has_transmission || material->has_sheen || material->has_volume || material->has_emissive_strength || material->has_iridescence || material->has_anisotropy || material->has_dispersion)
 	{
 		cgltf_write_line(context, "\"extensions\": {");
 		if (material->has_clearcoat)
@@ -794,6 +800,13 @@ static void cgltf_write_material(cgltf_write_context* context, const cgltf_mater
 			CGLTF_WRITE_TEXTURE_INFO("anisotropyTexture", params->anisotropy_texture);
 			cgltf_write_line(context, "}");
 		}
+		if (material->has_dispersion)
+		{
+			cgltf_write_line(context, "\"KHR_materials_dispersion\": {");
+			const cgltf_dispersion* params = &material->dispersion;
+			cgltf_write_floatprop(context, "dispersion", params->dispersion, 0.f);
+			cgltf_write_line(context, "}");
+		}
 		cgltf_write_line(context, "}");
 	}
 
@@ -1279,6 +1292,9 @@ static void cgltf_write_extensions(cgltf_write_context* context, uint32_t extens
 	if (extension_flags & CGLTF_EXTENSION_FLAG_MESH_GPU_INSTANCING) {
 		cgltf_write_stritem(context, "EXT_mesh_gpu_instancing");
 	}
+	if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_DISPERSION) {
+		cgltf_write_stritem(context, "KHR_materials_dispersion");
+	}
 }
 
 cgltf_size cgltf_write(const cgltf_options* options, char* buffer, cgltf_size size, const cgltf_data* data)