Merge pull request #596 from zeux/gltf-objext

gltfpack: Enhance .obj parsing by preserving more information

gltf/gltfpack.h

@@ -11,6 +11,10 @@
 #define _CRT_SECURE_NO_WARNINGS
 #endif
 
+#ifndef _CRT_NONSTDC_NO_WARNINGS
+#define _CRT_NONSTDC_NO_WARNINGS
+#endif
+
 #include "../extern/cgltf.h"
 
 #include <assert.h>

gltf/parseobj.cpp

@@ -21,11 +21,16 @@ static int textureIndex(const std::vector<std::string>& textures, const char* na
 	return -1;
 }
 
-static cgltf_data* parseSceneObj(fastObjMesh* obj)
+static void fixupUri(char* uri)
 {
-	cgltf_data* data = (cgltf_data*)calloc(1, sizeof(cgltf_data));
-	data->memory.free_func = defaultFree;
+	// Some .obj paths come with back slashes, that are invalid as URI separators and won't open on macOS/Linux when embedding textures
+	for (char* s = uri; *s; ++s)
+		if (*s == '\\')
+			*s = '/';
+}
 
+static void parseMaterialsObj(fastObjMesh* obj, cgltf_data* data)
+{
 	std::vector<std::string> textures;
 
 	for (unsigned int mi = 0; mi < obj->material_count; ++mi)
@@ -41,8 +46,8 @@ static cgltf_data* parseSceneObj(fastObjMesh* obj)
 
 	for (size_t i = 0; i < textures.size(); ++i)
 	{
-		data->images[i].uri = (char*)malloc(textures[i].size() + 1);
-		strcpy(data->images[i].uri, textures[i].c_str());
+		data->images[i].uri = strdup(textures[i].c_str());
+		fixupUri(data->images[i].uri);
 	}
 
 	data->textures = (cgltf_texture*)calloc(textures.size(), sizeof(cgltf_texture));
@@ -58,14 +63,19 @@ static cgltf_data* parseSceneObj(fastObjMesh* obj)
 
 	for (unsigned int mi = 0; mi < obj->material_count; ++mi)
 	{
+		const fastObjMaterial& om = obj->materials[mi];
 		cgltf_material& gm = data->materials[mi];
-		fastObjMaterial& om = obj->materials[mi];
+
+		if (om.name)
+			gm.name = strdup(om.name);
 
 		gm.has_pbr_metallic_roughness = true;
+
 		gm.pbr_metallic_roughness.base_color_factor[0] = 1.0f;
 		gm.pbr_metallic_roughness.base_color_factor[1] = 1.0f;
 		gm.pbr_metallic_roughness.base_color_factor[2] = 1.0f;
 		gm.pbr_metallic_roughness.base_color_factor[3] = 1.0f;
+
 		gm.pbr_metallic_roughness.metallic_factor = 0.0f;
 		gm.pbr_metallic_roughness.roughness_factor = 1.0f;
 
@@ -78,17 +88,58 @@ static cgltf_data* parseSceneObj(fastObjMesh* obj)
 
 			gm.alpha_mode = (om.illum == 4 || om.illum == 6 || om.illum == 7 || om.illum == 9) ? cgltf_alpha_mode_mask : cgltf_alpha_mode_opaque;
 		}
+		else
+		{
+			gm.pbr_metallic_roughness.base_color_factor[0] = om.Kd[0];
+			gm.pbr_metallic_roughness.base_color_factor[1] = om.Kd[1];
+			gm.pbr_metallic_roughness.base_color_factor[2] = om.Kd[2];
+		}
 
 		if (om.map_d.name)
 		{
+			if (om.map_Kd.name && strcmp(om.map_Kd.name, om.map_d.name) != 0)
+				fprintf(stderr, "Warning: material has different diffuse and alpha textures (Kd: %s, d: %s) and might not render correctly\n", om.map_Kd.name, om.map_d.name);
+
+			gm.alpha_mode = cgltf_alpha_mode_blend;
+		}
+		else if (om.d < 1.0f)
+		{
+			gm.pbr_metallic_roughness.base_color_factor[3] = om.d;
+
 			gm.alpha_mode = cgltf_alpha_mode_blend;
 		}
 	}
+}
+
+static void parseNodesObj(fastObjMesh* obj, cgltf_data* data)
+{
+	data->nodes = (cgltf_node*)calloc(obj->object_count, sizeof(cgltf_node));
+	data->nodes_count = obj->object_count;
+
+	for (unsigned int oi = 0; oi < obj->object_count; ++oi)
+	{
+		const fastObjGroup& og = obj->objects[oi];
+		cgltf_node* node = &data->nodes[oi];
+
+		if (og.name)
+			node->name = strdup(og.name);
+
+		node->rotation[3] = 1.0f;
+		node->scale[0] = 1.0f;
+		node->scale[1] = 1.0f;
+		node->scale[2] = 1.0f;
+	}
 
 	data->scenes = (cgltf_scene*)calloc(1, sizeof(cgltf_scene));
 	data->scenes_count = 1;
 
-	return data;
+	data->scene = data->scenes;
+
+	data->scenes->nodes = (cgltf_node**)calloc(obj->object_count, sizeof(cgltf_node*));
+	data->scenes->nodes_count = obj->object_count;
+
+	for (unsigned int oi = 0; oi < obj->object_count; ++oi)
+		data->scenes->nodes[oi] = &data->nodes[oi];
 }
 
 static void parseMeshObj(fastObjMesh* obj, unsigned int face_offset, unsigned int face_vertex_offset, unsigned int face_count, unsigned int face_vertex_count, unsigned int index_count, Mesh& mesh)
@@ -179,19 +230,20 @@ static void parseMeshObj(fastObjMesh* obj, unsigned int face_offset, unsigned in
 	assert(index_offset == index_count);
 }
 
-static void parseMeshesObj(fastObjMesh* obj, cgltf_data* data, std::vector<Mesh>& meshes)
+static void parseMeshGroupObj(fastObjMesh* obj, const fastObjGroup& og, cgltf_data* data, cgltf_node* node, std::vector<Mesh>& meshes)
 {
-	unsigned int face_vertex_offset = 0;
+	unsigned int face_vertex_offset = og.index_offset;
+	unsigned int face_end_offset = og.face_offset + og.face_count;
 
-	for (unsigned int face_offset = 0; face_offset < obj->face_count; )
+	for (unsigned int face_offset = og.face_offset; face_offset < face_end_offset; )
 	{
 		unsigned int mi = obj->face_materials[face_offset];
 
 		unsigned int face_count = 0;
 		unsigned int face_vertex_count = 0;
 		unsigned int index_count = 0;
 
-		for (unsigned int fj = face_offset; fj < obj->face_count && obj->face_materials[fj] == mi; ++fj)
+		for (unsigned int fj = face_offset; fj < face_end_offset && obj->face_materials[fj] == mi; ++fj)
 		{
 			face_count += 1;
 			face_vertex_count += obj->face_vertices[fj];
@@ -210,6 +262,9 @@ static void parseMeshesObj(fastObjMesh* obj, cgltf_data* data, std::vector<Mesh>
 		mesh.type = cgltf_primitive_type_triangles;
 		mesh.targets = 0;
 
+		if (node)
+			mesh.nodes.push_back(node);
+
 		parseMeshObj(obj, face_offset, face_vertex_offset, face_count, face_vertex_count, index_count, mesh);
 
 		face_offset += face_count;
@@ -227,9 +282,16 @@ cgltf_data* parseObj(const char* path, std::vector<Mesh>& meshes, const char** e
 		return 0;
 	}
 
-	cgltf_data* data = parseSceneObj(obj);
+	cgltf_data* data = (cgltf_data*)calloc(1, sizeof(cgltf_data));
+	data->memory.free_func = defaultFree;
+
+	parseMaterialsObj(obj, data);
+
+	parseNodesObj(obj, data);
+	assert(data->nodes_count == obj->object_count);
 
-	parseMeshesObj(obj, data, meshes);
+	for (unsigned int oi = 0; oi < obj->object_count; ++oi)
+		parseMeshGroupObj(obj, obj->objects[oi], data, &data->nodes[oi], meshes);
 
 	fast_obj_destroy(obj);