[#79] Start re-implementing loadMesh.

The new function is not complete, so the old one is still kept around.

modules/asset_loader/include/vkcv/asset/asset_loader.hpp

@@ -254,17 +254,21 @@ int loadScene(const std::filesystem::path &path, Scene &scene);
 int probeScene(const std::filesystem::path &path, Scene &scene);
 
 /**
- * This function loads a single mesh from the given file into the given Scene.
- * TODO document whather this function extends or overwrites the given scene
- * The names of meshes can be obtained by calling probeScene() and iterating
- * through the array of meshes from the probed scene.
+ * This function loads a single mesh from the given file and adds it to the
+ * given scene. The scene must already be initialized (via probeScene()).
+ * The mesh_index refers to the Scenes meshes array and identifies the mesh to
+ * load. To find the mesh you want, iterate over the probed scene and check the
+ * meshes details (eg. name).
  * Besides the mesh, this function will also add any associated data to the
  * Scene struct such as Materials and Textures required by the Mesh.
  *
  * @param path	must be the path to a glTF- or glb-file.
  * @param scene	is the scene struct to which the results will be written.
  */
-int loadMesh(const std::filesystem::path &path, const std::string &name, Scene &scene);
+int loadMesh(Scene &scene, const int mesh_index);
+
+// The old loadMesh-function, to be removed
+int loadMesh(const std::filesystem::path &path, const std::string &name, Scene &scene) {
 
 
 struct TextureData {

modules/asset_loader/src/vkcv/asset/asset_loader.cpp

@@ -460,7 +460,7 @@ int createVertexGroups(fx::gltf::Mesh const& objectMesh,
 		std::vector<uint8_t> indexBufferData = {};
 		const fx::gltf::Accessor& indexAccessor = sceneObjects.accessors[objectPrimitive.indices];
 		int indexBufferURI;
-		if (objectPrimitive.indices >= 0 && !probe) { // if there is no index buffer, -1 is returned from fx-gltf
+		if (objectPrimitive.indices >= 0) { // if there is no index buffer, -1 is returned from fx-gltf
 			const fx::gltf::BufferView& indexBufferView = sceneObjects.bufferViews[indexAccessor.bufferView];
 			const fx::gltf::Buffer& indexBuffer = sceneObjects.buffers[indexBufferView.buffer];
 			if (known_uris.count(indexBuffer.uri)) {
@@ -471,7 +471,7 @@ int createVertexGroups(fx::gltf::Mesh const& objectMesh,
 			}
 
 			indexBufferData.resize(indexBufferView.byteLength);
-			{
+			if (!probe) {
 				const size_t off = indexBufferView.byteOffset;
 				const void* const ptr = ((char*)indexBuffer.data.data()) + off;
 				if (!memcpy(indexBufferData.data(), ptr, indexBufferView.byteLength)) {
@@ -818,6 +818,20 @@ int probeScene(const std::filesystem::path& path, Scene& scene) {
 }
 
 
+int loadMesh(Scene &scene, const int idx)
+{
+	if (idx < 0 || (size_t)idx >= scene.meshes.size()) {
+		vkcv_log(LogLevel::ERROR, "mesh index out of range: %d", idx);
+		return ASSET_ERROR;
+	}
+	Mesh &mesh = scene.meshes[idx];
+
+	// TODO go through all vertex groups of the mesh and load the
+	// associated materials and index/vertex buffers
+	return ASSET_SUCCESS;
+}
+
+
 int loadMesh(const std::filesystem::path &path, const std::string &name, Scene &scene) {
 	fx::gltf::Document sceneObjects;