code: /*************************************************************************/
  /*  editor_scene_importer_gltf.cpp                                       */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
  /*                                                                       */
  /* Permission is hereby granted, free of charge, to any person obtaining */
  /* a copy of this software and associated documentation files (the       */
  /* "Software"), to deal in the Software without restriction, including   */
  /* without limitation the rights to use, copy, modify, merge, publish,   */
  /* distribute, sublicense, and/or sell copies of the Software, and to    */
  /* permit persons to whom the Software is furnished to do so, subject to */
  /* the following conditions:                                             */
  /*                                                                       */
  /* The above copyright notice and this permission notice shall be        */
  /* included in all copies or substantial portions of the Software.       */
  /*                                                                       */
  /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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  /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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  /*************************************************************************/
  
  #include "core/crypto/crypto_core.h"
  #include "core/io/json.h"
  #include "core/math/disjoint_set.h"
  #include "core/math/math_defs.h"
  #include "core/os/file_access.h"
  #include "core/os/os.h"
  #include "editor/import/resource_importer_scene.h"
  #include "modules/gltf/gltf_state.h"
  #include "modules/regex/regex.h"
  #include "scene/3d/bone_attachment_3d.h"
  #include "scene/3d/camera_3d.h"
  #include "scene/3d/mesh_instance_3d.h"
  #include "scene/animation/animation_player.h"
  #include "scene/resources/packed_scene.h"
  #include "scene/resources/surface_tool.h"
  
  #include "modules/gltf/editor_scene_importer_gltf.h"
  
  uint32_t EditorSceneImporterGLTF::get_import_flags() const {
  	return ImportFlags::IMPORT_SCENE | ImportFlags::IMPORT_ANIMATION;
  }
  
  void EditorSceneImporterGLTF::get_extensions(List<String> *r_extensions) const {
  	r_extensions->push_back("gltf");
  	r_extensions->push_back("glb");
  }
  
  Node *EditorSceneImporterGLTF::import_scene(const String &p_path,
  		uint32_t p_flags, int p_bake_fps,
  		List<String> *r_missing_deps,
  		Error *r_err) {
  	Ref<PackedSceneGLTF> importer;
  	importer.instance();
  	return importer->import_scene(p_path, p_flags, p_bake_fps, r_missing_deps, r_err, Ref<GLTFState>());
  }
  
  Ref<Animation> EditorSceneImporterGLTF::import_animation(const String &p_path,
  		uint32_t p_flags,
  		int p_bake_fps) {
  	return Ref<Animation>();
  }
  
  void PackedSceneGLTF::_bind_methods() {
  	ClassDB::bind_method(
  			D_METHOD("export_gltf", "node", "path", "flags", "bake_fps"),
  			&PackedSceneGLTF::export_gltf, DEFVAL(0), DEFVAL(1000.0f));
  	ClassDB::bind_method(D_METHOD("pack_gltf", "path", "flags", "bake_fps", "state"),
  			&PackedSceneGLTF::pack_gltf, DEFVAL(0), DEFVAL(1000.0f), DEFVAL(Ref<GLTFState>()));
  	ClassDB::bind_method(D_METHOD("import_gltf_scene", "path", "flags", "bake_fps", "state"),
  			&PackedSceneGLTF::import_gltf_scene, DEFVAL(0), DEFVAL(1000.0f), DEFVAL(Ref<GLTFState>()));
  }
  Node *PackedSceneGLTF::import_gltf_scene(const String &p_path, uint32_t p_flags, float p_bake_fps, Ref<GLTFState> r_state) {
  	Error err = FAILED;
  	List<String> deps;
  	return import_scene(p_path, p_flags, p_bake_fps, &deps, &err, r_state);
  }
  
  Node *PackedSceneGLTF::import_scene(const String &p_path, uint32_t p_flags,
  		int p_bake_fps,
  		List<String> *r_missing_deps,
  		Error *r_err,
  		Ref<GLTFState> r_state) {
  	if (r_state == Ref<GLTFState>()) {
  		r_state.instance();
  	}
  	r_state->use_named_skin_binds =
  			p_flags & EditorSceneImporter::IMPORT_USE_NAMED_SKIN_BINDS;
  
  	Ref<GLTFDocument> gltf_document;
  	gltf_document.instance();
  	Error err = gltf_document->parse(r_state, p_path);
  	*r_err = err;
  	ERR_FAIL_COND_V(err != Error::OK, nullptr);
  
  	Node3D *root = memnew(Node3D);
  	for (int32_t root_i = 0; root_i < r_state->root_nodes.size(); root_i++) {
  		gltf_document->_generate_scene_node(r_state, root, root, r_state->root_nodes[root_i]);
  	}
  	gltf_document->_process_mesh_instances(r_state, root);
  	if (r_state->animations.size()) {
  		AnimationPlayer *ap = memnew(AnimationPlayer);
  		root->add_child(ap);
  		ap->set_owner(root);
  		for (int i = 0; i < r_state->animations.size(); i++) {
  			gltf_document->_import_animation(r_state, ap, i, p_bake_fps);
  		}
  	}
  
  	return cast_to<Node3D>(root);
  }
  
  void PackedSceneGLTF::pack_gltf(String p_path, int32_t p_flags,
  		real_t p_bake_fps, Ref<GLTFState> r_state) {
  	Error err = FAILED;
  	List<String> deps;
  	Node *root = import_scene(p_path, p_flags, p_bake_fps, &deps, &err, r_state);
  	ERR_FAIL_COND(err != OK);
  	pack(root);
  }
  
  void PackedSceneGLTF::save_scene(Node *p_node, const String &p_path,
  		const String &p_src_path, uint32_t p_flags,
  		int p_bake_fps, List<String> *r_missing_deps,
  		Error *r_err) {
  	Error err = FAILED;
  	if (r_err) {
  		*r_err = err;
  	}
  	Ref<GLTFDocument> gltf_document;
  	gltf_document.instance();
  	Ref<GLTFState> state;
  	state.instance();
  	err = gltf_document->serialize(state, p_node, p_path);
  	if (r_err) {
  		*r_err = err;
  	}
  }
  
  void PackedSceneGLTF::_build_parent_hierachy(Ref<GLTFState> state) {
  	// build the hierarchy
  	for (GLTFNodeIndex node_i = 0; node_i < state->nodes.size(); node_i++) {
  		for (int j = 0; j < state->nodes[node_i]->children.size(); j++) {
  			GLTFNodeIndex child_i = state->nodes[node_i]->children[j];
  			ERR_FAIL_INDEX(child_i, state->nodes.size());
  			if (state->nodes.write[child_i]->parent != -1) {
  				continue;
  			}
  			state->nodes.write[child_i]->parent = node_i;
  		}
  	}
  }
  
  Error PackedSceneGLTF::export_gltf(Node *p_root, String p_path,
  		int32_t p_flags,
  		real_t p_bake_fps) {
  	ERR_FAIL_COND_V(!p_root, FAILED);
  	List<String> deps;
  	Error err;
  	String path = p_path;
  	int32_t flags = p_flags;
  	real_t baked_fps = p_bake_fps;
  	Ref<PackedSceneGLTF> exporter;
  	exporter.instance();
  	exporter->save_scene(p_root, path, "", flags, baked_fps, &deps, &err);
  	int32_t error_code = err;
  	if (error_code != 0) {
  		return Error(error_code);
  	}
  	return OK;
  }
  