Auto LOD fixes and improvements

* Fixed LODs for shadow meshes.
* Added a merging step before simplification. This helps with tesselated
  meshes that were previously left untouched. The angle difference at
  wich edges ar considered "hard" can be tweaked as an import setting.
* LODs will now start with the highest decimation possible and keep
  doubling (approximately) the number of triangles from there. This
  makes sure that very low triangle counts are included when possible.
* Given more weight to normal preservation.
* Modified MeshOptimizer to report distance-based error instead of
  including attributes in the reported metrics.
* Added attribute transference between the original mesh and the
  various LODs. Right now only normals are taken into account,
  but it could be expanded to other attributes in the future.

1 files changed, 64 insertions, 0 deletions

diff --git a/modules/raycast/static_raycaster.h b/modules/raycast/static_raycaster.h
new file mode 100644
index 0000000000..6b13ecf690
--- /dev/null
+++ b/modules/raycast/static_raycaster.h
@@ -0,0 +1,64 @@
+/*************************************************************************/
+/*  static_raycaster.h                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 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,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifdef TOOLS_ENABLED
+
+#include "core/math/static_raycaster.h"
+
+#include <embree3/rtcore.h>
+
+class StaticRaycasterEmbree : public StaticRaycaster {
+	GDCLASS(StaticRaycasterEmbree, StaticRaycaster);
+
+private:
+	static RTCDevice embree_device;
+	RTCScene embree_scene;
+
+	Set<int> filter_meshes;
+
+public:
+	virtual bool intersect(Ray &p_ray) override;
+	virtual void intersect(Vector<Ray> &r_rays) override;
+
+	virtual void add_mesh(const PackedVector3Array &p_vertices, const PackedInt32Array &p_indices, unsigned int p_id) override;
+	virtual void commit() override;
+
+	virtual void set_mesh_filter(const Set<int> &p_mesh_ids) override;
+	virtual void clear_mesh_filter() override;
+
+	static StaticRaycaster *create_embree_raycaster();
+	static void make_default_raycaster();
+	static void free();
+
+	StaticRaycasterEmbree();
+	~StaticRaycasterEmbree();
+};
+
+#endif