initial commit, 4.5 stable

core/math/convex_hull.h

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+/**************************************************************************/
+/*  convex_hull.h                                                         */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* 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.                 */
+/**************************************************************************/
+
+#pragma once
+
+/*
+Copyright (c) 2011 Ole Kniemeyer, MAXON, www.maxon.net
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it freely,
+subject to the following restrictions:
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "core/math/geometry_3d.h"
+#include "core/math/vector3.h"
+#include "core/templates/local_vector.h"
+#include "core/templates/vector.h"
+
+/// Convex hull implementation based on Preparata and Hong
+/// See https://code.google.com/archive/p/bullet/issues/275
+/// Ole Kniemeyer, MAXON Computer GmbH
+class ConvexHullComputer {
+public:
+	class Edge {
+	private:
+		int32_t next = 0;
+		int32_t reverse = 0;
+		int32_t target_vertex = 0;
+
+		friend class ConvexHullComputer;
+
+	public:
+		int32_t get_next_relative() const {
+			return next;
+		}
+
+		int32_t get_source_vertex() const {
+			return (this + reverse)->target_vertex;
+		}
+
+		int32_t get_target_vertex() const {
+			return target_vertex;
+		}
+
+		const Edge *get_next_edge_of_vertex() const // clockwise list of all edges of a vertex
+		{
+			return this + next;
+		}
+
+		const Edge *get_next_edge_of_face() const // counter-clockwise list of all edges of a face
+		{
+			return (this + reverse)->get_next_edge_of_vertex();
+		}
+
+		const Edge *get_reverse_edge() const {
+			return this + reverse;
+		}
+	};
+
+	// Vertices of the output hull
+	LocalVector<Vector3> vertices;
+
+	// Edges of the output hull
+	LocalVector<Edge> edges;
+
+	// Faces of the convex hull. Each entry is an index into the "edges" array pointing to an edge of the face. Faces are planar n-gons
+	LocalVector<int32_t> faces;
+
+	/*
+		Compute convex hull of "count" vertices stored in "coords".
+		If "shrink" is positive, the convex hull is shrunken by that amount (each face is moved by "shrink" length units
+		towards the center along its normal).
+		If "shrinkClamp" is positive, "shrink" is clamped to not exceed "shrinkClamp * innerRadius", where "innerRadius"
+		is the minimum distance of a face to the center of the convex hull.
+		The returned value is the amount by which the hull has been shrunken. If it is negative, the amount was so large
+		that the resulting convex hull is empty.
+		The output convex hull can be found in the member variables "vertices", "edges", "faces".
+		*/
+	real_t compute(const Vector3 *p_coords, int32_t p_count, real_t p_shrink, real_t p_shrink_clamp);
+
+	static Error convex_hull(const Vector<Vector3> &p_points, Geometry3D::MeshData &r_mesh);
+};