176 lines
6.1 KiB
C++
176 lines
6.1 KiB
C++
/*************************************************************************/
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/* delaunay.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef DELAUNAY_H
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#define DELAUNAY_H
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#include "core/math/rect2.h"
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class Delaunay2D {
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public:
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struct Triangle {
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int points[3];
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bool bad;
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Triangle() { bad = false; }
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Triangle(int p_a, int p_b, int p_c) {
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points[0] = p_a;
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points[1] = p_b;
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points[2] = p_c;
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bad = false;
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}
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};
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struct Edge {
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int edge[2];
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bool bad;
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Edge() { bad = false; }
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Edge(int p_a, int p_b) {
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bad = false;
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edge[0] = p_a;
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edge[1] = p_b;
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}
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};
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static bool circum_circle_contains(const Vector<Vector2> &p_vertices, const Triangle &p_triangle, int p_vertex) {
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Vector2 p1 = p_vertices[p_triangle.points[0]];
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Vector2 p2 = p_vertices[p_triangle.points[1]];
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Vector2 p3 = p_vertices[p_triangle.points[2]];
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real_t ab = p1.x * p1.x + p1.y * p1.y;
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real_t cd = p2.x * p2.x + p2.y * p2.y;
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real_t ef = p3.x * p3.x + p3.y * p3.y;
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Vector2 circum(
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(ab * (p3.y - p2.y) + cd * (p1.y - p3.y) + ef * (p2.y - p1.y)) / (p1.x * (p3.y - p2.y) + p2.x * (p1.y - p3.y) + p3.x * (p2.y - p1.y)),
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(ab * (p3.x - p2.x) + cd * (p1.x - p3.x) + ef * (p2.x - p1.x)) / (p1.y * (p3.x - p2.x) + p2.y * (p1.x - p3.x) + p3.y * (p2.x - p1.x)));
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circum *= 0.5;
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float r = p1.distance_squared_to(circum);
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float d = p_vertices[p_vertex].distance_squared_to(circum);
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return d <= r;
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}
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static bool edge_compare(const Vector<Vector2> &p_vertices, const Edge &p_a, const Edge &p_b) {
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if (Math::is_zero_approx(p_vertices[p_a.edge[0]].distance_to(p_vertices[p_b.edge[0]])) && Math::is_zero_approx(p_vertices[p_a.edge[1]].distance_to(p_vertices[p_b.edge[1]]))) {
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return true;
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}
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if (Math::is_zero_approx(p_vertices[p_a.edge[0]].distance_to(p_vertices[p_b.edge[1]])) && Math::is_zero_approx(p_vertices[p_a.edge[1]].distance_to(p_vertices[p_b.edge[0]]))) {
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return true;
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}
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return false;
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}
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static Vector<Triangle> triangulate(const Vector<Vector2> &p_points) {
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Vector<Vector2> points = p_points;
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Vector<Triangle> triangles;
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Rect2 rect;
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for (int i = 0; i < p_points.size(); i++) {
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if (i == 0) {
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rect.position = p_points[i];
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} else {
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rect.expand_to(p_points[i]);
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}
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}
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float delta_max = MAX(rect.size.width, rect.size.height);
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Vector2 center = rect.position + rect.size * 0.5;
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points.push_back(Vector2(center.x - 20 * delta_max, center.y - delta_max));
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points.push_back(Vector2(center.x, center.y + 20 * delta_max));
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points.push_back(Vector2(center.x + 20 * delta_max, center.y - delta_max));
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triangles.push_back(Triangle(p_points.size() + 0, p_points.size() + 1, p_points.size() + 2));
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for (int i = 0; i < p_points.size(); i++) {
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//std::cout << "Traitement du point " << *p << std::endl;
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//std::cout << "_triangles contains " << _triangles.size() << " elements" << std::endl;
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Vector<Edge> polygon;
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for (int j = 0; j < triangles.size(); j++) {
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if (circum_circle_contains(points, triangles[j], i)) {
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triangles.write[j].bad = true;
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polygon.push_back(Edge(triangles[j].points[0], triangles[j].points[1]));
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polygon.push_back(Edge(triangles[j].points[1], triangles[j].points[2]));
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polygon.push_back(Edge(triangles[j].points[2], triangles[j].points[0]));
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}
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}
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for (int j = 0; j < triangles.size(); j++) {
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if (triangles[j].bad) {
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triangles.remove(j);
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j--;
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}
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}
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for (int j = 0; j < polygon.size(); j++) {
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for (int k = j + 1; k < polygon.size(); k++) {
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if (edge_compare(points, polygon[j], polygon[k])) {
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polygon.write[j].bad = true;
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polygon.write[k].bad = true;
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}
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}
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}
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for (int j = 0; j < polygon.size(); j++) {
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if (polygon[j].bad) {
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continue;
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}
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triangles.push_back(Triangle(polygon[j].edge[0], polygon[j].edge[1], i));
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}
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}
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for (int i = 0; i < triangles.size(); i++) {
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bool invalid = false;
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for (int j = 0; j < 3; j++) {
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if (triangles[i].points[j] >= p_points.size()) {
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invalid = true;
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break;
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}
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}
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if (invalid) {
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triangles.remove(i);
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i--;
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}
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}
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return triangles;
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}
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};
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#endif // DELAUNAY_H
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