forked from bit/DotRecastNetSim
95 lines
3.4 KiB
C#
95 lines
3.4 KiB
C#
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/*
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recast4j copyright (c) 2021 Piotr Piastucki piotr@jtilia.org
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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using System;
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namespace DotRecast.Detour;
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using static DetourCommon;
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public interface PolygonByCircleConstraint {
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float[] aply(float[] polyVerts, float[] circleCenter, float radius);
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public static PolygonByCircleConstraint noop() {
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return new NoOpPolygonByCircleConstraint();
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}
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public static PolygonByCircleConstraint strict() {
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return new StrictPolygonByCircleConstraint();
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}
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public class NoOpPolygonByCircleConstraint : PolygonByCircleConstraint {
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public float[] aply(float[] polyVerts, float[] circleCenter, float radius) {
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return polyVerts;
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}
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}
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/**
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* Calculate the intersection between a polygon and a circle. A dodecagon is used as an approximation of the circle.
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*/
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public class StrictPolygonByCircleConstraint : PolygonByCircleConstraint {
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private const int CIRCLE_SEGMENTS = 12;
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private static float[] unitCircle;
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public float[] aply(float[] verts, float[] center, float radius) {
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float radiusSqr = radius * radius;
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int outsideVertex = -1;
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for (int pv = 0; pv < verts.Length; pv += 3) {
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if (vDist2DSqr(center, verts, pv) > radiusSqr) {
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outsideVertex = pv;
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break;
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}
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}
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if (outsideVertex == -1) {
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// polygon inside circle
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return verts;
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}
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float[] qCircle = circle(center, radius);
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float[] intersection = ConvexConvexIntersection.intersect(verts, qCircle);
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if (intersection == null && pointInPolygon(center, verts, verts.Length / 3)) {
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// circle inside polygon
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return qCircle;
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}
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return intersection;
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}
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private float[] circle(float[] center, float radius) {
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if (unitCircle == null) {
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unitCircle = new float[CIRCLE_SEGMENTS * 3];
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for (int i = 0; i < CIRCLE_SEGMENTS; i++) {
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double a = i * Math.PI * 2 / CIRCLE_SEGMENTS;
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unitCircle[3 * i] = (float) Math.Cos(a);
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unitCircle[3 * i + 1] = 0;
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unitCircle[3 * i + 2] = (float) -Math.Sin(a);
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}
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}
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float[] circle = new float[12 * 3];
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for (int i = 0; i < CIRCLE_SEGMENTS * 3; i += 3) {
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circle[i] = unitCircle[i] * radius + center[0];
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circle[i + 1] = center[1];
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circle[i + 2] = unitCircle[i + 2] * radius + center[2];
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}
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return circle;
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}
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}
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}
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