forked from mirror/DotRecast
132 lines
3.8 KiB
C#
132 lines
3.8 KiB
C#
/*
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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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using DotRecast.Core;
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using static DotRecast.Detour.DetourCommon;
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namespace DotRecast.Recast.Demo.Geom;
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public class Intersections
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{
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public static float? intersectSegmentTriangle(float[] sp, float[] sq, float[] a, float[] b, float[] c)
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{
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float v, w;
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float[] ab = vSub(b, a);
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float[] ac = vSub(c, a);
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float[] qp = vSub(sp, sq);
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// Compute triangle normal. Can be precalculated or cached if
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// intersecting multiple segments against the same triangle
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float[] norm = DemoMath.vCross(ab, ac);
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// Compute denominator d. If d <= 0, segment is parallel to or points
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// away from triangle, so exit early
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float d = DemoMath.vDot(qp, norm);
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if (d <= 0.0f)
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{
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return null;
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}
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// Compute intersection t value of pq with plane of triangle. A ray
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// intersects iff 0 <= t. Segment intersects iff 0 <= t <= 1. Delay
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// dividing by d until intersection has been found to pierce triangle
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float[] ap = vSub(sp, a);
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float t = DemoMath.vDot(ap, norm);
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if (t < 0.0f)
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{
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return null;
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}
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if (t > d)
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{
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return null; // For segment; exclude this code line for a ray test
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}
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// Compute barycentric coordinate components and test if within bounds
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float[] e = DemoMath.vCross(qp, ap);
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v = DemoMath.vDot(ac, e);
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if (v < 0.0f || v > d)
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{
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return null;
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}
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w = -DemoMath.vDot(ab, e);
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if (w < 0.0f || v + w > d)
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{
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return null;
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}
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// Segment/ray intersects triangle. Perform delayed division
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t /= d;
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return t;
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}
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public static float[] intersectSegmentAABB(float[] sp, float[] sq, float[] amin, float[] amax)
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{
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float EPS = 1e-6f;
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float[] d = new float[3];
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d[0] = sq[0] - sp[0];
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d[1] = sq[1] - sp[1];
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d[2] = sq[2] - sp[2];
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float tmin = 0.0f;
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float tmax = 1.0f;
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for (int i = 0; i < 3; i++)
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{
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if (Math.Abs(d[i]) < EPS)
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{
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if (sp[i] < amin[i] || sp[i] > amax[i])
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{
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return null;
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}
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}
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else
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{
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float ood = 1.0f / d[i];
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float t1 = (amin[i] - sp[i]) * ood;
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float t2 = (amax[i] - sp[i]) * ood;
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if (t1 > t2)
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{
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float tmp = t1;
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t1 = t2;
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t2 = tmp;
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}
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if (t1 > tmin)
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{
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tmin = t1;
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}
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if (t2 < tmax)
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{
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tmax = t2;
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}
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if (tmin > tmax)
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{
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return null;
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}
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}
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}
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return new float[] { tmin, tmax };
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}
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} |