forked from mirror/DotRecast
134 lines
4.3 KiB
C#
134 lines
4.3 KiB
C#
/*
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Copyright (c) 2009-2010 Mikko Mononen memon@inside.org
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recast4j copyright (c) 2021 Piotr Piastucki piotr@jtilia.org
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DotRecast Copyright (c) 2023 Choi Ikpil ikpil@naver.com
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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.Numerics;
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namespace DotRecast.Core
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{
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public static class RcIntersections
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{
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public static bool IntersectSegmentTriangle(RcVec3f sp, RcVec3f sq, RcVec3f a, RcVec3f b, RcVec3f c, out float t)
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{
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t = 0;
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float v, w;
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RcVec3f ab = RcVec3f.Subtract(b, a);
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RcVec3f ac = RcVec3f.Subtract(c, a);
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RcVec3f qp = RcVec3f.Subtract(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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RcVec3f norm = RcVec3f.Cross(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 = RcVec3f.Dot(qp, norm);
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if (d <= 0.0f)
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{
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return false;
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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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RcVec3f ap = RcVec3f.Subtract(sp, a);
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t = RcVec3f.Dot(ap, norm);
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if (t < 0.0f)
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{
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return false;
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}
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if (t > d)
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{
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return false; // 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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RcVec3f e = RcVec3f.Cross(qp, ap);
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v = RcVec3f.Dot(ac, e);
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if (v < 0.0f || v > d)
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{
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return false;
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}
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w = -RcVec3f.Dot(ab, e);
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if (w < 0.0f || v + w > d)
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{
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return false;
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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 true;
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}
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public static bool IsectSegAABB(RcVec3f sp, RcVec3f sq, RcVec3f amin, RcVec3f amax, out float tmin, out float tmax)
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{
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const float EPS = 1e-6f;
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RcVec3f d = new RcVec3f();
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d.X = sq.X - sp.X;
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d.Y = sq.Y - sp.Y;
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d.Z = sq.Z - sp.Z;
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tmin = 0.0f;
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tmax = float.MaxValue;
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for (int i = 0; i < 3; i++)
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{
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if (MathF.Abs(d.Get(i)) < EPS)
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{
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if (sp.Get(i) < amin.Get(i) || sp.Get(i) > amax.Get(i))
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{
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return false;
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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.Get(i);
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float t1 = (amin.Get(i) - sp.Get(i)) * ood;
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float t2 = (amax.Get(i) - sp.Get(i)) * ood;
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if (t1 > t2)
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{
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(t1, t2) = (t2, t1);
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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 false;
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}
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}
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}
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return true;
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}
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}
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} |