60 lines
3.1 KiB
C++
60 lines
3.1 KiB
C++
/********************************************************************************
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* ReactPhysics3D physics library, http://www.reactphysics3d.com *
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* Copyright (c) 2010-2015 Daniel Chappuis *
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*********************************************************************************
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* *
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* This software is provided 'as-is', without any express or implied warranty. *
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* In no event will the authors be held liable for any damages arising from the *
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* use of this software. *
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* *
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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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* *
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* 1. The origin of this software must not be misrepresented; you must not claim *
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* that you wrote the original software. If you use this software in a *
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* product, an acknowledgment in the product documentation would be *
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* appreciated but is not required. *
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* *
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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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* *
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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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********************************************************************************/
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// Libraries
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#include "mathematics_functions.h"
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#include "Vector3.h"
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using namespace reactphysics3d;
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/// Compute the barycentric coordinates u, v, w of a point p inside the triangle (a, b, c)
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/// This method uses the technique described in the book Real-Time collision detection by
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/// Christer Ericson.
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void reactphysics3d::computeBarycentricCoordinatesInTriangle(const Vector3& a, const Vector3& b, const Vector3& c,
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const Vector3& p, decimal& u, decimal& v, decimal& w) {
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const Vector3 v0 = b - a;
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const Vector3 v1 = c - a;
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const Vector3 v2 = p - a;
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decimal d00 = v0.dot(v0);
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decimal d01 = v0.dot(v1);
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decimal d11 = v1.dot(v1);
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decimal d20 = v2.dot(v0);
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decimal d21 = v2.dot(v1);
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decimal denom = d00 * d11 - d01 * d01;
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v = (d11 * d20 - d01 * d21) / denom;
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w = (d00 * d21 - d01 * d20) / denom;
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u = decimal(1.0) - v - w;
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}
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// Clamp a vector such that it is no longer than a given maximum length
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Vector3 reactphysics3d::clamp(const Vector3& vector, decimal maxLength) {
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if (vector.lengthSquare() > maxLength * maxLength) {
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return vector.getUnit() * maxLength;
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}
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return vector;
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}
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