c1eabd3e2b
git-svn-id: https://reactphysics3d.googlecode.com/svn/trunk@460 92aac97c-a6ce-11dd-a772-7fcde58d38e6
116 lines
7.1 KiB
C++
116 lines
7.1 KiB
C++
/********************************************************************************
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* ReactPhysics3D physics library, http://code.google.com/p/reactphysics3d/ *
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* Copyright (c) 2010-2012 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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#ifndef SIMPLEX_H
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#define SIMPLEX_H
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// Libraries
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#include "../../../mathematics/mathematics.h"
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#include <vector>
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// ReactPhysics3D namespace
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namespace reactphysics3d {
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// Type definitions
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typedef unsigned int Bits;
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/* -------------------------------------------------------------------
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Class Simplex :
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This class represents a simplex which is a set of 3D points. This
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class is used in the GJK algorithm. This implementation is based on
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the implementation discussed in the book "Collision Detection in 3D
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Environments". This class implements the Johnson's algorithm for
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computing the point of a simplex that is closest to the origin and also
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the smallest simplex needed to represent that closest point.
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-------------------------------------------------------------------
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*/
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class Simplex {
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private:
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Vector3 points[4]; // Current points
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decimal pointsLengthSquare[4]; // pointsLengthSquare[i] = (points[i].length)^2
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decimal maxLengthSquare; // Maximum length of pointsLengthSquare[i]
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Vector3 suppPointsA[4]; // Support points of object A in local coordinates
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Vector3 suppPointsB[4]; // Support points of object B in local coordinates
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Vector3 diffLength[4][4]; // diff[i][j] contains points[i] - points[j]
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decimal det[16][4]; // Cached determinant values
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decimal normSquare[4][4]; // norm[i][j] = (diff[i][j].length())^2
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Bits bitsCurrentSimplex; // 4 bits that identify the current points of the simplex
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// For instance, 0101 means that points[1] and points[3] are in the simplex
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Bits lastFound; // Number between 1 and 4 that identify the last found support point
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Bits lastFoundBit; // Position of the last found support point (lastFoundBit = 0x1 << lastFound)
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Bits allBits; // allBits = bitsCurrentSimplex | lastFoundBit;
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bool overlap(Bits a, Bits b) const; // Return true if some bits of "a" overlap with bits of "b"
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bool isSubset(Bits a, Bits b) const; // Return true if the bits of "b" is a subset of the bits of "a"
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bool isValidSubset(Bits subset) const; // Return true if the subset is a valid one for the closest point computation
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bool isProperSubset(Bits subset) const; // Return true if the subset is a proper subset
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void updateCache(); // Update the cached values used during the GJK algorithm
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void computeDeterminants(); // Compute the cached determinant values
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Vector3 computeClosestPointForSubset(Bits subset); // Return the closest point "v" in the convex hull of a subset of points
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public:
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Simplex(); // Constructor
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~Simplex(); // Destructor
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bool isFull() const; // Return true if the simplex contains 4 points
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bool isEmpty() const; // Return true if the simple is empty
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unsigned int getSimplex(Vector3* suppPointsA, Vector3* suppPointsB, Vector3* points) const; // Return the points of the simplex
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decimal getMaxLengthSquareOfAPoint() const; // Return the maximum squared length of a point
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void addPoint(const Vector3& point, const Vector3& suppPointA, const Vector3& suppPointB); // Addd a point to the simplex
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bool isPointInSimplex(const Vector3& point) const; // Return true if the point is in the simplex
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bool isAffinelyDependent() const; // Return true if the set is affinely dependent
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void backupClosestPointInSimplex(Vector3& point); // Backup the closest point
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void computeClosestPointsOfAandB(Vector3& pA, Vector3& pB) const; // Compute the closest points of object A and B
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bool computeClosestPoint(Vector3& v); // Compute the closest point to the origin of the current simplex
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};
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// Return true if some bits of "a" overlap with bits of "b"
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inline bool Simplex::overlap(Bits a, Bits b) const {
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return ((a & b) != 0x0);
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}
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// Return true if the bits of "b" is a subset of the bits of "a"
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inline bool Simplex::isSubset(Bits a, Bits b) const {
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return ((a & b) == a);
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}
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// Return true if the simplex contains 4 points
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inline bool Simplex::isFull() const {
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return (bitsCurrentSimplex == 0xf);
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}
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// Return true if the simple is empty
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inline bool Simplex::isEmpty() const {
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return (bitsCurrentSimplex == 0x0);
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}
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// Return the maximum squared length of a point
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inline decimal Simplex::getMaxLengthSquareOfAPoint() const {
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return maxLengthSquare;
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}
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} // End of the ReactPhysics3D namespace
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#endif |