481 lines
15 KiB
C++
481 lines
15 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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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 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 freely,
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subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be 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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#include "btGjkPairDetector.h"
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#include "BulletCollision/CollisionShapes/btConvexShape.h"
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#include "BulletCollision/NarrowPhaseCollision/btSimplexSolverInterface.h"
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#include "BulletCollision/NarrowPhaseCollision/btConvexPenetrationDepthSolver.h"
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#if defined(DEBUG) || defined (_DEBUG)
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//#define TEST_NON_VIRTUAL 1
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#include <stdio.h> //for debug printf
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#ifdef __SPU__
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#include <spu_printf.h>
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#define printf spu_printf
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//#define DEBUG_SPU_COLLISION_DETECTION 1
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#endif //__SPU__
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#endif
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//must be above the machine epsilon
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#define REL_ERROR2 btScalar(1.0e-6)
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//temp globals, to improve GJK/EPA/penetration calculations
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int gNumDeepPenetrationChecks = 0;
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int gNumGjkChecks = 0;
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btGjkPairDetector::btGjkPairDetector(const btConvexShape* objectA,const btConvexShape* objectB,btSimplexSolverInterface* simplexSolver,btConvexPenetrationDepthSolver* penetrationDepthSolver)
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:m_cachedSeparatingAxis(btScalar(0.),btScalar(1.),btScalar(0.)),
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m_penetrationDepthSolver(penetrationDepthSolver),
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m_simplexSolver(simplexSolver),
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m_minkowskiA(objectA),
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m_minkowskiB(objectB),
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m_shapeTypeA(objectA->getShapeType()),
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m_shapeTypeB(objectB->getShapeType()),
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m_marginA(objectA->getMargin()),
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m_marginB(objectB->getMargin()),
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m_ignoreMargin(false),
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m_lastUsedMethod(-1),
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m_catchDegeneracies(1),
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m_fixContactNormalDirection(1)
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{
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}
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btGjkPairDetector::btGjkPairDetector(const btConvexShape* objectA,const btConvexShape* objectB,int shapeTypeA,int shapeTypeB,btScalar marginA, btScalar marginB, btSimplexSolverInterface* simplexSolver,btConvexPenetrationDepthSolver* penetrationDepthSolver)
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:m_cachedSeparatingAxis(btScalar(0.),btScalar(1.),btScalar(0.)),
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m_penetrationDepthSolver(penetrationDepthSolver),
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m_simplexSolver(simplexSolver),
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m_minkowskiA(objectA),
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m_minkowskiB(objectB),
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m_shapeTypeA(shapeTypeA),
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m_shapeTypeB(shapeTypeB),
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m_marginA(marginA),
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m_marginB(marginB),
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m_ignoreMargin(false),
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m_lastUsedMethod(-1),
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m_catchDegeneracies(1),
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m_fixContactNormalDirection(1)
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{
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}
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void btGjkPairDetector::getClosestPoints(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw,bool swapResults)
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{
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(void)swapResults;
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getClosestPointsNonVirtual(input,output,debugDraw);
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}
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#ifdef __SPU__
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void btGjkPairDetector::getClosestPointsNonVirtual(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw)
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#else
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void btGjkPairDetector::getClosestPointsNonVirtual(const ClosestPointInput& input,Result& output,class btIDebugDraw* debugDraw)
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#endif
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{
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m_cachedSeparatingDistance = 0.f;
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btScalar distance=btScalar(0.);
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btVector3 normalInB(btScalar(0.),btScalar(0.),btScalar(0.));
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btVector3 pointOnA,pointOnB;
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btTransform localTransA = input.m_transformA;
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btTransform localTransB = input.m_transformB;
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btVector3 positionOffset = (localTransA.getOrigin() + localTransB.getOrigin()) * btScalar(0.5);
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localTransA.getOrigin() -= positionOffset;
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localTransB.getOrigin() -= positionOffset;
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bool check2d = m_minkowskiA->isConvex2d() && m_minkowskiB->isConvex2d();
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btScalar marginA = m_marginA;
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btScalar marginB = m_marginB;
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gNumGjkChecks++;
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#ifdef DEBUG_SPU_COLLISION_DETECTION
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spu_printf("inside gjk\n");
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#endif
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//for CCD we don't use margins
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if (m_ignoreMargin)
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{
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marginA = btScalar(0.);
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marginB = btScalar(0.);
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#ifdef DEBUG_SPU_COLLISION_DETECTION
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spu_printf("ignoring margin\n");
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#endif
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}
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m_curIter = 0;
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int gGjkMaxIter = 1000;//this is to catch invalid input, perhaps check for #NaN?
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m_cachedSeparatingAxis.setValue(0,1,0);
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bool isValid = false;
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bool checkSimplex = false;
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bool checkPenetration = true;
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m_degenerateSimplex = 0;
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m_lastUsedMethod = -1;
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{
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btScalar squaredDistance = BT_LARGE_FLOAT;
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btScalar delta = btScalar(0.);
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btScalar margin = marginA + marginB;
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m_simplexSolver->reset();
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for ( ; ; )
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//while (true)
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{
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btVector3 seperatingAxisInA = (-m_cachedSeparatingAxis)* input.m_transformA.getBasis();
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btVector3 seperatingAxisInB = m_cachedSeparatingAxis* input.m_transformB.getBasis();
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#if 1
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btVector3 pInA = m_minkowskiA->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInA);
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btVector3 qInB = m_minkowskiB->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInB);
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// btVector3 pInA = localGetSupportingVertexWithoutMargin(m_shapeTypeA, m_minkowskiA, seperatingAxisInA,input.m_convexVertexData[0]);//, &featureIndexA);
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// btVector3 qInB = localGetSupportingVertexWithoutMargin(m_shapeTypeB, m_minkowskiB, seperatingAxisInB,input.m_convexVertexData[1]);//, &featureIndexB);
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#else
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#ifdef __SPU__
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btVector3 pInA = m_minkowskiA->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInA);
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btVector3 qInB = m_minkowskiB->localGetSupportVertexWithoutMarginNonVirtual(seperatingAxisInB);
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#else
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btVector3 pInA = m_minkowskiA->localGetSupportingVertexWithoutMargin(seperatingAxisInA);
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btVector3 qInB = m_minkowskiB->localGetSupportingVertexWithoutMargin(seperatingAxisInB);
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#ifdef TEST_NON_VIRTUAL
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btVector3 pInAv = m_minkowskiA->localGetSupportingVertexWithoutMargin(seperatingAxisInA);
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btVector3 qInBv = m_minkowskiB->localGetSupportingVertexWithoutMargin(seperatingAxisInB);
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btAssert((pInAv-pInA).length() < 0.0001);
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btAssert((qInBv-qInB).length() < 0.0001);
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#endif //
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#endif //__SPU__
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#endif
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btVector3 pWorld = localTransA(pInA);
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btVector3 qWorld = localTransB(qInB);
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#ifdef DEBUG_SPU_COLLISION_DETECTION
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spu_printf("got local supporting vertices\n");
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#endif
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if (check2d)
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{
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pWorld[2] = 0.f;
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qWorld[2] = 0.f;
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}
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btVector3 w = pWorld - qWorld;
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delta = m_cachedSeparatingAxis.dot(w);
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// potential exit, they don't overlap
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if ((delta > btScalar(0.0)) && (delta * delta > squaredDistance * input.m_maximumDistanceSquared))
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{
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m_degenerateSimplex = 10;
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checkSimplex=true;
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//checkPenetration = false;
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break;
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}
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//exit 0: the new point is already in the simplex, or we didn't come any closer
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if (m_simplexSolver->inSimplex(w))
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{
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m_degenerateSimplex = 1;
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checkSimplex = true;
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break;
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}
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// are we getting any closer ?
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btScalar f0 = squaredDistance - delta;
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btScalar f1 = squaredDistance * REL_ERROR2;
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if (f0 <= f1)
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{
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if (f0 <= btScalar(0.))
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{
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m_degenerateSimplex = 2;
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} else
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{
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m_degenerateSimplex = 11;
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}
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checkSimplex = true;
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break;
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}
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#ifdef DEBUG_SPU_COLLISION_DETECTION
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spu_printf("addVertex 1\n");
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#endif
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//add current vertex to simplex
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m_simplexSolver->addVertex(w, pWorld, qWorld);
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#ifdef DEBUG_SPU_COLLISION_DETECTION
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spu_printf("addVertex 2\n");
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#endif
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btVector3 newCachedSeparatingAxis;
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//calculate the closest point to the origin (update vector v)
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if (!m_simplexSolver->closest(newCachedSeparatingAxis))
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{
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m_degenerateSimplex = 3;
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checkSimplex = true;
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break;
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}
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if(newCachedSeparatingAxis.length2()<REL_ERROR2)
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{
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m_cachedSeparatingAxis = newCachedSeparatingAxis;
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m_degenerateSimplex = 6;
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checkSimplex = true;
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break;
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}
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btScalar previousSquaredDistance = squaredDistance;
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squaredDistance = newCachedSeparatingAxis.length2();
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#if 0
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///warning: this termination condition leads to some problems in 2d test case see Bullet/Demos/Box2dDemo
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if (squaredDistance>previousSquaredDistance)
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{
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m_degenerateSimplex = 7;
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squaredDistance = previousSquaredDistance;
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checkSimplex = false;
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break;
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}
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#endif //
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//redundant m_simplexSolver->compute_points(pointOnA, pointOnB);
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//are we getting any closer ?
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if (previousSquaredDistance - squaredDistance <= SIMD_EPSILON * previousSquaredDistance)
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{
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// m_simplexSolver->backup_closest(m_cachedSeparatingAxis);
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checkSimplex = true;
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m_degenerateSimplex = 12;
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break;
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}
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m_cachedSeparatingAxis = newCachedSeparatingAxis;
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//degeneracy, this is typically due to invalid/uninitialized worldtransforms for a btCollisionObject
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if (m_curIter++ > gGjkMaxIter)
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{
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#if defined(DEBUG) || defined (_DEBUG) || defined (DEBUG_SPU_COLLISION_DETECTION)
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printf("btGjkPairDetector maxIter exceeded:%i\n",m_curIter);
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printf("sepAxis=(%f,%f,%f), squaredDistance = %f, shapeTypeA=%i,shapeTypeB=%i\n",
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m_cachedSeparatingAxis.getX(),
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m_cachedSeparatingAxis.getY(),
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m_cachedSeparatingAxis.getZ(),
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squaredDistance,
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m_minkowskiA->getShapeType(),
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m_minkowskiB->getShapeType());
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#endif
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break;
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}
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bool check = (!m_simplexSolver->fullSimplex());
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//bool check = (!m_simplexSolver->fullSimplex() && squaredDistance > SIMD_EPSILON * m_simplexSolver->maxVertex());
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if (!check)
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{
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//do we need this backup_closest here ?
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// m_simplexSolver->backup_closest(m_cachedSeparatingAxis);
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m_degenerateSimplex = 13;
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break;
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}
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}
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if (checkSimplex)
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{
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m_simplexSolver->compute_points(pointOnA, pointOnB);
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normalInB = m_cachedSeparatingAxis;
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btScalar lenSqr =m_cachedSeparatingAxis.length2();
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//valid normal
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if (lenSqr < 0.0001)
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{
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m_degenerateSimplex = 5;
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}
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if (lenSqr > SIMD_EPSILON*SIMD_EPSILON)
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{
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btScalar rlen = btScalar(1.) / btSqrt(lenSqr );
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normalInB *= rlen; //normalize
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btScalar s = btSqrt(squaredDistance);
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btAssert(s > btScalar(0.0));
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pointOnA -= m_cachedSeparatingAxis * (marginA / s);
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pointOnB += m_cachedSeparatingAxis * (marginB / s);
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distance = ((btScalar(1.)/rlen) - margin);
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isValid = true;
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m_lastUsedMethod = 1;
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} else
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{
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m_lastUsedMethod = 2;
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}
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}
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bool catchDegeneratePenetrationCase =
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(m_catchDegeneracies && m_penetrationDepthSolver && m_degenerateSimplex && ((distance+margin) < 0.01));
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//if (checkPenetration && !isValid)
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if (checkPenetration && (!isValid || catchDegeneratePenetrationCase ))
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{
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//penetration case
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//if there is no way to handle penetrations, bail out
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if (m_penetrationDepthSolver)
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{
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// Penetration depth case.
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btVector3 tmpPointOnA,tmpPointOnB;
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gNumDeepPenetrationChecks++;
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m_cachedSeparatingAxis.setZero();
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bool isValid2 = m_penetrationDepthSolver->calcPenDepth(
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*m_simplexSolver,
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m_minkowskiA,m_minkowskiB,
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localTransA,localTransB,
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m_cachedSeparatingAxis, tmpPointOnA, tmpPointOnB,
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debugDraw
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);
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if (isValid2)
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{
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btVector3 tmpNormalInB = tmpPointOnB-tmpPointOnA;
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btScalar lenSqr = tmpNormalInB.length2();
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if (lenSqr <= (SIMD_EPSILON*SIMD_EPSILON))
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{
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tmpNormalInB = m_cachedSeparatingAxis;
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lenSqr = m_cachedSeparatingAxis.length2();
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}
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if (lenSqr > (SIMD_EPSILON*SIMD_EPSILON))
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{
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tmpNormalInB /= btSqrt(lenSqr);
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btScalar distance2 = -(tmpPointOnA-tmpPointOnB).length();
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//only replace valid penetrations when the result is deeper (check)
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if (!isValid || (distance2 < distance))
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{
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distance = distance2;
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pointOnA = tmpPointOnA;
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pointOnB = tmpPointOnB;
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normalInB = tmpNormalInB;
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isValid = true;
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m_lastUsedMethod = 3;
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} else
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{
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m_lastUsedMethod = 8;
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}
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} else
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{
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m_lastUsedMethod = 9;
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}
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} else
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{
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///this is another degenerate case, where the initial GJK calculation reports a degenerate case
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///EPA reports no penetration, and the second GJK (using the supporting vector without margin)
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///reports a valid positive distance. Use the results of the second GJK instead of failing.
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///thanks to Jacob.Langford for the reproduction case
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///http://code.google.com/p/bullet/issues/detail?id=250
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if (m_cachedSeparatingAxis.length2() > btScalar(0.))
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{
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btScalar distance2 = (tmpPointOnA-tmpPointOnB).length()-margin;
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//only replace valid distances when the distance is less
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if (!isValid || (distance2 < distance))
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{
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distance = distance2;
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pointOnA = tmpPointOnA;
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pointOnB = tmpPointOnB;
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pointOnA -= m_cachedSeparatingAxis * marginA ;
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pointOnB += m_cachedSeparatingAxis * marginB ;
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normalInB = m_cachedSeparatingAxis;
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normalInB.normalize();
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isValid = true;
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m_lastUsedMethod = 6;
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} else
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{
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m_lastUsedMethod = 5;
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}
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}
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}
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}
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}
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}
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if (isValid && ((distance < 0) || (distance*distance < input.m_maximumDistanceSquared)))
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{
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#if 0
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///some debugging
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// if (check2d)
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{
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printf("n = %2.3f,%2.3f,%2.3f. ",normalInB[0],normalInB[1],normalInB[2]);
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printf("distance = %2.3f exit=%d deg=%d\n",distance,m_lastUsedMethod,m_degenerateSimplex);
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}
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#endif
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if (m_fixContactNormalDirection)
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{
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///@workaround for sticky convex collisions
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//in some degenerate cases (usually when the use uses very small margins)
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//the contact normal is pointing the wrong direction
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//so fix it now (until we can deal with all degenerate cases in GJK and EPA)
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//contact normals need to point from B to A in all cases, so we can simply check if the contact normal really points from B to A
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//We like to use a dot product of the normal against the difference of the centroids,
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//once the centroid is available in the API
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//until then we use the center of the aabb to approximate the centroid
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btVector3 aabbMin,aabbMax;
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m_minkowskiA->getAabb(localTransA,aabbMin,aabbMax);
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btVector3 posA = (aabbMax+aabbMin)*btScalar(0.5);
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m_minkowskiB->getAabb(localTransB,aabbMin,aabbMax);
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btVector3 posB = (aabbMin+aabbMax)*btScalar(0.5);
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btVector3 diff = posA-posB;
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if (diff.dot(normalInB) < 0.f)
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normalInB *= -1.f;
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}
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m_cachedSeparatingAxis = normalInB;
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m_cachedSeparatingDistance = distance;
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output.addContactPoint(
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normalInB,
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pointOnB+positionOffset,
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distance);
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}
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}
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