161 lines
4.8 KiB
C++
161 lines
4.8 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 "btSubSimplexConvexCast.h"
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#include "BulletCollision/CollisionShapes/btConvexShape.h"
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#include "BulletCollision/CollisionShapes/btMinkowskiSumShape.h"
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#include "BulletCollision/NarrowPhaseCollision/btSimplexSolverInterface.h"
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#include "btPointCollector.h"
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#include "LinearMath/btTransformUtil.h"
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btSubsimplexConvexCast::btSubsimplexConvexCast (const btConvexShape* convexA,const btConvexShape* convexB,btSimplexSolverInterface* simplexSolver)
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:m_simplexSolver(simplexSolver),
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m_convexA(convexA),m_convexB(convexB)
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{
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}
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///Typically the conservative advancement reaches solution in a few iterations, clip it to 32 for degenerate cases.
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///See discussion about this here http://continuousphysics.com/Bullet/phpBB2/viewtopic.php?t=565
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#ifdef BT_USE_DOUBLE_PRECISION
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#define MAX_ITERATIONS 64
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#else
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#define MAX_ITERATIONS 32
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#endif
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bool btSubsimplexConvexCast::calcTimeOfImpact(
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const btTransform& fromA,
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const btTransform& toA,
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const btTransform& fromB,
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const btTransform& toB,
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CastResult& result)
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{
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m_simplexSolver->reset();
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btVector3 linVelA,linVelB;
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linVelA = toA.getOrigin()-fromA.getOrigin();
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linVelB = toB.getOrigin()-fromB.getOrigin();
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btScalar lambda = btScalar(0.);
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btTransform interpolatedTransA = fromA;
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btTransform interpolatedTransB = fromB;
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///take relative motion
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btVector3 r = (linVelA-linVelB);
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btVector3 v;
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btVector3 supVertexA = fromA(m_convexA->localGetSupportingVertex(-r*fromA.getBasis()));
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btVector3 supVertexB = fromB(m_convexB->localGetSupportingVertex(r*fromB.getBasis()));
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v = supVertexA-supVertexB;
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int maxIter = MAX_ITERATIONS;
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btVector3 n;
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n.setValue(btScalar(0.),btScalar(0.),btScalar(0.));
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btVector3 c;
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btScalar dist2 = v.length2();
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#ifdef BT_USE_DOUBLE_PRECISION
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btScalar epsilon = btScalar(0.0001);
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#else
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btScalar epsilon = btScalar(0.0001);
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#endif //BT_USE_DOUBLE_PRECISION
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btVector3 w,p;
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btScalar VdotR;
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while ( (dist2 > epsilon) && maxIter--)
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{
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supVertexA = interpolatedTransA(m_convexA->localGetSupportingVertex(-v*interpolatedTransA.getBasis()));
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supVertexB = interpolatedTransB(m_convexB->localGetSupportingVertex(v*interpolatedTransB.getBasis()));
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w = supVertexA-supVertexB;
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btScalar VdotW = v.dot(w);
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if (lambda > btScalar(1.0))
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{
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return false;
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}
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if ( VdotW > btScalar(0.))
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{
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VdotR = v.dot(r);
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if (VdotR >= -(SIMD_EPSILON*SIMD_EPSILON))
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return false;
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else
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{
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lambda = lambda - VdotW / VdotR;
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//interpolate to next lambda
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// x = s + lambda * r;
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interpolatedTransA.getOrigin().setInterpolate3(fromA.getOrigin(),toA.getOrigin(),lambda);
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interpolatedTransB.getOrigin().setInterpolate3(fromB.getOrigin(),toB.getOrigin(),lambda);
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//m_simplexSolver->reset();
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//check next line
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w = supVertexA-supVertexB;
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n = v;
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}
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}
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///Just like regular GJK only add the vertex if it isn't already (close) to current vertex, it would lead to divisions by zero and NaN etc.
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if (!m_simplexSolver->inSimplex(w))
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m_simplexSolver->addVertex( w, supVertexA , supVertexB);
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if (m_simplexSolver->closest(v))
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{
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dist2 = v.length2();
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//todo: check this normal for validity
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//n=v;
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//printf("V=%f , %f, %f\n",v[0],v[1],v[2]);
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//printf("DIST2=%f\n",dist2);
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//printf("numverts = %i\n",m_simplexSolver->numVertices());
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} else
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{
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dist2 = btScalar(0.);
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}
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}
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//int numiter = MAX_ITERATIONS - maxIter;
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// printf("number of iterations: %d", numiter);
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//don't report a time of impact when moving 'away' from the hitnormal
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result.m_fraction = lambda;
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if (n.length2() >= (SIMD_EPSILON*SIMD_EPSILON))
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result.m_normal = n.normalized();
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else
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result.m_normal = btVector3(btScalar(0.0), btScalar(0.0), btScalar(0.0));
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//don't report time of impact for motion away from the contact normal (or causes minor penetration)
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if (result.m_normal.dot(r)>=-result.m_allowedPenetration)
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return false;
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btVector3 hitA,hitB;
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m_simplexSolver->compute_points(hitA,hitB);
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result.m_hitPoint=hitB;
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return true;
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}
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