mirror of https://github.com/axmolengine/axmol.git
165 lines
4.4 KiB
C++
165 lines
4.4 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 "btGjkConvexCast.h"
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#include "BulletCollision/CollisionShapes/btSphereShape.h"
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#include "btGjkPairDetector.h"
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#include "btPointCollector.h"
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#include "LinearMath/btTransformUtil.h"
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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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btGjkConvexCast::btGjkConvexCast(const btConvexShape* convexA, const btConvexShape* convexB, btSimplexSolverInterface* simplexSolver)
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: m_simplexSolver(simplexSolver),
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m_convexA(convexA),
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m_convexB(convexB)
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{
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}
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bool btGjkConvexCast::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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/// compute linear velocity for this interval, to interpolate
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//assume no rotation/angular velocity, assert here?
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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 radius = btScalar(0.001);
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btScalar lambda = btScalar(0.);
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btVector3 v(1, 0, 0);
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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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bool hasResult = false;
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btVector3 c;
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btVector3 r = (linVelA - linVelB);
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btScalar lastLambda = lambda;
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//btScalar epsilon = btScalar(0.001);
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int numIter = 0;
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//first solution, using GJK
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btTransform identityTrans;
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identityTrans.setIdentity();
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// result.drawCoordSystem(sphereTr);
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btPointCollector pointCollector;
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btGjkPairDetector gjk(m_convexA, m_convexB, m_simplexSolver, 0); //m_penetrationDepthSolver);
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btGjkPairDetector::ClosestPointInput input;
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//we don't use margins during CCD
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// gjk.setIgnoreMargin(true);
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input.m_transformA = fromA;
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input.m_transformB = fromB;
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gjk.getClosestPoints(input, pointCollector, 0);
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hasResult = pointCollector.m_hasResult;
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c = pointCollector.m_pointInWorld;
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if (hasResult)
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{
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btScalar dist;
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dist = pointCollector.m_distance;
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n = pointCollector.m_normalOnBInWorld;
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//not close enough
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while (dist > radius)
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{
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numIter++;
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if (numIter > maxIter)
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{
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return false; //todo: report a failure
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}
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btScalar dLambda = btScalar(0.);
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btScalar projectedLinearVelocity = r.dot(n);
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dLambda = dist / (projectedLinearVelocity);
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lambda = lambda - dLambda;
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if (lambda > btScalar(1.))
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return false;
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if (lambda < btScalar(0.))
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return false;
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//todo: next check with relative epsilon
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if (lambda <= lastLambda)
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{
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return false;
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//n.setValue(0,0,0);
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break;
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}
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lastLambda = lambda;
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//interpolate to next lambda
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result.DebugDraw(lambda);
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input.m_transformA.getOrigin().setInterpolate3(fromA.getOrigin(), toA.getOrigin(), lambda);
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input.m_transformB.getOrigin().setInterpolate3(fromB.getOrigin(), toB.getOrigin(), lambda);
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gjk.getClosestPoints(input, pointCollector, 0);
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if (pointCollector.m_hasResult)
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{
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if (pointCollector.m_distance < btScalar(0.))
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{
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result.m_fraction = lastLambda;
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n = pointCollector.m_normalOnBInWorld;
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result.m_normal = n;
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result.m_hitPoint = pointCollector.m_pointInWorld;
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return true;
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}
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c = pointCollector.m_pointInWorld;
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n = pointCollector.m_normalOnBInWorld;
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dist = pointCollector.m_distance;
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}
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else
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{
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//??
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return false;
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}
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}
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//is n normalized?
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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 (n.dot(r) >= -result.m_allowedPenetration)
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return false;
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result.m_fraction = lambda;
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result.m_normal = n;
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result.m_hitPoint = c;
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return true;
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}
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return false;
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}
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