154 lines
5.5 KiB
C++
154 lines
5.5 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 "btContactConstraint.h"
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#include "BulletDynamics/Dynamics/btRigidBody.h"
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#include "LinearMath/btVector3.h"
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#include "btJacobianEntry.h"
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#include "btContactSolverInfo.h"
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#include "LinearMath/btMinMax.h"
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#include "BulletCollision/NarrowPhaseCollision/btManifoldPoint.h"
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btContactConstraint::btContactConstraint(btPersistentManifold* contactManifold, btRigidBody& rbA, btRigidBody& rbB)
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: btTypedConstraint(CONTACT_CONSTRAINT_TYPE, rbA, rbB),
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m_contactManifold(*contactManifold)
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{
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}
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btContactConstraint::~btContactConstraint()
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{
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}
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void btContactConstraint::setContactManifold(btPersistentManifold* contactManifold)
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{
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m_contactManifold = *contactManifold;
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}
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void btContactConstraint::getInfo1(btConstraintInfo1* info)
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{
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}
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void btContactConstraint::getInfo2(btConstraintInfo2* info)
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{
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}
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void btContactConstraint::buildJacobian()
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{
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}
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#include "btContactConstraint.h"
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#include "BulletDynamics/Dynamics/btRigidBody.h"
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#include "LinearMath/btVector3.h"
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#include "btJacobianEntry.h"
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#include "btContactSolverInfo.h"
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#include "LinearMath/btMinMax.h"
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#include "BulletCollision/NarrowPhaseCollision/btManifoldPoint.h"
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//response between two dynamic objects without friction and no restitution, assuming 0 penetration depth
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btScalar resolveSingleCollision(
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btRigidBody* body1,
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btCollisionObject* colObj2,
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const btVector3& contactPositionWorld,
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const btVector3& contactNormalOnB,
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const btContactSolverInfo& solverInfo,
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btScalar distance)
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{
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btRigidBody* body2 = btRigidBody::upcast(colObj2);
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const btVector3& normal = contactNormalOnB;
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btVector3 rel_pos1 = contactPositionWorld - body1->getWorldTransform().getOrigin();
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btVector3 rel_pos2 = contactPositionWorld - colObj2->getWorldTransform().getOrigin();
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btVector3 vel1 = body1->getVelocityInLocalPoint(rel_pos1);
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btVector3 vel2 = body2 ? body2->getVelocityInLocalPoint(rel_pos2) : btVector3(0, 0, 0);
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btVector3 vel = vel1 - vel2;
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btScalar rel_vel;
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rel_vel = normal.dot(vel);
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btScalar combinedRestitution = 0.f;
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btScalar restitution = combinedRestitution * -rel_vel;
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btScalar positionalError = solverInfo.m_erp * -distance / solverInfo.m_timeStep;
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btScalar velocityError = -(1.0f + restitution) * rel_vel; // * damping;
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btScalar denom0 = body1->computeImpulseDenominator(contactPositionWorld, normal);
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btScalar denom1 = body2 ? body2->computeImpulseDenominator(contactPositionWorld, normal) : 0.f;
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btScalar relaxation = 1.f;
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btScalar jacDiagABInv = relaxation / (denom0 + denom1);
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btScalar penetrationImpulse = positionalError * jacDiagABInv;
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btScalar velocityImpulse = velocityError * jacDiagABInv;
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btScalar normalImpulse = penetrationImpulse + velocityImpulse;
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normalImpulse = 0.f > normalImpulse ? 0.f : normalImpulse;
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body1->applyImpulse(normal * (normalImpulse), rel_pos1);
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if (body2)
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body2->applyImpulse(-normal * (normalImpulse), rel_pos2);
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return normalImpulse;
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}
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//bilateral constraint between two dynamic objects
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void resolveSingleBilateral(btRigidBody& body1, const btVector3& pos1,
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btRigidBody& body2, const btVector3& pos2,
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btScalar distance, const btVector3& normal, btScalar& impulse, btScalar timeStep)
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{
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(void)timeStep;
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(void)distance;
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btScalar normalLenSqr = normal.length2();
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btAssert(btFabs(normalLenSqr) < btScalar(1.1));
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if (normalLenSqr > btScalar(1.1))
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{
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impulse = btScalar(0.);
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return;
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}
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btVector3 rel_pos1 = pos1 - body1.getCenterOfMassPosition();
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btVector3 rel_pos2 = pos2 - body2.getCenterOfMassPosition();
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//this jacobian entry could be re-used for all iterations
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btVector3 vel1 = body1.getVelocityInLocalPoint(rel_pos1);
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btVector3 vel2 = body2.getVelocityInLocalPoint(rel_pos2);
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btVector3 vel = vel1 - vel2;
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btJacobianEntry jac(body1.getCenterOfMassTransform().getBasis().transpose(),
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body2.getCenterOfMassTransform().getBasis().transpose(),
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rel_pos1, rel_pos2, normal, body1.getInvInertiaDiagLocal(), body1.getInvMass(),
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body2.getInvInertiaDiagLocal(), body2.getInvMass());
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btScalar jacDiagAB = jac.getDiagonal();
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btScalar jacDiagABInv = btScalar(1.) / jacDiagAB;
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btScalar rel_vel = jac.getRelativeVelocity(
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body1.getLinearVelocity(),
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body1.getCenterOfMassTransform().getBasis().transpose() * body1.getAngularVelocity(),
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body2.getLinearVelocity(),
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body2.getCenterOfMassTransform().getBasis().transpose() * body2.getAngularVelocity());
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rel_vel = normal.dot(vel);
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//todo: move this into proper structure
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btScalar contactDamping = btScalar(0.2);
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#ifdef ONLY_USE_LINEAR_MASS
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btScalar massTerm = btScalar(1.) / (body1.getInvMass() + body2.getInvMass());
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impulse = -contactDamping * rel_vel * massTerm;
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#else
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btScalar velocityImpulse = -contactDamping * rel_vel * jacDiagABInv;
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impulse = velocityImpulse;
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#endif
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}
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