1 /* 2 Bullet Continuous Collision Detection and Physics Library 3 Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/ 4 5 This software is provided 'as-is', without any express or implied warranty. 6 In no event will the authors be held liable for any damages arising from the use of this software. 7 Permission is granted to anyone to use this software for any purpose, 8 including commercial applications, and to alter it and redistribute it freely, 9 subject to the following restrictions: 10 11 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. 12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 13 3. This notice may not be removed or altered from any source distribution. 14 */ 15 16 17 #include "btContactConstraint.h" 18 #include "BulletDynamics/Dynamics/btRigidBody.h" 19 #include "LinearMath/btVector3.h" 20 #include "btJacobianEntry.h" 21 #include "btContactSolverInfo.h" 22 #include "LinearMath/btMinMax.h" 23 #include "BulletCollision/NarrowPhaseCollision/btManifoldPoint.h" 24 25 26 27 btContactConstraint::btContactConstraint(btPersistentManifold* contactManifold,btRigidBody& rbA,btRigidBody& rbB) 28 :btTypedConstraint(CONTACT_CONSTRAINT_TYPE,rbA,rbB), 29 m_contactManifold(*contactManifold) 30 { 31 32 } 33 34 btContactConstraint::~btContactConstraint() 35 { 36 37 } 38 39 void btContactConstraint::setContactManifold(btPersistentManifold* contactManifold) 40 { 41 m_contactManifold = *contactManifold; 42 } 43 44 void btContactConstraint::getInfo1 (btConstraintInfo1* info) 45 { 46 47 } 48 49 void btContactConstraint::getInfo2 (btConstraintInfo2* info) 50 { 51 52 } 53 54 void btContactConstraint::buildJacobian() 55 { 56 57 } 58 59 60 61 62 63 #include "btContactConstraint.h" 64 #include "BulletDynamics/Dynamics/btRigidBody.h" 65 #include "LinearMath/btVector3.h" 66 #include "btJacobianEntry.h" 67 #include "btContactSolverInfo.h" 68 #include "LinearMath/btMinMax.h" 69 #include "BulletCollision/NarrowPhaseCollision/btManifoldPoint.h" 70 71 72 73 //response between two dynamic objects without friction and no restitution, assuming 0 penetration depth 74 btScalar resolveSingleCollision( 75 btRigidBody* body1, 76 btCollisionObject* colObj2, 77 const btVector3& contactPositionWorld, 78 const btVector3& contactNormalOnB, 79 const btContactSolverInfo& solverInfo, 80 btScalar distance) 81 { 82 btRigidBody* body2 = btRigidBody::upcast(colObj2); 83 84 85 const btVector3& normal = contactNormalOnB; 86 87 btVector3 rel_pos1 = contactPositionWorld - body1->getWorldTransform().getOrigin(); 88 btVector3 rel_pos2 = contactPositionWorld - colObj2->getWorldTransform().getOrigin(); 89 90 btVector3 vel1 = body1->getVelocityInLocalPoint(rel_pos1); 91 btVector3 vel2 = body2? body2->getVelocityInLocalPoint(rel_pos2) : btVector3(0,0,0); 92 btVector3 vel = vel1 - vel2; 93 btScalar rel_vel; 94 rel_vel = normal.dot(vel); 95 96 btScalar combinedRestitution = 0.f; 97 btScalar restitution = combinedRestitution* -rel_vel; 98 99 btScalar positionalError = solverInfo.m_erp *-distance /solverInfo.m_timeStep ; 100 btScalar velocityError = -(1.0f + restitution) * rel_vel;// * damping; 101 btScalar denom0 = body1->computeImpulseDenominator(contactPositionWorld,normal); 102 btScalar denom1 = body2? body2->computeImpulseDenominator(contactPositionWorld,normal) : 0.f; 103 btScalar relaxation = 1.f; 104 btScalar jacDiagABInv = relaxation/(denom0+denom1); 105 106 btScalar penetrationImpulse = positionalError * jacDiagABInv; 107 btScalar velocityImpulse = velocityError * jacDiagABInv; 108 109 btScalar normalImpulse = penetrationImpulse+velocityImpulse; 110 normalImpulse = 0.f > normalImpulse ? 0.f: normalImpulse; 111 112 body1->applyImpulse(normal*(normalImpulse), rel_pos1); 113 if (body2) 114 body2->applyImpulse(-normal*(normalImpulse), rel_pos2); 115 116 return normalImpulse; 117 } 118 119 120 //bilateral constraint between two dynamic objects 121 void resolveSingleBilateral(btRigidBody& body1, const btVector3& pos1, 122 btRigidBody& body2, const btVector3& pos2, 123 btScalar distance, const btVector3& normal,btScalar& impulse ,btScalar timeStep) 124 { 125 (void)timeStep; 126 (void)distance; 127 128 129 btScalar normalLenSqr = normal.length2(); 130 btAssert(btFabs(normalLenSqr) < btScalar(1.1)); 131 if (normalLenSqr > btScalar(1.1)) 132 { 133 impulse = btScalar(0.); 134 return; 135 } 136 btVector3 rel_pos1 = pos1 - body1.getCenterOfMassPosition(); 137 btVector3 rel_pos2 = pos2 - body2.getCenterOfMassPosition(); 138 //this jacobian entry could be re-used for all iterations 139 140 btVector3 vel1 = body1.getVelocityInLocalPoint(rel_pos1); 141 btVector3 vel2 = body2.getVelocityInLocalPoint(rel_pos2); 142 btVector3 vel = vel1 - vel2; 143 144 145 btJacobianEntry jac(body1.getCenterOfMassTransform().getBasis().transpose(), 146 body2.getCenterOfMassTransform().getBasis().transpose(), 147 rel_pos1,rel_pos2,normal,body1.getInvInertiaDiagLocal(),body1.getInvMass(), 148 body2.getInvInertiaDiagLocal(),body2.getInvMass()); 149 150 btScalar jacDiagAB = jac.getDiagonal(); 151 btScalar jacDiagABInv = btScalar(1.) / jacDiagAB; 152 153 btScalar rel_vel = jac.getRelativeVelocity( 154 body1.getLinearVelocity(), 155 body1.getCenterOfMassTransform().getBasis().transpose() * body1.getAngularVelocity(), 156 body2.getLinearVelocity(), 157 body2.getCenterOfMassTransform().getBasis().transpose() * body2.getAngularVelocity()); 158 159 160 161 rel_vel = normal.dot(vel); 162 163 //todo: move this into proper structure 164 btScalar contactDamping = btScalar(0.2); 165 166 #ifdef ONLY_USE_LINEAR_MASS 167 btScalar massTerm = btScalar(1.) / (body1.getInvMass() + body2.getInvMass()); 168 impulse = - contactDamping * rel_vel * massTerm; 169 #else 170 btScalar velocityImpulse = -contactDamping * rel_vel * jacDiagABInv; 171 impulse = velocityImpulse; 172 #endif 173 } 174 175 176 177 178
