118 lines
4.0 KiB
C++
118 lines
4.0 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 "btPoint2PointConstraint.h"
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#include "BulletDynamics/Dynamics/btRigidBody.h"
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#include <new>
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btPoint2PointConstraint::btPoint2PointConstraint()
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:btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE)
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{
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}
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btPoint2PointConstraint::btPoint2PointConstraint(btRigidBody& rbA,btRigidBody& rbB, const btVector3& pivotInA,const btVector3& pivotInB)
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:btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE,rbA,rbB),m_pivotInA(pivotInA),m_pivotInB(pivotInB)
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{
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}
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btPoint2PointConstraint::btPoint2PointConstraint(btRigidBody& rbA,const btVector3& pivotInA)
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:btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE,rbA),m_pivotInA(pivotInA),m_pivotInB(rbA.getCenterOfMassTransform()(pivotInA))
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{
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}
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void btPoint2PointConstraint::buildJacobian()
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{
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m_appliedImpulse = btScalar(0.);
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btVector3 normal(0,0,0);
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for (int i=0;i<3;i++)
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{
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normal[i] = 1;
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new (&m_jac[i]) btJacobianEntry(
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m_rbA.getCenterOfMassTransform().getBasis().transpose(),
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m_rbB.getCenterOfMassTransform().getBasis().transpose(),
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m_rbA.getCenterOfMassTransform()*m_pivotInA - m_rbA.getCenterOfMassPosition(),
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m_rbB.getCenterOfMassTransform()*m_pivotInB - m_rbB.getCenterOfMassPosition(),
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normal,
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m_rbA.getInvInertiaDiagLocal(),
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m_rbA.getInvMass(),
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m_rbB.getInvInertiaDiagLocal(),
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m_rbB.getInvMass());
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normal[i] = 0;
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}
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}
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void btPoint2PointConstraint::solveConstraint(btScalar timeStep)
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{
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btVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_pivotInA;
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btVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_pivotInB;
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btVector3 normal(0,0,0);
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// btVector3 angvelA = m_rbA.getCenterOfMassTransform().getBasis().transpose() * m_rbA.getAngularVelocity();
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// btVector3 angvelB = m_rbB.getCenterOfMassTransform().getBasis().transpose() * m_rbB.getAngularVelocity();
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for (int i=0;i<3;i++)
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{
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normal[i] = 1;
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btScalar jacDiagABInv = btScalar(1.) / m_jac[i].getDiagonal();
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btVector3 rel_pos1 = pivotAInW - m_rbA.getCenterOfMassPosition();
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btVector3 rel_pos2 = pivotBInW - m_rbB.getCenterOfMassPosition();
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//this jacobian entry could be re-used for all iterations
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btVector3 vel1 = m_rbA.getVelocityInLocalPoint(rel_pos1);
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btVector3 vel2 = m_rbB.getVelocityInLocalPoint(rel_pos2);
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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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/*
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//velocity error (first order error)
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btScalar rel_vel = m_jac[i].getRelativeVelocity(m_rbA.getLinearVelocity(),angvelA,
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m_rbB.getLinearVelocity(),angvelB);
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*/
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//positional error (zeroth order error)
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btScalar depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
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btScalar impulse = depth*m_setting.m_tau/timeStep * jacDiagABInv - m_setting.m_damping * rel_vel * jacDiagABInv;
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m_appliedImpulse+=impulse;
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btVector3 impulse_vector = normal * impulse;
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m_rbA.applyImpulse(impulse_vector, pivotAInW - m_rbA.getCenterOfMassPosition());
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m_rbB.applyImpulse(-impulse_vector, pivotBInW - m_rbB.getCenterOfMassPosition());
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normal[i] = 0;
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}
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}
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void btPoint2PointConstraint::updateRHS(btScalar timeStep)
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{
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(void)timeStep;
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}
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