240 lines
7.4 KiB
C++
240 lines
7.4 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2006 Erwin Coumans https://bulletphysics.org
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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 "btSolve2LinearConstraint.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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void btSolve2LinearConstraint::resolveUnilateralPairConstraint(
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btRigidBody* body1,
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btRigidBody* body2,
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const btMatrix3x3& world2A,
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const btMatrix3x3& world2B,
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const btVector3& invInertiaADiag,
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const btScalar invMassA,
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const btVector3& linvelA, const btVector3& angvelA,
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const btVector3& rel_posA1,
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const btVector3& invInertiaBDiag,
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const btScalar invMassB,
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const btVector3& linvelB, const btVector3& angvelB,
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const btVector3& rel_posA2,
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btScalar depthA, const btVector3& normalA,
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const btVector3& rel_posB1, const btVector3& rel_posB2,
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btScalar depthB, const btVector3& normalB,
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btScalar& imp0, btScalar& imp1)
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{
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(void)linvelA;
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(void)linvelB;
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(void)angvelB;
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(void)angvelA;
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imp0 = btScalar(0.);
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imp1 = btScalar(0.);
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btScalar len = btFabs(normalA.length()) - btScalar(1.);
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if (btFabs(len) >= SIMD_EPSILON)
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return;
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btAssert(len < SIMD_EPSILON);
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//this jacobian entry could be re-used for all iterations
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btJacobianEntry jacA(world2A, world2B, rel_posA1, rel_posA2, normalA, invInertiaADiag, invMassA,
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invInertiaBDiag, invMassB);
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btJacobianEntry jacB(world2A, world2B, rel_posB1, rel_posB2, normalB, invInertiaADiag, invMassA,
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invInertiaBDiag, invMassB);
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//const btScalar vel0 = jacA.getRelativeVelocity(linvelA,angvelA,linvelB,angvelB);
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//const btScalar vel1 = jacB.getRelativeVelocity(linvelA,angvelA,linvelB,angvelB);
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const btScalar vel0 = normalA.dot(body1->getVelocityInLocalPoint(rel_posA1) - body2->getVelocityInLocalPoint(rel_posA1));
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const btScalar vel1 = normalB.dot(body1->getVelocityInLocalPoint(rel_posB1) - body2->getVelocityInLocalPoint(rel_posB1));
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// btScalar penetrationImpulse = (depth*contactTau*timeCorrection) * massTerm;//jacDiagABInv
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btScalar massTerm = btScalar(1.) / (invMassA + invMassB);
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// calculate rhs (or error) terms
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const btScalar dv0 = depthA * m_tau * massTerm - vel0 * m_damping;
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const btScalar dv1 = depthB * m_tau * massTerm - vel1 * m_damping;
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// dC/dv * dv = -C
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// jacobian * impulse = -error
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//
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//impulse = jacobianInverse * -error
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// inverting 2x2 symmetric system (offdiagonal are equal!)
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//
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btScalar nonDiag = jacA.getNonDiagonal(jacB, invMassA, invMassB);
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btScalar invDet = btScalar(1.0) / (jacA.getDiagonal() * jacB.getDiagonal() - nonDiag * nonDiag);
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//imp0 = dv0 * jacA.getDiagonal() * invDet + dv1 * -nonDiag * invDet;
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//imp1 = dv1 * jacB.getDiagonal() * invDet + dv0 * - nonDiag * invDet;
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imp0 = dv0 * jacA.getDiagonal() * invDet + dv1 * -nonDiag * invDet;
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imp1 = dv1 * jacB.getDiagonal() * invDet + dv0 * -nonDiag * invDet;
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//[a b] [d -c]
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//[c d] inverse = (1 / determinant) * [-b a] where determinant is (ad - bc)
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//[jA nD] * [imp0] = [dv0]
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//[nD jB] [imp1] [dv1]
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}
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void btSolve2LinearConstraint::resolveBilateralPairConstraint(
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btRigidBody* body1,
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btRigidBody* body2,
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const btMatrix3x3& world2A,
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const btMatrix3x3& world2B,
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const btVector3& invInertiaADiag,
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const btScalar invMassA,
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const btVector3& linvelA, const btVector3& angvelA,
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const btVector3& rel_posA1,
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const btVector3& invInertiaBDiag,
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const btScalar invMassB,
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const btVector3& linvelB, const btVector3& angvelB,
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const btVector3& rel_posA2,
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btScalar depthA, const btVector3& normalA,
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const btVector3& rel_posB1, const btVector3& rel_posB2,
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btScalar depthB, const btVector3& normalB,
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btScalar& imp0, btScalar& imp1)
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{
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(void)linvelA;
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(void)linvelB;
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(void)angvelA;
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(void)angvelB;
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imp0 = btScalar(0.);
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imp1 = btScalar(0.);
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btScalar len = btFabs(normalA.length()) - btScalar(1.);
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if (btFabs(len) >= SIMD_EPSILON)
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return;
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btAssert(len < SIMD_EPSILON);
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//this jacobian entry could be re-used for all iterations
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btJacobianEntry jacA(world2A, world2B, rel_posA1, rel_posA2, normalA, invInertiaADiag, invMassA,
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invInertiaBDiag, invMassB);
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btJacobianEntry jacB(world2A, world2B, rel_posB1, rel_posB2, normalB, invInertiaADiag, invMassA,
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invInertiaBDiag, invMassB);
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//const btScalar vel0 = jacA.getRelativeVelocity(linvelA,angvelA,linvelB,angvelB);
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//const btScalar vel1 = jacB.getRelativeVelocity(linvelA,angvelA,linvelB,angvelB);
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const btScalar vel0 = normalA.dot(body1->getVelocityInLocalPoint(rel_posA1) - body2->getVelocityInLocalPoint(rel_posA1));
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const btScalar vel1 = normalB.dot(body1->getVelocityInLocalPoint(rel_posB1) - body2->getVelocityInLocalPoint(rel_posB1));
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// calculate rhs (or error) terms
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const btScalar dv0 = depthA * m_tau - vel0 * m_damping;
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const btScalar dv1 = depthB * m_tau - vel1 * m_damping;
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// dC/dv * dv = -C
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// jacobian * impulse = -error
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//
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//impulse = jacobianInverse * -error
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// inverting 2x2 symmetric system (offdiagonal are equal!)
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//
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btScalar nonDiag = jacA.getNonDiagonal(jacB, invMassA, invMassB);
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btScalar invDet = btScalar(1.0) / (jacA.getDiagonal() * jacB.getDiagonal() - nonDiag * nonDiag);
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//imp0 = dv0 * jacA.getDiagonal() * invDet + dv1 * -nonDiag * invDet;
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//imp1 = dv1 * jacB.getDiagonal() * invDet + dv0 * - nonDiag * invDet;
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imp0 = dv0 * jacA.getDiagonal() * invDet + dv1 * -nonDiag * invDet;
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imp1 = dv1 * jacB.getDiagonal() * invDet + dv0 * -nonDiag * invDet;
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//[a b] [d -c]
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//[c d] inverse = (1 / determinant) * [-b a] where determinant is (ad - bc)
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//[jA nD] * [imp0] = [dv0]
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//[nD jB] [imp1] [dv1]
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if (imp0 > btScalar(0.0))
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{
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if (imp1 > btScalar(0.0))
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{
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//both positive
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}
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else
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{
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imp1 = btScalar(0.);
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// now imp0>0 imp1<0
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imp0 = dv0 / jacA.getDiagonal();
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if (imp0 > btScalar(0.0))
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{
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}
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else
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{
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imp0 = btScalar(0.);
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}
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}
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}
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else
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{
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imp0 = btScalar(0.);
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imp1 = dv1 / jacB.getDiagonal();
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if (imp1 <= btScalar(0.0))
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{
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imp1 = btScalar(0.);
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// now imp0>0 imp1<0
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imp0 = dv0 / jacA.getDiagonal();
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if (imp0 > btScalar(0.0))
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{
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}
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else
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{
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imp0 = btScalar(0.);
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}
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}
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else
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{
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}
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}
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}
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/*
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void btSolve2LinearConstraint::resolveAngularConstraint( const btMatrix3x3& invInertiaAWS,
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const btScalar invMassA,
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const btVector3& linvelA,const btVector3& angvelA,
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const btVector3& rel_posA1,
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const btMatrix3x3& invInertiaBWS,
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const btScalar invMassB,
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const btVector3& linvelB,const btVector3& angvelB,
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const btVector3& rel_posA2,
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btScalar depthA, const btVector3& normalA,
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const btVector3& rel_posB1,const btVector3& rel_posB2,
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btScalar depthB, const btVector3& normalB,
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btScalar& imp0,btScalar& imp1)
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{
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}
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*/
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