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Added btMultiBodyPoint2Point, it can be used between btMultiBody vs btMultiBody or btMultiBody vs btRigidBody

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Allow picking of btMultiBody, using a btMultiBodyPoint2Point constraint, with limited strength to avoid adding too much energy to the system (= blowup)
Add btMultiBodyJointMotor, it can be used in combination with joint limit (just add the joint limit after the motor, to avoid jitter)
This commit is contained in:
erwin.coumans@gmail.com
2013-10-05 01:46:32 +00:00
parent 2fb686b937
commit 488dd44835
18 changed files with 1418 additions and 475 deletions
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284
src/BulletDynamics/Featherstone/btMultiBodyJointLimitConstraint.cpp
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@@ -1,3 +1,19 @@
/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2013 Erwin Coumans http://bulletphysics.org
This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it freely,
subject to the following restrictions:
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.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
///This file was written by Erwin Coumans
#include "btMultiBodyJointLimitConstraint.h"
#include "btMultiBody.h"
@@ -73,243 +89,45 @@ void btMultiBodyJointLimitConstraint::createConstraintRows(btMultiBodyConstraint
btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing();
constraintRow.m_multiBodyA = m_bodyA;
constraintRow.m_multiBodyB = m_bodyB;
btScalar penetration = getPosition(row);
fillConstraintRow(constraintRow,data,jacobianA(row),jacobianB(row),penetration,0,0,infoGlobal);
btScalar rel_vel = fillConstraintRowMultiBodyMultiBody(constraintRow,data,jacobianA(row),jacobianB(row),infoGlobal,0,0,1e30);
{
btScalar penetration = getPosition(row);
btScalar positionalError = 0.f;
btScalar velocityError = - rel_vel;// * damping;
btScalar erp = infoGlobal.m_erp2;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
erp = infoGlobal.m_erp;
}
if (penetration>0)
{
positionalError = 0;
velocityError = -penetration / infoGlobal.m_timeStep;
} else
{
positionalError = -penetration * erp/infoGlobal.m_timeStep;
}
btScalar penetrationImpulse = positionalError*constraintRow.m_jacDiagABInv;
btScalar velocityImpulse = velocityError *constraintRow.m_jacDiagABInv;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
//combine position and velocity into rhs
constraintRow.m_rhs = penetrationImpulse+velocityImpulse;
constraintRow.m_rhsPenetration = 0.f;
} else
{
//split position and velocity into rhs and m_rhsPenetration
constraintRow.m_rhs = velocityImpulse;
constraintRow.m_rhsPenetration = penetrationImpulse;
}
}
}
}
void btMultiBodyJointLimitConstraint::fillConstraintRow(btMultiBodySolverConstraint& constraintRow,
btMultiBodyJacobianData& data,
btScalar* jacOrgA,btScalar* jacOrgB,
btScalar penetration,btScalar combinedFrictionCoeff, btScalar combinedRestitutionCoeff,
const btContactSolverInfo& infoGlobal)
{
btMultiBody* multiBodyA = constraintRow.m_multiBodyA;
btMultiBody* multiBodyB = constraintRow.m_multiBodyB;
if (multiBodyA)
{
const int ndofA = multiBodyA->getNumLinks() + 6;
constraintRow.m_deltaVelAindex = multiBodyA->getCompanionId();
if (constraintRow.m_deltaVelAindex <0)
{
constraintRow.m_deltaVelAindex = data.m_deltaVelocities.size();
multiBodyA->setCompanionId(constraintRow.m_deltaVelAindex);
data.m_deltaVelocities.resize(data.m_deltaVelocities.size()+ndofA);
} else
{
btAssert(data.m_deltaVelocities.size() >= constraintRow.m_deltaVelAindex+ndofA);
}
constraintRow.m_jacAindex = data.m_jacobians.size();
data.m_jacobians.resize(data.m_jacobians.size()+ndofA);
data.m_deltaVelocitiesUnitImpulse.resize(data.m_deltaVelocitiesUnitImpulse.size()+ndofA);
btAssert(data.m_jacobians.size() == data.m_deltaVelocitiesUnitImpulse.size());
for (int i=0;i<ndofA;i++)
data.m_jacobians[constraintRow.m_jacAindex+i] = jacOrgA[i];
float* delta = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacAindex];
multiBodyA->calcAccelerationDeltas(&data.m_jacobians[constraintRow.m_jacAindex],delta,data.scratch_r, data.scratch_v);
}
if (multiBodyB)
{
const int ndofB = multiBodyB->getNumLinks() + 6;
constraintRow.m_deltaVelBindex = multiBodyB->getCompanionId();
if (constraintRow.m_deltaVelBindex <0)
{
constraintRow.m_deltaVelBindex = data.m_deltaVelocities.size();
multiBodyB->setCompanionId(constraintRow.m_deltaVelBindex);
data.m_deltaVelocities.resize(data.m_deltaVelocities.size()+ndofB);
}
constraintRow.m_jacBindex = data.m_jacobians.size();
data.m_jacobians.resize(data.m_jacobians.size()+ndofB);
for (int i=0;i<ndofB;i++)
data.m_jacobians[constraintRow.m_jacBindex+i] = jacOrgB[i];
data.m_deltaVelocitiesUnitImpulse.resize(data.m_deltaVelocitiesUnitImpulse.size()+ndofB);
btAssert(data.m_jacobians.size() == data.m_deltaVelocitiesUnitImpulse.size());
multiBodyB->calcAccelerationDeltas(&data.m_jacobians[constraintRow.m_jacBindex],&data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacBindex],data.scratch_r, data.scratch_v);
}
{
btVector3 vec;
btScalar denom0 = 0.f;
btScalar denom1 = 0.f;
btScalar* jacB = 0;
btScalar* jacA = 0;
btScalar* lambdaA =0;
btScalar* lambdaB =0;
int ndofA = 0;
if (multiBodyA)
{
ndofA = multiBodyA->getNumLinks() + 6;
jacA = &data.m_jacobians[constraintRow.m_jacAindex];
lambdaA = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacAindex];
for (int i = 0; i < ndofA; ++i)
{
float j = jacA[i] ;
float l =lambdaA[i];
denom0 += j*l;
}
}
if (multiBodyB)
{
const int ndofB = multiBodyB->getNumLinks() + 6;
jacB = &data.m_jacobians[constraintRow.m_jacBindex];
lambdaB = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacBindex];
for (int i = 0; i < ndofB; ++i)
{
float j = jacB[i] ;
float l =lambdaB[i];
denom1 += j*l;
}
}
if (multiBodyA && (multiBodyA==multiBodyB))
{
// ndof1 == ndof2 in this case
for (int i = 0; i < ndofA; ++i)
{
denom1 += jacB[i] * lambdaA[i];
denom1 += jacA[i] * lambdaB[i];
}
}
float d = denom0+denom1;
if (btFabs(d)>SIMD_EPSILON)
{
constraintRow.m_jacDiagABInv = 1.f/(d);
} else
{
constraintRow.m_jacDiagABInv = 1.f;
}
}
//compute rhs and remaining constraintRow fields
btScalar rel_vel = 0.f;
int ndofA = 0;
int ndofB = 0;
{
btVector3 vel1,vel2;
if (multiBodyA)
{
ndofA = multiBodyA->getNumLinks() + 6;
btScalar* jacA = &data.m_jacobians[constraintRow.m_jacAindex];
for (int i = 0; i < ndofA ; ++i)
rel_vel += multiBodyA->getVelocityVector()[i] * jacA[i];
}
if (multiBodyB)
{
ndofB = multiBodyB->getNumLinks() + 6;
btScalar* jacB = &data.m_jacobians[constraintRow.m_jacBindex];
for (int i = 0; i < ndofB ; ++i)
rel_vel += multiBodyB->getVelocityVector()[i] * jacB[i];
}
constraintRow.m_friction = combinedFrictionCoeff;
}
/*
///warm starting (or zero if disabled)
if (infoGlobal.m_solverMode & SOLVER_USE_WARMSTARTING)
{
constraintRow.m_appliedImpulse = isFriction ? 0 : cp.m_appliedImpulse * infoGlobal.m_warmstartingFactor;
if (constraintRow.m_appliedImpulse)
{
if (multiBodyA)
{
btScalar impulse = constraintRow.m_appliedImpulse;
btScalar* deltaV = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacAindex];
multiBodyA->applyDeltaVee(deltaV,impulse);
applyDeltaVee(deltaV,impulse,constraintRow.m_deltaVelAindex,ndofA);
}
if (multiBodyB)
{
btScalar impulse = constraintRow.m_appliedImpulse;
btScalar* deltaV = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacBindex];
multiBodyB->applyDeltaVee(deltaV,impulse);
applyDeltaVee(deltaV,impulse,constraintRow.m_deltaVelBindex,ndofB);
}
}
}
else
*/
{
constraintRow.m_appliedImpulse = 0.f;
}
constraintRow.m_appliedPushImpulse = 0.f;
{
float desiredVelocity = -0.3;
btScalar positionalError = 0.f;
btScalar velocityError = - rel_vel;// * damping;
btScalar erp = infoGlobal.m_erp2;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
erp = infoGlobal.m_erp;
}
if (penetration>0)
{
positionalError = 0;
velocityError = -penetration / infoGlobal.m_timeStep;
} else
{
positionalError = -penetration * erp/infoGlobal.m_timeStep;
}
btScalar penetrationImpulse = positionalError*constraintRow.m_jacDiagABInv;
btScalar velocityImpulse = velocityError *constraintRow.m_jacDiagABInv;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
//combine position and velocity into rhs
constraintRow.m_rhs = penetrationImpulse+velocityImpulse;
constraintRow.m_rhsPenetration = 0.f;
} else
{
//split position and velocity into rhs and m_rhsPenetration
constraintRow.m_rhs = velocityImpulse;
constraintRow.m_rhsPenetration = penetrationImpulse;
}
constraintRow.m_cfm = 0.f;
constraintRow.m_lowerLimit = 0;
constraintRow.m_upperLimit = 1e10f;
}
}