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Add contact handling between multibody and softbody.

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This commit is contained in:
yunfeibai
2016-11-02 13:21:01 -07:00
parent 295c1b7c88
commit ab6ce65abe
2 changed files with 49 additions and 6 deletions
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2
examples/RoboticsLearning/GripperGraspExample.cpp
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@@ -604,7 +604,7 @@ public:
args.m_startPosition.setValue(0,0,0);
args.m_startOrientation.setEulerZYX(0,0,0);
args.m_forceOverrideFixedBase = true;
args.m_useMultiBody = true;
args.m_useMultiBody = false;
b3RobotSimLoadFileResults results;
m_robotSim.loadFile(args,results);
}

51
src/BulletSoftBody/btSoftBody.cpp
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@@ -3020,6 +3020,7 @@ void btSoftBody::PSolve_Anchors(btSoftBody* psb,btScalar kst,btScalar ti)
}
}
//
void btSoftBody::PSolve_RContacts(btSoftBody* psb, btScalar kst, btScalar ti)
{
@@ -3031,8 +3032,38 @@ void btSoftBody::PSolve_RContacts(btSoftBody* psb, btScalar kst, btScalar ti)
const sCti& cti = c.m_cti;
if (cti.m_colObj->hasContactResponse())
{
btRigidBody* tmpRigid = (btRigidBody*)btRigidBody::upcast(cti.m_colObj);
const btVector3 va = tmpRigid ? tmpRigid->getVelocityInLocalPoint(c.m_c1)*dt : btVector3(0,0,0);
btVector3 va(0,0,0);
btRigidBody* rigidCol;
btMultiBodyLinkCollider* multibodyLinkCol;
btScalar* deltaV;
if (cti.m_colObj->getInternalType() == btCollisionObject::CO_RIGID_BODY)
{
rigidCol = (btRigidBody*)btRigidBody::upcast(cti.m_colObj);
va = rigidCol ? rigidCol->getVelocityInLocalPoint(c.m_c1)*dt : btVector3(0,0,0);
}
else if (cti.m_colObj->getInternalType() == btCollisionObject::CO_FEATHERSTONE_LINK)
{
multibodyLinkCol = (btMultiBodyLinkCollider*)btMultiBodyLinkCollider::upcast(cti.m_colObj);
if (multibodyLinkCol)
{
const int ndof = multibodyLinkCol->m_multiBody->getNumDofs() + 6;
btMultiBodyJacobianData jacobianData;
jacobianData.m_jacobians.resize(ndof);
jacobianData.m_deltaVelocitiesUnitImpulse.resize(ndof);
btScalar* jac=&jacobianData.m_jacobians[0];
multibodyLinkCol->m_multiBody->fillContactJacobianMultiDof(multibodyLinkCol->m_link, c.m_node->m_x, cti.m_normal, jac, jacobianData.scratch_r, jacobianData.scratch_v, jacobianData.scratch_m);
deltaV = &jacobianData.m_deltaVelocitiesUnitImpulse[0];
multibodyLinkCol->m_multiBody->calcAccelerationDeltasMultiDof(&jacobianData.m_jacobians[0],deltaV,jacobianData.scratch_r, jacobianData.scratch_v);
btScalar vel = 0.0;
for (int j = 0; j < ndof ; ++j) {
vel += multibodyLinkCol->m_multiBody->getVelocityVector()[j] * jac[j];
}
va = cti.m_normal*vel*dt;
}
}
const btVector3 vb = c.m_node->m_x-c.m_node->m_q;
const btVector3 vr = vb-va;
const btScalar dn = btDot(vr, cti.m_normal);
@@ -3043,8 +3074,20 @@ void btSoftBody::PSolve_RContacts(btSoftBody* psb, btScalar kst, btScalar ti)
// c0 is the impulse matrix, c3 is 1 - the friction coefficient or 0, c4 is the contact hardness coefficient
const btVector3 impulse = c.m_c0 * ( (vr - (fv * c.m_c3) + (cti.m_normal * (dp * c.m_c4))) * kst );
c.m_node->m_x -= impulse * c.m_c2;
if (tmpRigid)
tmpRigid->applyImpulse(impulse,c.m_c1);
if (cti.m_colObj->getInternalType() == btCollisionObject::CO_RIGID_BODY)
{
if (rigidCol)
rigidCol->applyImpulse(impulse,c.m_c1);
}
else if (cti.m_colObj->getInternalType() == btCollisionObject::CO_FEATHERSTONE_LINK)
{
if (multibodyLinkCol)
{
double multiplier = 0.2;
multibodyLinkCol->m_multiBody->applyDeltaVeeMultiDof(deltaV,-impulse.length()*multiplier);
}
}
}
}
}