void btHingeConstraint::getInfo2NonVirtual (btConstraintInfo2* info,const btTransform& transA,const btTransform& transB,const btVector3& angVelA,const btVector3& angVelB)
{
///the regular (virtual) implementation getInfo2 already performs 'testLimit' during getInfo1, so we need to do it now
testLimit(transA,transB);
getInfo2Internal(info,transA,transB,angVelA,angVelB);
}
void btHingeConstraint::getInfo1(btConstraintInfo1* info)
{
if (m_useSolveConstraintObsolete)
{
info->m_numConstraintRows = 0;
info->nub = 0;
}
else
{
info->m_numConstraintRows = 5; // Fixed 3 linear + 2 angular
info->nub = 1;
//prepare constraint
testLimit();
if(getSolveLimit() || getEnableAngularMotor())
{
info->m_numConstraintRows++; // limit 3rd anguar as well
info->nub--;
}
}
}
void btHingeConstraint::getInfo1(btConstraintInfo1* info)
{
if (m_useSolveConstraintObsolete)
{
info->m_numConstraintRows = 0;
info->nub = 0;
}
else
{
info->m_numConstraintRows = 5; // Fixed 3 linear + 2 angular
info->nub = 1;
//always add the row, to avoid computation (data is not available yet)
//prepare constraint
testLimit(m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform());
if(getSolveLimit() || getEnableAngularMotor())
{
info->m_numConstraintRows++; // limit 3rd anguar as well
info->nub--;
}
}
}
void btHingeConstraint::buildJacobian()
{
if (m_useSolveConstraintObsolete)
{
m_appliedImpulse = btScalar(0.);
m_accMotorImpulse = btScalar(0.);
if (!m_angularOnly)
{
btVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_rbAFrame.getOrigin();
btVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_rbBFrame.getOrigin();
btVector3 relPos = pivotBInW - pivotAInW;
btVector3 normal[3];
if (relPos.length2() > SIMD_EPSILON)
{
normal[0] = relPos.normalized();
}
else
{
normal[0].setValue(btScalar(1.0),0,0);
}
btPlaneSpace1(normal[0], normal[1], normal[2]);
for (int i=0;i<3;i++)
{
new (&m_jac[i]) btJacobianEntry(
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
pivotAInW - m_rbA.getCenterOfMassPosition(),
pivotBInW - m_rbB.getCenterOfMassPosition(),
normal[i],
m_rbA.getInvInertiaDiagLocal(),
m_rbA.getInvMass(),
m_rbB.getInvInertiaDiagLocal(),
m_rbB.getInvMass());
}
}
//calculate two perpendicular jointAxis, orthogonal to hingeAxis
//these two jointAxis require equal angular velocities for both bodies
//this is unused for now, it's a todo
btVector3 jointAxis0local;
btVector3 jointAxis1local;
btPlaneSpace1(m_rbAFrame.getBasis().getColumn(2),jointAxis0local,jointAxis1local);
btVector3 jointAxis0 = getRigidBodyA().getCenterOfMassTransform().getBasis() * jointAxis0local;
btVector3 jointAxis1 = getRigidBodyA().getCenterOfMassTransform().getBasis() * jointAxis1local;
btVector3 hingeAxisWorld = getRigidBodyA().getCenterOfMassTransform().getBasis() * m_rbAFrame.getBasis().getColumn(2);
new (&m_jacAng[0]) btJacobianEntry(jointAxis0,
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
m_rbA.getInvInertiaDiagLocal(),
m_rbB.getInvInertiaDiagLocal());
new (&m_jacAng[1]) btJacobianEntry(jointAxis1,
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
m_rbA.getInvInertiaDiagLocal(),
m_rbB.getInvInertiaDiagLocal());
new (&m_jacAng[2]) btJacobianEntry(hingeAxisWorld,
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
m_rbA.getInvInertiaDiagLocal(),
m_rbB.getInvInertiaDiagLocal());
// clear accumulator
m_accLimitImpulse = btScalar(0.);
// test angular limit
testLimit(m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform());
//Compute K = J*W*J' for hinge axis
btVector3 axisA = getRigidBodyA().getCenterOfMassTransform().getBasis() * m_rbAFrame.getBasis().getColumn(2);
m_kHinge = 1.0f / (getRigidBodyA().computeAngularImpulseDenominator(axisA) +
getRigidBodyB().computeAngularImpulseDenominator(axisA));
}
}