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dgregorius: added accumulated impulse and function for computation of angles around each constraint axis as preparation for angular limits...

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dondickied
2006-06-24 19:32:23 +00:00
parent 2eed545a70
commit 3cf1fb3646
2 changed files with 105 additions and 23 deletions
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100
BulletDynamics/ConstraintSolver/Generic6DofConstraint.cpp
View File

@@ -27,11 +27,26 @@ Generic6DofConstraint::Generic6DofConstraint()
{
}
Generic6DofConstraint::Generic6DofConstraint(RigidBody& rbA, RigidBody& rbB, const SimdTransform& frameInA, const SimdTransform& frameInB )
Generic6DofConstraint::Generic6DofConstraint(RigidBody& rbA, RigidBody& rbB, const SimdTransform& frameInA, const SimdTransform& frameInB)
: TypedConstraint(rbA, rbB)
, m_frameInA(frameInA)
, m_frameInB(frameInB)
{
m_accumulatedLinearImpulse[0] = 0.0f;
m_accumulatedLinearImpulse[1] = 0.0f;
m_accumulatedLinearImpulse[2] = 0.0f;
m_accumulatedAngularImpulse[0] = 0.0f;
m_accumulatedAngularImpulse[1] = 0.0f;
m_accumulatedAngularImpulse[2] = 0.0f;
m_angularLowerLimit[0] = 0.0f;
m_angularLowerLimit[1] = 0.0f;
m_angularLowerLimit[2] = 0.0f;
m_angularUpperLimit[0] = 0.0f;
m_angularUpperLimit[1] = 0.0f;
m_angularUpperLimit[2] = 0.0f;
}
@@ -43,12 +58,19 @@ void Generic6DofConstraint::BuildJacobian()
const SimdVector3& pivotInA = m_frameInA.getOrigin();
const SimdVector3& pivotInB = m_frameInB.getOrigin();
SimdVector3 pivotAInW = m_rbA.getCenterOfMassTransform() * m_frameInA.getOrigin();
SimdVector3 pivotBInW = m_rbB.getCenterOfMassTransform() * m_frameInB.getOrigin();
SimdVector3 rel_pos1 = pivotAInW - m_rbA.getCenterOfMassPosition();
SimdVector3 rel_pos2 = pivotBInW - m_rbB.getCenterOfMassPosition();
int i;
//linear part
for (i=0;i<3;i++)
{
normal[i] = 1;
// Create linear atom
new (&m_jac[i]) JacobianEntry(
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
@@ -60,37 +82,36 @@ void Generic6DofConstraint::BuildJacobian()
m_rbB.getInvInertiaDiagLocal(),
m_rbB.getInvMass());
// Apply accumulated impulse
SimdVector3 impulse_vector = m_accumulatedLinearImpulse[i] * normal;
m_rbA.applyImpulse( impulse_vector, rel_pos1);
m_rbB.applyImpulse(-impulse_vector, rel_pos2);
normal[i] = 0;
}
// angular part
for (i=0;i<3;i++)
{
#if 0
SimdVector3 axisInA = m_frameInA.getBasis().getColumn(i);
SimdVector3 axisInB = m_frameInB.getBasis().getColumn(i);
new (&m_jacAng[i]) JacobianEntry(axisInA, axisInB,
m_rbA.getInvInertiaDiagLocal(),
m_rbB.getInvInertiaDiagLocal());
#else
SimdVector3 axisA = m_rbA.getCenterOfMassTransform().getBasis() * m_frameInA.getBasis().getColumn( kAxisA[i] );
SimdVector3 axisB = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn( kAxisB[i] );
// Dirk: This is IMO mathematically the correct way, but we should consider axisA and axisB being near parallel
// Dirk: This is IMO mathematically the correct way, but we should consider axisA and axisB being near parallel maybe
SimdVector3 axis = kSign[i] * axisA.cross(axisB);
// Create angular atom
new (&m_jacAng[i]) JacobianEntry(axis,
m_rbA.getCenterOfMassTransform().getBasis().transpose(),
m_rbB.getCenterOfMassTransform().getBasis().transpose(),
m_rbA.getInvInertiaDiagLocal(),
m_rbB.getInvInertiaDiagLocal());
#endif
// Apply accumulated impulse
SimdVector3 impulse_vector = m_accumulatedAngularImpulse[i] * axis;
m_rbA.applyTorqueImpulse( impulse_vector);
m_rbB.applyTorqueImpulse(-impulse_vector);
}
}
@@ -126,6 +147,7 @@ void Generic6DofConstraint::SolveConstraint(SimdScalar timeStep)
SimdScalar depth = -(pivotAInW - pivotBInW).dot(normal);
SimdScalar impulse = (tau*depth/timeStep - damping*rel_vel) * jacDiagABInv;
m_accumulatedLinearImpulse[i] += impulse;
SimdVector3 impulse_vector = normal * impulse;
m_rbA.applyImpulse( impulse_vector, rel_pos1);
@@ -154,6 +176,7 @@ void Generic6DofConstraint::SolveConstraint(SimdScalar timeStep)
//impulse
SimdScalar impulse = -(tau*rel_pos/timeStep + damping*rel_vel) * jacDiagABInv;
m_accumulatedAngularImpulse[i] += impulse;
// Dirk: Not needed - we could actually project onto Jacobian entry here (same as above)
SimdVector3 axis = kSign[i] * axisA.cross(axisB);
@@ -169,3 +192,52 @@ void Generic6DofConstraint::UpdateRHS(SimdScalar timeStep)
}
SimdScalar Generic6DofConstraint::ComputeAngle(int axis) const
{
SimdScalar angle;
switch (axis)
{
case 0:
{
SimdVector3 v1 = m_rbA.getCenterOfMassTransform().getBasis() * m_frameInA.getBasis().getColumn(1);
SimdVector3 v2 = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn(1);
SimdVector3 w2 = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn(2);
SimdScalar s = v1.dot(w2);
SimdScalar c = v1.dot(v2);
angle = SimdAtan2( s, c );
}
break;
case 1:
{
SimdVector3 w1 = m_rbA.getCenterOfMassTransform().getBasis() * m_frameInA.getBasis().getColumn(2);
SimdVector3 w2 = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn(2);
SimdVector3 u2 = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn(0);
SimdScalar s = w1.dot(u2);
SimdScalar c = w1.dot(w2);
angle = SimdAtan2( s, c );
}
break;
case 2:
{
SimdVector3 u1 = m_rbA.getCenterOfMassTransform().getBasis() * m_frameInA.getBasis().getColumn(0);
SimdVector3 u2 = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn(0);
SimdVector3 v2 = m_rbB.getCenterOfMassTransform().getBasis() * m_frameInB.getBasis().getColumn(1);
SimdScalar s = u1.dot(v2);
SimdScalar c = u1.dot(u2);
angle = SimdAtan2( s, c );
}
break;
}
return angle;
}

16
BulletDynamics/ConstraintSolver/Generic6DofConstraint.h
View File

@@ -33,12 +33,14 @@ class Generic6DofConstraint : public TypedConstraint
JacobianEntry m_jac[3]; // 3 orthogonal linear constraints
JacobianEntry m_jacAng[3]; // 3 orthogonal angular constraints
SimdTransform m_frameInA; // the constraint space w.r.t body A
SimdTransform m_frameInB; // the constraint space w.r.t body B
SimdScalar m_lowerLimit[6]; // the constraint lower limits
SimdScalar m_upperLimit[6]; // the constraint upper limits
SimdScalar m_accumulatedLinearImpulse[3];
SimdScalar m_accumulatedAngularImpulse[3];
SimdScalar m_angularLowerLimit[3]; // the constraint lower limits
SimdScalar m_angularUpperLimit[3]; // the constraint upper limits
public:
@@ -52,6 +54,14 @@ public:
void UpdateRHS(SimdScalar timeStep);
SimdScalar ComputeAngle(int axis) const;
void SetAngularLimit(int axis, SimdScalar lo, SimdScalar hi)
{
m_angularLowerLimit[axis] = lo;
m_angularUpperLimit[axis] = hi;
}
const RigidBody& GetRigidBodyA() const
{
return m_rbA;