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Improved Slider, Hinge and Generic6DOF constraint setup.

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Turned on by default, use m_useOffsetForConstraintFrame = false to use old setup
Use "O" (capital 'o') button to toggle it in SliderConstraintDemo and ConstraintDemo

Total applied impulse copied back from btSolverConstraint to btTypedConstraint
This commit is contained in:
rponom
2009-11-25 23:52:12 +00:00
parent eea73bc76a
commit f919baf03d
15 changed files with 1082 additions and 114 deletions
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266
src/BulletDynamics/ConstraintSolver/btHingeConstraint.cpp
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@@ -23,8 +23,10 @@ subject to the following restrictions:
//#define HINGE_USE_OBSOLETE_SOLVER false
#define HINGE_USE_OBSOLETE_SOLVER false
#define HINGE_USE_FRAME_OFFSET true
#ifndef __SPU__
@@ -32,6 +34,7 @@ btHingeConstraint::btHingeConstraint()
: btTypedConstraint (HINGE_CONSTRAINT_TYPE),
m_enableAngularMotor(false),
m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
m_useReferenceFrameA(false)
{
m_referenceSign = m_useReferenceFrameA ? btScalar(-1.f) : btScalar(1.f);
@@ -45,6 +48,7 @@ btHingeConstraint::btHingeConstraint(btRigidBody& rbA,btRigidBody& rbB, const bt
m_angularOnly(false),
m_enableAngularMotor(false),
m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
m_useReferenceFrameA(useReferenceFrameA)
{
m_rbAFrame.getOrigin() = pivotInA;
@@ -93,6 +97,7 @@ btHingeConstraint::btHingeConstraint(btRigidBody& rbA,btRigidBody& rbB, const bt
btHingeConstraint::btHingeConstraint(btRigidBody& rbA,const btVector3& pivotInA,btVector3& axisInA, bool useReferenceFrameA)
:btTypedConstraint(HINGE_CONSTRAINT_TYPE, rbA), m_angularOnly(false), m_enableAngularMotor(false),
m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
m_useReferenceFrameA(useReferenceFrameA)
{
@@ -136,6 +141,7 @@ btHingeConstraint::btHingeConstraint(btRigidBody& rbA,btRigidBody& rbB,
m_angularOnly(false),
m_enableAngularMotor(false),
m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
m_useReferenceFrameA(useReferenceFrameA)
{
//start with free
@@ -155,6 +161,7 @@ btHingeConstraint::btHingeConstraint(btRigidBody& rbA, const btTransform& rbAFra
m_angularOnly(false),
m_enableAngularMotor(false),
m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER),
m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET),
m_useReferenceFrameA(useReferenceFrameA)
{
///not providing rigidbody B means implicitly using worldspace for body B
@@ -460,7 +467,14 @@ void btHingeConstraint::getInfo1NonVirtual(btConstraintInfo1* info)
void btHingeConstraint::getInfo2 (btConstraintInfo2* info)
{
getInfo2Internal(info, m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform(),m_rbA.getAngularVelocity(),m_rbB.getAngularVelocity());
if(m_useOffsetForConstraintFrame)
{
getInfo2InternalUsingFrameOffset(info, m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform(),m_rbA.getAngularVelocity(),m_rbB.getAngularVelocity());
}
else
{
getInfo2Internal(info, m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform(),m_rbA.getAngularVelocity(),m_rbB.getAngularVelocity());
}
}
@@ -810,3 +824,253 @@ void btHingeConstraint::setMotorTarget(btScalar targetAngle, btScalar dt)
}
void btHingeConstraint::getInfo2InternalUsingFrameOffset(btConstraintInfo2* info, const btTransform& transA,const btTransform& transB,const btVector3& angVelA,const btVector3& angVelB)
{
btAssert(!m_useSolveConstraintObsolete);
int i, s = info->rowskip;
// transforms in world space
btTransform trA = transA*m_rbAFrame;
btTransform trB = transB*m_rbBFrame;
// pivot point
btVector3 pivotAInW = trA.getOrigin();
btVector3 pivotBInW = trB.getOrigin();
#if 1
// difference between frames in WCS
btVector3 ofs = trB.getOrigin() - trA.getOrigin();
// now get weight factors depending on masses
btScalar miA = getRigidBodyA().getInvMass();
btScalar miB = getRigidBodyB().getInvMass();
bool hasStaticBody = (miA < SIMD_EPSILON) || (miB < SIMD_EPSILON);
btScalar miS = miA + miB;
btScalar factA, factB;
if(miS > btScalar(0.f))
{
factA = miB / miS;
}
else
{
factA = btScalar(0.5f);
}
factB = btScalar(1.0f) - factA;
// get the desired direction of hinge axis
// as weighted sum of Z-orthos of frameA and frameB in WCS
btVector3 ax1A = trA.getBasis().getColumn(2);
btVector3 ax1B = trB.getBasis().getColumn(2);
btVector3 ax1 = ax1A * factA + ax1B * factB;
ax1.normalize();
// fill first 3 rows
// we want: velA + wA x relA == velB + wB x relB
btTransform bodyA_trans = transA;
btTransform bodyB_trans = transB;
int s0 = 0;
int s1 = s;
int s2 = s * 2;
int nrow = 2; // last filled row
btVector3 tmpA, tmpB, relA, relB, p, q;
// get vector from bodyB to frameB in WCS
relB = trB.getOrigin() - bodyB_trans.getOrigin();
// get its projection to hinge axis
btVector3 projB = ax1 * relB.dot(ax1);
// get vector directed from bodyB to hinge axis (and orthogonal to it)
btVector3 orthoB = relB - projB;
// same for bodyA
relA = trA.getOrigin() - bodyA_trans.getOrigin();
btVector3 projA = ax1 * relA.dot(ax1);
btVector3 orthoA = relA - projA;
btVector3 totalDist = projA - projB;
// get offset vectors relA and relB
relA = orthoA + totalDist * factA;
relB = orthoB - totalDist * factB;
// now choose average ortho to hinge axis
p = orthoB * factA + orthoA * factB;
btScalar len2 = p.length2();
if(len2 > SIMD_EPSILON)
{
p /= btSqrt(len2);
}
else
{
p = trA.getBasis().getColumn(1);
}
// make one more ortho
q = ax1.cross(p);
// fill three rows
tmpA = relA.cross(p);
tmpB = relB.cross(p);
for (i=0; i<3; i++) info->m_J1angularAxis[s0+i] = tmpA[i];
for (i=0; i<3; i++) info->m_J2angularAxis[s0+i] = -tmpB[i];
tmpA = relA.cross(q);
tmpB = relB.cross(q);
if(hasStaticBody && getSolveLimit())
{ // to make constraint between static and dynamic objects more rigid
// remove wA (or wB) from equation if angular limit is hit
tmpB *= factB;
tmpA *= factA;
}
for (i=0; i<3; i++) info->m_J1angularAxis[s1+i] = tmpA[i];
for (i=0; i<3; i++) info->m_J2angularAxis[s1+i] = -tmpB[i];
tmpA = relA.cross(ax1);
tmpB = relB.cross(ax1);
if(hasStaticBody)
{ // to make constraint between static and dynamic objects more rigid
// remove wA (or wB) from equation
tmpB *= factB;
tmpA *= factA;
}
for (i=0; i<3; i++) info->m_J1angularAxis[s2+i] = tmpA[i];
for (i=0; i<3; i++) info->m_J2angularAxis[s2+i] = -tmpB[i];
for (i=0; i<3; i++) info->m_J1linearAxis[s0+i] = p[i];
for (i=0; i<3; i++) info->m_J1linearAxis[s1+i] = q[i];
for (i=0; i<3; i++) info->m_J1linearAxis[s2+i] = ax1[i];
// compute three elements of right hand side
btScalar k = info->fps * info->erp;
btScalar rhs = k * p.dot(ofs);
info->m_constraintError[s0] = rhs;
rhs = k * q.dot(ofs);
info->m_constraintError[s1] = rhs;
rhs = k * ax1.dot(ofs);
info->m_constraintError[s2] = rhs;
// the hinge axis should be the only unconstrained
// rotational axis, the angular velocity of the two bodies perpendicular to
// the hinge axis should be equal. thus the constraint equations are
// p*w1 - p*w2 = 0
// q*w1 - q*w2 = 0
// where p and q are unit vectors normal to the hinge axis, and w1 and w2
// are the angular velocity vectors of the two bodies.
int s3 = 3 * s;
int s4 = 4 * s;
info->m_J1angularAxis[s3 + 0] = p[0];
info->m_J1angularAxis[s3 + 1] = p[1];
info->m_J1angularAxis[s3 + 2] = p[2];
info->m_J1angularAxis[s4 + 0] = q[0];
info->m_J1angularAxis[s4 + 1] = q[1];
info->m_J1angularAxis[s4 + 2] = q[2];
info->m_J2angularAxis[s3 + 0] = -p[0];
info->m_J2angularAxis[s3 + 1] = -p[1];
info->m_J2angularAxis[s3 + 2] = -p[2];
info->m_J2angularAxis[s4 + 0] = -q[0];
info->m_J2angularAxis[s4 + 1] = -q[1];
info->m_J2angularAxis[s4 + 2] = -q[2];
// compute the right hand side of the constraint equation. set relative
// body velocities along p and q to bring the hinge back into alignment.
// if ax1A,ax1B are the unit length hinge axes as computed from bodyA and
// bodyB, we need to rotate both bodies along the axis u = (ax1 x ax2).
// if "theta" is the angle between ax1 and ax2, we need an angular velocity
// along u to cover angle erp*theta in one step :
// |angular_velocity| = angle/time = erp*theta / stepsize
// = (erp*fps) * theta
// angular_velocity = |angular_velocity| * (ax1 x ax2) / |ax1 x ax2|
// = (erp*fps) * theta * (ax1 x ax2) / sin(theta)
// ...as ax1 and ax2 are unit length. if theta is smallish,
// theta ~= sin(theta), so
// angular_velocity = (erp*fps) * (ax1 x ax2)
// ax1 x ax2 is in the plane space of ax1, so we project the angular
// velocity to p and q to find the right hand side.
k = info->fps * info->erp;
btVector3 u = ax1A.cross(ax1B);
info->m_constraintError[s3] = k * u.dot(p);
info->m_constraintError[s4] = k * u.dot(q);
#endif
// check angular limits
nrow = 4; // last filled row
int srow;
btScalar limit_err = btScalar(0.0);
int limit = 0;
if(getSolveLimit())
{
limit_err = m_correction * m_referenceSign;
limit = (limit_err > btScalar(0.0)) ? 1 : 2;
}
// if the hinge has joint limits or motor, add in the extra row
int powered = 0;
if(getEnableAngularMotor())
{
powered = 1;
}
if(limit || powered)
{
nrow++;
srow = nrow * info->rowskip;
info->m_J1angularAxis[srow+0] = ax1[0];
info->m_J1angularAxis[srow+1] = ax1[1];
info->m_J1angularAxis[srow+2] = ax1[2];
info->m_J2angularAxis[srow+0] = -ax1[0];
info->m_J2angularAxis[srow+1] = -ax1[1];
info->m_J2angularAxis[srow+2] = -ax1[2];
btScalar lostop = getLowerLimit();
btScalar histop = getUpperLimit();
if(limit && (lostop == histop))
{ // the joint motor is ineffective
powered = 0;
}
info->m_constraintError[srow] = btScalar(0.0f);
if(powered)
{
info->cfm[srow] = btScalar(0.0);
btScalar mot_fact = getMotorFactor(m_hingeAngle, lostop, histop, m_motorTargetVelocity, info->fps * info->erp);
info->m_constraintError[srow] += mot_fact * m_motorTargetVelocity * m_referenceSign;
info->m_lowerLimit[srow] = - m_maxMotorImpulse;
info->m_upperLimit[srow] = m_maxMotorImpulse;
}
if(limit)
{
k = info->fps * info->erp;
info->m_constraintError[srow] += k * limit_err;
info->cfm[srow] = btScalar(0.0);
if(lostop == histop)
{
// limited low and high simultaneously
info->m_lowerLimit[srow] = -SIMD_INFINITY;
info->m_upperLimit[srow] = SIMD_INFINITY;
}
else if(limit == 1)
{ // low limit
info->m_lowerLimit[srow] = 0;
info->m_upperLimit[srow] = SIMD_INFINITY;
}
else
{ // high limit
info->m_lowerLimit[srow] = -SIMD_INFINITY;
info->m_upperLimit[srow] = 0;
}
// bounce (we'll use slider parameter abs(1.0 - m_dampingLimAng) for that)
btScalar bounce = m_relaxationFactor;
if(bounce > btScalar(0.0))
{
btScalar vel = angVelA.dot(ax1);
vel -= angVelB.dot(ax1);
// only apply bounce if the velocity is incoming, and if the
// resulting c[] exceeds what we already have.
if(limit == 1)
{ // low limit
if(vel < 0)
{
btScalar newc = -bounce * vel;
if(newc > info->m_constraintError[srow])
{
info->m_constraintError[srow] = newc;
}
}
}
else
{ // high limit - all those computations are reversed
if(vel > 0)
{
btScalar newc = -bounce * vel;
if(newc < info->m_constraintError[srow])
{
info->m_constraintError[srow] = newc;
}
}
}
}
info->m_constraintError[srow] *= m_biasFactor;
} // if(limit)
} // if angular limit or powered
}