Files
bullet3/Extras/quickstep/btOdeTypedJoint.cpp
erwin.coumans e80feca36b Big work-in-progress refactoring of the constraint solver:
1) Add fast branchless SIMD support for constraint solver (Windows only until we get other contributions).
See resolveSingleConstraintRowGenericSIMD in Bullet/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
resolveSingleConstraintRowGenericSIMD can be used for all constraints, including contact, point 2 point, hinge, generic etc.

2) During this refactoring, all constraints support the obsolete 'solveConstraintObsolete' while we add 'getInfo1' and 'getInfo2' support.
This interface is almost identical interface to Open Dynamics Engine, to make it easier to port Dantzig LCP solver.

3) Some minor refactoring to reduce huge constructor overhead in math classes.
2008-12-01 06:41:25 +00:00

861 lines
27 KiB
C++

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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.
*/
#include "btOdeTypedJoint.h"
#include "btOdeSolverBody.h"
#include "btOdeMacros.h"
#include <stdio.h>
void btOdeTypedJoint::GetInfo1(Info1 *info)
{
int joint_type = m_constraint->getConstraintType();
switch (joint_type)
{
case POINT2POINT_CONSTRAINT_TYPE:
{
OdeP2PJoint p2pjoint(m_constraint,m_index,m_swapBodies,m_body0,m_body1);
p2pjoint.GetInfo1(info);
}
break;
case D6_CONSTRAINT_TYPE:
{
OdeD6Joint d6joint(m_constraint,m_index,m_swapBodies,m_body0,m_body1);
d6joint.GetInfo1(info);
}
break;
case SLIDER_CONSTRAINT_TYPE:
{
OdeSliderJoint sliderjoint(m_constraint,m_index,m_swapBodies,m_body0,m_body1);
sliderjoint.GetInfo1(info);
}
break;
};
}
void btOdeTypedJoint::GetInfo2(Info2 *info)
{
int joint_type = m_constraint->getConstraintType();
switch (joint_type)
{
case POINT2POINT_CONSTRAINT_TYPE:
{
OdeP2PJoint p2pjoint(m_constraint,m_index,m_swapBodies,m_body0,m_body1);
p2pjoint.GetInfo2(info);
}
break;
case D6_CONSTRAINT_TYPE:
{
OdeD6Joint d6joint(m_constraint,m_index,m_swapBodies,m_body0,m_body1);
d6joint.GetInfo2(info);
}
break;
case SLIDER_CONSTRAINT_TYPE:
{
OdeSliderJoint sliderjoint(m_constraint,m_index,m_swapBodies,m_body0,m_body1);
sliderjoint.GetInfo2(info);
}
break;
};
}
OdeP2PJoint::OdeP2PJoint(
btTypedConstraint * constraint,
int index,bool swap,btOdeSolverBody* body0,btOdeSolverBody* body1):
btOdeTypedJoint(constraint,index,swap,body0,body1)
{
}
void OdeP2PJoint::GetInfo1(Info1 *info)
{
info->m_numConstraintRows = 3;
info->nub = 3;
}
void OdeP2PJoint::GetInfo2(Info2 *info)
{
btPoint2PointConstraint * p2pconstraint = this->getP2PConstraint();
//retrieve matrices
btTransform body0_trans;
if (m_body0)
{
body0_trans = m_body0->m_originalBody->getCenterOfMassTransform();
}
btTransform body1_trans;
if (m_body1)
{
body1_trans = m_body1->m_originalBody->getCenterOfMassTransform();
}
// anchor points in global coordinates with respect to body PORs.
int s = info->rowskip;
// set jacobian
info->m_J1linearAxis[0] = 1;
info->m_J1linearAxis[s+1] = 1;
info->m_J1linearAxis[2*s+2] = 1;
btVector3 a1,a2;
a1 = body0_trans.getBasis()*p2pconstraint->getPivotInA();
//dMULTIPLY0_331 (a1, body0_mat,m_constraint->m_pivotInA);
dCROSSMAT (info->m_J1angularAxis,a1,s,-,+);
if (m_body1)
{
info->m_J2linearAxis[0] = -1;
info->m_J2linearAxis[s+1] = -1;
info->m_J2linearAxis[2*s+2] = -1;
a2 = body1_trans.getBasis()*p2pconstraint->getPivotInB();
//dMULTIPLY0_331 (a2,body1_mat,m_constraint->m_pivotInB);
dCROSSMAT (info->m_J2angularAxis,a2,s,+,-);
}
// set right hand side
btScalar k = info->fps * info->erp;
if (m_body1)
{
for (int j=0; j<3; j++)
{
info->m_constraintError[j] = k * (a2[j] + body1_trans.getOrigin()[j] - a1[j] - body0_trans.getOrigin()[j]);
printf("info->m_constraintError[%d]=%f\n",j,info->m_constraintError[j]);
}
}
else
{
for (int j=0; j<3; j++)
{
info->m_constraintError[j] = k * (p2pconstraint->getPivotInB()[j] - a1[j] - body0_trans.getOrigin()[j]);
printf("info->m_constraintError[%d]=%f\n",j,info->m_constraintError[j]);
}
}
}
///////////////////limit motor support
/*! \pre testLimitValue must be called on limot*/
int bt_get_limit_motor_info2(
btRotationalLimitMotor * limot,
btRigidBody * body0, btRigidBody * body1,
btOdeJoint::Info2 *info, int row, btVector3& ax1, int rotational)
{
int srow = row * info->rowskip;
// if the joint is powered, or has joint limits, add in the extra row
int powered = limot->m_enableMotor;
int limit = limot->m_currentLimit;
if (powered || limit)
{
btScalar *J1 = rotational ? info->m_J1angularAxis : info->m_J1linearAxis;
btScalar *J2 = rotational ? info->m_J2angularAxis : info->m_J2linearAxis;
J1[srow+0] = ax1[0];
J1[srow+1] = ax1[1];
J1[srow+2] = ax1[2];
if (body1)
{
J2[srow+0] = -ax1[0];
J2[srow+1] = -ax1[1];
J2[srow+2] = -ax1[2];
}
// linear limot torque decoupling step:
//
// if this is a linear limot (e.g. from a slider), we have to be careful
// that the linear constraint forces (+/- ax1) applied to the two bodies
// do not create a torque couple. in other words, the points that the
// constraint force is applied at must lie along the same ax1 axis.
// a torque couple will result in powered or limited slider-jointed free
// bodies from gaining angular momentum.
// the solution used here is to apply the constraint forces at the point
// halfway between the body centers. there is no penalty (other than an
// extra tiny bit of computation) in doing this adjustment. note that we
// only need to do this if the constraint connects two bodies.
btVector3 ltd; // Linear Torque Decoupling vector (a torque)
if (!rotational && body1)
{
btVector3 c;
c[0]=btScalar(0.5)*(body1->getCenterOfMassPosition()[0]
-body0->getCenterOfMassPosition()[0]);
c[1]=btScalar(0.5)*(body1->getCenterOfMassPosition()[1]
-body0->getCenterOfMassPosition()[1]);
c[2]=btScalar(0.5)*(body1->getCenterOfMassPosition()[2]
-body0->getCenterOfMassPosition()[2]);
ltd = c.cross(ax1);
info->m_J1angularAxis[srow+0] = ltd[0];
info->m_J1angularAxis[srow+1] = ltd[1];
info->m_J1angularAxis[srow+2] = ltd[2];
info->m_J2angularAxis[srow+0] = ltd[0];
info->m_J2angularAxis[srow+1] = ltd[1];
info->m_J2angularAxis[srow+2] = ltd[2];
}
// if we're limited low and high simultaneously, the joint motor is
// ineffective
if (limit && (limot->m_loLimit == limot->m_hiLimit)) powered = 0;
if (powered)
{
info->cfm[row] = 0.0f;//limot->m_normalCFM;
if (! limit)
{
info->m_constraintError[row] = limot->m_targetVelocity;
info->m_lowerLimit[row] = -limot->m_maxMotorForce;
info->m_higherLimit[row] = limot->m_maxMotorForce;
}
}
if (limit)
{
btScalar k = info->fps * limot->m_ERP;
info->m_constraintError[row] = -k * limot->m_currentLimitError;
info->cfm[row] = 0.0f;//limot->m_stopCFM;
if (limot->m_loLimit == limot->m_hiLimit)
{
// limited low and high simultaneously
info->m_lowerLimit[row] = -dInfinity;
info->m_higherLimit[row] = dInfinity;
}
else
{
if (limit == 1)
{
// low limit
info->m_lowerLimit[row] = 0;
info->m_higherLimit[row] = SIMD_INFINITY;
}
else
{
// high limit
info->m_lowerLimit[row] = -SIMD_INFINITY;
info->m_higherLimit[row] = 0;
}
// deal with bounce
if (limot->m_bounce > 0)
{
// calculate joint velocity
btScalar vel;
if (rotational)
{
vel = body0->getAngularVelocity().dot(ax1);
if (body1)
vel -= body1->getAngularVelocity().dot(ax1);
}
else
{
vel = body0->getLinearVelocity().dot(ax1);
if (body1)
vel -= body1->getLinearVelocity().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 = -limot->m_bounce* vel;
if (newc > info->m_constraintError[row])
info->m_constraintError[row] = newc;
}
}
else
{
// high limit - all those computations are reversed
if (vel > 0)
{
btScalar newc = -limot->m_bounce * vel;
if (newc < info->m_constraintError[row])
info->m_constraintError[row] = newc;
}
}
}
}
}
return 1;
}
else return 0;
}
///////////////////OdeD6Joint
OdeD6Joint::OdeD6Joint(
btTypedConstraint * constraint,
int index,bool swap,btOdeSolverBody* body0,btOdeSolverBody* body1):
btOdeTypedJoint(constraint,index,swap,body0,body1)
{
}
void OdeD6Joint::GetInfo1(Info1 *info)
{
btGeneric6DofConstraint * d6constraint = this->getD6Constraint();
//prepare constraint
d6constraint->calculateTransforms();
info->m_numConstraintRows = 3;
info->nub = 3;
//test angular limits
for (int i=0;i<3 ;i++ )
{
//if(i==2) continue;
if(d6constraint->testAngularLimitMotor(i))
{
info->m_numConstraintRows++;
}
}
}
int OdeD6Joint::setLinearLimits(Info2 *info)
{
btGeneric6DofConstraint * d6constraint = this->getD6Constraint();
//retrieve matrices
btTransform body0_trans;
if (m_body0)
{
body0_trans = m_body0->m_originalBody->getCenterOfMassTransform();
}
btTransform body1_trans;
if (m_body1)
{
body1_trans = m_body1->m_originalBody->getCenterOfMassTransform();
}
// anchor points in global coordinates with respect to body PORs.
int s = info->rowskip;
// set jacobian
info->m_J1linearAxis[0] = 1;
info->m_J1linearAxis[s+1] = 1;
info->m_J1linearAxis[2*s+2] = 1;
btVector3 a1,a2;
a1 = body0_trans.getBasis()*d6constraint->getFrameOffsetA().getOrigin();
//dMULTIPLY0_331 (a1, body0_mat,m_constraint->m_pivotInA);
dCROSSMAT (info->m_J1angularAxis,a1,s,-,+);
if (m_body1)
{
info->m_J2linearAxis[0] = -1;
info->m_J2linearAxis[s+1] = -1;
info->m_J2linearAxis[2*s+2] = -1;
a2 = body1_trans.getBasis()*d6constraint->getFrameOffsetB().getOrigin();
//dMULTIPLY0_331 (a2,body1_mat,m_constraint->m_pivotInB);
dCROSSMAT (info->m_J2angularAxis,a2,s,+,-);
}
// set right hand side
btScalar k = info->fps * info->erp;
if (m_body1)
{
for (int j=0; j<3; j++)
{
info->m_constraintError[j] = k * (a2[j] + body1_trans.getOrigin()[j] -
a1[j] - body0_trans.getOrigin()[j]);
}
}
else
{
for (int j=0; j<3; j++)
{
info->m_constraintError[j] = k * (d6constraint->getCalculatedTransformB().getOrigin()[j] - a1[j] -
body0_trans.getOrigin()[j]);
}
}
return 3;
}
int OdeD6Joint::setAngularLimits(Info2 *info, int row_offset)
{
btGeneric6DofConstraint * d6constraint = this->getD6Constraint();
int row = row_offset;
//solve angular limits
for (int i=0;i<3 ;i++ )
{
//if(i==2) continue;
if(d6constraint->getRotationalLimitMotor(i)->needApplyTorques())
{
btVector3 axis = d6constraint->getAxis(i);
row += bt_get_limit_motor_info2(
d6constraint->getRotationalLimitMotor(i),
m_body0->m_originalBody,
m_body1 ? m_body1->m_originalBody : NULL,
info,row,axis,1);
}
}
return row;
}
void OdeD6Joint::GetInfo2(Info2 *info)
{
int row = setLinearLimits(info);
setAngularLimits(info, row);
}
//----------------------------------------------------------------------------------
//----------------------------------------------------------------------------------
//----------------------------------------------------------------------------------
//----------------------------------------------------------------------------------
/*
OdeSliderJoint
Ported from ODE by Roman Ponomarev (rponom@gmail.com)
April 24, 2008
*/
OdeSliderJoint::OdeSliderJoint(
btTypedConstraint * constraint,
int index,bool swap, btOdeSolverBody* body0, btOdeSolverBody* body1):
btOdeTypedJoint(constraint,index,swap,body0,body1)
{
} // OdeSliderJoint::OdeSliderJoint()
//----------------------------------------------------------------------------------
void OdeSliderJoint::GetInfo1(Info1* info)
{
info->nub = 4;
info->m_numConstraintRows = 4; // Fixed 2 linear + 2 angular
btSliderConstraint * slider = this->getSliderConstraint();
//prepare constraint
slider->calculateTransforms();
slider->testLinLimits();
if(slider->getSolveLinLimit() || slider->getPoweredLinMotor())
{
info->m_numConstraintRows++; // limit 3rd linear as well
}
slider->testAngLimits();
if(slider->getSolveAngLimit() || slider->getPoweredAngMotor())
{
info->m_numConstraintRows++; // limit 3rd angular as well
}
} // OdeSliderJoint::GetInfo1()
//----------------------------------------------------------------------------------
void OdeSliderJoint::GetInfo2(Info2 *info)
{
int i, s = info->rowskip;
btSliderConstraint * slider = this->getSliderConstraint();
const btTransform& trA = slider->getCalculatedTransformA();
const btTransform& trB = slider->getCalculatedTransformB();
// make rotations around Y and Z equal
// the slider axis should be the only unconstrained
// rotational axis, the angular velocity of the two bodies perpendicular to
// the slider 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 slider axis, and w1 and w2
// are the angular velocity vectors of the two bodies.
// get slider axis (X)
btVector3 ax1 = trA.getBasis().getColumn(0);
// get 2 orthos to slider axis (Y, Z)
btVector3 p = trA.getBasis().getColumn(1);
btVector3 q = trA.getBasis().getColumn(2);
// set the two slider rows
info->m_J1angularAxis[0] = p[0];
info->m_J1angularAxis[1] = p[1];
info->m_J1angularAxis[2] = p[2];
info->m_J1angularAxis[s+0] = q[0];
info->m_J1angularAxis[s+1] = q[1];
info->m_J1angularAxis[s+2] = q[2];
if(m_body1)
{
info->m_J2angularAxis[0] = -p[0];
info->m_J2angularAxis[1] = -p[1];
info->m_J2angularAxis[2] = -p[2];
info->m_J2angularAxis[s+0] = -q[0];
info->m_J2angularAxis[s+1] = -q[1];
info->m_J2angularAxis[s+2] = -q[2];
}
// compute the right hand side of the constraint equation. set relative
// body velocities along p and q to bring the slider back into alignment.
// if ax1,ax2 are the unit length slider axes as computed from body1 and
// body2, 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.
btScalar k = info->fps * info->erp * slider->getSoftnessOrthoAng();
btVector3 ax2 = trB.getBasis().getColumn(0);
btVector3 u;
if(m_body1)
{
u = ax1.cross(ax2);
}
else
{
u = ax2.cross(ax1);
}
info->m_constraintError[0] = k * u.dot(p);
info->m_constraintError[1] = k * u.dot(q);
// pull out pos and R for both bodies. also get the connection
// vector c = pos2-pos1.
// next two rows. we want: vel2 = vel1 + w1 x c ... but this would
// result in three equations, so we project along the planespace vectors
// so that sliding along the slider axis is disregarded. for symmetry we
// also substitute (w1+w2)/2 for w1, as w1 is supposed to equal w2.
btTransform bodyA_trans = m_body0->m_originalBody->getCenterOfMassTransform();
btTransform bodyB_trans;
if(m_body1)
{
bodyB_trans = m_body1->m_originalBody->getCenterOfMassTransform();
}
int s2 = 2 * s, s3 = 3 * s;
btVector3 c;
if(m_body1)
{
c = bodyB_trans.getOrigin() - bodyA_trans.getOrigin();
btVector3 tmp = btScalar(0.5) * c.cross(p);
for (i=0; i<3; i++) info->m_J1angularAxis[s2+i] = tmp[i];
for (i=0; i<3; i++) info->m_J2angularAxis[s2+i] = tmp[i];
tmp = btScalar(0.5) * c.cross(q);
for (i=0; i<3; i++) info->m_J1angularAxis[s3+i] = tmp[i];
for (i=0; i<3; i++) info->m_J2angularAxis[s3+i] = tmp[i];
for (i=0; i<3; i++) info->m_J2linearAxis[s2+i] = -p[i];
for (i=0; i<3; i++) info->m_J2linearAxis[s3+i] = -q[i];
}
for (i=0; i<3; i++) info->m_J1linearAxis[s2+i] = p[i];
for (i=0; i<3; i++) info->m_J1linearAxis[s3+i] = q[i];
// compute two elements of right hand side. we want to align the offset
// point (in body 2's frame) with the center of body 1.
btVector3 ofs; // offset point in global coordinates
if(m_body1)
{
ofs = trB.getOrigin() - trA.getOrigin();
}
else
{
ofs = trA.getOrigin() - trB.getOrigin();
}
k = info->fps * info->erp * slider->getSoftnessOrthoLin();
info->m_constraintError[2] = k * p.dot(ofs);
info->m_constraintError[3] = k * q.dot(ofs);
int nrow = 3; // last filled row
int srow;
// check linear limits linear
btScalar limit_err = btScalar(0.0);
int limit = 0;
if(slider->getSolveLinLimit())
{
limit_err = slider->getLinDepth();
if(m_body1)
{
limit = (limit_err > btScalar(0.0)) ? 1 : 2;
}
else
{
limit = (limit_err > btScalar(0.0)) ? 2 : 1;
}
}
int powered = 0;
if(slider->getPoweredLinMotor())
{
powered = 1;
}
// if the slider has joint limits, add in the extra row
if (limit || powered)
{
nrow++;
srow = nrow * info->rowskip;
info->m_J1linearAxis[srow+0] = ax1[0];
info->m_J1linearAxis[srow+1] = ax1[1];
info->m_J1linearAxis[srow+2] = ax1[2];
if(m_body1)
{
info->m_J2linearAxis[srow+0] = -ax1[0];
info->m_J2linearAxis[srow+1] = -ax1[1];
info->m_J2linearAxis[srow+2] = -ax1[2];
}
// linear torque decoupling step:
//
// we have to be careful that the linear constraint forces (+/- ax1) applied to the two bodies
// do not create a torque couple. in other words, the points that the
// constraint force is applied at must lie along the same ax1 axis.
// a torque couple will result in limited slider-jointed free
// bodies from gaining angular momentum.
// the solution used here is to apply the constraint forces at the point
// halfway between the body centers. there is no penalty (other than an
// extra tiny bit of computation) in doing this adjustment. note that we
// only need to do this if the constraint connects two bodies.
if (m_body1)
{
dVector3 ltd; // Linear Torque Decoupling vector (a torque)
c = btScalar(0.5) * c;
dCROSS (ltd,=,c,ax1);
info->m_J1angularAxis[srow+0] = ltd[0];
info->m_J1angularAxis[srow+1] = ltd[1];
info->m_J1angularAxis[srow+2] = ltd[2];
info->m_J2angularAxis[srow+0] = ltd[0];
info->m_J2angularAxis[srow+1] = ltd[1];
info->m_J2angularAxis[srow+2] = ltd[2];
}
// right-hand part
btScalar lostop = slider->getLowerLinLimit();
btScalar histop = slider->getUpperLinLimit();
if(limit && (lostop == histop))
{ // the joint motor is ineffective
powered = 0;
}
if(powered)
{
info->cfm[nrow] = btScalar(0.0);
if(!limit)
{
info->m_constraintError[nrow] = slider->getTargetLinMotorVelocity();
info->m_lowerLimit[nrow] = -slider->getMaxLinMotorForce() * info->fps;
info->m_higherLimit[nrow] = slider->getMaxLinMotorForce() * info->fps;
}
}
if(limit)
{
k = info->fps * info->erp;
if(m_body1)
{
info->m_constraintError[nrow] = k * limit_err;
}
else
{
info->m_constraintError[nrow] = - k * limit_err;
}
info->cfm[nrow] = btScalar(0.0); // stop_cfm;
if(lostop == histop)
{
// limited low and high simultaneously
info->m_lowerLimit[nrow] = -SIMD_INFINITY;
info->m_higherLimit[nrow] = SIMD_INFINITY;
}
else
{
if(limit == 1)
{
// low limit
info->m_lowerLimit[nrow] = 0;
info->m_higherLimit[nrow] = SIMD_INFINITY;
}
else
{
// high limit
info->m_lowerLimit[nrow] = -SIMD_INFINITY;
info->m_higherLimit[nrow] = 0;
}
}
// bounce (we'll use slider parameter abs(1.0 - m_dampingLimLin) for that)
btScalar bounce = btFabs(btScalar(1.0) - slider->getDampingLimLin());
if(bounce > btScalar(0.0))
{
btScalar vel = m_body0->m_originalBody->getLinearVelocity().dot(ax1);
if(m_body1)
{
vel -= m_body1->m_originalBody->getLinearVelocity().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[nrow])
info->m_constraintError[nrow] = newc;
}
}
else
{
// high limit - all those computations are reversed
if(vel > 0)
{
btScalar newc = -bounce * vel;
if(newc < info->m_constraintError[nrow])
info->m_constraintError[nrow] = newc;
}
}
}
info->m_constraintError[nrow] *= slider->getSoftnessLimLin();
} // if(limit)
} // if linear limit
// check angular limits
limit_err = btScalar(0.0);
limit = 0;
if(slider->getSolveAngLimit())
{
limit_err = slider->getAngDepth();
if(m_body1)
{
limit = (limit_err > btScalar(0.0)) ? 1 : 2;
}
else
{
limit = (limit_err > btScalar(0.0)) ? 2 : 1;
}
}
// if the slider has joint limits, add in the extra row
powered = 0;
if(slider->getPoweredAngMotor())
{
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];
if(m_body1)
{
info->m_J2angularAxis[srow+0] = -ax1[0];
info->m_J2angularAxis[srow+1] = -ax1[1];
info->m_J2angularAxis[srow+2] = -ax1[2];
}
btScalar lostop = slider->getLowerAngLimit();
btScalar histop = slider->getUpperAngLimit();
if(limit && (lostop == histop))
{ // the joint motor is ineffective
powered = 0;
}
if(powered)
{
info->cfm[nrow] = btScalar(0.0);
if(!limit)
{
info->m_constraintError[nrow] = slider->getTargetAngMotorVelocity();
info->m_lowerLimit[nrow] = -slider->getMaxAngMotorForce() * info->fps;
info->m_higherLimit[nrow] = slider->getMaxAngMotorForce() * info->fps;
}
}
if(limit)
{
k = info->fps * info->erp;
if (m_body1)
{
info->m_constraintError[nrow] = k * limit_err;
}
else
{
info->m_constraintError[nrow] = -k * limit_err;
}
info->cfm[nrow] = btScalar(0.0); // stop_cfm;
if(lostop == histop)
{
// limited low and high simultaneously
info->m_lowerLimit[nrow] = -SIMD_INFINITY;
info->m_higherLimit[nrow] = SIMD_INFINITY;
}
else
{
if (limit == 1)
{
// low limit
info->m_lowerLimit[nrow] = 0;
info->m_higherLimit[nrow] = SIMD_INFINITY;
}
else
{
// high limit
info->m_lowerLimit[nrow] = -SIMD_INFINITY;
info->m_higherLimit[nrow] = 0;
}
}
// bounce (we'll use slider parameter abs(1.0 - m_dampingLimAng) for that)
btScalar bounce = btFabs(btScalar(1.0) - slider->getDampingLimAng());
if(bounce > btScalar(0.0))
{
btScalar vel = m_body0->m_originalBody->getAngularVelocity().dot(ax1);
if(m_body1)
{
vel -= m_body1->m_originalBody->getAngularVelocity().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[nrow]) info->m_constraintError[nrow] = newc;
}
}
else
{
// high limit - all those computations are reversed
if(vel > 0)
{
btScalar newc = -bounce * vel;
if(newc < info->m_constraintError[nrow]) info->m_constraintError[nrow] = newc;
}
}
}
info->m_constraintError[nrow] *= slider->getSoftnessLimAng();
} // if(limit)
} // if angular limit or powered
} // OdeSliderJoint::GetInfo2()
//----------------------------------------------------------------------------------
//----------------------------------------------------------------------------------