// Project Gauss Seidel or the equivalent Sequential Impulse
void btSequentialImpulseConstraintSolver::resolveSingleConstraintRowGeneric(btSolverBody& body1,btSolverBody& body2,const btSolverConstraint& c)
{
btScalar deltaImpulse = c.m_rhs-btScalar(c.m_appliedImpulse)*c.m_cfm;
const btScalar deltaVel1Dotn = c.m_contactNormal.dot(body1.m_deltaLinearVelocity) + c.m_relpos1CrossNormal.dot(body1.m_deltaAngularVelocity);
const btScalar deltaVel2Dotn = -c.m_contactNormal.dot(body2.m_deltaLinearVelocity) + c.m_relpos2CrossNormal.dot(body2.m_deltaAngularVelocity);
const btScalar delta_rel_vel = deltaVel1Dotn-deltaVel2Dotn;
deltaImpulse -= deltaVel1Dotn*c.m_jacDiagABInv;
deltaImpulse -= deltaVel2Dotn*c.m_jacDiagABInv;
const btScalar sum = btScalar(c.m_appliedImpulse) + deltaImpulse;
if (sum < c.m_lowerLimit)
{
deltaImpulse = c.m_lowerLimit-c.m_appliedImpulse;
c.m_appliedImpulse = c.m_lowerLimit;
}
else if (sum > c.m_upperLimit)
{
deltaImpulse = c.m_upperLimit-c.m_appliedImpulse;
c.m_appliedImpulse = c.m_upperLimit;
}
else
{
c.m_appliedImpulse = sum;
}
body1.applyImpulse(c.m_contactNormal*body1.m_invMass,c.m_angularComponentA,deltaImpulse);
body2.applyImpulse(-c.m_contactNormal*body2.m_invMass,c.m_angularComponentB,deltaImpulse);
}
void btSliderConstraint::solveConstraintInt(btRigidBody& rbA, btSolverBody& bodyA,btRigidBody& rbB, btSolverBody& bodyB)
{
int i;
// linear
btVector3 velA;
bodyA.getVelocityInLocalPointObsolete(m_relPosA,velA);
btVector3 velB;
bodyB.getVelocityInLocalPointObsolete(m_relPosB,velB);
btVector3 vel = velA - velB;
for(i = 0; i < 3; i++)
{
const btVector3& normal = m_jacLin[i].m_linearJointAxis;
btScalar rel_vel = normal.dot(vel);
// calculate positional error
btScalar depth = m_depth[i];
// get parameters
btScalar softness = (i) ? m_softnessOrthoLin : (m_solveLinLim ? m_softnessLimLin : m_softnessDirLin);
btScalar restitution = (i) ? m_restitutionOrthoLin : (m_solveLinLim ? m_restitutionLimLin : m_restitutionDirLin);
btScalar damping = (i) ? m_dampingOrthoLin : (m_solveLinLim ? m_dampingLimLin : m_dampingDirLin);
// calcutate and apply impulse
btScalar normalImpulse = softness * (restitution * depth / m_timeStep - damping * rel_vel) * m_jacLinDiagABInv[i];
btVector3 impulse_vector = normal * normalImpulse;
//rbA.applyImpulse( impulse_vector, m_relPosA);
//rbB.applyImpulse(-impulse_vector, m_relPosB);
{
btVector3 ftorqueAxis1 = m_relPosA.cross(normal);
btVector3 ftorqueAxis2 = m_relPosB.cross(normal);
bodyA.applyImpulse(normal*rbA.getInvMass(), rbA.getInvInertiaTensorWorld()*ftorqueAxis1,normalImpulse);
bodyB.applyImpulse(normal*rbB.getInvMass(), rbB.getInvInertiaTensorWorld()*ftorqueAxis2,-normalImpulse);
}
if(m_poweredLinMotor && (!i))
{ // apply linear motor
if(m_accumulatedLinMotorImpulse < m_maxLinMotorForce)
{
btScalar desiredMotorVel = m_targetLinMotorVelocity;
btScalar motor_relvel = desiredMotorVel + rel_vel;
normalImpulse = -motor_relvel * m_jacLinDiagABInv[i];
// clamp accumulated impulse
btScalar new_acc = m_accumulatedLinMotorImpulse + btFabs(normalImpulse);
if(new_acc > m_maxLinMotorForce)
{
new_acc = m_maxLinMotorForce;
}
btScalar del = new_acc - m_accumulatedLinMotorImpulse;
if(normalImpulse < btScalar(0.0))
{
normalImpulse = -del;
}
else
{
normalImpulse = del;
}
m_accumulatedLinMotorImpulse = new_acc;
// apply clamped impulse
impulse_vector = normal * normalImpulse;
//rbA.applyImpulse( impulse_vector, m_relPosA);
//rbB.applyImpulse(-impulse_vector, m_relPosB);
{
btVector3 ftorqueAxis1 = m_relPosA.cross(normal);
btVector3 ftorqueAxis2 = m_relPosB.cross(normal);
bodyA.applyImpulse(normal*rbA.getInvMass(), rbA.getInvInertiaTensorWorld()*ftorqueAxis1,normalImpulse);
bodyB.applyImpulse(normal*rbB.getInvMass(), rbB.getInvInertiaTensorWorld()*ftorqueAxis2,-normalImpulse);
}
}
}
}
// angular
// get axes in world space
btVector3 axisA = m_calculatedTransformA.getBasis().getColumn(0);
btVector3 axisB = m_calculatedTransformB.getBasis().getColumn(0);
btVector3 angVelA;
bodyA.getAngularVelocity(angVelA);
btVector3 angVelB;
bodyB.getAngularVelocity(angVelB);
btVector3 angVelAroundAxisA = axisA * axisA.dot(angVelA);
btVector3 angVelAroundAxisB = axisB * axisB.dot(angVelB);
btVector3 angAorthog = angVelA - angVelAroundAxisA;
btVector3 angBorthog = angVelB - angVelAroundAxisB;
btVector3 velrelOrthog = angAorthog-angBorthog;
//solve orthogonal angular velocity correction
btScalar len = velrelOrthog.length();
btScalar orthorImpulseMag = 0.f;
if (len > btScalar(0.00001))
{
btVector3 normal = velrelOrthog.normalized();
btScalar denom = rbA.computeAngularImpulseDenominator(normal) + rbB.computeAngularImpulseDenominator(normal);
//velrelOrthog *= (btScalar(1.)/denom) * m_dampingOrthoAng * m_softnessOrthoAng;
orthorImpulseMag = (btScalar(1.)/denom) * m_dampingOrthoAng * m_softnessOrthoAng;
}
//solve angular positional correction
btVector3 angularError = axisA.cross(axisB) *(btScalar(1.)/m_timeStep);
btVector3 angularAxis = angularError;
btScalar angularImpulseMag = 0;
btScalar len2 = angularError.length();
if (len2>btScalar(0.00001))
{
btVector3 normal2 = angularError.normalized();
btScalar denom2 = rbA.computeAngularImpulseDenominator(normal2) + rbB.computeAngularImpulseDenominator(normal2);
angularImpulseMag = (btScalar(1.)/denom2) * m_restitutionOrthoAng * m_softnessOrthoAng;
angularError *= angularImpulseMag;
}
// apply impulse
//rbA.applyTorqueImpulse(-velrelOrthog+angularError);
//rbB.applyTorqueImpulse(velrelOrthog-angularError);
bodyA.applyImpulse(btVector3(0,0,0), rbA.getInvInertiaTensorWorld()*velrelOrthog,-orthorImpulseMag);
bodyB.applyImpulse(btVector3(0,0,0), rbB.getInvInertiaTensorWorld()*velrelOrthog,orthorImpulseMag);
bodyA.applyImpulse(btVector3(0,0,0), rbA.getInvInertiaTensorWorld()*angularAxis,angularImpulseMag);
bodyB.applyImpulse(btVector3(0,0,0), rbB.getInvInertiaTensorWorld()*angularAxis,-angularImpulseMag);
btScalar impulseMag;
//solve angular limits
if(m_solveAngLim)
{
impulseMag = (angVelB - angVelA).dot(axisA) * m_dampingLimAng + m_angDepth * m_restitutionLimAng / m_timeStep;
impulseMag *= m_kAngle * m_softnessLimAng;
}
else
{
impulseMag = (angVelB - angVelA).dot(axisA) * m_dampingDirAng + m_angDepth * m_restitutionDirAng / m_timeStep;
impulseMag *= m_kAngle * m_softnessDirAng;
}
btVector3 impulse = axisA * impulseMag;
//rbA.applyTorqueImpulse(impulse);
//rbB.applyTorqueImpulse(-impulse);
bodyA.applyImpulse(btVector3(0,0,0), rbA.getInvInertiaTensorWorld()*axisA,impulseMag);
bodyB.applyImpulse(btVector3(0,0,0), rbB.getInvInertiaTensorWorld()*axisA,-impulseMag);
//apply angular motor
if(m_poweredAngMotor)
{
if(m_accumulatedAngMotorImpulse < m_maxAngMotorForce)
{
btVector3 velrel = angVelAroundAxisA - angVelAroundAxisB;
btScalar projRelVel = velrel.dot(axisA);
btScalar desiredMotorVel = m_targetAngMotorVelocity;
btScalar motor_relvel = desiredMotorVel - projRelVel;
btScalar angImpulse = m_kAngle * motor_relvel;
// clamp accumulated impulse
btScalar new_acc = m_accumulatedAngMotorImpulse + btFabs(angImpulse);
if(new_acc > m_maxAngMotorForce)
{
new_acc = m_maxAngMotorForce;
}
btScalar del = new_acc - m_accumulatedAngMotorImpulse;
if(angImpulse < btScalar(0.0))
{
angImpulse = -del;
}
else
{
angImpulse = del;
}
m_accumulatedAngMotorImpulse = new_acc;
// apply clamped impulse
btVector3 motorImp = angImpulse * axisA;
//rbA.applyTorqueImpulse(motorImp);
//rbB.applyTorqueImpulse(-motorImp);
bodyA.applyImpulse(btVector3(0,0,0), rbA.getInvInertiaTensorWorld()*axisA,angImpulse);
bodyB.applyImpulse(btVector3(0,0,0), rbB.getInvInertiaTensorWorld()*axisA,-angImpulse);
}
}
}
void btHingeConstraint::solveConstraintObsolete(btSolverBody& bodyA,btSolverBody& bodyB,btScalar timeStep)
{
///for backwards compatibility during the transition to 'getInfo/getInfo2'
if (m_useSolveConstraintObsolete)
{
btVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_rbAFrame.getOrigin();
btVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_rbBFrame.getOrigin();
btScalar tau = btScalar(0.3);
//linear part
if (!m_angularOnly)
{
btVector3 rel_pos1 = pivotAInW - m_rbA.getCenterOfMassPosition();
btVector3 rel_pos2 = pivotBInW - m_rbB.getCenterOfMassPosition();
btVector3 vel1,vel2;
bodyA.getVelocityInLocalPointObsolete(rel_pos1,vel1);
bodyB.getVelocityInLocalPointObsolete(rel_pos2,vel2);
btVector3 vel = vel1 - vel2;
for (int i=0;i<3;i++)
{
const btVector3& normal = m_jac[i].m_linearJointAxis;
btScalar jacDiagABInv = btScalar(1.) / m_jac[i].getDiagonal();
btScalar rel_vel;
rel_vel = normal.dot(vel);
//positional error (zeroth order error)
btScalar depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
btScalar impulse = depth*tau/timeStep * jacDiagABInv - rel_vel * jacDiagABInv;
m_appliedImpulse += impulse;
btVector3 impulse_vector = normal * impulse;
btVector3 ftorqueAxis1 = rel_pos1.cross(normal);
btVector3 ftorqueAxis2 = rel_pos2.cross(normal);
bodyA.applyImpulse(normal*m_rbA.getInvMass(), m_rbA.getInvInertiaTensorWorld()*ftorqueAxis1,impulse);
bodyB.applyImpulse(normal*m_rbB.getInvMass(), m_rbB.getInvInertiaTensorWorld()*ftorqueAxis2,-impulse);
}
}
{
///solve angular part
// get axes in world space
btVector3 axisA = getRigidBodyA().getCenterOfMassTransform().getBasis() * m_rbAFrame.getBasis().getColumn(2);
btVector3 axisB = getRigidBodyB().getCenterOfMassTransform().getBasis() * m_rbBFrame.getBasis().getColumn(2);
btVector3 angVelA;
bodyA.getAngularVelocity(angVelA);
btVector3 angVelB;
bodyB.getAngularVelocity(angVelB);
btVector3 angVelAroundHingeAxisA = axisA * axisA.dot(angVelA);
btVector3 angVelAroundHingeAxisB = axisB * axisB.dot(angVelB);
btVector3 angAorthog = angVelA - angVelAroundHingeAxisA;
btVector3 angBorthog = angVelB - angVelAroundHingeAxisB;
btVector3 velrelOrthog = angAorthog-angBorthog;
{
//solve orthogonal angular velocity correction
btScalar len = velrelOrthog.length();
if (len > btScalar(0.00001))
{
btVector3 normal = velrelOrthog.normalized();
btScalar denom = getRigidBodyA().computeAngularImpulseDenominator(normal) +
getRigidBodyB().computeAngularImpulseDenominator(normal);
// scale for mass and relaxation
//velrelOrthog *= (btScalar(1.)/denom) * m_relaxationFactor;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*velrelOrthog,-(btScalar(1.)/denom));
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*velrelOrthog,(btScalar(1.)/denom));
}
//solve angular positional correction
btVector3 angularError = axisA.cross(axisB) *(btScalar(1.)/timeStep);
btScalar len2 = angularError.length();
if (len2>btScalar(0.00001))
{
btVector3 normal2 = angularError.normalized();
btScalar denom2 = getRigidBodyA().computeAngularImpulseDenominator(normal2) +
getRigidBodyB().computeAngularImpulseDenominator(normal2);
//angularError *= (btScalar(1.)/denom2) * relaxation;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*angularError,(btScalar(1.)/denom2));
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*angularError,-(btScalar(1.)/denom2));
}
// solve limit
if (m_solveLimit)
{
btScalar amplitude = ( (angVelB - angVelA).dot( axisA )*m_relaxationFactor + m_correction* (btScalar(1.)/timeStep)*m_biasFactor ) * m_limitSign;
btScalar impulseMag = amplitude * m_kHinge;
// Clamp the accumulated impulse
btScalar temp = m_accLimitImpulse;
m_accLimitImpulse = btMax(m_accLimitImpulse + impulseMag, btScalar(0) );
impulseMag = m_accLimitImpulse - temp;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*axisA,impulseMag * m_limitSign);
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*axisA,-(impulseMag * m_limitSign));
}
}
//apply motor
if (m_enableAngularMotor)
{
//todo: add limits too
btVector3 angularLimit(0,0,0);
btVector3 velrel = angVelAroundHingeAxisA - angVelAroundHingeAxisB;
btScalar projRelVel = velrel.dot(axisA);
btScalar desiredMotorVel = m_motorTargetVelocity;
btScalar motor_relvel = desiredMotorVel - projRelVel;
btScalar unclippedMotorImpulse = m_kHinge * motor_relvel;;
// accumulated impulse clipping:
btScalar fMaxImpulse = m_maxMotorImpulse;
btScalar newAccImpulse = m_accMotorImpulse + unclippedMotorImpulse;
btScalar clippedMotorImpulse = unclippedMotorImpulse;
if (newAccImpulse > fMaxImpulse)
{
newAccImpulse = fMaxImpulse;
clippedMotorImpulse = newAccImpulse - m_accMotorImpulse;
}
else if (newAccImpulse < -fMaxImpulse)
{
newAccImpulse = -fMaxImpulse;
clippedMotorImpulse = newAccImpulse - m_accMotorImpulse;
}
m_accMotorImpulse += clippedMotorImpulse;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*axisA,clippedMotorImpulse);
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*axisA,-clippedMotorImpulse);
}
}
}
}
void btPoint2PointConstraint::solveConstraintObsolete(btSolverBody& bodyA,btSolverBody& bodyB,btScalar timeStep)
{
if (m_useSolveConstraintObsolete)
{
btVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_pivotInA;
btVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_pivotInB;
btVector3 normal(0,0,0);
// btVector3 angvelA = m_rbA.getCenterOfMassTransform().getBasis().transpose() * m_rbA.getAngularVelocity();
// btVector3 angvelB = m_rbB.getCenterOfMassTransform().getBasis().transpose() * m_rbB.getAngularVelocity();
for (int i=0;i<3;i++)
{
normal[i] = 1;
btScalar jacDiagABInv = btScalar(1.) / m_jac[i].getDiagonal();
btVector3 rel_pos1 = pivotAInW - m_rbA.getCenterOfMassPosition();
btVector3 rel_pos2 = pivotBInW - m_rbB.getCenterOfMassPosition();
//this jacobian entry could be re-used for all iterations
btVector3 vel1,vel2;
bodyA.getVelocityInLocalPointObsolete(rel_pos1,vel1);
bodyB.getVelocityInLocalPointObsolete(rel_pos2,vel2);
btVector3 vel = vel1 - vel2;
btScalar rel_vel;
rel_vel = normal.dot(vel);
/*
//velocity error (first order error)
btScalar rel_vel = m_jac[i].getRelativeVelocity(m_rbA.getLinearVelocity(),angvelA,
m_rbB.getLinearVelocity(),angvelB);
*/
//positional error (zeroth order error)
btScalar depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
btScalar deltaImpulse = depth*m_setting.m_tau/timeStep * jacDiagABInv - m_setting.m_damping * rel_vel * jacDiagABInv;
btScalar impulseClamp = m_setting.m_impulseClamp;
const btScalar sum = btScalar(m_appliedImpulse) + deltaImpulse;
if (sum < -impulseClamp)
{
deltaImpulse = -impulseClamp-m_appliedImpulse;
m_appliedImpulse = -impulseClamp;
}
else if (sum > impulseClamp)
{
deltaImpulse = impulseClamp-m_appliedImpulse;
m_appliedImpulse = impulseClamp;
}
else
{
m_appliedImpulse = sum;
}
btVector3 impulse_vector = normal * deltaImpulse;
btVector3 ftorqueAxis1 = rel_pos1.cross(normal);
btVector3 ftorqueAxis2 = rel_pos2.cross(normal);
bodyA.applyImpulse(normal*m_rbA.getInvMass(), m_rbA.getInvInertiaTensorWorld()*ftorqueAxis1,deltaImpulse);
bodyB.applyImpulse(normal*m_rbB.getInvMass(), m_rbB.getInvInertiaTensorWorld()*ftorqueAxis2,-deltaImpulse);
normal[i] = 0;
}
}
}
void btConeTwistConstraint::solveConstraintObsolete(btSolverBody& bodyA,btSolverBody& bodyB,btScalar timeStep)
{
if (m_useSolveConstraintObsolete)
{
btVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_rbAFrame.getOrigin();
btVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_rbBFrame.getOrigin();
btScalar tau = btScalar(0.3);
//linear part
if (!m_angularOnly)
{
btVector3 rel_pos1 = pivotAInW - m_rbA.getCenterOfMassPosition();
btVector3 rel_pos2 = pivotBInW - m_rbB.getCenterOfMassPosition();
btVector3 vel1;
bodyA.getVelocityInLocalPointObsolete(rel_pos1,vel1);
btVector3 vel2;
bodyB.getVelocityInLocalPointObsolete(rel_pos2,vel2);
btVector3 vel = vel1 - vel2;
for (int i=0;i<3;i++)
{
const btVector3& normal = m_jac[i].m_linearJointAxis;
btScalar jacDiagABInv = btScalar(1.) / m_jac[i].getDiagonal();
btScalar rel_vel;
rel_vel = normal.dot(vel);
//positional error (zeroth order error)
btScalar depth = -(pivotAInW - pivotBInW).dot(normal); //this is the error projected on the normal
btScalar impulse = depth*tau/timeStep * jacDiagABInv - rel_vel * jacDiagABInv;
m_appliedImpulse += impulse;
btVector3 ftorqueAxis1 = rel_pos1.cross(normal);
btVector3 ftorqueAxis2 = rel_pos2.cross(normal);
bodyA.applyImpulse(normal*m_rbA.getInvMass(), m_rbA.getInvInertiaTensorWorld()*ftorqueAxis1,impulse);
bodyB.applyImpulse(normal*m_rbB.getInvMass(), m_rbB.getInvInertiaTensorWorld()*ftorqueAxis2,-impulse);
}
}
// apply motor
if (m_bMotorEnabled)
{
// compute current and predicted transforms
btTransform trACur = m_rbA.getCenterOfMassTransform();
btTransform trBCur = m_rbB.getCenterOfMassTransform();
btVector3 omegaA; bodyA.getAngularVelocity(omegaA);
btVector3 omegaB; bodyB.getAngularVelocity(omegaB);
btTransform trAPred; trAPred.setIdentity();
btVector3 zerovec(0,0,0);
btTransformUtil::integrateTransform(
trACur, zerovec, omegaA, timeStep, trAPred);
btTransform trBPred; trBPred.setIdentity();
btTransformUtil::integrateTransform(
trBCur, zerovec, omegaB, timeStep, trBPred);
// compute desired transforms in world
btTransform trPose(m_qTarget);
btTransform trABDes = m_rbBFrame * trPose * m_rbAFrame.inverse();
btTransform trADes = trBPred * trABDes;
btTransform trBDes = trAPred * trABDes.inverse();
// compute desired omegas in world
btVector3 omegaADes, omegaBDes;
btTransformUtil::calculateVelocity(trACur, trADes, timeStep, zerovec, omegaADes);
btTransformUtil::calculateVelocity(trBCur, trBDes, timeStep, zerovec, omegaBDes);
// compute delta omegas
btVector3 dOmegaA = omegaADes - omegaA;
btVector3 dOmegaB = omegaBDes - omegaB;
// compute weighted avg axis of dOmega (weighting based on inertias)
btVector3 axisA, axisB;
btScalar kAxisAInv = 0, kAxisBInv = 0;
if (dOmegaA.length2() > SIMD_EPSILON)
{
axisA = dOmegaA.normalized();
kAxisAInv = getRigidBodyA().computeAngularImpulseDenominator(axisA);
}
if (dOmegaB.length2() > SIMD_EPSILON)
{
axisB = dOmegaB.normalized();
kAxisBInv = getRigidBodyB().computeAngularImpulseDenominator(axisB);
}
btVector3 avgAxis = kAxisAInv * axisA + kAxisBInv * axisB;
static bool bDoTorque = true;
if (bDoTorque && avgAxis.length2() > SIMD_EPSILON)
{
avgAxis.normalize();
kAxisAInv = getRigidBodyA().computeAngularImpulseDenominator(avgAxis);
kAxisBInv = getRigidBodyB().computeAngularImpulseDenominator(avgAxis);
btScalar kInvCombined = kAxisAInv + kAxisBInv;
btVector3 impulse = (kAxisAInv * dOmegaA - kAxisBInv * dOmegaB) /
(kInvCombined * kInvCombined);
if (m_maxMotorImpulse >= 0)
{
btScalar fMaxImpulse = m_maxMotorImpulse;
if (m_bNormalizedMotorStrength)
fMaxImpulse = fMaxImpulse/kAxisAInv;
btVector3 newUnclampedAccImpulse = m_accMotorImpulse + impulse;
btScalar newUnclampedMag = newUnclampedAccImpulse.length();
if (newUnclampedMag > fMaxImpulse)
{
newUnclampedAccImpulse.normalize();
newUnclampedAccImpulse *= fMaxImpulse;
impulse = newUnclampedAccImpulse - m_accMotorImpulse;
}
m_accMotorImpulse += impulse;
}
btScalar impulseMag = impulse.length();
btVector3 impulseAxis = impulse / impulseMag;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*impulseAxis, impulseMag);
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*impulseAxis, -impulseMag);
}
}
else if (m_damping > SIMD_EPSILON) // no motor: do a little damping
{
btVector3 angVelA; bodyA.getAngularVelocity(angVelA);
btVector3 angVelB; bodyB.getAngularVelocity(angVelB);
btVector3 relVel = angVelB - angVelA;
if (relVel.length2() > SIMD_EPSILON)
{
btVector3 relVelAxis = relVel.normalized();
btScalar m_kDamping = btScalar(1.) /
(getRigidBodyA().computeAngularImpulseDenominator(relVelAxis) +
getRigidBodyB().computeAngularImpulseDenominator(relVelAxis));
btVector3 impulse = m_damping * m_kDamping * relVel;
btScalar impulseMag = impulse.length();
btVector3 impulseAxis = impulse / impulseMag;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*impulseAxis, impulseMag);
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*impulseAxis, -impulseMag);
}
}
// joint limits
{
///solve angular part
btVector3 angVelA;
bodyA.getAngularVelocity(angVelA);
btVector3 angVelB;
bodyB.getAngularVelocity(angVelB);
// solve swing limit
if (m_solveSwingLimit)
{
btScalar amplitude = m_swingLimitRatio * m_swingCorrection*m_biasFactor/timeStep;
btScalar relSwingVel = (angVelB - angVelA).dot(m_swingAxis);
if (relSwingVel > 0)
amplitude += m_swingLimitRatio * relSwingVel * m_relaxationFactor;
btScalar impulseMag = amplitude * m_kSwing;
// Clamp the accumulated impulse
btScalar temp = m_accSwingLimitImpulse;
m_accSwingLimitImpulse = btMax(m_accSwingLimitImpulse + impulseMag, btScalar(0.0) );
impulseMag = m_accSwingLimitImpulse - temp;
btVector3 impulse = m_swingAxis * impulseMag;
// don't let cone response affect twist
// (this can happen since body A's twist doesn't match body B's AND we use an elliptical cone limit)
{
btVector3 impulseTwistCouple = impulse.dot(m_twistAxisA) * m_twistAxisA;
btVector3 impulseNoTwistCouple = impulse - impulseTwistCouple;
impulse = impulseNoTwistCouple;
}
impulseMag = impulse.length();
btVector3 noTwistSwingAxis = impulse / impulseMag;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*noTwistSwingAxis, impulseMag);
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*noTwistSwingAxis, -impulseMag);
}
// solve twist limit
if (m_solveTwistLimit)
{
btScalar amplitude = m_twistLimitRatio * m_twistCorrection*m_biasFactor/timeStep;
btScalar relTwistVel = (angVelB - angVelA).dot( m_twistAxis );
if (relTwistVel > 0) // only damp when moving towards limit (m_twistAxis flipping is important)
amplitude += m_twistLimitRatio * relTwistVel * m_relaxationFactor;
btScalar impulseMag = amplitude * m_kTwist;
// Clamp the accumulated impulse
btScalar temp = m_accTwistLimitImpulse;
m_accTwistLimitImpulse = btMax(m_accTwistLimitImpulse + impulseMag, btScalar(0.0) );
impulseMag = m_accTwistLimitImpulse - temp;
btVector3 impulse = m_twistAxis * impulseMag;
bodyA.applyImpulse(btVector3(0,0,0), m_rbA.getInvInertiaTensorWorld()*m_twistAxis,impulseMag);
bodyB.applyImpulse(btVector3(0,0,0), m_rbB.getInvInertiaTensorWorld()*m_twistAxis,-impulseMag);
}
}
}
}
btScalar btTranslationalLimitMotor::solveLinearAxis(
btScalar timeStep,
btScalar jacDiagABInv,
btRigidBody& body1,btSolverBody& bodyA,const btVector3 &pointInA,
btRigidBody& body2,btSolverBody& bodyB,const btVector3 &pointInB,
int limit_index,
const btVector3 & axis_normal_on_a,
const btVector3 & anchorPos)
{
///find relative velocity
// btVector3 rel_pos1 = pointInA - body1.getCenterOfMassPosition();
// btVector3 rel_pos2 = pointInB - body2.getCenterOfMassPosition();
btVector3 rel_pos1 = anchorPos - body1.getCenterOfMassPosition();
btVector3 rel_pos2 = anchorPos - body2.getCenterOfMassPosition();
btVector3 vel1;
bodyA.getVelocityInLocalPointObsolete(rel_pos1,vel1);
btVector3 vel2;
bodyB.getVelocityInLocalPointObsolete(rel_pos2,vel2);
btVector3 vel = vel1 - vel2;
btScalar rel_vel = axis_normal_on_a.dot(vel);
/// apply displacement correction
//positional error (zeroth order error)
btScalar depth = -(pointInA - pointInB).dot(axis_normal_on_a);
btScalar lo = btScalar(-1e30);
btScalar hi = btScalar(1e30);
btScalar minLimit = m_lowerLimit[limit_index];
btScalar maxLimit = m_upperLimit[limit_index];
//handle the limits
if (minLimit < maxLimit)
{
{
if (depth > maxLimit)
{
depth -= maxLimit;
lo = btScalar(0.);
}
else
{
if (depth < minLimit)
{
depth -= minLimit;
hi = btScalar(0.);
}
else
{
return 0.0f;
}
}
}
}
btScalar normalImpulse= m_limitSoftness*(m_restitution*depth/timeStep - m_damping*rel_vel) * jacDiagABInv;
btScalar oldNormalImpulse = m_accumulatedImpulse[limit_index];
btScalar sum = oldNormalImpulse + normalImpulse;
m_accumulatedImpulse[limit_index] = sum > hi ? btScalar(0.) : sum < lo ? btScalar(0.) : sum;
normalImpulse = m_accumulatedImpulse[limit_index] - oldNormalImpulse;
btVector3 impulse_vector = axis_normal_on_a * normalImpulse;
//body1.applyImpulse( impulse_vector, rel_pos1);
//body2.applyImpulse(-impulse_vector, rel_pos2);
btVector3 ftorqueAxis1 = rel_pos1.cross(axis_normal_on_a);
btVector3 ftorqueAxis2 = rel_pos2.cross(axis_normal_on_a);
bodyA.applyImpulse(axis_normal_on_a*body1.getInvMass(), body1.getInvInertiaTensorWorld()*ftorqueAxis1,normalImpulse);
bodyB.applyImpulse(axis_normal_on_a*body2.getInvMass(), body2.getInvInertiaTensorWorld()*ftorqueAxis2,-normalImpulse);
return normalImpulse;
}
btScalar btRotationalLimitMotor::solveAngularLimits(
btScalar timeStep,btVector3& axis,btScalar jacDiagABInv,
btRigidBody * body0, btSolverBody& bodyA, btRigidBody * body1, btSolverBody& bodyB)
{
if (needApplyTorques()==false) return 0.0f;
btScalar target_velocity = m_targetVelocity;
btScalar maxMotorForce = m_maxMotorForce;
//current error correction
if (m_currentLimit!=0)
{
target_velocity = -m_ERP*m_currentLimitError/(timeStep);
maxMotorForce = m_maxLimitForce;
}
maxMotorForce *= timeStep;
// current velocity difference
btVector3 angVelA;
bodyA.getAngularVelocity(angVelA);
btVector3 angVelB;
bodyB.getAngularVelocity(angVelB);
btVector3 vel_diff;
vel_diff = angVelA-angVelB;
btScalar rel_vel = axis.dot(vel_diff);
// correction velocity
btScalar motor_relvel = m_limitSoftness*(target_velocity - m_damping*rel_vel);
if ( motor_relvel < SIMD_EPSILON && motor_relvel > -SIMD_EPSILON )
{
return 0.0f;//no need for applying force
}
// correction impulse
btScalar unclippedMotorImpulse = (1+m_bounce)*motor_relvel*jacDiagABInv;
// clip correction impulse
btScalar clippedMotorImpulse;
///@todo: should clip against accumulated impulse
if (unclippedMotorImpulse>0.0f)
{
clippedMotorImpulse = unclippedMotorImpulse > maxMotorForce? maxMotorForce: unclippedMotorImpulse;
}
else
{
clippedMotorImpulse = unclippedMotorImpulse < -maxMotorForce ? -maxMotorForce: unclippedMotorImpulse;
}
// sort with accumulated impulses
btScalar lo = btScalar(-1e30);
btScalar hi = btScalar(1e30);
btScalar oldaccumImpulse = m_accumulatedImpulse;
btScalar sum = oldaccumImpulse + clippedMotorImpulse;
m_accumulatedImpulse = sum > hi ? btScalar(0.) : sum < lo ? btScalar(0.) : sum;
clippedMotorImpulse = m_accumulatedImpulse - oldaccumImpulse;
btVector3 motorImp = clippedMotorImpulse * axis;
//body0->applyTorqueImpulse(motorImp);
//body1->applyTorqueImpulse(-motorImp);
bodyA.applyImpulse(btVector3(0,0,0), body0->getInvInertiaTensorWorld()*axis,clippedMotorImpulse);
bodyB.applyImpulse(btVector3(0,0,0), body1->getInvInertiaTensorWorld()*axis,-clippedMotorImpulse);
return clippedMotorImpulse;
}