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Damping for spring motors added

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see btGeneric6DofSpringConstraint::setDamping()
This commit is contained in:
rponom
2009-06-02 01:10:43 +00:00
parent d58a14b4cd
commit ee664e7750
6 changed files with 21 additions and 3 deletions
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2
Demos/ConstraintDemo/ConstraintDemo.cpp
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@@ -383,8 +383,10 @@ void ConstraintDemo::initPhysics()
pGen6DOFSpring->enableSpring(0, true);
pGen6DOFSpring->setStiffness(0, 39.478f);
pGen6DOFSpring->setDamping(0, 0.5f);
pGen6DOFSpring->enableSpring(5, true);
pGen6DOFSpring->setStiffness(5, 39.478f);
pGen6DOFSpring->setDamping(0, 0.3f);
pGen6DOFSpring->setEquilibriumPoint();
}
#endif

16
src/BulletDynamics/ConstraintSolver/btGeneric6DofSpringConstraint.cpp
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@@ -26,6 +26,7 @@ btGeneric6DofSpringConstraint::btGeneric6DofSpringConstraint(btRigidBody& rbA, b
m_springEnabled[i] = false;
m_equilibriumPoint[i] = btScalar(0.f);
m_springStiffness[i] = btScalar(0.f);
m_springDamping[i] = btScalar(1.f);
}
}
@@ -53,6 +54,13 @@ void btGeneric6DofSpringConstraint::setStiffness(int index, btScalar stiffness)
}
void btGeneric6DofSpringConstraint::setDamping(int index, btScalar damping)
{
btAssert((index >= 0) && (index < 6));
m_springDamping[index] = damping;
}
void btGeneric6DofSpringConstraint::setEquilibriumPoint()
{
calculateTransforms();
@@ -99,8 +107,9 @@ void btGeneric6DofSpringConstraint::internalUpdateSprings(btConstraintInfo2* inf
btScalar delta = currPos - m_equilibriumPoint[i];
// spring force is (delta * m_stiffness) according to Hooke's Law
btScalar force = delta * m_springStiffness[i];
m_linearLimits.m_targetVelocity[i] = force * info->fps;
m_linearLimits.m_maxMotorForce[i] = btFabs(force) / info->fps;
btScalar velFactor = info->fps * m_springDamping[i] / btScalar(info->m_numIterations);
m_linearLimits.m_targetVelocity[i] = velFactor * force;
m_linearLimits.m_maxMotorForce[i] = btFabs(force) / info->fps;
}
}
for(i = 0; i < 3; i++)
@@ -113,7 +122,8 @@ void btGeneric6DofSpringConstraint::internalUpdateSprings(btConstraintInfo2* inf
btScalar delta = currPos - m_equilibriumPoint[i+3];
// spring force is (-delta * m_stiffness) according to Hooke's Law
btScalar force = -delta * m_springStiffness[i+3];
m_angularLimits[i].m_targetVelocity = force * info->fps;
btScalar velFactor = info->fps * m_springDamping[i+3] / btScalar(info->m_numIterations);
m_angularLimits[i].m_targetVelocity = velFactor * force;
m_angularLimits[i].m_maxMotorForce = btFabs(force) / info->fps;
}
}

2
src/BulletDynamics/ConstraintSolver/btGeneric6DofSpringConstraint.h
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@@ -38,11 +38,13 @@ protected:
bool m_springEnabled[6];
btScalar m_equilibriumPoint[6];
btScalar m_springStiffness[6];
btScalar m_springDamping[6]; // between 0 and 1 (1 == no damping)
void internalUpdateSprings(btConstraintInfo2* info);
public:
btGeneric6DofSpringConstraint(btRigidBody& rbA, btRigidBody& rbB, const btTransform& frameInA, const btTransform& frameInB ,bool useLinearReferenceFrameA);
void enableSpring(int index, bool onOff);
void setStiffness(int index, btScalar stiffness);
void setDamping(int index, btScalar damping);
void setEquilibriumPoint(); // set the current constraint position/orientation as an equilibrium point for all DOF
void setEquilibriumPoint(int index); // set the current constraint position/orientation as an equilibrium point for given DOF
virtual void getInfo2 (btConstraintInfo2* info);

1
src/BulletDynamics/ConstraintSolver/btHinge2Constraint.cpp
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@@ -60,6 +60,7 @@ btHinge2Constraint::btHinge2Constraint(btRigidBody& rbA, btRigidBody& rbB, btVec
// enable suspension
enableSpring(2, true);
setStiffness(2, SIMD_PI * SIMD_PI * 4.f); // period 1 sec for 1 kilogramm weel :-)
setDamping(2, 0.01f);
setEquilibriumPoint();
}

1
src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
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@@ -730,6 +730,7 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
info2.cfm = &currentConstraintRow->m_cfm;
info2.m_lowerLimit = &currentConstraintRow->m_lowerLimit;
info2.m_upperLimit = &currentConstraintRow->m_upperLimit;
info2.m_numIterations = infoGlobal.m_numIterations;
constraints[i]->getInfo2(&info2);
///finalize the constraint setup

2
src/BulletDynamics/ConstraintSolver/btTypedConstraint.h
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@@ -97,6 +97,8 @@ public:
// note that the returned indexes are relative to the first index of
// the constraint.
int *findex;
// number of solver iterations
int m_numIterations;
};
///internal method used by the constraint solver, don't use them directly