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Revert "replace unstable Gyroscopic force calculations with stable back Euler derived"

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This reverts commit 0ce687853d.
This commit is contained in:
emMichael Alexander Ewert/em
2014-12-12 16:35:40 -08:00
parent 92dabdc07d
commit d4be7a4823
8 changed files with 31 additions and 69 deletions
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2
Extras/Serialize/BulletWorldImporter/btBulletWorldImporter.cpp
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@@ -171,6 +171,7 @@ bool btBulletWorldImporter::convertAllObjects( bParse::btBulletFile* bulletFile
solverInfo.m_linearSlop = btScalar(solverInfoData->m_solverInfo.m_linearSlop);
solverInfo.m_warmstartingFactor = btScalar(solverInfoData->m_solverInfo.m_warmstartingFactor);
solverInfo.m_maxGyroscopicForce = btScalar(solverInfoData->m_solverInfo.m_maxGyroscopicForce);
solverInfo.m_singleAxisRollingFrictionThreshold = btScalar(solverInfoData->m_solverInfo.m_singleAxisRollingFrictionThreshold);
solverInfo.m_numIterations = solverInfoData->m_solverInfo.m_numIterations;
@@ -206,6 +207,7 @@ bool btBulletWorldImporter::convertAllObjects( bParse::btBulletFile* bulletFile
solverInfo.m_linearSlop = solverInfoData->m_solverInfo.m_linearSlop;
solverInfo.m_warmstartingFactor = solverInfoData->m_solverInfo.m_warmstartingFactor;
solverInfo.m_maxGyroscopicForce = solverInfoData->m_solverInfo.m_maxGyroscopicForce;
solverInfo.m_singleAxisRollingFrictionThreshold = solverInfoData->m_solverInfo.m_singleAxisRollingFrictionThreshold;
solverInfo.m_numIterations = solverInfoData->m_solverInfo.m_numIterations;

4
src/Bullet3Dynamics/ConstraintSolver/b3ContactSolverInfo.h
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@@ -56,6 +56,7 @@ struct b3ContactSolverInfoData
int m_solverMode;
int m_restingContactRestitutionThreshold;
int m_minimumSolverBatchSize;
b3Scalar m_maxGyroscopicForce;
b3Scalar m_singleAxisRollingFrictionThreshold;
@@ -88,6 +89,7 @@ struct b3ContactSolverInfo : public b3ContactSolverInfoData
m_solverMode = B3_SOLVER_USE_WARMSTARTING | B3_SOLVER_SIMD;// | B3_SOLVER_RANDMIZE_ORDER;
m_restingContactRestitutionThreshold = 2;//unused as of 2.81
m_minimumSolverBatchSize = 128; //try to combine islands until the amount of constraints reaches this limit
m_maxGyroscopicForce = 100.f; ///only used to clamp forces for bodies that have their B3_ENABLE_GYROPSCOPIC_FORCE flag set (using b3RigidBody::setFlag)
m_singleAxisRollingFrictionThreshold = 1e30f;///if the velocity is above this threshold, it will use a single constraint row (axis), otherwise 3 rows.
}
};
@@ -109,6 +111,7 @@ struct b3ContactSolverInfoDoubleData
double m_splitImpulseTurnErp;
double m_linearSlop;
double m_warmstartingFactor;
double m_maxGyroscopicForce;
double m_singleAxisRollingFrictionThreshold;
int m_numIterations;
@@ -139,6 +142,7 @@ struct b3ContactSolverInfoFloatData
float m_linearSlop;
float m_warmstartingFactor;
float m_maxGyroscopicForce;
float m_singleAxisRollingFrictionThreshold;
int m_numIterations;

2
src/Bullet3Serialize/Bullet2FileLoader/autogenerated/bullet2.h
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@@ -782,6 +782,7 @@ typedef struct bInvalidHandle {
double m_splitImpulseTurnErp;
double m_linearSlop;
double m_warmstartingFactor;
double m_maxGyroscopicForce;
double m_singleAxisRollingFrictionThreshold;
int m_numIterations;
int m_solverMode;
@@ -810,6 +811,7 @@ typedef struct bInvalidHandle {
float m_splitImpulseTurnErp;
float m_linearSlop;
float m_warmstartingFactor;
float m_maxGyroscopicForce;
float m_singleAxisRollingFrictionThreshold;
int m_numIterations;
int m_solverMode;

4
src/BulletDynamics/ConstraintSolver/btContactSolverInfo.h
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@@ -56,6 +56,7 @@ struct btContactSolverInfoData
int m_solverMode;
int m_restingContactRestitutionThreshold;
int m_minimumSolverBatchSize;
btScalar m_maxGyroscopicForce;
btScalar m_singleAxisRollingFrictionThreshold;
@@ -88,6 +89,7 @@ struct btContactSolverInfo : public btContactSolverInfoData
m_solverMode = SOLVER_USE_WARMSTARTING | SOLVER_SIMD;// | SOLVER_RANDMIZE_ORDER;
m_restingContactRestitutionThreshold = 2;//unused as of 2.81
m_minimumSolverBatchSize = 128; //try to combine islands until the amount of constraints reaches this limit
m_maxGyroscopicForce = 100.f; ///only used to clamp forces for bodies that have their BT_ENABLE_GYROPSCOPIC_FORCE flag set (using btRigidBody::setFlag)
m_singleAxisRollingFrictionThreshold = 1e30f;///if the velocity is above this threshold, it will use a single constraint row (axis), otherwise 3 rows.
}
};
@@ -109,6 +111,7 @@ struct btContactSolverInfoDoubleData
double m_splitImpulseTurnErp;
double m_linearSlop;
double m_warmstartingFactor;
double m_maxGyroscopicForce;
double m_singleAxisRollingFrictionThreshold;
int m_numIterations;
@@ -139,6 +142,7 @@ struct btContactSolverInfoFloatData
float m_linearSlop;
float m_warmstartingFactor;
float m_maxGyroscopicForce;
float m_singleAxisRollingFrictionThreshold;
int m_numIterations;

4
src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
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@@ -1270,8 +1270,8 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
btVector3 gyroForce (0,0,0);
if (body->getFlags()&BT_ENABLE_GYROPSCOPIC_FORCE)
{
gyroForce = body->computeGyroscopicImpulse( infoGlobal.m_timeStep );
solverBody.m_externalTorqueImpulse += gyroForce;
gyroForce = body->computeGyroscopicForce(infoGlobal.m_maxGyroscopicForce);
solverBody.m_externalTorqueImpulse -= gyroForce*body->getInvInertiaTensorWorld()*infoGlobal.m_timeStep;
}
}
}

1
src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp
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@@ -1431,6 +1431,7 @@ void btDiscreteDynamicsWorld::serializeDynamicsWorldInfo(btSerializer* serialize
worldInfo->m_solverInfo.m_linearSlop = getSolverInfo().m_linearSlop;
worldInfo->m_solverInfo.m_warmstartingFactor = getSolverInfo().m_warmstartingFactor;
worldInfo->m_solverInfo.m_maxGyroscopicForce = getSolverInfo().m_maxGyroscopicForce;
worldInfo->m_solverInfo.m_singleAxisRollingFrictionThreshold = getSolverInfo().m_singleAxisRollingFrictionThreshold;
worldInfo->m_solverInfo.m_numIterations = getSolverInfo().m_numIterations;

79
src/BulletDynamics/Dynamics/btRigidBody.cpp
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@@ -256,71 +256,22 @@ void btRigidBody::updateInertiaTensor()
m_invInertiaTensorWorld = m_worldTransform.getBasis().scaled(m_invInertiaLocal) * m_worldTransform.getBasis().transpose();
}
btVector3 btRigidBody::getLocalInertia() const
btVector3 btRigidBody::computeGyroscopicForce(btScalar maxGyroscopicForce) const
{
btVector3 inertiaLocal;
const btVector3 inertia = m_invInertiaLocal;
inertiaLocal.setValue(inertia.x() != btScalar(0.0) ? btScalar(1.0) / inertia.x(): btScalar(0.0),
inertia.y() != btScalar(0.0) ? btScalar(1.0) / inertia.y(): btScalar(0.0),
inertia.z() != btScalar(0.0) ? btScalar(1.0) / inertia.z(): btScalar(0.0));
return inertiaLocal;
}
inline btVector3 evalEulerEqn( const btVector3 w1, const btVector3 w0, const btVector3 T, const btScalar dt,
const btMatrix3x3 &I )
{
const btVector3 w2 = I*w1 + w1.cross(I*w1)*dt - (T*dt + I*w0);
return w2;
}
inline btMatrix3x3 evalEulerEqnDeriv( const btVector3 w1, const btVector3 w0, const btScalar dt,
const btMatrix3x3 &I )
{
btMatrix3x3 w1x, Iw1x;
const btVector3 Iwi = (I*w1);
w1.getSkewSymmetricMatrix(&w1x[0], &w1x[1], &w1x[2]);
Iwi.getSkewSymmetricMatrix(&Iw1x[0], &Iw1x[1], &Iw1x[2]);
const btMatrix3x3 dfw1 = I + (w1x*I - Iw1x)*dt;
return dfw1;
}
btVector3 btRigidBody::computeGyroscopicImpulse(btScalar step) const
{
// use full newton-euler eqations. common practice to drop the wxIw term. want it for better tumbling behavior.
// calculate using implicit euler step so it's stable.
const btVector3 inertiaLocal = getLocalInertia();
const btVector3 w0 = getAngularVelocity();
btMatrix3x3 I;
I = m_worldTransform.getBasis().scaled(inertiaLocal) *
m_worldTransform.getBasis().transpose();
// use newtons method to find implicit solution for new angular velocity (w')
// f(w') = -(T*step + Iw) + Iw' + w' + w'xIw'*step = 0
// df/dw' = I + 1xIw'*step + w'xI*step
btVector3 w1 = w0;
// one step of newton's method
{
const btVector3 fw = evalEulerEqn(w1, w0, btVector3(0,0,0), step, I);
const btMatrix3x3 dfw = evalEulerEqnDeriv(w1, w0, step, I);
const btMatrix3x3 dfw_inv = dfw.inverse();
btVector3 dw;
dw = dfw_inv*fw;
w1 -= dw;
}
btVector3 gf = (w1-w0);
return gf;
btVector3 inertiaLocal;
inertiaLocal[0] = 1.f/getInvInertiaDiagLocal()[0];
inertiaLocal[1] = 1.f/getInvInertiaDiagLocal()[1];
inertiaLocal[2] = 1.f/getInvInertiaDiagLocal()[2];
btMatrix3x3 inertiaTensorWorld = getWorldTransform().getBasis().scaled(inertiaLocal) * getWorldTransform().getBasis().transpose();
btVector3 tmp = inertiaTensorWorld*getAngularVelocity();
btVector3 gf = getAngularVelocity().cross(tmp);
btScalar l2 = gf.length2();
if (l2>maxGyroscopicForce*maxGyroscopicForce)
{
gf *= btScalar(1.)/btSqrt(l2)*maxGyroscopicForce;
}
return gf;
}
void btRigidBody::integrateVelocities(btScalar step)

4
src/BulletDynamics/Dynamics/btRigidBody.h
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@@ -529,9 +529,7 @@ public:
return m_rigidbodyFlags;
}
btVector3 getLocalInertia() const;
btVector3 computeGyroscopicImpulse(btScalar dt) const;
btVector3 computeGyroscopicForce(btScalar maxGyroscopicForce) const;
///////////////////////////////////////////////