Bart/bullet3
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

added Erin Catto's 'local' implicit coriolis/gyroscopic force, next to 'Ewert', Cooper, explicit and none

Browse Source 
Configured the gyroscopic demo to show the Dzhanibekov effect
see also https://www.youtube.com/watch?v=L2o9eBl_Gzw
This commit is contained in:
Erwin Coumans
2015-03-24 23:16:45 -07:00
parent 1e13454511
commit 0a04a745dd
4 changed files with 83 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
src/BulletDynamics/Dynamics/btRigidBody.cpp
View File

@@ -87,7 +87,7 @@ void btRigidBody::setupRigidBody(const btRigidBody::btRigidBodyConstructionInfo&
setMassProps(constructionInfo.m_mass, constructionInfo.m_localInertia);
updateInertiaTensor();
m_rigidbodyFlags = BT_ENABLE_GYROPSCOPIC_FORCE_IMPLICIT_EWERT;
m_rigidbodyFlags = BT_ENABLE_GYROSCOPIC_FORCE_IMPLICIT_EWERT;
m_deltaLinearVelocity.setZero();
@@ -311,6 +311,46 @@ void btSetCrossMatrixMinus(btMatrix3x3& res, const btVector3& a)
+a_1, -a_0, 0);
}
btVector3 btRigidBody::computeGyroscopicImpulseImplicit_Catto(btScalar step) const
{
btVector3 idl = getLocalInertia();
btVector3 omega1 = getAngularVelocity();
btQuaternion q = getWorldTransform().getRotation();
// Convert to body coordinates
btVector3 omegab = quatRotate(q.inverse(), omega1);
btMatrix3x3 Ib;
Ib.setValue(idl.x(),0,0,
0,idl.y(),0,
0,0,idl.z());
btVector3 ibo = Ib*omegab;
// Residual vector
btVector3 f = step * omegab.cross(ibo);
btMatrix3x3 skew0;
omegab.getSkewSymmetricMatrix(&skew0[0], &skew0[1], &skew0[2]);
btVector3 om = Ib*omegab;
btMatrix3x3 skew1;
om.getSkewSymmetricMatrix(&skew1[0],&skew1[1],&skew1[2]);
// Jacobian
btMatrix3x3 J = Ib + (skew0*Ib - skew1)*step;
btMatrix3x3 Jinv = J.inverse();
btVector3 omega_div = Jinv*f;
// Single Newton-Raphson update
omegab = omegab - omega_div;//Solve33(J, f);
// Back to world coordinates
btVector3 omega2 = quatRotate(q,omegab);
btVector3 gf = omega2-omega1;
return gf;
}
btVector3 btRigidBody::computeGyroscopicImpulseImplicit_Cooper(btScalar step) const
{
#if 0
@@ -394,6 +434,7 @@ if (dInvertMatrix3(itInv, Itild) != 0) {
}
#endif
btVector3 tau0 = Itild * L;
printf("tau0 = %f,%f,%f\n",tau0.x(),tau0.y(),tau0.z());
return tau0;
return btVector3(0, 0, 0);
}