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improve rolling friction using anisotropic direction, to avoid resting in an instable position

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(for implicit capsule, cylinder and cone shape)
See Bullet/Demos/RollingFrictionDemo for an example
This commit is contained in:
erwin.coumans
2012-09-16 17:01:25 +00:00
parent 26c713423f
commit 22fb7d5c1e
8 changed files with 120 additions and 43 deletions
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37
src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
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@@ -324,12 +324,12 @@ btScalar btSequentialImpulseConstraintSolver::restitutionCurve(btScalar rel_vel,
static void applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection);
static void applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection)
static void applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection, int frictionMode);
static void applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection, int frictionMode)
{
if (colObj && colObj->hasAnisotropicFriction())
if (colObj && colObj->hasAnisotropicFriction(frictionMode))
{
// transform to local coordinates
btVector3 loc_lateral = frictionDirection * colObj->getWorldTransform().getBasis();
@@ -807,15 +807,24 @@ void btSequentialImpulseConstraintSolver::convertContact(btPersistentManifold* m
if (relAngVel.length()>infoGlobal.m_singleAxisRollingFrictionThreshold)
{
relAngVel.normalize();
addRollingFrictionConstraint(relAngVel,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
applyAnisotropicFriction(colObj0,relAngVel,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
applyAnisotropicFriction(colObj1,relAngVel,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
if (relAngVel.length()>0.001)
addRollingFrictionConstraint(relAngVel,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
} else
{
addRollingFrictionConstraint(cp.m_normalWorldOnB,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
btVector3 axis0,axis1;
btPlaneSpace1(cp.m_normalWorldOnB,axis0,axis1);
addRollingFrictionConstraint(axis0,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
addRollingFrictionConstraint(axis1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
applyAnisotropicFriction(colObj0,axis0,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
applyAnisotropicFriction(colObj1,axis0,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
applyAnisotropicFriction(colObj0,axis1,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
applyAnisotropicFriction(colObj1,axis1,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
if (axis0.length()>0.001)
addRollingFrictionConstraint(axis0,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
if (axis1.length()>0.001)
addRollingFrictionConstraint(axis1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
}
}
@@ -834,14 +843,14 @@ void btSequentialImpulseConstraintSolver::convertContact(btPersistentManifold* m
{
cp.m_lateralFrictionDir2 = cp.m_lateralFrictionDir1.cross(cp.m_normalWorldOnB);
cp.m_lateralFrictionDir2.normalize();//??
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2);
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
}
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1);
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
@@ -853,13 +862,13 @@ void btSequentialImpulseConstraintSolver::convertContact(btPersistentManifold* m
if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
{
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2);
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
}
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1);
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);