//response between two dynamic objects without friction, assuming 0 penetration depth
public static float ResolveSingleCollision(
RigidBody body1,
CollisionObject colObj2,
ref IndexedVector3 contactPositionWorld,
ref IndexedVector3 contactNormalOnB,
ContactSolverInfo solverInfo,
float distance)
{
RigidBody body2 = RigidBody.Upcast(colObj2);
IndexedVector3 normal = contactNormalOnB;
IndexedVector3 rel_pos1 = contactPositionWorld - body1.GetWorldTransform()._origin;
IndexedVector3 rel_pos2 = contactPositionWorld - colObj2.GetWorldTransform()._origin;
IndexedVector3 vel1 = body1.GetVelocityInLocalPoint(ref rel_pos1);
IndexedVector3 vel2 = body2 != null ? body2.GetVelocityInLocalPoint(ref rel_pos2) : IndexedVector3.Zero;
IndexedVector3 vel = vel1 - vel2;
float rel_vel = normal.Dot(ref vel);
float combinedRestitution = body1.GetRestitution() * colObj2.GetRestitution();
float restitution = combinedRestitution * -rel_vel;
float positionalError = solverInfo.m_erp * -distance / solverInfo.m_timeStep;
float velocityError = -(1.0f + restitution) * rel_vel;// * damping;
float denom0 = body1.ComputeImpulseDenominator(ref contactPositionWorld, ref normal);
float denom1 = body2 != null ? body2.ComputeImpulseDenominator(ref contactPositionWorld, ref normal) : 0.0f;
float relaxation = 1.0f;
float jacDiagABInv = relaxation / (denom0 + denom1);
float penetrationImpulse = positionalError * jacDiagABInv;
float velocityImpulse = velocityError * jacDiagABInv;
float normalImpulse = penetrationImpulse + velocityImpulse;
normalImpulse = 0.0f > normalImpulse ? 0.0f : normalImpulse;
body1.ApplyImpulse(normal * (normalImpulse), rel_pos1);
if (body2 != null)
{
body2.ApplyImpulse(-normal * (normalImpulse), rel_pos2);
}
return normalImpulse;
}
public bool Callback(ref ManifoldPoint cp, CollisionObject colObj0, int partId0, int index0, CollisionObject colObj1, int partId1, int index1)
{
bool enable = true;
if (enable)
{
InternalEdgeUtility.AdjustInternalEdgeContacts(cp,colObj1,colObj0, partId1,index1,BulletXNA.BulletCollision.CollisionDispatch.InternalEdgeUtility.InternalEdgeAdjustFlags.BT_TRIANGLE_CONVEX_BACKFACE_NONE);
//btAdjustInternalEdgeContacts(cp,colObj1,colObj0, partId1,index1, BT_TRIANGLE_CONVEX_BACKFACE_MODE);
//btAdjustInternalEdgeContacts(cp,colObj1,colObj0, partId1,index1, BT_TRIANGLE_CONVEX_DOUBLE_SIDED+BT_TRIANGLE_CONCAVE_DOUBLE_SIDED);
}
float friction0 = colObj0.GetFriction();
float friction1 = colObj1.GetFriction();
float restitution0 = colObj0.GetRestitution();
float restitution1 = colObj1.GetRestitution();
if ((colObj0.GetCollisionFlags() & CollisionFlags.CF_CUSTOM_MATERIAL_CALLBACK) != 0)
{
friction0 = 1.0f;//partId0,index0
restitution0 = 0.0f;
}
if ((colObj1.GetCollisionFlags() & CollisionFlags.CF_CUSTOM_MATERIAL_CALLBACK) != 0)
{
if ((index1&1) != 0)
{
friction1 = 1.0f;//partId1,index1
}
else
{
friction1 = 0.0f;
}
restitution1 = 0.0f;
}
cp.m_combinedFriction = CalculateCombinedFriction(friction0,friction1);
cp.m_combinedRestitution = CalculateCombinedRestitution(restitution0,restitution1);
//this return value is currently ignored, but to be on the safe side: return false if you don't calculate friction
return true;
}
private float CalculateCombinedRestitution(CollisionObject body0, CollisionObject body1)
{
return(body0.GetRestitution() * body1.GetRestitution());
}
private float CalculateCombinedRestitution(CollisionObject body0, CollisionObject body1)
{
return body0.GetRestitution() * body1.GetRestitution();
}
public bool Callback(ref ManifoldPoint cp, CollisionObject colObj0, int partId0, int index0, CollisionObject colObj1, int partId1, int index1)
{
float friction0 = colObj0.GetFriction();
float friction1 = colObj1.GetFriction();
float restitution0 = colObj0.GetRestitution();
float restitution1 = colObj1.GetRestitution();
if ((colObj0.GetCollisionFlags() & CollisionFlags.CF_CUSTOM_MATERIAL_CALLBACK) != 0)
{
friction0 = 1.0f;//partId0,index0
restitution0 = 0.0f;
}
if ((colObj1.GetCollisionFlags() & CollisionFlags.CF_CUSTOM_MATERIAL_CALLBACK) != 0)
{
if ((index1&1) != 0)
{
friction1 = 1.0f;//partId1,index1
}
else
{
friction1 = 0f;
}
restitution1 = 0f;
}
cp.m_combinedFriction = CalculateCombinedFriction(friction0,friction1);
cp.m_combinedRestitution = calculateCombinedRestitution(restitution0,restitution1);
//this return value is currently ignored, but to be on the safe side: return false if you don't calculate friction
return true;
}
