//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; }