Example #1
0
        //velocity + friction
        //response  between two dynamic objects with friction
        public virtual float ResolveSingleCollisionCombinedCacheFriendly(
            SolverBody bodyA,
            SolverBody bodyB,
            SolverConstraint contactConstraint,
            ContactSolverInfo solverInfo)
        {
            float normalImpulse = 0;

            if (contactConstraint.Penetration < 0)
            {
                return(0);
            }

            float relVel;
            float velADotn = Vector3.Dot(contactConstraint.ContactNormal, bodyA.LinearVelocity)
                             + Vector3.Dot(contactConstraint.RelPosACrossNormal, bodyA.AngularVelocity);
            float velBDotn = Vector3.Dot(contactConstraint.ContactNormal, bodyB.LinearVelocity)
                             + Vector3.Dot(contactConstraint.RelPosBCrossNormal, bodyB.AngularVelocity);

            relVel = velADotn - velBDotn;

            float positionalError = contactConstraint.Penetration;
            float velocityError   = contactConstraint.Restitution - relVel;          // * damping;

            float penetrationImpulse = positionalError * contactConstraint.JacDiagABInv;
            float velocityImpulse    = velocityError * contactConstraint.JacDiagABInv;

            normalImpulse = penetrationImpulse + velocityImpulse;

            // See Erin Catto's GDC 2006 paper: Clamp the accumulated impulse
            float oldNormalImpulse = contactConstraint.AppliedImpulse;
            float sum = oldNormalImpulse + normalImpulse;

            contactConstraint.AppliedImpulse = 0 > sum ? 0 : sum;

            float oldVelocityImpulse = contactConstraint.AppliedVelocityImpulse;
            float velocitySum        = oldVelocityImpulse + velocityImpulse;

            contactConstraint.AppliedVelocityImpulse = 0 > velocitySum ? 0 : velocitySum;

            normalImpulse = contactConstraint.AppliedImpulse - oldNormalImpulse;

            if (bodyA.InvMass != 0)
            {
                bodyA.ApplyImpulse(contactConstraint.ContactNormal * bodyA.InvMass,
                                   contactConstraint.AngularComponentA, normalImpulse);
            }
            if (bodyB.InvMass != 0)
            {
                bodyB.ApplyImpulse(contactConstraint.ContactNormal * bodyB.InvMass,
                                   contactConstraint.AngularComponentB, -normalImpulse);
            }

            return(normalImpulse);
        }
Example #2
0
        public virtual float ResolveSingleFrictionCacheFriendly(
            SolverBody bodyA,
            SolverBody bodyB,
            SolverConstraint contactConstraint,
            ContactSolverInfo solverInfo,
            float appliedNormalImpulse)
        {
            float combinedFriction = contactConstraint.Friction;
            float limit            = appliedNormalImpulse * combinedFriction;

            if (appliedNormalImpulse > 0)
            //friction
            {
                float j1;
                {
                    float relVel;
                    float velADotn = Vector3.Dot(contactConstraint.ContactNormal, bodyA.LinearVelocity)
                                     + Vector3.Dot(contactConstraint.RelPosACrossNormal, bodyA.AngularVelocity);
                    float velBDotn = Vector3.Dot(contactConstraint.ContactNormal, bodyB.LinearVelocity)
                                     + Vector3.Dot(contactConstraint.RelPosBCrossNormal, bodyB.AngularVelocity);
                    relVel = velADotn - velBDotn;

                    // calculate j that moves us to zero relative velocity
                    j1 = -relVel * contactConstraint.JacDiagABInv;
                    float oldTangentImpulse = contactConstraint.AppliedImpulse;
                    contactConstraint.AppliedImpulse = oldTangentImpulse + j1;

                    float test = contactConstraint.AppliedImpulse;
                    MathHelper.SetMin(ref test, limit);
                    MathHelper.SetMax(ref test, -limit);
                    contactConstraint.AppliedImpulse = test;

                    j1 = contactConstraint.AppliedImpulse - oldTangentImpulse;
                }

                if (bodyA.InvMass != 0)
                {
                    bodyA.ApplyImpulse(contactConstraint.ContactNormal * bodyA.InvMass, contactConstraint.AngularComponentA, j1);
                }
                if (bodyB.InvMass != 0)
                {
                    bodyB.ApplyImpulse(contactConstraint.ContactNormal * bodyB.InvMass, contactConstraint.AngularComponentB, -j1);
                }
            }
            return(0);
        }
		public virtual float SolveGroupCacheFriendly(List<CollisionObject> bodies, List<PersistentManifold> manifolds, int numManifolds, List<TypedConstraint> constraints, ContactSolverInfo infoGlobal, IDebugDraw debugDrawer)
		{
			if (constraints.Count + numManifolds == 0)
			{
				return 0;
			}

			for (int i = 0; i < numManifolds; i++)
			{
				PersistentManifold manifold = manifolds[i];
				RigidBody rbA = (RigidBody)manifold.BodyA;
				RigidBody rbB = (RigidBody)manifold.BodyB;

				manifold.RefreshContactPoints(rbA.CenterOfMassTransform, rbB.CenterOfMassTransform);
			}

			int minReservation = manifolds.Count * 2;

			_tmpSolverBodyPool = new List<SolverBody>(minReservation);

			for (int i = 0; i < bodies.Count; i++)
			{
				RigidBody rb = RigidBody.Upcast(bodies[i]);
				if (rb != null && rb.IslandTag >= 0)
				{
					BulletDebug.Assert(rb.CompanionID < 0);
					int solverBodyId = _tmpSolverBodyPool.Count;
					SolverBody solverBody;
					InitSolverBody(out solverBody, rb);
					_tmpSolverBodyPool.Add(solverBody);
					rb.CompanionID = solverBodyId;
				}
			}

			_tmpSolverConstraintPool = new List<SolverConstraint>(minReservation);
			_tmpSolverFrictionConstraintPool = new List<SolverConstraint>(minReservation);

			for (int i = 0; i < numManifolds; i++)
			{
				PersistentManifold manifold = manifolds[i];
				RigidBody rb0 = (RigidBody)manifold.BodyA;
				RigidBody rb1 = (RigidBody)manifold.BodyB;

				int solverBodyIdA = -1;
				int solverBodyIdB = -1;

				//if (i == 89)
				//    System.Diagnostics.Debugger.Break();

				if (manifold.ContactsCount != 0)
				{
					if (rb0.IslandTag >= 0)
					{
						solverBodyIdA = rb0.CompanionID;
					}
					else
					{
						//create a static body
						solverBodyIdA = _tmpSolverBodyPool.Count;
						SolverBody solverBody;
						InitSolverBody(out solverBody, rb0);
						_tmpSolverBodyPool.Add(solverBody);
					}

					if (rb1.IslandTag >= 0)
					{
						solverBodyIdB = rb1.CompanionID;
					}
					else
					{
						//create a static body
						solverBodyIdB = _tmpSolverBodyPool.Count;
						SolverBody solverBody;
						InitSolverBody(out solverBody, rb1);
						_tmpSolverBodyPool.Add(solverBody);
					}
				}

				if (solverBodyIdB == -1 || solverBodyIdA == -1)
					System.Diagnostics.Debug.WriteLine(string.Format("We're in ass ! {0}", i));

				for (int j = 0; j < manifold.ContactsCount; j++)
				{
					ManifoldPoint cp = manifold.GetContactPoint(j);

					int frictionIndex = _tmpSolverConstraintPool.Count;

					if (cp.Distance <= 0)
					{

						Vector3 pos1 = cp.PositionWorldOnA;
						Vector3 pos2 = cp.PositionWorldOnB;

						Vector3 rel_pos1 = pos1 - rb0.CenterOfMassPosition;
						Vector3 rel_pos2 = pos2 - rb1.CenterOfMassPosition;

						float relaxation = 1;
						{
							SolverConstraint solverConstraint = new SolverConstraint();
							_tmpSolverConstraintPool.Add(solverConstraint);

							solverConstraint.SolverBodyIdA = solverBodyIdA;
							solverConstraint.SolverBodyIdB = solverBodyIdB;
							solverConstraint.ConstraintType = SolverConstraint.SolverConstraintType.Contact;

							//can be optimized, the cross products are already calculated
							float denom0 = rb0.ComputeImpulseDenominator(pos1, cp.NormalWorldOnB);
							float denom1 = rb1.ComputeImpulseDenominator(pos2, cp.NormalWorldOnB);
							float denom = relaxation / (denom0 + denom1);
							solverConstraint.JacDiagABInv = denom;

							solverConstraint.ContactNormal = cp.NormalWorldOnB;
							solverConstraint.RelPosACrossNormal = Vector3.Cross(rel_pos1, cp.NormalWorldOnB);
							solverConstraint.RelPosBCrossNormal = Vector3.Cross(rel_pos2, cp.NormalWorldOnB);

							Vector3 vel1 = rb0.GetVelocityInLocalPoint(rel_pos1);
							Vector3 vel2 = rb1.GetVelocityInLocalPoint(rel_pos2);

							Vector3 vel = vel1 - vel2;
							float rel_vel;
							rel_vel = Vector3.Dot(cp.NormalWorldOnB, vel);


							solverConstraint.Penetration = cp.Distance;//btScalar(infoGlobal.m_numIterations);
							solverConstraint.Friction = cp.CombinedFriction;
							float rest = RestitutionCurve(rel_vel, cp.CombinedRestitution);
							if (rest <= 0)
							{
								rest = 0;
							}

							float penVel = -solverConstraint.Penetration / infoGlobal.TimeStep;
							if (rest > penVel)
							{
								rest = 0;
							}
							solverConstraint.Restitution = rest;

							solverConstraint.Penetration *= -(infoGlobal.Erp / infoGlobal.TimeStep);

							solverConstraint.AppliedImpulse = 0f;
							solverConstraint.AppliedVelocityImpulse = 0f;

#warning Check to see if we need Vector3.Transform
							Vector3 torqueAxis0 = Vector3.Cross(rel_pos1, cp.NormalWorldOnB);
							solverConstraint.AngularComponentA = Vector3.TransformNormal(torqueAxis0, rb0.InvInertiaTensorWorld);
							Vector3 torqueAxis1 = Vector3.Cross(rel_pos2, cp.NormalWorldOnB);
							solverConstraint.AngularComponentB = Vector3.TransformNormal(torqueAxis1, rb1.InvInertiaTensorWorld);
						}
						//create 2 '1d axis' constraints for 2 tangential friction directions

						//re-calculate friction direction every frame, todo: check if this is really needed
						Vector3 frictionTangential0a = new Vector3(),
								frictionTangential1b = new Vector3();

						MathHelper.PlaneSpace1(cp.NormalWorldOnB, ref frictionTangential0a, ref frictionTangential1b);
						{
							SolverConstraint solverConstraint = new SolverConstraint();
							_tmpSolverFrictionConstraintPool.Add(solverConstraint);
							solverConstraint.ContactNormal = frictionTangential0a;

							solverConstraint.SolverBodyIdA = solverBodyIdA;
							solverConstraint.SolverBodyIdB = solverBodyIdB;
							solverConstraint.ConstraintType = SolverConstraint.SolverConstraintType.Friction;
							solverConstraint.FrictionIndex = frictionIndex;

							solverConstraint.Friction = cp.CombinedFriction;

							solverConstraint.AppliedImpulse = 0;
							solverConstraint.AppliedVelocityImpulse = 0;

							float denom0 = rb0.ComputeImpulseDenominator(pos1, solverConstraint.ContactNormal);
							float denom1 = rb1.ComputeImpulseDenominator(pos2, solverConstraint.ContactNormal);
							float denom = relaxation / (denom0 + denom1);
							solverConstraint.JacDiagABInv = denom;

							{
								Vector3 ftorqueAxis0 = Vector3.Cross(rel_pos1, solverConstraint.ContactNormal);
								solverConstraint.RelPosACrossNormal = ftorqueAxis0;
								solverConstraint.AngularComponentA = Vector3.TransformNormal(ftorqueAxis0, rb0.InvInertiaTensorWorld);
							}
							{
								Vector3 ftorqueAxis0 = Vector3.Cross(rel_pos2, solverConstraint.ContactNormal);
								solverConstraint.RelPosBCrossNormal = ftorqueAxis0;
								solverConstraint.AngularComponentB = Vector3.TransformNormal(ftorqueAxis0, rb1.InvInertiaTensorWorld);
							}
						}


						{

							SolverConstraint solverConstraint = new SolverConstraint();
							_tmpSolverFrictionConstraintPool.Add(solverConstraint);
							solverConstraint.ContactNormal = frictionTangential1b;

							solverConstraint.SolverBodyIdA = solverBodyIdA;
							solverConstraint.SolverBodyIdB = solverBodyIdB;
							solverConstraint.ConstraintType = SolverConstraint.SolverConstraintType.Friction;
							solverConstraint.FrictionIndex = frictionIndex;

							solverConstraint.Friction = cp.CombinedFriction;

							solverConstraint.AppliedImpulse = 0;
							solverConstraint.AppliedVelocityImpulse = 0;

							float denom0 = rb0.ComputeImpulseDenominator(pos1, solverConstraint.ContactNormal);
							float denom1 = rb1.ComputeImpulseDenominator(pos2, solverConstraint.ContactNormal);
							float denom = relaxation / (denom0 + denom1);
							solverConstraint.JacDiagABInv = denom;
							{
								Vector3 ftorqueAxis1 = Vector3.Cross(rel_pos1, solverConstraint.ContactNormal);
								solverConstraint.RelPosACrossNormal = ftorqueAxis1;
								solverConstraint.AngularComponentA = Vector3.TransformNormal(ftorqueAxis1, rb0.InvInertiaTensorWorld);
							}
							{
								Vector3 ftorqueAxis1 = Vector3.Cross(rel_pos2, solverConstraint.ContactNormal);
								solverConstraint.RelPosBCrossNormal = ftorqueAxis1;
								solverConstraint.AngularComponentB = Vector3.TransformNormal(ftorqueAxis1, rb1.InvInertiaTensorWorld);
							}
						}
					}
				}
			}

			ContactSolverInfo info = infoGlobal;
			{
				for (int j = 0; j < constraints.Count; j++)
				{
					TypedConstraint constraint = constraints[j];
					constraint.BuildJacobian();
				}
			}

			int numConstraintPool = _tmpSolverConstraintPool.Count;
			int numFrictionPool = _tmpSolverFrictionConstraintPool.Count;

			//todo: use stack allocator for such temporarily memory, same for solver bodies/constraints
			List<int> gOrderTmpConstraintPool = new List<int>(numConstraintPool);
			List<int> gOrderFrictionConstraintPool = new List<int>(numFrictionPool);
			{
				for (int i = 0; i < numConstraintPool; i++)
				{
					gOrderTmpConstraintPool.Add(i);
				}
				for (int i = 0; i < numFrictionPool; i++)
				{
					gOrderFrictionConstraintPool.Add(i);
				}
			}

			//should traverse the contacts random order...
			int iteration;
			{
				for (iteration = 0; iteration < info.IterationsCount; iteration++)
				{

					int j;
					if ((_solverMode & SolverMode.RandomizeOrder) != SolverMode.None)
					{
						if ((iteration & 7) == 0)
						{
							for (j = 0; j < numConstraintPool; ++j)
							{
								int tmp = gOrderTmpConstraintPool[j];
								int swapi = RandInt2(j + 1);
								gOrderTmpConstraintPool[j] = gOrderTmpConstraintPool[swapi];
								gOrderTmpConstraintPool[swapi] = tmp;
							}

							for (j = 0; j < numFrictionPool; ++j)
							{
								int tmp = gOrderFrictionConstraintPool[j];
								int swapi = RandInt2(j + 1);
								gOrderFrictionConstraintPool[j] = gOrderFrictionConstraintPool[swapi];
								gOrderFrictionConstraintPool[swapi] = tmp;
							}
						}
					}

					for (j = 0; j < constraints.Count; j++)
					{
						TypedConstraint constraint = constraints[j];
						//todo: use solver bodies, so we don't need to copy from/to btRigidBody

						if ((constraint.RigidBodyA.IslandTag >= 0) && (constraint.RigidBodyA.CompanionID >= 0))
						{
							_tmpSolverBodyPool[constraint.RigidBodyA.CompanionID].WriteBackVelocity();
						}
						if ((constraint.RigidBodyB.IslandTag >= 0) && (constraint.RigidBodyB.CompanionID >= 0))
						{
							_tmpSolverBodyPool[constraint.RigidBodyB.CompanionID].WriteBackVelocity();
						}

						constraint.SolveConstraint(info.TimeStep);

						if ((constraint.RigidBodyA.IslandTag >= 0) && (constraint.RigidBodyA.CompanionID >= 0))
						{
							_tmpSolverBodyPool[constraint.RigidBodyA.CompanionID].ReadVelocity();
						}
						if ((constraint.RigidBodyB.IslandTag >= 0) && (constraint.RigidBodyB.CompanionID >= 0))
						{
							_tmpSolverBodyPool[constraint.RigidBodyB.CompanionID].ReadVelocity();
						}

					}

					{
						int numPoolConstraints = _tmpSolverConstraintPool.Count;
						for (j = 0; j < numPoolConstraints; j++)
						{
							SolverConstraint solveManifold = _tmpSolverConstraintPool[gOrderTmpConstraintPool[j]];
							ResolveSingleCollisionCombinedCacheFriendly(_tmpSolverBodyPool[solveManifold.SolverBodyIdA],
								_tmpSolverBodyPool[solveManifold.SolverBodyIdB], solveManifold, info);
						}
					}

					{
						int numFrictionPoolConstraints = _tmpSolverFrictionConstraintPool.Count;
						for (j = 0; j < numFrictionPoolConstraints; j++)
						{
							SolverConstraint solveManifold = _tmpSolverFrictionConstraintPool[gOrderFrictionConstraintPool[j]];
							float appliedNormalImpulse = _tmpSolverConstraintPool[solveManifold.FrictionIndex].AppliedImpulse;

							ResolveSingleFrictionCacheFriendly(_tmpSolverBodyPool[solveManifold.SolverBodyIdA],
								_tmpSolverBodyPool[solveManifold.SolverBodyIdB], solveManifold, info, appliedNormalImpulse);
						}
					}
				}
			}

			for (int i = 0; i < _tmpSolverBodyPool.Count; i++)
			{
				_tmpSolverBodyPool[i].WriteBackVelocity();
			}

			_tmpSolverBodyPool.Clear();
			_tmpSolverConstraintPool.Clear();
			_tmpSolverFrictionConstraintPool.Clear();

			return 0;
		}
		public virtual float ResolveSingleFrictionCacheFriendly(
			SolverBody bodyA,
			SolverBody bodyB,
			SolverConstraint contactConstraint,
			ContactSolverInfo solverInfo,
			float appliedNormalImpulse)
		{
			float combinedFriction = contactConstraint.Friction;
			float limit = appliedNormalImpulse * combinedFriction;

			if (appliedNormalImpulse > 0)
			//friction
			{
				float j1;
				{
					float relVel;
					float velADotn = Vector3.Dot(contactConstraint.ContactNormal, bodyA.LinearVelocity)
								+ Vector3.Dot(contactConstraint.RelPosACrossNormal, bodyA.AngularVelocity);
					float velBDotn = Vector3.Dot(contactConstraint.ContactNormal, bodyB.LinearVelocity)
						+ Vector3.Dot(contactConstraint.RelPosBCrossNormal, bodyB.AngularVelocity);
					relVel = velADotn - velBDotn;

					// calculate j that moves us to zero relative velocity
					j1 = -relVel * contactConstraint.JacDiagABInv;
					float oldTangentImpulse = contactConstraint.AppliedImpulse;
					contactConstraint.AppliedImpulse = oldTangentImpulse + j1;

					float test = contactConstraint.AppliedImpulse;
					MathHelper.SetMin(ref test, limit);
					MathHelper.SetMax(ref test, -limit);
					contactConstraint.AppliedImpulse = test;

					j1 = contactConstraint.AppliedImpulse - oldTangentImpulse;
				}

				if (bodyA.InvMass != 0)
				{
					bodyA.ApplyImpulse(contactConstraint.ContactNormal * bodyA.InvMass, contactConstraint.AngularComponentA, j1);
				}
				if (bodyB.InvMass != 0)
				{
					bodyB.ApplyImpulse(contactConstraint.ContactNormal * bodyB.InvMass, contactConstraint.AngularComponentB, -j1);
				}
			}
			return 0;
		}
		//velocity + friction
		//response  between two dynamic objects with friction
		public virtual float ResolveSingleCollisionCombinedCacheFriendly(
			SolverBody bodyA,
			SolverBody bodyB,
			SolverConstraint contactConstraint,
			ContactSolverInfo solverInfo)
		{
			float normalImpulse = 0;

			if (contactConstraint.Penetration < 0)
				return 0;

			float relVel;
			float velADotn = Vector3.Dot(contactConstraint.ContactNormal,bodyA.LinearVelocity)
						+ Vector3.Dot(contactConstraint.RelPosACrossNormal,bodyA.AngularVelocity);
			float velBDotn = Vector3.Dot(contactConstraint.ContactNormal,bodyB.LinearVelocity)
						+ Vector3.Dot(contactConstraint.RelPosBCrossNormal,bodyB.AngularVelocity);

			relVel = velADotn - velBDotn;

			float positionalError = contactConstraint.Penetration;
			float velocityError = contactConstraint.Restitution - relVel;// * damping;

			float penetrationImpulse = positionalError * contactConstraint.JacDiagABInv;
			float velocityImpulse = velocityError * contactConstraint.JacDiagABInv;
			normalImpulse = penetrationImpulse + velocityImpulse;

			// See Erin Catto's GDC 2006 paper: Clamp the accumulated impulse
			float oldNormalImpulse = contactConstraint.AppliedImpulse;
			float sum = oldNormalImpulse + normalImpulse;
			contactConstraint.AppliedImpulse = 0 > sum ? 0 : sum;

			float oldVelocityImpulse = contactConstraint.AppliedVelocityImpulse;
			float velocitySum = oldVelocityImpulse + velocityImpulse;
			contactConstraint.AppliedVelocityImpulse = 0 > velocitySum ? 0 : velocitySum;

			normalImpulse = contactConstraint.AppliedImpulse - oldNormalImpulse;

			if (bodyA.InvMass != 0)
			{
				bodyA.ApplyImpulse(contactConstraint.ContactNormal * bodyA.InvMass,
					contactConstraint.AngularComponentA, normalImpulse);
			}
			if (bodyB.InvMass != 0)
			{
				bodyB.ApplyImpulse(contactConstraint.ContactNormal * bodyB.InvMass,
					contactConstraint.AngularComponentB, -normalImpulse);
			}

			return normalImpulse;
		}
Example #6
0
        public virtual float SolveGroupCacheFriendly(List <CollisionObject> bodies, List <PersistentManifold> manifolds, int numManifolds, List <TypedConstraint> constraints, ContactSolverInfo infoGlobal, IDebugDraw debugDrawer)
        {
            if (constraints.Count + numManifolds == 0)
            {
                return(0);
            }

            for (int i = 0; i < numManifolds; i++)
            {
                PersistentManifold manifold = manifolds[i];
                RigidBody          rbA      = (RigidBody)manifold.BodyA;
                RigidBody          rbB      = (RigidBody)manifold.BodyB;

                manifold.RefreshContactPoints(rbA.CenterOfMassTransform, rbB.CenterOfMassTransform);
            }

            int minReservation = manifolds.Count * 2;

            _tmpSolverBodyPool = new List <SolverBody>(minReservation);

            for (int i = 0; i < bodies.Count; i++)
            {
                RigidBody rb = RigidBody.Upcast(bodies[i]);
                if (rb != null && rb.IslandTag >= 0)
                {
                    BulletDebug.Assert(rb.CompanionID < 0);
                    int        solverBodyId = _tmpSolverBodyPool.Count;
                    SolverBody solverBody;
                    InitSolverBody(out solverBody, rb);
                    _tmpSolverBodyPool.Add(solverBody);
                    rb.CompanionID = solverBodyId;
                }
            }

            _tmpSolverConstraintPool         = new List <SolverConstraint>(minReservation);
            _tmpSolverFrictionConstraintPool = new List <SolverConstraint>(minReservation);

            for (int i = 0; i < numManifolds; i++)
            {
                PersistentManifold manifold = manifolds[i];
                RigidBody          rb0      = (RigidBody)manifold.BodyA;
                RigidBody          rb1      = (RigidBody)manifold.BodyB;

                int solverBodyIdA = -1;
                int solverBodyIdB = -1;

                //if (i == 89)
                //    System.Diagnostics.Debugger.Break();

                if (manifold.ContactsCount != 0)
                {
                    if (rb0.IslandTag >= 0)
                    {
                        solverBodyIdA = rb0.CompanionID;
                    }
                    else
                    {
                        //create a static body
                        solverBodyIdA = _tmpSolverBodyPool.Count;
                        SolverBody solverBody;
                        InitSolverBody(out solverBody, rb0);
                        _tmpSolverBodyPool.Add(solverBody);
                    }

                    if (rb1.IslandTag >= 0)
                    {
                        solverBodyIdB = rb1.CompanionID;
                    }
                    else
                    {
                        //create a static body
                        solverBodyIdB = _tmpSolverBodyPool.Count;
                        SolverBody solverBody;
                        InitSolverBody(out solverBody, rb1);
                        _tmpSolverBodyPool.Add(solverBody);
                    }
                }

                if (solverBodyIdB == -1 || solverBodyIdA == -1)
                {
                    System.Diagnostics.Debug.WriteLine(string.Format("We're in ass ! {0}", i));
                }

                for (int j = 0; j < manifold.ContactsCount; j++)
                {
                    ManifoldPoint cp = manifold.GetContactPoint(j);

                    int frictionIndex = _tmpSolverConstraintPool.Count;

                    if (cp.Distance <= 0)
                    {
                        Vector3 pos1 = cp.PositionWorldOnA;
                        Vector3 pos2 = cp.PositionWorldOnB;

                        Vector3 rel_pos1 = pos1 - rb0.CenterOfMassPosition;
                        Vector3 rel_pos2 = pos2 - rb1.CenterOfMassPosition;

                        float relaxation = 1;
                        {
                            SolverConstraint solverConstraint = new SolverConstraint();
                            _tmpSolverConstraintPool.Add(solverConstraint);

                            solverConstraint.SolverBodyIdA  = solverBodyIdA;
                            solverConstraint.SolverBodyIdB  = solverBodyIdB;
                            solverConstraint.ConstraintType = SolverConstraint.SolverConstraintType.Contact;

                            //can be optimized, the cross products are already calculated
                            float denom0 = rb0.ComputeImpulseDenominator(pos1, cp.NormalWorldOnB);
                            float denom1 = rb1.ComputeImpulseDenominator(pos2, cp.NormalWorldOnB);
                            float denom  = relaxation / (denom0 + denom1);
                            solverConstraint.JacDiagABInv = denom;

                            solverConstraint.ContactNormal      = cp.NormalWorldOnB;
                            solverConstraint.RelPosACrossNormal = Vector3.Cross(rel_pos1, cp.NormalWorldOnB);
                            solverConstraint.RelPosBCrossNormal = Vector3.Cross(rel_pos2, cp.NormalWorldOnB);

                            Vector3 vel1 = rb0.GetVelocityInLocalPoint(rel_pos1);
                            Vector3 vel2 = rb1.GetVelocityInLocalPoint(rel_pos2);

                            Vector3 vel = vel1 - vel2;
                            float   rel_vel;
                            rel_vel = Vector3.Dot(cp.NormalWorldOnB, vel);


                            solverConstraint.Penetration = cp.Distance;                            //btScalar(infoGlobal.m_numIterations);
                            solverConstraint.Friction    = cp.CombinedFriction;
                            float rest = RestitutionCurve(rel_vel, cp.CombinedRestitution);
                            if (rest <= 0)
                            {
                                rest = 0;
                            }

                            float penVel = -solverConstraint.Penetration / infoGlobal.TimeStep;
                            if (rest > penVel)
                            {
                                rest = 0;
                            }
                            solverConstraint.Restitution = rest;

                            solverConstraint.Penetration *= -(infoGlobal.Erp / infoGlobal.TimeStep);

                            solverConstraint.AppliedImpulse         = 0f;
                            solverConstraint.AppliedVelocityImpulse = 0f;

#warning Check to see if we need Vector3.Transform
                            Vector3 torqueAxis0 = Vector3.Cross(rel_pos1, cp.NormalWorldOnB);
                            solverConstraint.AngularComponentA = Vector3.TransformNormal(torqueAxis0, rb0.InvInertiaTensorWorld);
                            Vector3 torqueAxis1 = Vector3.Cross(rel_pos2, cp.NormalWorldOnB);
                            solverConstraint.AngularComponentB = Vector3.TransformNormal(torqueAxis1, rb1.InvInertiaTensorWorld);
                        }
                        //create 2 '1d axis' constraints for 2 tangential friction directions

                        //re-calculate friction direction every frame, todo: check if this is really needed
                        Vector3 frictionTangential0a = new Vector3(),
                                frictionTangential1b = new Vector3();

                        MathHelper.PlaneSpace1(cp.NormalWorldOnB, ref frictionTangential0a, ref frictionTangential1b);
                        {
                            SolverConstraint solverConstraint = new SolverConstraint();
                            _tmpSolverFrictionConstraintPool.Add(solverConstraint);
                            solverConstraint.ContactNormal = frictionTangential0a;

                            solverConstraint.SolverBodyIdA  = solverBodyIdA;
                            solverConstraint.SolverBodyIdB  = solverBodyIdB;
                            solverConstraint.ConstraintType = SolverConstraint.SolverConstraintType.Friction;
                            solverConstraint.FrictionIndex  = frictionIndex;

                            solverConstraint.Friction = cp.CombinedFriction;

                            solverConstraint.AppliedImpulse         = 0;
                            solverConstraint.AppliedVelocityImpulse = 0;

                            float denom0 = rb0.ComputeImpulseDenominator(pos1, solverConstraint.ContactNormal);
                            float denom1 = rb1.ComputeImpulseDenominator(pos2, solverConstraint.ContactNormal);
                            float denom  = relaxation / (denom0 + denom1);
                            solverConstraint.JacDiagABInv = denom;

                            {
                                Vector3 ftorqueAxis0 = Vector3.Cross(rel_pos1, solverConstraint.ContactNormal);
                                solverConstraint.RelPosACrossNormal = ftorqueAxis0;
                                solverConstraint.AngularComponentA  = Vector3.TransformNormal(ftorqueAxis0, rb0.InvInertiaTensorWorld);
                            }
                            {
                                Vector3 ftorqueAxis0 = Vector3.Cross(rel_pos2, solverConstraint.ContactNormal);
                                solverConstraint.RelPosBCrossNormal = ftorqueAxis0;
                                solverConstraint.AngularComponentB  = Vector3.TransformNormal(ftorqueAxis0, rb1.InvInertiaTensorWorld);
                            }
                        }


                        {
                            SolverConstraint solverConstraint = new SolverConstraint();
                            _tmpSolverFrictionConstraintPool.Add(solverConstraint);
                            solverConstraint.ContactNormal = frictionTangential1b;

                            solverConstraint.SolverBodyIdA  = solverBodyIdA;
                            solverConstraint.SolverBodyIdB  = solverBodyIdB;
                            solverConstraint.ConstraintType = SolverConstraint.SolverConstraintType.Friction;
                            solverConstraint.FrictionIndex  = frictionIndex;

                            solverConstraint.Friction = cp.CombinedFriction;

                            solverConstraint.AppliedImpulse         = 0;
                            solverConstraint.AppliedVelocityImpulse = 0;

                            float denom0 = rb0.ComputeImpulseDenominator(pos1, solverConstraint.ContactNormal);
                            float denom1 = rb1.ComputeImpulseDenominator(pos2, solverConstraint.ContactNormal);
                            float denom  = relaxation / (denom0 + denom1);
                            solverConstraint.JacDiagABInv = denom;
                            {
                                Vector3 ftorqueAxis1 = Vector3.Cross(rel_pos1, solverConstraint.ContactNormal);
                                solverConstraint.RelPosACrossNormal = ftorqueAxis1;
                                solverConstraint.AngularComponentA  = Vector3.TransformNormal(ftorqueAxis1, rb0.InvInertiaTensorWorld);
                            }
                            {
                                Vector3 ftorqueAxis1 = Vector3.Cross(rel_pos2, solverConstraint.ContactNormal);
                                solverConstraint.RelPosBCrossNormal = ftorqueAxis1;
                                solverConstraint.AngularComponentB  = Vector3.TransformNormal(ftorqueAxis1, rb1.InvInertiaTensorWorld);
                            }
                        }
                    }
                }
            }

            ContactSolverInfo info = infoGlobal;
            {
                for (int j = 0; j < constraints.Count; j++)
                {
                    TypedConstraint constraint = constraints[j];
                    constraint.BuildJacobian();
                }
            }

            int numConstraintPool = _tmpSolverConstraintPool.Count;
            int numFrictionPool   = _tmpSolverFrictionConstraintPool.Count;

            //todo: use stack allocator for such temporarily memory, same for solver bodies/constraints
            List <int> gOrderTmpConstraintPool      = new List <int>(numConstraintPool);
            List <int> gOrderFrictionConstraintPool = new List <int>(numFrictionPool);
            {
                for (int i = 0; i < numConstraintPool; i++)
                {
                    gOrderTmpConstraintPool.Add(i);
                }
                for (int i = 0; i < numFrictionPool; i++)
                {
                    gOrderFrictionConstraintPool.Add(i);
                }
            }

            //should traverse the contacts random order...
            int iteration;
            {
                for (iteration = 0; iteration < info.IterationsCount; iteration++)
                {
                    int j;
                    if ((_solverMode & SolverMode.RandomizeOrder) != SolverMode.None)
                    {
                        if ((iteration & 7) == 0)
                        {
                            for (j = 0; j < numConstraintPool; ++j)
                            {
                                int tmp   = gOrderTmpConstraintPool[j];
                                int swapi = RandInt2(j + 1);
                                gOrderTmpConstraintPool[j]     = gOrderTmpConstraintPool[swapi];
                                gOrderTmpConstraintPool[swapi] = tmp;
                            }

                            for (j = 0; j < numFrictionPool; ++j)
                            {
                                int tmp   = gOrderFrictionConstraintPool[j];
                                int swapi = RandInt2(j + 1);
                                gOrderFrictionConstraintPool[j]     = gOrderFrictionConstraintPool[swapi];
                                gOrderFrictionConstraintPool[swapi] = tmp;
                            }
                        }
                    }

                    for (j = 0; j < constraints.Count; j++)
                    {
                        TypedConstraint constraint = constraints[j];
                        //todo: use solver bodies, so we don't need to copy from/to btRigidBody

                        if ((constraint.RigidBodyA.IslandTag >= 0) && (constraint.RigidBodyA.CompanionID >= 0))
                        {
                            _tmpSolverBodyPool[constraint.RigidBodyA.CompanionID].WriteBackVelocity();
                        }
                        if ((constraint.RigidBodyB.IslandTag >= 0) && (constraint.RigidBodyB.CompanionID >= 0))
                        {
                            _tmpSolverBodyPool[constraint.RigidBodyB.CompanionID].WriteBackVelocity();
                        }

                        constraint.SolveConstraint(info.TimeStep);

                        if ((constraint.RigidBodyA.IslandTag >= 0) && (constraint.RigidBodyA.CompanionID >= 0))
                        {
                            _tmpSolverBodyPool[constraint.RigidBodyA.CompanionID].ReadVelocity();
                        }
                        if ((constraint.RigidBodyB.IslandTag >= 0) && (constraint.RigidBodyB.CompanionID >= 0))
                        {
                            _tmpSolverBodyPool[constraint.RigidBodyB.CompanionID].ReadVelocity();
                        }
                    }

                    {
                        int numPoolConstraints = _tmpSolverConstraintPool.Count;
                        for (j = 0; j < numPoolConstraints; j++)
                        {
                            SolverConstraint solveManifold = _tmpSolverConstraintPool[gOrderTmpConstraintPool[j]];
                            ResolveSingleCollisionCombinedCacheFriendly(_tmpSolverBodyPool[solveManifold.SolverBodyIdA],
                                                                        _tmpSolverBodyPool[solveManifold.SolverBodyIdB], solveManifold, info);
                        }
                    }

                    {
                        int numFrictionPoolConstraints = _tmpSolverFrictionConstraintPool.Count;
                        for (j = 0; j < numFrictionPoolConstraints; j++)
                        {
                            SolverConstraint solveManifold        = _tmpSolverFrictionConstraintPool[gOrderFrictionConstraintPool[j]];
                            float            appliedNormalImpulse = _tmpSolverConstraintPool[solveManifold.FrictionIndex].AppliedImpulse;

                            ResolveSingleFrictionCacheFriendly(_tmpSolverBodyPool[solveManifold.SolverBodyIdA],
                                                               _tmpSolverBodyPool[solveManifold.SolverBodyIdB], solveManifold, info, appliedNormalImpulse);
                        }
                    }
                }
            }

            for (int i = 0; i < _tmpSolverBodyPool.Count; i++)
            {
                _tmpSolverBodyPool[i].WriteBackVelocity();
            }

            _tmpSolverBodyPool.Clear();
            _tmpSolverConstraintPool.Clear();
            _tmpSolverFrictionConstraintPool.Clear();

            return(0);
        }