示例#1
0
        ///<summary>
        /// Updates the time of impact for the pair.
        ///</summary>
        ///<param name="requester">Collidable requesting the update.</param>
        ///<param name="dt">Timestep duration.</param>
        public override void UpdateTimeOfImpact(Collidable requester, float dt)
        {
            //Notice that we don't test for convex entity null explicitly.  The convex.IsActive property does that for us.
            if (convex.IsActive && convex.entity.PositionUpdateMode == PositionUpdateMode.Continuous)
            {
                //TODO: This system could be made more robust by using a similar region-based rejection of edges.
                //CCD events are awfully rare under normal circumstances, so this isn't usually an issue.

                //Only perform the test if the minimum radii are small enough relative to the size of the velocity.
                System.Numerics.Vector3 velocity;
                Vector3Ex.Multiply(ref convex.entity.linearVelocity, dt, out velocity);
                float velocitySquared = velocity.LengthSquared();

                var minimumRadius = convex.Shape.MinimumRadius * MotionSettings.CoreShapeScaling;
                timeOfImpact = 1;
                if (minimumRadius * minimumRadius < velocitySquared)
                {
                    var triangle = PhysicsThreadResources.GetTriangle();
                    triangle.collisionMargin = 0;
                    //Spherecast against all triangles to find the earliest time.
                    for (int i = 0; i < MeshManifold.overlappedTriangles.Count; i++)
                    {
                        mesh.Shape.TriangleMeshData.GetTriangle(MeshManifold.overlappedTriangles.Elements[i], out triangle.vA, out triangle.vB, out triangle.vC);
                        //Put the triangle into 'localish' space of the convex.
                        Vector3Ex.Subtract(ref triangle.vA, ref convex.worldTransform.Position, out triangle.vA);
                        Vector3Ex.Subtract(ref triangle.vB, ref convex.worldTransform.Position, out triangle.vB);
                        Vector3Ex.Subtract(ref triangle.vC, ref convex.worldTransform.Position, out triangle.vC);

                        RayHit rayHit;
                        if (GJKToolbox.CCDSphereCast(new Ray(Toolbox.ZeroVector, velocity), minimumRadius, triangle, ref Toolbox.RigidIdentity, timeOfImpact, out rayHit) &&
                            rayHit.T > Toolbox.BigEpsilon)
                        {
                            if (mesh.sidedness != TriangleSidedness.DoubleSided)
                            {
                                System.Numerics.Vector3 AB, AC;
                                Vector3Ex.Subtract(ref triangle.vB, ref triangle.vA, out AB);
                                Vector3Ex.Subtract(ref triangle.vC, ref triangle.vA, out AC);
                                System.Numerics.Vector3 normal;
                                Vector3Ex.Cross(ref AB, ref AC, out normal);
                                float dot;
                                Vector3Ex.Dot(ref normal, ref rayHit.Normal, out dot);
                                //Only perform sweep if the object is in danger of hitting the object.
                                //Triangles can be one sided, so check the impact normal against the triangle normal.
                                if (mesh.sidedness == TriangleSidedness.Counterclockwise && dot < 0 ||
                                    mesh.sidedness == TriangleSidedness.Clockwise && dot > 0)
                                {
                                    timeOfImpact = rayHit.T;
                                }
                            }
                            else
                            {
                                timeOfImpact = rayHit.T;
                            }
                        }
                    }
                    PhysicsThreadResources.GiveBack(triangle);
                }
            }
        }
示例#2
0
        /// <summary>
        /// Casts a convex shape against the collidable.
        /// </summary>
        /// <param name="castShape">Shape to cast.</param>
        /// <param name="startingTransform">Initial transform of the shape.</param>
        /// <param name="sweep">Sweep to apply to the shape.</param>
        /// <param name="hit">Hit data, if any.</param>
        /// <returns>Whether or not the cast hit anything.</returns>
        public override bool ConvexCast(CollisionShapes.ConvexShapes.ConvexShape castShape, ref RigidTransform startingTransform, ref Vector3 sweep, out RayHit hit)
        {
            hit = new RayHit();
            BoundingBox boundingBox;

            castShape.GetSweptLocalBoundingBox(ref startingTransform, ref worldTransform, ref sweep, out boundingBox);
            var tri         = PhysicsThreadResources.GetTriangle();
            var hitElements = CommonResources.GetIntList();

            if (this.Shape.TriangleMesh.Tree.GetOverlaps(boundingBox, hitElements))
            {
                hit.T = float.MaxValue;
                for (int i = 0; i < hitElements.Count; i++)
                {
                    Shape.TriangleMesh.Data.GetTriangle(hitElements[i], out tri.vA, out tri.vB, out tri.vC);
                    AffineTransform.Transform(ref tri.vA, ref worldTransform, out tri.vA);
                    AffineTransform.Transform(ref tri.vB, ref worldTransform, out tri.vB);
                    AffineTransform.Transform(ref tri.vC, ref worldTransform, out tri.vC);
                    Vector3 center;
                    Vector3.Add(ref tri.vA, ref tri.vB, out center);
                    Vector3.Add(ref center, ref tri.vC, out center);
                    Vector3.Multiply(ref center, 1f / 3f, out center);
                    Vector3.Subtract(ref tri.vA, ref center, out tri.vA);
                    Vector3.Subtract(ref tri.vB, ref center, out tri.vB);
                    Vector3.Subtract(ref tri.vC, ref center, out tri.vC);
                    tri.MaximumRadius = tri.vA.LengthSquared();
                    float radius = tri.vB.LengthSquared();
                    if (tri.MaximumRadius < radius)
                    {
                        tri.MaximumRadius = radius;
                    }
                    radius = tri.vC.LengthSquared();
                    if (tri.MaximumRadius < radius)
                    {
                        tri.MaximumRadius = radius;
                    }
                    tri.MaximumRadius   = (float)Math.Sqrt(tri.MaximumRadius);
                    tri.collisionMargin = 0;
                    var triangleTransform = new RigidTransform {
                        Orientation = Quaternion.Identity, Position = center
                    };
                    RayHit tempHit;
                    if (MPRToolbox.Sweep(castShape, tri, ref sweep, ref Toolbox.ZeroVector, ref startingTransform, ref triangleTransform, out tempHit) && tempHit.T < hit.T)
                    {
                        hit = tempHit;
                    }
                }
                tri.MaximumRadius = 0;
                PhysicsThreadResources.GiveBack(tri);
                CommonResources.GiveBack(hitElements);
                return(hit.T != float.MaxValue);
            }
            PhysicsThreadResources.GiveBack(tri);
            CommonResources.GiveBack(hitElements);
            return(false);
        }
示例#3
0
        /// <summary>
        /// Casts a convex shape against the collidable.
        /// </summary>
        /// <param name="castShape">Shape to cast.</param>
        /// <param name="startingTransform">Initial transform of the shape.</param>
        /// <param name="sweep">Sweep to apply to the shape.</param>
        /// <param name="hit">Hit data, if any.</param>
        /// <returns>Whether or not the cast hit anything.</returns>
        public override bool ConvexCast(CollisionShapes.ConvexShapes.ConvexShape castShape, ref RigidTransform startingTransform, ref Vector3f sweep, out RayHit hit)
        {
            hit = new RayHit();
            BoundingBox localSpaceBoundingBox;

            castShape.GetSweptLocalBoundingBox(ref startingTransform, ref worldTransform, ref sweep, out localSpaceBoundingBox);
            var tri         = PhysicsThreadResources.GetTriangle();
            var hitElements = new QuickList <int>(BufferPools <int> .Thread);

            if (Shape.GetOverlaps(localSpaceBoundingBox, ref hitElements))
            {
                hit.T = float.MaxValue;
                for (int i = 0; i < hitElements.Count; i++)
                {
                    Shape.GetTriangle(hitElements.Elements[i], ref worldTransform, out tri.vA, out tri.vB, out tri.vC);
                    Vector3f center;
                    Vector3f.Add(ref tri.vA, ref tri.vB, out center);
                    Vector3f.Add(ref center, ref tri.vC, out center);
                    Vector3f.Multiply(ref center, 1f / 3f, out center);
                    Vector3f.Subtract(ref tri.vA, ref center, out tri.vA);
                    Vector3f.Subtract(ref tri.vB, ref center, out tri.vB);
                    Vector3f.Subtract(ref tri.vC, ref center, out tri.vC);
                    tri.MaximumRadius = tri.vA.LengthSquared;
                    float radius = tri.vB.LengthSquared;
                    if (tri.MaximumRadius < radius)
                    {
                        tri.MaximumRadius = radius;
                    }
                    radius = tri.vC.LengthSquared;
                    if (tri.MaximumRadius < radius)
                    {
                        tri.MaximumRadius = radius;
                    }
                    tri.MaximumRadius   = (float)Math.Sqrt(tri.MaximumRadius);
                    tri.collisionMargin = 0;
                    var triangleTransform = new RigidTransform {
                        Orientation = Quaternion.Identity, Position = center
                    };
                    RayHit tempHit;
                    if (MPRToolbox.Sweep(castShape, tri, ref sweep, ref Toolbox.ZeroVector, ref startingTransform, ref triangleTransform, out tempHit) && tempHit.T < hit.T)
                    {
                        hit = tempHit;
                    }
                }
                tri.MaximumRadius = 0;
                PhysicsThreadResources.GiveBack(tri);
                hitElements.Dispose();
                return(hit.T != float.MaxValue);
            }
            PhysicsThreadResources.GiveBack(tri);
            hitElements.Dispose();
            return(false);
        }
示例#4
0
        ///<summary>
        /// Updates the time of impact for the pair.
        ///</summary>
        ///<param name="requester">Collidable requesting the update.</param>
        ///<param name="dt">Timestep duration.</param>
        public override void UpdateTimeOfImpact(Collidable requester, float dt)
        {
            var overlap    = BroadPhaseOverlap;
            var meshMode   = mobileMesh.entity == null ? PositionUpdateMode.Discrete : mobileMesh.entity.PositionUpdateMode;
            var convexMode = convex.entity == null ? PositionUpdateMode.Discrete : convex.entity.PositionUpdateMode;

            if (
                (mobileMesh.IsActive || convex.IsActive) &&     //At least one has to be active.
                (
                    (
                        convexMode == PositionUpdateMode.Continuous &&       //If both are continuous, only do the process for A.
                        meshMode == PositionUpdateMode.Continuous &&
                        overlap.entryA == requester
                    ) ||
                    (
                        convexMode == PositionUpdateMode.Continuous ^       //If only one is continuous, then we must do it.
                        meshMode == PositionUpdateMode.Continuous
                    )
                )
                )
            {
                //TODO: This system could be made more robust by using a similar region-based rejection of edges.
                //CCD events are awfully rare under normal circumstances, so this isn't usually an issue.

                //Only perform the test if the minimum radii are small enough relative to the size of the velocity.
                Vector3 velocity;
                if (convexMode == PositionUpdateMode.Discrete)
                {
                    //Convex is static for the purposes of CCD.
                    Vector3.Negate(ref mobileMesh.entity.linearVelocity, out velocity);
                }
                else if (meshMode == PositionUpdateMode.Discrete)
                {
                    //Mesh is static for the purposes of CCD.
                    velocity = convex.entity.linearVelocity;
                }
                else
                {
                    //Both objects can move.
                    Vector3.Subtract(ref convex.entity.linearVelocity, ref mobileMesh.entity.linearVelocity, out velocity);
                }
                Vector3.Multiply(ref velocity, dt, out velocity);
                float velocitySquared = velocity.LengthSquared();

                var minimumRadius = convex.Shape.MinimumRadius * MotionSettings.CoreShapeScaling;
                timeOfImpact = 1;
                if (minimumRadius * minimumRadius < velocitySquared)
                {
                    TriangleSidedness sidedness = mobileMesh.Shape.Sidedness;
                    Matrix3x3         orientation;
                    Matrix3x3.CreateFromQuaternion(ref mobileMesh.worldTransform.Orientation, out orientation);
                    var triangle = PhysicsThreadResources.GetTriangle();
                    triangle.collisionMargin = 0;
                    //Spherecast against all triangles to find the earliest time.
                    for (int i = 0; i < MeshManifold.overlappedTriangles.Count; i++)
                    {
                        MeshBoundingBoxTreeData data = mobileMesh.Shape.TriangleMesh.Data;
                        int triangleIndex            = MeshManifold.overlappedTriangles.Elements[i];
                        data.GetTriangle(triangleIndex, out triangle.vA, out triangle.vB, out triangle.vC);
                        Matrix3x3.Transform(ref triangle.vA, ref orientation, out triangle.vA);
                        Matrix3x3.Transform(ref triangle.vB, ref orientation, out triangle.vB);
                        Matrix3x3.Transform(ref triangle.vC, ref orientation, out triangle.vC);
                        Vector3.Add(ref triangle.vA, ref mobileMesh.worldTransform.Position, out triangle.vA);
                        Vector3.Add(ref triangle.vB, ref mobileMesh.worldTransform.Position, out triangle.vB);
                        Vector3.Add(ref triangle.vC, ref mobileMesh.worldTransform.Position, out triangle.vC);
                        //Put the triangle into 'localish' space of the convex.
                        Vector3.Subtract(ref triangle.vA, ref convex.worldTransform.Position, out triangle.vA);
                        Vector3.Subtract(ref triangle.vB, ref convex.worldTransform.Position, out triangle.vB);
                        Vector3.Subtract(ref triangle.vC, ref convex.worldTransform.Position, out triangle.vC);

                        RayHit rayHit;
                        if (GJKToolbox.CCDSphereCast(new Ray(Toolbox.ZeroVector, velocity), minimumRadius, triangle, ref Toolbox.RigidIdentity, timeOfImpact, out rayHit) &&
                            rayHit.T > Toolbox.BigEpsilon)
                        {
                            if (sidedness != TriangleSidedness.DoubleSided)
                            {
                                Vector3 AB, AC;
                                Vector3.Subtract(ref triangle.vB, ref triangle.vA, out AB);
                                Vector3.Subtract(ref triangle.vC, ref triangle.vA, out AC);
                                Vector3 normal;
                                Vector3.Cross(ref AB, ref AC, out normal);
                                float dot;
                                Vector3.Dot(ref normal, ref rayHit.Normal, out dot);
                                //Only perform sweep if the object is in danger of hitting the object.
                                //Triangles can be one sided, so check the impact normal against the triangle normal.
                                if (sidedness == TriangleSidedness.Counterclockwise && dot < 0 ||
                                    sidedness == TriangleSidedness.Clockwise && dot > 0)
                                {
                                    timeOfImpact = rayHit.T;
                                }
                            }
                            else
                            {
                                timeOfImpact = rayHit.T;
                            }
                        }
                    }
                    PhysicsThreadResources.GiveBack(triangle);
                }
            }
        }
示例#5
0
        ///<summary>
        /// Updates the manifold.
        ///</summary>
        ///<param name="dt">Timestep duration.</param>
        public override void Update(float dt)
        {
            //First, refresh all existing contacts.  This is an incremental manifold.
            var transform = MeshTransform;

            ContactRefresher.ContactRefresh(contacts, supplementData, ref convex.worldTransform, ref transform, contactIndicesToRemove);

            RemoveQueuedContacts();


            CleanUpOverlappingTriangles();
            //Get all the overlapped triangle indices.
            //Note that the collection of triangles is left up to the child implementation.
            //We're basically treating the child class like an indexable collection.
            //A little gross to have it organized this way instead of an explicit collection to separate the logic up. Would be nice to improve someday!
            int triangleCount = FindOverlappingTriangles(dt);

            //Just use 32 elements for all the lists and sets in this system.
            const int    bufferPoolSizePower = 5;
            BoundarySets boundarySets;

            if (UseImprovedBoundaryHandling)
            {
                boundarySets = new BoundarySets(bufferPoolSizePower);
            }
            else
            {
                boundarySets = new BoundarySets();
            }

            var candidatesToAdd = new QuickList <ContactData>(BufferPools <ContactData> .Thread, bufferPoolSizePower);

            //A single triangle shape will be reused for all operations. It's pulled from a thread local pool to avoid holding a TriangleShape around for every single contact manifold or pair tester.
            var localTriangleShape = PhysicsThreadResources.GetTriangle();

            //Precompute the transform to take triangles from their native local space to the convex's local space.
            RigidTransform inverseConvexWorldTransform;

            RigidTransform.Invert(ref convex.worldTransform, out inverseConvexWorldTransform);
            AffineTransform convexInverseWorldTransform;

            AffineTransform.CreateFromRigidTransform(ref inverseConvexWorldTransform, out convexInverseWorldTransform);
            AffineTransform fromMeshLocalToConvexLocal;

            PrecomputeTriangleTransform(ref convexInverseWorldTransform, out fromMeshLocalToConvexLocal);

            //Grab the convex's local space bounding box up front. This will be used for a secondary pruning step.
            BoundingBox convexLocalBoundingBox;

            convex.Shape.GetBoundingBox(ref Toolbox.RigidIdentity, out convexLocalBoundingBox);

            Matrix3x3 orientation;

            Matrix3x3.CreateFromQuaternion(ref convex.worldTransform.Orientation, out orientation);
            var guaranteedContacts = 0;

            for (int i = 0; i < triangleCount; i++)
            {
                //Initialize the local triangle.
                TriangleIndices indices;
                if (ConfigureLocalTriangle(i, localTriangleShape, out indices))
                {
                    //Put the triangle into the local space of the convex.
                    AffineTransform.Transform(ref localTriangleShape.vA, ref fromMeshLocalToConvexLocal, out localTriangleShape.vA);
                    AffineTransform.Transform(ref localTriangleShape.vB, ref fromMeshLocalToConvexLocal, out localTriangleShape.vB);
                    AffineTransform.Transform(ref localTriangleShape.vC, ref fromMeshLocalToConvexLocal, out localTriangleShape.vC);

                    //Do one last AABB test between the convex and triangle in the convex's local space.
                    //This can prune out a lot of triangles when dealing with larger objects, and it's pretty cheap to do.
                    BoundingBox triangleBoundingBox;
                    Toolbox.GetTriangleBoundingBox(ref localTriangleShape.vA, ref localTriangleShape.vB, ref localTriangleShape.vC, out triangleBoundingBox);

                    bool intersecting;
                    triangleBoundingBox.Intersects(ref convexLocalBoundingBox, out intersecting);
                    if (!intersecting)
                    {
                        continue;
                    }

                    //Find a pairtester for the triangle.
                    TrianglePairTester pairTester;
                    if (!activePairTesters.TryGetValue(indices, out pairTester))
                    {
                        pairTester = GetTester();
                        pairTester.Initialize(convex.Shape);
                        activePairTesters.Add(indices, pairTester);
                    }
                    pairTester.Updated = true;


                    //Now, generate a contact between the two shapes.
                    TinyStructList <ContactData> contactList;
                    if (pairTester.GenerateContactCandidates(localTriangleShape, out contactList))
                    {
                        for (int j = 0; j < contactList.Count; j++)
                        {
                            ContactData contact;
                            contactList.Get(j, out contact);


                            if (UseImprovedBoundaryHandling)
                            {
                                if (AnalyzeCandidate(ref indices, localTriangleShape, pairTester, ref contact, ref boundarySets))
                                {
                                    //This is let through if there's a face contact. Face contacts cannot be blocked.
                                    guaranteedContacts++;
                                    AddLocalContact(ref contact, ref orientation, ref candidatesToAdd);
                                }
                            }
                            else
                            {
                                AddLocalContact(ref contact, ref orientation, ref candidatesToAdd);
                            }
                        }
                    }

                    //Get the voronoi region from the contact candidate generation.  Possibly just recalculate, since most of the systems don't calculate it.
                    //Depending on which voronoi region it is in (Switch on enumeration), identify the indices composing that region.  For face contacts, don't bother- just add it if unique.
                    //For AB, AC, or BC, add an Edge to the blockedEdgeRegions set with the corresponding indices.
                    //For A, B, or C, add the index of the vertex to the blockedVertexRegions set.
                    //If the edge/vertex is already present in the set, then DO NOT add the contact.
                    //When adding a contact, add ALL other voronoi regions to the blocked sets.
                }
            }



            if (UseImprovedBoundaryHandling)
            {
                //If there were no face contacts that absolutely must be included, we may get into a very rare situation
                //where absolutely no contacts get created.  For example, a sphere falling directly on top of a vertex in a flat terrain.
                //It will generally get locked out of usage by belonging only to restricted regions (numerical issues make it visible by both edges and vertices).
                //In some cases, the contacts will be ignored instead of corrected (e.g. spheres).
                //To prevent objects from just falling through the ground in such a situation, force-correct the contacts regardless of the pair tester's desires.
                //Sure, it might not be necessary under normal circumstances, but it's a better option than having no contacts.
                //TODO: There is another option: Changing restricted regions so that a vertex only restricts the other two vertices and the far edge,
                //and an edge only restricts the far vertex and other two edges.  This introduces an occasional bump though...

                //It's possible, in very specific instances, for an object to wedge itself between two adjacent triangles.
                //For this state to continue beyond a brief instant generally requires the object be orientation locked and slender.
                //However, some characters fit this description, so it can't be ignored!

                //Conceptually, this issue can occur at either a vertex junction or a shared edge (usually on extremely flat surfaces only).
                //However, an object stuck between multiple triangles is not in a stable state.  In the edge case, the object gets shoved to one side
                //as one contact 'wins' the solver war.  That's not enough to escape, unfortunately.
                //The vertex case, on the other hand, is degenerate and decays into an edge case rapidly thanks to this lack of stability.
                //So, we don't have to explicitly handle the somewhat more annoying and computationally expensive vertex unstucking case, because the edge case handles both! :)

                //This isn't a completely free operation, but it's guarded behind pretty rare conditions.
                //Essentially, we will check to see if there's just edge contacts fighting against each other.
                //If they are, then we will correct any stuck-contributing normals to the triangle normal.
                if (boundarySets.VertexContacts.Count == 0 && guaranteedContacts == 0 && boundarySets.EdgeContacts.Count > 1)
                {
                    //There are only edge contacts, check to see if:
                    //all normals are coplanar, and
                    //at least one normal faces against the other normals (meaning it's probably stuck, as opposed to just colliding on a corner).

                    bool allNormalsInSamePlane   = true;
                    bool atLeastOneNormalAgainst = false;

                    var firstNormal = boundarySets.EdgeContacts.Elements[0].ContactData.Normal;
                    boundarySets.EdgeContacts.Elements[0].CorrectedNormal.Normalize();
                    float dot;
                    Vector3Ex.Dot(ref firstNormal, ref boundarySets.EdgeContacts.Elements[0].CorrectedNormal, out dot);
                    if (Math.Abs(dot) > .01f)
                    {
                        //Go ahead and test the first contact separately, since we're using its contact normal to determine coplanarity.
                        allNormalsInSamePlane = false;
                    }
                    else
                    {
                        //TODO: Note that we're only checking the new edge contacts, not the existing contacts.
                        //It's possible that some existing contacts could interfere and cause issues, but for the sake of simplicity and due to rarity
                        //we'll ignore that possibility for now.
                        for (int i = 1; i < boundarySets.EdgeContacts.Count; i++)
                        {
                            Vector3Ex.Dot(ref boundarySets.EdgeContacts.Elements[i].ContactData.Normal, ref firstNormal, out dot);
                            if (dot < 0)
                            {
                                atLeastOneNormalAgainst = true;
                            }
                            //Check to see if the normal is outside the plane.
                            Vector3Ex.Dot(ref boundarySets.EdgeContacts.Elements[i].ContactData.Normal, ref boundarySets.EdgeContacts.Elements[0].CorrectedNormal, out dot);

                            if (Math.Abs(dot) > .01f)
                            {
                                //We are not stuck!
                                allNormalsInSamePlane = false;
                                break;
                            }
                        }
                    }

                    if (allNormalsInSamePlane && atLeastOneNormalAgainst)
                    {
                        //Uh oh! all the normals are parallel... The object is probably in a weird situation.
                        //Let's correct the normals!

                        //Already normalized the first contact above.
                        //We don't need to perform the perpendicularity test here- we did that before! We know it's perpendicular already.
                        boundarySets.EdgeContacts.Elements[0].ContactData.Normal = boundarySets.EdgeContacts.Elements[0].CorrectedNormal;
                        boundarySets.EdgeContacts.Elements[0].ShouldCorrect      = true;

                        for (int i = 1; i < boundarySets.EdgeContacts.Count; i++)
                        {
                            //Must normalize the corrected normal before using it.
                            boundarySets.EdgeContacts.Elements[i].CorrectedNormal.Normalize();
                            Vector3Ex.Dot(ref boundarySets.EdgeContacts.Elements[i].CorrectedNormal, ref boundarySets.EdgeContacts.Elements[i].ContactData.Normal, out dot);
                            if (dot < .01)
                            {
                                //Only bother doing the correction if the normal appears to be pointing nearly horizontally- implying that it's a contributor to the stuckness!
                                //If it's blocked, the next section will use the corrected normal- if it's not blocked, the next section will use the direct normal.
                                //Make them the same thing :)
                                boundarySets.EdgeContacts.Elements[i].ContactData.Normal = boundarySets.EdgeContacts.Elements[i].CorrectedNormal;
                                boundarySets.EdgeContacts.Elements[i].ShouldCorrect      = true;
                                //Note that the penetration depth is NOT corrected.  The contact's depth no longer represents the true depth.
                                //However, we only need to have some penetration depth to get the object to escape the rut.
                                //Furthermore, the depth computed from the horizontal opposing contacts is known to be less than the depth in the perpendicular direction.
                                //If the current depth was NOT less than the true depth along the corrected normal, then the collision detection system
                                //would have picked a different depth, as it finds a reasonable approximation of the minimum penetration!
                                //As a consequence, this contact will not be active beyond the object's destuckification, because its contact depth will be negative (or very close to it).
                            }
                        }
                    }
                }



                for (int i = 0; i < boundarySets.EdgeContacts.Count; i++)
                {
                    //Only correct if it's allowed AND it's blocked.
                    //If it's not blocked, the contact being created is necessary!
                    //The normal generated by the triangle-convex tester is already known not to
                    //violate the triangle sidedness.
                    if (!boundarySets.BlockedEdgeRegions.Contains(boundarySets.EdgeContacts.Elements[i].Edge))
                    {
                        //If it's not blocked, use the contact as-is without correcting it.
                        AddLocalContact(ref boundarySets.EdgeContacts.Elements[i].ContactData, ref orientation, ref candidatesToAdd);
                    }
                    else if (boundarySets.EdgeContacts.Elements[i].ShouldCorrect || guaranteedContacts == 0)
                    {
                        //If it is blocked, we can still make use of the contact.  But first, we need to change the contact normal to ensure that
                        //it will not interfere (and cause a bump or something).
                        float dot;
                        boundarySets.EdgeContacts.Elements[i].CorrectedNormal.Normalize();
                        Vector3Ex.Dot(ref boundarySets.EdgeContacts.Elements[i].CorrectedNormal, ref boundarySets.EdgeContacts.Elements[i].ContactData.Normal, out dot);
                        boundarySets.EdgeContacts.Elements[i].ContactData.Normal            = boundarySets.EdgeContacts.Elements[i].CorrectedNormal;
                        boundarySets.EdgeContacts.Elements[i].ContactData.PenetrationDepth *= MathHelper.Max(0, dot); //Never cause a negative penetration depth.
                        AddLocalContact(ref boundarySets.EdgeContacts.Elements[i].ContactData, ref orientation, ref candidatesToAdd);
                    }
                    //If it's blocked AND it doesn't allow correction, ignore its existence.
                }



                for (int i = 0; i < boundarySets.VertexContacts.Count; i++)
                {
                    if (!boundarySets.BlockedVertexRegions.Contains(boundarySets.VertexContacts.Elements[i].Vertex))
                    {
                        //If it's not blocked, use the contact as-is without correcting it.
                        AddLocalContact(ref boundarySets.VertexContacts.Elements[i].ContactData, ref orientation, ref candidatesToAdd);
                    }
                    else if (boundarySets.VertexContacts.Elements[i].ShouldCorrect || guaranteedContacts == 0)
                    {
                        //If it is blocked, we can still make use of the contact.  But first, we need to change the contact normal to ensure that
                        //it will not interfere (and cause a bump or something).
                        float dot;
                        boundarySets.VertexContacts.Elements[i].CorrectedNormal.Normalize();
                        Vector3Ex.Dot(ref boundarySets.VertexContacts.Elements[i].CorrectedNormal, ref boundarySets.VertexContacts.Elements[i].ContactData.Normal, out dot);
                        boundarySets.VertexContacts.Elements[i].ContactData.Normal            = boundarySets.VertexContacts.Elements[i].CorrectedNormal;
                        boundarySets.VertexContacts.Elements[i].ContactData.PenetrationDepth *= MathHelper.Max(0, dot); //Never cause a negative penetration depth.
                        AddLocalContact(ref boundarySets.VertexContacts.Elements[i].ContactData, ref orientation, ref candidatesToAdd);
                    }
                    //If it's blocked AND it doesn't allow correction, ignore its existence.
                }


                boundarySets.Dispose();
            }



            //Remove stale pair testers.
            for (int i = activePairTesters.Count - 1; i >= 0; --i)
            {
                var tester = activePairTesters.Values[i];
                if (!tester.Updated)
                {
                    tester.CleanUp();
                    GiveBackTester(tester);
                    activePairTesters.FastRemove(activePairTesters.Keys[i]);
                }
                else
                {
                    tester.Updated = false;
                }
            }

            //Some child types will want to do some extra post processing on the manifold.
            ProcessCandidates(ref candidatesToAdd);


            //Check if adding the new contacts would overflow the manifold.
            if (contacts.Count + candidatesToAdd.Count > 4)
            {
                //Adding all the contacts would overflow the manifold.  Reduce to the best subset.
                var reducedCandidates = new QuickList <ContactData>(BufferPools <ContactData> .Thread, bufferPoolSizePower);
                ContactReducer.ReduceContacts(contacts, ref candidatesToAdd, contactIndicesToRemove, ref reducedCandidates);
                RemoveQueuedContacts();
                for (int i = reducedCandidates.Count - 1; i >= 0; i--)
                {
                    Add(ref reducedCandidates.Elements[i]);
                    reducedCandidates.RemoveAt(i);
                }
                reducedCandidates.Dispose();
            }
            else if (candidatesToAdd.Count > 0)
            {
                //Won't overflow the manifold, so just toss it in PROVIDED that it isn't too close to something else.
                for (int i = 0; i < candidatesToAdd.Count; i++)
                {
                    Add(ref candidatesToAdd.Elements[i]);
                }
            }


            PhysicsThreadResources.GiveBack(localTriangleShape);
            candidatesToAdd.Dispose();
        }
        /// <summary>
        /// Casts a convex shape against the collidable.
        /// </summary>
        /// <param name="castShape">Shape to cast.</param>
        /// <param name="startingTransform">Initial transform of the shape.</param>
        /// <param name="sweep">Sweep to apply to the shape.</param>
        /// <param name="hit">Hit data, if any.</param>
        /// <returns>Whether or not the cast hit anything.</returns>
        public override bool ConvexCast(ConvexShape castShape, ref RigidTransform startingTransform, ref Vector3 sweep, out RayHit hit)
        {
            if (Shape.solidity == MobileMeshSolidity.Solid)
            {
                //If the convex cast is inside the mesh and the mesh is solid, it should return t = 0.
                var ray = new Ray()
                {
                    Position = startingTransform.Position, Direction = Toolbox.UpVector
                };
                if (Shape.IsLocalRayOriginInMesh(ref ray, out hit))
                {
                    hit = new RayHit()
                    {
                        Location = startingTransform.Position, Normal = new Vector3(), T = F64.C0
                    };
                    return(true);
                }
            }
            hit = new RayHit();
            BoundingBox boundingBox;
            var         transform = new AffineTransform {
                Translation = worldTransform.Position
            };

            Matrix3x3.CreateFromQuaternion(ref worldTransform.Orientation, out transform.LinearTransform);
            castShape.GetSweptLocalBoundingBox(ref startingTransform, ref transform, ref sweep, out boundingBox);
            var tri         = PhysicsThreadResources.GetTriangle();
            var hitElements = CommonResources.GetIntList();

            if (this.Shape.TriangleMesh.Tree.GetOverlaps(boundingBox, hitElements))
            {
                hit.T = Fix64.MaxValue;
                for (int i = 0; i < hitElements.Count; i++)
                {
                    Shape.TriangleMesh.Data.GetTriangle(hitElements[i], out tri.vA, out tri.vB, out tri.vC);
                    AffineTransform.Transform(ref tri.vA, ref transform, out tri.vA);
                    AffineTransform.Transform(ref tri.vB, ref transform, out tri.vB);
                    AffineTransform.Transform(ref tri.vC, ref transform, out tri.vC);
                    Vector3 center;
                    Vector3.Add(ref tri.vA, ref tri.vB, out center);
                    Vector3.Add(ref center, ref tri.vC, out center);
                    Vector3.Multiply(ref center, F64.OneThird, out center);
                    Vector3.Subtract(ref tri.vA, ref center, out tri.vA);
                    Vector3.Subtract(ref tri.vB, ref center, out tri.vB);
                    Vector3.Subtract(ref tri.vC, ref center, out tri.vC);
                    tri.MaximumRadius = tri.vA.LengthSquared();
                    Fix64 radius = tri.vB.LengthSquared();
                    if (tri.MaximumRadius < radius)
                    {
                        tri.MaximumRadius = radius;
                    }
                    radius = tri.vC.LengthSquared();
                    if (tri.MaximumRadius < radius)
                    {
                        tri.MaximumRadius = radius;
                    }
                    tri.MaximumRadius   = Fix64.Sqrt(tri.MaximumRadius);
                    tri.collisionMargin = F64.C0;
                    var triangleTransform = new RigidTransform {
                        Orientation = Quaternion.Identity, Position = center
                    };
                    RayHit tempHit;
                    if (MPRToolbox.Sweep(castShape, tri, ref sweep, ref Toolbox.ZeroVector, ref startingTransform, ref triangleTransform, out tempHit) && tempHit.T < hit.T)
                    {
                        hit = tempHit;
                    }
                }
                tri.MaximumRadius = F64.C0;
                PhysicsThreadResources.GiveBack(tri);
                CommonResources.GiveBack(hitElements);
                return(hit.T != Fix64.MaxValue);
            }
            PhysicsThreadResources.GiveBack(tri);
            CommonResources.GiveBack(hitElements);
            return(false);
        }