Exemple #1
0
        //TODO: At the time of writing this, the default project configuration for the Xbox360 didn't allow optional parameters.  Could compress this.

        protected void TryToAdd(Collidable a, Collidable b)
        {
            TryToAdd(a, b, null, null);
        }
Exemple #2
0
 protected void TryToAdd(Collidable a, Collidable b, Material materialA)
 {
     TryToAdd(a, b, materialA, null);
 }
Exemple #3
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);
                }
            }
        }