public override void UpdateCollision(float dt)
{
WasContaining = Containing;
WasTouching = Touching;
mobileTriangle.collisionMargin = mesh.Shape.MeshCollisionMargin;
//Scan the pairs in sequence, updating the state as we go.
//Touching can be set to true by a single touching subpair.
Touching = false;
//Containing can be set to false by a single noncontaining or nontouching subpair.
Containing = true;
var meshData = mesh.Shape.TriangleMesh.Data;
RigidTransform mobileTriangleTransform, detectorTriangleTransform;
mobileTriangleTransform.Orientation = Quaternion.Identity;
detectorTriangleTransform.Orientation = Quaternion.Identity;
for (int i = 0; i < meshData.Indices.Length; i += 3)
{
//Grab a triangle associated with the mobile mesh.
meshData.GetTriangle(i, out mobileTriangle.vA, out mobileTriangle.vB, out mobileTriangle.vC);
RigidTransform.Transform(ref mobileTriangle.vA, ref mesh.worldTransform, out mobileTriangle.vA);
RigidTransform.Transform(ref mobileTriangle.vB, ref mesh.worldTransform, out mobileTriangle.vB);
RigidTransform.Transform(ref mobileTriangle.vC, ref mesh.worldTransform, out mobileTriangle.vC);
Vector3.Add(ref mobileTriangle.vA, ref mobileTriangle.vB, out mobileTriangleTransform.Position);
Vector3.Add(ref mobileTriangle.vC, ref mobileTriangleTransform.Position, out mobileTriangleTransform.Position);
Vector3.Multiply(ref mobileTriangleTransform.Position, 1 / 3f, out mobileTriangleTransform.Position);
Vector3.Subtract(ref mobileTriangle.vA, ref mobileTriangleTransform.Position, out mobileTriangle.vA);
Vector3.Subtract(ref mobileTriangle.vB, ref mobileTriangleTransform.Position, out mobileTriangle.vB);
Vector3.Subtract(ref mobileTriangle.vC, ref mobileTriangleTransform.Position, out mobileTriangle.vC);
//Go through all the detector volume triangles which are near the mobile mesh triangle.
bool triangleTouching, triangleContaining;
BoundingBox mobileBoundingBox;
mobileTriangle.GetBoundingBox(ref mobileTriangleTransform, out mobileBoundingBox);
DetectorVolume.TriangleMesh.Tree.GetOverlaps(mobileBoundingBox, overlaps);
for (int j = 0; j < overlaps.Count; j++)
{
DetectorVolume.TriangleMesh.Data.GetTriangle(overlaps.Elements[j], out detectorTriangle.vA, out detectorTriangle.vB, out detectorTriangle.vC);
Vector3.Add(ref detectorTriangle.vA, ref detectorTriangle.vB, out detectorTriangleTransform.Position);
Vector3.Add(ref detectorTriangle.vC, ref detectorTriangleTransform.Position, out detectorTriangleTransform.Position);
Vector3.Multiply(ref detectorTriangleTransform.Position, 1 / 3f, out detectorTriangleTransform.Position);
Vector3.Subtract(ref detectorTriangle.vA, ref detectorTriangleTransform.Position, out detectorTriangle.vA);
Vector3.Subtract(ref detectorTriangle.vB, ref detectorTriangleTransform.Position, out detectorTriangle.vB);
Vector3.Subtract(ref detectorTriangle.vC, ref detectorTriangleTransform.Position, out detectorTriangle.vC);
//If this triangle collides with the convex, we can stop immediately since we know we're touching and not containing.)))
//[MPR is used here in lieu of GJK because the MPR implementation tends to finish quicker than GJK when objects are overlapping. The GJK implementation does better on separated objects.]
if (MPRToolbox.AreShapesOverlapping(detectorTriangle, mobileTriangle, ref detectorTriangleTransform, ref mobileTriangleTransform))
{
triangleTouching = true;
//The convex can't be fully contained if it's still touching the surface.
triangleContaining = false;
overlaps.Clear();
goto finishTriangleTest;
}
}
overlaps.Clear();
//If we get here, then there was no shell intersection.
//If the convex's center point is contained by the mesh, then the convex is fully contained.
//This test is only needed if containment hasn't yet been outlawed or a touching state hasn't been established.
if ((!Touching || Containing) && DetectorVolume.IsPointContained(ref mobileTriangleTransform.Position, overlaps))
{
triangleTouching = true;
triangleContaining = true;
goto finishTriangleTest;
}
//If we get here, then there was no surface intersection and the convex's center is not contained- the volume and convex are separate!
triangleTouching = false;
triangleContaining = false;
finishTriangleTest:
//Analyze the results of the triangle test.
if (triangleTouching)
{
Touching = true; //If one child is touching, then we are touching too.
}
else
{
Containing = false; //If one child isn't touching, then we aren't containing.
}
if (!triangleContaining) //If one child isn't containing, then we aren't containing.
{
Containing = false;
}
if (!Containing && Touching)
{
//If it's touching but not containing, no further pairs will change the state.
//Containment has been invalidated by something that either didn't touch or wasn't contained.
//Touching has been ensured by at least one object touching.
break;
}
}
//There is a possibility that the MobileMesh is solid and fully contains the DetectorVolume.
//In this case, we should be Touching, but currently we are not.
if (mesh.Shape.solidity == MobileMeshSolidity.Solid && !Containing && !Touching)
{
//To determine if the detector volume is fully contained, check if one of the detector mesh's vertices
//are in the mobile mesh.
//This *could* fail if the mobile mesh is actually multiple pieces, but that's not a common or really supported case for solids.
Vector3 vertex;
DetectorVolume.TriangleMesh.Data.GetVertexPosition(0, out vertex);
Ray ray;
ray.Direction = Vector3.Up;
RayHit hit;
RigidTransform.TransformByInverse(ref vertex, ref mesh.worldTransform, out ray.Position);
if (mesh.Shape.IsLocalRayOriginInMesh(ref ray, out hit))
{
Touching = true;
}
}
NotifyDetectorVolumeOfChanges();
}