public override void UpdateCollision(float dt)
{
WasContaining = Containing;
WasTouching = Touching;
RigidTransform transform = new RigidTransform {
Orientation = Quaternion.Identity
};
DetectorVolume.TriangleMesh.Tree.GetOverlaps(convex.boundingBox, overlaps);
for (int i = 0; i < overlaps.Count; i++)
{
DetectorVolume.TriangleMesh.Data.GetTriangle(overlaps.Elements[i], out triangle.vA, out triangle.vB,
out triangle.vC);
Vector3.Add(ref triangle.vA, ref triangle.vB, out transform.Position);
Vector3.Add(ref triangle.vC, ref transform.Position, out transform.Position);
Vector3.Multiply(ref transform.Position, 1 / 3f, out transform.Position);
Vector3.Subtract(ref triangle.vA, ref transform.Position, out triangle.vA);
Vector3.Subtract(ref triangle.vB, ref transform.Position, out triangle.vB);
Vector3.Subtract(ref triangle.vC, ref transform.Position, out triangle.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 when objects are overlapping than GJK. The GJK implementation does better on separated objects.]
if (MPRToolbox.AreShapesOverlapping(convex.Shape, triangle, ref convex.worldTransform, ref transform))
{
Touching = true;
//The convex can't be fully contained if it's still touching the surface.
Containing = false;
overlaps.Clear();
goto events;
}
}
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.
//If this is a child pair, the CheckContainment flag may be set to false. This is because the parent has
//already determined that it is not contained (another child performed the check and found that it was not contained)
//and that it is already touching somehow (either by intersection or by containment).
//so further containment tests are unnecessary.
if (CheckContainment && DetectorVolume.IsPointContained(ref convex.worldTransform.Position, overlaps))
{
Touching = true;
Containing = true;
goto events;
}
//If we get here, then there was no surface intersection and the convex's center is not contained- the volume and convex are separate!
Touching = false;
Containing = false;
events:
NotifyDetectorVolumeOfChanges();
}
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);
Vector3f.Add(ref mobileTriangle.vA, ref mobileTriangle.vB, out mobileTriangleTransform.Position);
Vector3f.Add(ref mobileTriangle.vC, ref mobileTriangleTransform.Position, out mobileTriangleTransform.Position);
Vector3f.Multiply(ref mobileTriangleTransform.Position, 1 / 3f, out mobileTriangleTransform.Position);
Vector3f.Subtract(ref mobileTriangle.vA, ref mobileTriangleTransform.Position, out mobileTriangle.vA);
Vector3f.Subtract(ref mobileTriangle.vB, ref mobileTriangleTransform.Position, out mobileTriangle.vB);
Vector3f.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);
Vector3f.Add(ref detectorTriangle.vA, ref detectorTriangle.vB, out detectorTriangleTransform.Position);
Vector3f.Add(ref detectorTriangle.vC, ref detectorTriangleTransform.Position, out detectorTriangleTransform.Position);
Vector3f.Multiply(ref detectorTriangleTransform.Position, 1 / 3f, out detectorTriangleTransform.Position);
Vector3f.Subtract(ref detectorTriangle.vA, ref detectorTriangleTransform.Position, out detectorTriangle.vA);
Vector3f.Subtract(ref detectorTriangle.vB, ref detectorTriangleTransform.Position, out detectorTriangle.vB);
Vector3f.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.
Vector3f vertex;
DetectorVolume.TriangleMesh.Data.GetVertexPosition(0, out vertex);
Ray ray;
ray.Direction = VectorHelper.Up;
RayHit hit;
RigidTransform.TransformByInverse(ref vertex, ref mesh.worldTransform, out ray.Position);
if (mesh.Shape.IsLocalRayOriginInMesh(ref ray, out hit))
{
Touching = true;
}
}
NotifyDetectorVolumeOfChanges();
}
/// <summary>
/// Constructs a new demo.
/// </summary>
/// <param name="game">Game owning this demo.</param>
public BooleanConvexTestDemo(DemosGame game)
: base(game)
{
var random = new Random();
int numberOfConfigurations = 1000;
int numberOfTestsPerConfiguration = 10000;
float size = 2;
var aPositionBounds = new BoundingBox(new Vector3(-size, -size, -size), new Vector3(size, size, size));
var bPositionBounds = new BoundingBox(new Vector3(-size, -size, -size), new Vector3(size, size, size));
size = 1;
var aShapeBounds = new BoundingBox(new Vector3(-size, -size, -size), new Vector3(size, size, size));
var bShapeBounds = new BoundingBox(new Vector3(-size, -size, -size), new Vector3(size, size, size));
int pointsInA = 10;
int pointsInB = 10;
RawList <Vector3> points = new RawList <Vector3>();
long accumulatedMPR = 0;
long accumulatedGJK = 0;
long accumulatedGJKSeparatingAxis = 0;
for (int i = 0; i < numberOfConfigurations; i++)
{
//Create two convex hull shapes.
for (int j = 0; j < pointsInA; j++)
{
Vector3 point;
GetRandomPointInBoundingBox(random, ref aShapeBounds, out point);
points.Add(point);
}
var a = new ConvexHullShape(points);
points.Clear();
for (int j = 0; j < pointsInB; j++)
{
Vector3 point;
GetRandomPointInBoundingBox(random, ref bShapeBounds, out point);
points.Add(point);
}
var b = new ConvexHullShape(points);
points.Clear();
//Generate some random tranforms for the shapes.
RigidTransform aTransform;
var axis = Vector3.Normalize(new Vector3((float)((random.NextDouble() - .5f) * 2), (float)((random.NextDouble() - .5f) * 2), (float)((random.NextDouble() - .5f) * 2)));
var angle = (float)random.NextDouble() * MathHelper.TwoPi;
Quaternion.CreateFromAxisAngle(ref axis, angle, out aTransform.Orientation);
GetRandomPointInBoundingBox(random, ref aPositionBounds, out aTransform.Position);
RigidTransform bTransform;
axis = Vector3.Normalize(new Vector3((float)((random.NextDouble() - .5f) * 2), (float)((random.NextDouble() - .5f) * 2), (float)((random.NextDouble() - .5f) * 2)));
angle = (float)random.NextDouble() * MathHelper.TwoPi;
Quaternion.CreateFromAxisAngle(ref axis, angle, out bTransform.Orientation);
GetRandomPointInBoundingBox(random, ref bPositionBounds, out bTransform.Position);
//Perform MPR tests.
//Warm up the cache a bit.
MPRToolbox.AreShapesOverlapping(a, b, ref aTransform, ref bTransform);
long start = Stopwatch.GetTimestamp();
for (int j = 0; j < numberOfTestsPerConfiguration; j++)
{
if (MPRToolbox.AreShapesOverlapping(a, b, ref aTransform, ref bTransform))
{
overlapsMPR++;
}
}
long end = Stopwatch.GetTimestamp();
accumulatedMPR += end - start;
//Perform GJK tests.
//Warm up the cache a bit.
GJKToolbox.AreShapesIntersecting(a, b, ref aTransform, ref bTransform);
start = Stopwatch.GetTimestamp();
for (int j = 0; j < numberOfTestsPerConfiguration; j++)
{
if (GJKToolbox.AreShapesIntersecting(a, b, ref aTransform, ref bTransform))
{
overlapsGJK++;
}
}
end = Stopwatch.GetTimestamp();
accumulatedGJK += end - start;
//Perform GJK Separating Axis tests.
//Warm up the cache a bit.
Vector3 localSeparatingAxis = Vector3.Up;
GJKToolbox.AreShapesIntersecting(a, b, ref aTransform, ref bTransform, ref localSeparatingAxis);
start = Stopwatch.GetTimestamp();
for (int j = 0; j < numberOfTestsPerConfiguration; j++)
{
if (GJKToolbox.AreShapesIntersecting(a, b, ref aTransform, ref bTransform, ref localSeparatingAxis))
{
overlapsGJKSeparatingAxis++;
}
}
end = Stopwatch.GetTimestamp();
accumulatedGJKSeparatingAxis += end - start;
}
//Compute the actual time per test.
long denominator = Stopwatch.Frequency * numberOfConfigurations * numberOfTestsPerConfiguration;
timeMPR = (double)accumulatedMPR / denominator;
timeGJK = (double)accumulatedGJK / denominator;
timeGJKSeparatingAxis = (double)accumulatedGJKSeparatingAxis / denominator;
}