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Fix ConvexHullPairTester get wrong contacts with parallel edges cases #329

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Fix ConvexHullPairTester get wrong contacts with parallel edges cases #329

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66 changes: 29 additions & 37 deletions BepuPhysics/CollisionDetection/CollisionTasks/ConvexHullPairTester.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -153,46 +153,38 @@ public static unsafe void Test(ref ConvexHullWide a, ref ConvexHullWide b, ref V
if (numerator < earliestExit * denominator)
earliestExit = numerator / denominator;
}
else if (numerator < 0)
{
//The B edge is parallel and outside the edge A, so there can be no intersection.
earliestExit = float.MinValue;
latestEntry = float.MaxValue;
}
//Parallel edges are ignored. If the edge is parallel, it will not contribute to the contact manifold.
}
//We now have bounds on B's edge.
//Denominator signs are opposed; comparison flipped.
if (latestEntry <= earliestExit)

//This edge of B was actually contained in A's face. Add contacts for it.
latestEntry = latestEntry < 0 ? 0 : latestEntry;
earliestExit = earliestExit > 1 ? 1 : earliestExit;
//Create max contact if max >= min.
//Create min if min < max and min > 0.
var startId = (previousIndexB.BundleIndex << BundleIndexing.VectorShift) + previousIndexB.InnerIndex;
var endId = (indexB.BundleIndex << BundleIndexing.VectorShift) + indexB.InnerIndex;
var baseFeatureId = (startId ^ endId) << 8;
if (earliestExit >= latestEntry && candidateCount < maximumCandidateCount)
{
//This edge of B was actually contained in A's face. Add contacts for it.
latestEntry = latestEntry < 0 ? 0 : latestEntry;
earliestExit = earliestExit > 1 ? 1 : earliestExit;
//Create max contact if max >= min.
//Create min if min < max and min > 0.
var startId = (previousIndexB.BundleIndex << BundleIndexing.VectorShift) + previousIndexB.InnerIndex;
var endId = (indexB.BundleIndex << BundleIndexing.VectorShift) + indexB.InnerIndex;
var baseFeatureId = (startId ^ endId) << 8;
if (earliestExit >= latestEntry && candidateCount < maximumCandidateCount)
{
//Create max contact.
var point = edgeOffsetB * earliestExit + previousVertexB - bFaceOrigin;
var newContactIndex = candidateCount++;
ref var candidate = ref candidates[newContactIndex];
candidate.X = Vector3.Dot(point, bFaceX);
candidate.Y = Vector3.Dot(point, bFaceY);
candidate.FeatureId = baseFeatureId + endId;
}
if (latestEntry < earliestExit && latestEntry > 0 && candidateCount < maximumCandidateCount)
{
//Create min contact.
var point = edgeOffsetB * latestEntry + previousVertexB - bFaceOrigin;
var newContactIndex = candidateCount++;
ref var candidate = ref candidates[newContactIndex];
candidate.X = Vector3.Dot(point, bFaceX);
candidate.Y = Vector3.Dot(point, bFaceY);
candidate.FeatureId = baseFeatureId + startId;
}
//Create max contact.
var point = edgeOffsetB * earliestExit + previousVertexB - bFaceOrigin;
var newContactIndex = candidateCount++;
ref var candidate = ref candidates[newContactIndex];
candidate.X = Vector3.Dot(point, bFaceX);
candidate.Y = Vector3.Dot(point, bFaceY);
candidate.FeatureId = baseFeatureId + endId;
}
if (latestEntry < earliestExit && latestEntry > 0 && candidateCount < maximumCandidateCount)
{
//Create min contact.
var point = edgeOffsetB * latestEntry + previousVertexB - bFaceOrigin;
var newContactIndex = candidateCount++;
ref var candidate = ref candidates[newContactIndex];
candidate.X = Vector3.Dot(point, bFaceX);
candidate.Y = Vector3.Dot(point, bFaceY);
candidate.FeatureId = baseFeatureId + startId;
}

previousIndexB = indexB;
previousVertexB = vertexB;
}
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