// BEN-PATCH: Someone else's patch... needs testing but the idea seems correct.
/// <summary>
/// GetTrianglesIntersectingtAABox
/// </summary>
/// <param name="triangles"></param>
/// <param name="maxTriangles"></param>
/// <param name="bb"></param>
/// <returns>int</returns>
public unsafe int GetTrianglesIntersectingtAABox(int *triangles, int maxTriangles, ref BoundingBox bb)
{
// rotated aabb
BoundingBox rotBB = bb;
Vector3 bbCorner = new Vector3();
Vector3 bbCornerT;
for (int a = 0; a < 2; a++)
{
for (int b = 0; b < 2; b++)
{
for (int c = 0; c < 2; c++)
{
bbCorner.X = ((a == 0) ? bb.Min.X : bb.Max.X);
bbCorner.Y = ((b == 0) ? bb.Min.Y : bb.Max.Y);
bbCorner.Z = ((c == 0) ? bb.Min.Z : bb.Max.Z);
bbCornerT = Vector3.Transform(bbCorner, invTransform);
BoundingBoxHelper.AddPoint(ref bbCornerT, ref rotBB);
}
}
}
return(octree.GetTrianglesIntersectingtAABox(triangles, maxTriangles, ref rotBB));
}
/// <summary>
/// SegmentIntersect
/// </summary>
/// <param name="frac"></param>
/// <param name="pos"></param>
/// <param name="normal"></param>
/// <param name="seg"></param>
/// <returns>bool</returns>
public override bool SegmentIntersect(out float frac, out Vector3 pos, out Vector3 normal, Segment seg)
{
// move segment into octree space
seg.Origin = Vector3.Transform(seg.Origin, invTransform);
seg.Delta = Vector3.TransformNormal(seg.Delta, invTransform);
BoundingBox segBox = BoundingBoxHelper.InitialBox;
BoundingBoxHelper.AddSegment(seg, ref segBox);
int[] potTriArray = DetectFunctor.IntStackAlloc();
int numTriangles = GetTrianglesIntersectingtAABox(potTriArray, DetectFunctor.MaxLocalStackTris, ref segBox);
float tv1, tv2;
pos = Vector3.Zero;
normal = Vector3.Zero;
float bestFrac = float.MaxValue;
for (int iTriangle = 0; iTriangle < numTriangles; ++iTriangle)
{
IndexedTriangle meshTriangle = GetTriangle(potTriArray[iTriangle]);
float thisFrac;
Triangle tri = new Triangle(GetVertex(meshTriangle.GetVertexIndex(0)),
GetVertex(meshTriangle.GetVertexIndex(1)),
GetVertex(meshTriangle.GetVertexIndex(2)));
if (Intersection.SegmentTriangleIntersection(out thisFrac, out tv1, out tv2, seg, tri))
{
if (thisFrac < bestFrac)
{
bestFrac = thisFrac;
// re-project
pos = Vector3.Transform(seg.GetPoint(thisFrac), transformMatrix);
normal = Vector3.TransformNormal(meshTriangle.Plane.Normal, transformMatrix);
}
}
}
frac = bestFrac;
if (bestFrac < float.MaxValue)
{
DetectFunctor.FreeStackAlloc(potTriArray);
return(true);
}
else
{
DetectFunctor.FreeStackAlloc(potTriArray);
return(false);
}
}
public unsafe int GetTrianglesIntersectingtAABox(int *triangles, int maxTriangles, ref BoundingBox bb)
{
// move segment into octree space
Vector3 aabbMin = Vector3.Transform(bb.Min, invTransform);
Vector3 aabbMax = Vector3.Transform(bb.Max, invTransform);
// rotated aabb
BoundingBox rotBB = bb;
BoundingBoxHelper.AddPoint(ref aabbMin, ref rotBB);
BoundingBoxHelper.AddPoint(ref aabbMax, ref rotBB);
return(octree.GetTrianglesIntersectingtAABox(triangles, maxTriangles, ref rotBB));
}
public override bool SegmentIntersect(out float frac, out Vector3 pos, out Vector3 normal, Segment seg)
{
BoundingBox segBox = BoundingBoxHelper.InitialBox;
BoundingBoxHelper.AddSegment(seg, ref segBox);
unsafe
{
#if USE_STACKALLOC
int *potentialTriangles = stackalloc int[MaxLocalStackTris];
{
#else
int[] potTriArray = DetectFunctor.IntStackAlloc();
fixed(int *potentialTriangles = potTriArray)
{
#endif
int numTriangles = GetTrianglesIntersectingtAABox(potentialTriangles, DetectFunctor.MaxLocalStackSCPI, ref segBox);
float tv1, tv2;
pos = Vector3.Zero;
normal = Vector3.Zero;
// move segment into octree space
seg.Origin = Vector3.Transform(seg.Origin, invTransform);
seg.Delta = Vector3.TransformNormal(seg.Delta, invTransform);
float bestFrac = float.MaxValue;
for (int iTriangle = 0; iTriangle < numTriangles; ++iTriangle)
{
IndexedTriangle meshTriangle = GetTriangle(potentialTriangles[iTriangle]);
float thisFrac;
Triangle tri = new Triangle(GetVertex(meshTriangle.GetVertexIndex(0)),
GetVertex(meshTriangle.GetVertexIndex(1)),
GetVertex(meshTriangle.GetVertexIndex(2)));
if (Intersection.SegmentTriangleIntersection(out thisFrac, out tv1, out tv2, seg, tri))
{
if (thisFrac < bestFrac)
{
bestFrac = thisFrac;
pos = seg.GetPoint(thisFrac);
normal = meshTriangle.Plane.Normal;
}
}
}
frac = bestFrac;
if (bestFrac < float.MaxValue)
{
DetectFunctor.FreeStackAlloc(potTriArray);
return(true);
}
else
{
DetectFunctor.FreeStackAlloc(potTriArray);
return(false);
}
#if USE_STACKALLOC
}
#else
}
#endif
}
}