/// <summary>
/// GetBoxTriangleIntersectionPoints
/// Pushes intersection points onto the back of pts. Returns the
/// number of points found.
/// Points that are close together (compared to
/// combinationDistance) get combined
/// </summary>
/// <param name="pts"></param>
/// <param name="box"></param>
/// <param name="triangle"></param>
/// <param name="combinationDistance"></param>
/// <returns>int</returns>
private static int GetBoxTriangleIntersectionPoints(List<Vector3> pts, Box box, Triangle triangle, float combinationDistance)
{
// first intersect each edge of the box with the triangle
Box.Edge[] edges;
box.GetEdges(out edges);
Vector3[] boxPts;
box.GetCornerPoints(out boxPts);
float tS;
float tv1, tv2;
// BEN-OPTIMISATION: Allocating just one Vector3 to be reused.
Vector3 point = new Vector3();
int iEdge;
for (iEdge = 0; iEdge < 12; ++iEdge)
{
Box.Edge edge = edges[iEdge];
Segment seg = new Segment(boxPts[(int)edge.Ind0], boxPts[(int)edge.Ind1] - boxPts[(int)edge.Ind0]);
if (Intersection.SegmentTriangleIntersection(out tS, out tv1, out tv2, seg, triangle))
{
// BEN-OPTIMISATION: Reusing the existing point variable instead allocating new ones.
// This also allows point to be based by reference.
seg.GetPoint(ref point, tS);
AddPoint(pts, ref point, combinationDistance * combinationDistance);
}
}
Vector3 pos, n;
// now each edge of the triangle with the box
for (iEdge = 0; iEdge < 3; ++iEdge)
{
#region "BEN-OPTIMISATION: Remove excess allocations and pass variables by reference."
// ORIGINAL CODE:
/*Vector3 pt0 = triangle.GetPoint(iEdge);
Vector3 pt1 = triangle.GetPoint((iEdge + 1) % 3);
Segment s1 = new Segment(pt0, pt1 - pt0);
Segment s2 = new Segment(pt1, pt0 - pt1);*/
// OPTIMISED CODE:
Vector3 pt0 = triangle.GetPoint(iEdge);
Vector3 pt1 = triangle.GetPoint((iEdge + 1) % 3);
Vector3 difference1;
Vector3 difference2;
Vector3.Subtract(ref pt1, ref pt0, out difference1);
Vector3.Subtract(ref pt0, ref pt1, out difference2);
Segment s1 = new Segment(ref pt0, ref difference1);
Segment s2 = new Segment(ref pt1, ref difference2);
#endregion
if (box.SegmentIntersect(out tS, out pos, out n, s1))
AddPoint(pts, ref pos, combinationDistance * combinationDistance);
if (box.SegmentIntersect(out tS, out pos, out n, s2))
AddPoint(pts, ref pos, combinationDistance * combinationDistance);
}
return pts.Count;
}
/// <summary>
/// GetBoxTriangleIntersectionPoints
/// Pushes intersection points onto the back of pts. Returns the
/// number of points found.
/// Points that are close together (compared to
/// combinationDistance) get combined
/// </summary>
/// <param name="pts"></param>
/// <param name="box"></param>
/// <param name="triangle"></param>
/// <param name="combinationDistance"></param>
/// <returns></returns>
private static int GetBoxTriangleIntersectionPoints(List<Vector3> pts, Box box, Triangle triangle, float combinationDistance)
{
// first intersect each edge of the box with the triangle
Box.Edge[] edges;
box.GetEdges(out edges);
Vector3[] boxPts;
box.GetCornerPoints(out boxPts);
float tS;
float tv1, tv2;
int iEdge;
for (iEdge = 0; iEdge < 12; ++iEdge)
{
Box.Edge edge = edges[iEdge];
Segment seg = new Segment(boxPts[(int)edge.Ind0], boxPts[(int)edge.Ind1] - boxPts[(int)edge.Ind0]);
if (Intersection.SegmentTriangleIntersection(out tS, out tv1, out tv2, seg, triangle))
{
AddPoint(pts, seg.GetPoint(tS), combinationDistance * combinationDistance);
}
}
Vector3 pos, n;
// now each edge of the triangle with the box
for (iEdge = 0; iEdge < 3; ++iEdge)
{
Vector3 pt0 = triangle.GetPoint(iEdge);
Vector3 pt1 = triangle.GetPoint((iEdge + 1) % 3);
Segment s1 = new Segment(pt0, pt1 - pt0);
Segment s2 = new Segment(pt1, pt0 - pt1);
if (box.SegmentIntersect(out tS, out pos, out n, s1))
AddPoint(pts, pos, combinationDistance * combinationDistance);
if (box.SegmentIntersect(out tS, out pos, out n, s2))
AddPoint(pts, pos, combinationDistance * combinationDistance);
}
return pts.Count;
}