/// <summary>
/// Indicates if a segment overlaps an AABox
/// </summary>
/// <param name="seg"></param>
/// <param name="AABox"></param>
/// <returns></returns>
public static bool SegmentAABoxOverlap(Segment seg, AABox AABox)
{
Vector3 p0 = seg.Origin;
Vector3 p1 = seg.GetEnd();
float[] faceOffsets = new float[2];
// The AABox faces are aligned with the world directions. Loop
// over the 3 directions and do the two tests.
for (int iDir = 0; iDir < 3; iDir++)
{
int jDir = (iDir + 1) % 3;
int kDir = (iDir + 2) % 3;
// one plane goes through the origin, one is offset
faceOffsets[0] = JiggleUnsafe.Get(AABox.MinPos, iDir);
faceOffsets[1] = JiggleUnsafe.Get(AABox.MaxPos, iDir);
for (int iFace = 0; iFace < 2; iFace++)
{
// distance of each point from to the face plane
float dist0 = JiggleUnsafe.Get(ref p0, iDir) - faceOffsets[iFace];
float dist1 = JiggleUnsafe.Get(ref p1, iDir) - faceOffsets[iFace];
float frac = -1.0f;
if (dist0 * dist1 < -JiggleMath.Epsilon)
frac = -dist0 / (dist1 - dist0);
else if (System.Math.Abs(dist0) < JiggleMath.Epsilon)
frac = 0.0f;
else if (System.Math.Abs(dist1) < JiggleMath.Epsilon)
frac = 1.0f;
if (frac >= 0.0f)
{
//Assert(frac <= 1.0f);
Vector3 pt = seg.GetPoint(frac);
// check the point is within the face rectangle
if ((JiggleUnsafe.Get(ref pt, jDir) > JiggleUnsafe.Get(AABox.MinPos, jDir) - JiggleMath.Epsilon) &&
(JiggleUnsafe.Get(ref pt, jDir) < JiggleUnsafe.Get(AABox.MaxPos, jDir) + JiggleMath.Epsilon) &&
(JiggleUnsafe.Get(ref pt, kDir) > JiggleUnsafe.Get(AABox.MinPos, kDir) - JiggleMath.Epsilon) &&
(JiggleUnsafe.Get(ref pt, kDir) < JiggleUnsafe.Get(AABox.MaxPos, kDir) + JiggleMath.Epsilon))
{
return true;
}
}
}
}
return false;
}
/// <summary>
/// Every skin must support a ray/segment intersection test -
/// operates on the new value of the primitives
/// </summary>
/// <param name="frac"></param>
/// <param name="pos"></param>
/// <param name="normal"></param>
/// <param name="seg"></param>
/// <returns></returns>
public bool SegmentIntersect(out float frac, out Vector3 pos, out Vector3 normal, Segment seg)
{
Vector3 segEnd = seg.GetEnd();
frac = float.MaxValue;
float thisSegLenRelToOrig = 1.0f;
Segment segCopy = seg;
pos = normal = Vector3.Zero;
for (int prim = primitivesNewWorld.Count; prim-- != 0; )
{
float thisFrac;
Vector3 newPosition = pos;
if (primitivesNewWorld[prim].SegmentIntersect(out thisFrac, out newPosition, out normal, segCopy))
{
pos = newPosition;
frac = thisFrac * thisSegLenRelToOrig;
segCopy.Delta *= thisFrac;
thisSegLenRelToOrig *= frac;
}
}
//System.Diagnostics.Debug.WriteLineIf(frac <= 1.0f, pos);
return (frac <= 1.0f);
}