//-----------------------------------------------------------------------------
// Name: IntersectTriangle()
// Desc: Given a ray origin (orig) and direction (dir), and three vertices of
// of a triangle, this function returns TRUE and the interpolated texture
// coordinates if the ray intersects the triangle
//-----------------------------------------------------------------------------
public static bool IntersectTriangle(ref Vector3 orig, ref Vector3 dir, ref Vector3 v0,
ref Vector3 v1, ref Vector3 v2, ref float t, ref float u, ref float v)
{
// Find vectors for two edges sharing vert0
Vector3 edge1 = DXUtils.Minus(v1, v0);
Vector3 edge2 = DXUtils.Minus(v2, v0);
// Begin calculating determinant - also used to calculate U parameter
Vector3 pvec = Vector3.Cross(dir, edge2);
// If determinant is near zero, ray lies in plane of triangle
float det = Vector3.Dot(edge1, pvec);
if (det < 0.0001f)
{
return(false);
}
// Calculate distance from vert0 to ray origin
Vector3 tvec = DXUtils.Minus(orig, v0);
// Calculate U parameter and test bounds
u = Vector3.Dot(tvec, pvec);
if (u < 0.0f || u > det)
{
return(false);
}
// Prepare to test V parameter
Vector3 qvec = Vector3.Cross(tvec, edge1);
// Calculate V parameter and test bounds
v = Vector3.Dot(dir, qvec);
if (v < 0.0f || u + v > det)
{
return(false);
}
// Calculate t, scale parameters, ray intersects triangle
t = Vector3.Dot(edge2, qvec);
float fInvDet = 1.0f / det;
t *= fInvDet;
u *= fInvDet;
v *= fInvDet;
return(true);
}
public static float Perimeter(ref Vector3 v1, ref Vector3 v2, ref Vector3 v3)
{
return(DXUtils.Dist(ref v1, ref v2) + DXUtils.Dist(ref v2, ref v3)
+ DXUtils.Dist(ref v1, ref v3));
}
