public static XMVector PointOnPlaneInsideTriangle(XMVector p, XMVector v0, XMVector v1, XMVector v2)
{
// Compute the triangle normal.
XMVector n = XMVector3.Cross(v2 - v0, v1 - v0);
// Compute the cross products of the vector from the base of each edge to
// the point with each edge vector.
XMVector c0 = XMVector3.Cross(p - v0, v1 - v0);
XMVector c1 = XMVector3.Cross(p - v1, v2 - v1);
XMVector c2 = XMVector3.Cross(p - v2, v0 - v2);
// If the cross product points in the same direction as the normal the the
// point is inside the edge (it is zero if is on the edge).
XMVector zero = XMGlobalConstants.Zero;
XMVector inside0 = XMVector.GreaterOrEqual(XMVector3.Dot(c0, n), zero);
XMVector inside1 = XMVector.GreaterOrEqual(XMVector3.Dot(c1, n), zero);
XMVector inside2 = XMVector.GreaterOrEqual(XMVector3.Dot(c2, n), zero);
// If the point inside all of the edges it is inside.
return(XMVector.AndInt(XMVector.AndInt(inside0, inside1), inside2));
}
