public static bool Intersects(XMVector origin, XMVector direction, XMVector v0, XMVector v1, XMVector v2, out float uCoordinate, out float vCoordinate, out float distance)
{
Debug.Assert(Internal.XMVector3IsUnit(direction), "Reviewed");
XMVector zero = XMGlobalConstants.Zero;
XMVector e1 = v1 - v0;
XMVector e2 = v2 - v0;
// p = Direction ^ e2;
XMVector p = XMVector3.Cross(direction, e2);
// det = e1 * p;
XMVector det = XMVector3.Dot(e1, p);
XMVector u, v, t;
if (XMVector3.GreaterOrEqual(det, CollisionGlobalConstants.RayEpsilon))
{
// Determinate is positive (front side of the triangle).
XMVector s = origin - v0;
// u = s * p;
u = XMVector3.Dot(s, p);
XMVector noIntersection = XMVector.Less(u, zero);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(u, det));
// q = s ^ e1;
XMVector q = XMVector3.Cross(s, e1);
// v = Direction * q;
v = XMVector3.Dot(direction, q);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(v, zero));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(u + v, det));
// t = e2 * q;
t = XMVector3.Dot(e2, q);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(t, zero));
if (XMVector4.EqualInt(noIntersection, XMVector.TrueInt))
{
uCoordinate = 0.0f;
vCoordinate = 0.0f;
distance = 0.0f;
return(false);
}
}
else if (XMVector3.LessOrEqual(det, CollisionGlobalConstants.RayNegEpsilon))
{
// Determinate is negative (back side of the triangle).
XMVector s = origin - v0;
// u = s * p;
u = XMVector3.Dot(s, p);
XMVector noIntersection = XMVector.Greater(u, zero);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(u, det));
// q = s ^ e1;
XMVector q = XMVector3.Cross(s, e1);
// v = Direction * q;
v = XMVector3.Dot(direction, q);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(v, zero));
noIntersection = XMVector.OrInt(noIntersection, XMVector.Less(u + v, det));
// t = e2 * q;
t = XMVector3.Dot(e2, q);
noIntersection = XMVector.OrInt(noIntersection, XMVector.Greater(t, zero));
if (XMVector4.EqualInt(noIntersection, XMVector.TrueInt))
{
uCoordinate = 0.0f;
vCoordinate = 0.0f;
distance = 0.0f;
return(false);
}
}
else
{
// Parallel ray.
uCoordinate = 0.0f;
vCoordinate = 0.0f;
distance = 0.0f;
return(false);
}
// (u / det) and (v / dev) are the barycentric coordinates of the intersection.
u = XMVector.Divide(u, det);
v = XMVector.Divide(v, det);
t = XMVector.Divide(t, det);
// Store the x-component to *pDist
u.StoreFloat(out uCoordinate);
v.StoreFloat(out vCoordinate);
t.StoreFloat(out distance);
return(true);
}
