/// <summary> Map ray *from* local frame coordinates into "world" coordinates </summary>
public Ray3f FromFrame(Ray3f r)
{
return(new Ray3f(FromFrameP(r.Origin), FromFrameV(r.Direction)));
}
///<summary> Map ray *into* local coordinates of Frame </summary>
public Ray3f ToFrame(Ray3f r)
{
return(new Ray3f(ToFrameP(r.Origin), ToFrameV(r.Direction)));
}
/// <summary> Map ray *from* local frame coordinates into "world" coordinates </summary>
public Ray3f FromFrame(ref Ray3f r)
{
return new Ray3f(FromFrameP(ref r.Origin), FromFrameV(ref r.Direction));
}
///<summary> Map ray *into* local coordinates of Frame </summary>
public Ray3f ToFrame(ref Ray3f r)
{
return new Ray3f(ToFrameP(ref r.Origin), ToFrameV(ref r.Direction));
}
public IntrRay3fTriangle3f(Ray3f r, Triangle3f t)
{
ray = r; triangle = t;
}
/// <summary>
/// minimal intersection test, computes ray-t
/// </summary>
public static bool Intersects(ref Ray3f ray, ref Vector3f V0, ref Vector3f V1, ref Vector3f V2, out float rayT)
{
// Compute the offset origin, edges, and normal.
Vector3f diff = ray.Origin - V0;
Vector3f edge1 = V1 - V0;
Vector3f edge2 = V2 - V0;
Vector3f normal = edge1.Cross(ref edge2);
rayT = float.MaxValue;
// Solve Q + t*D = b1*E1 + b2*E2 (Q = kDiff, D = ray direction,
// E1 = kEdge1, E2 = kEdge2, N = Cross(E1,E2)) by
// |Dot(D,N)|*b1 = sign(Dot(D,N))*Dot(D,Cross(Q,E2))
// |Dot(D,N)|*b2 = sign(Dot(D,N))*Dot(D,Cross(E1,Q))
// |Dot(D,N)|*t = -sign(Dot(D,N))*Dot(Q,N)
float DdN = ray.Direction.Dot(ref normal);
float sign;
if (DdN > MathUtil.ZeroTolerance)
{
sign = 1;
}
else if (DdN < -MathUtil.ZeroTolerance)
{
sign = -1;
DdN = -DdN;
}
else
{
// Ray and triangle are parallel, call it a "no intersection"
// even if the ray does intersect.
return(false);
}
Vector3f cross = diff.Cross(ref edge2);
float DdQxE2 = sign * ray.Direction.Dot(ref cross);
if (DdQxE2 >= 0)
{
cross = edge1.Cross(ref diff);
float DdE1xQ = sign * ray.Direction.Dot(ref cross);
if (DdE1xQ >= 0)
{
if (DdQxE2 + DdE1xQ <= DdN)
{
// Line intersects triangle, check if ray does.
float QdN = -sign *diff.Dot(ref normal);
if (QdN >= 0)
{
// Ray intersects triangle.
float inv = (1) / DdN;
rayT = QdN * inv;
return(true);
}
// else: t < 0, no intersection
}
// else: b1+b2 > 1, no intersection
}
// else: b2 < 0, no intersection
}
// else: b1 < 0, no intersection
return(false);
}
