/// <summary>
/// Returns whether a ray instersects with the triangle and fill the intersection structure if it does.
/// </summary>
/// <param name="ray"></param>
/// <param name="intersection"></param>
/// <returns></returns>
public override bool TryToIntersect(Ray ray, ref Intersection intersection)
{
Vector3 e1, e2, s1;
float divisor, invDivisor;
Vector3.Subtract(ref _vertices[1], ref _vertices[0], out e1);
Vector3.Subtract(ref _vertices[2], ref _vertices[0], out e2);
Vector3.Cross(ref ray.Direction, ref e2, out s1);
Vector3.Dot(ref s1, ref e1, out divisor);
if (divisor == 0f)
{
return(false);
}
invDivisor = 1 / divisor;
Vector3 s, s2;
Vector3.Subtract(ref ray.Origin, ref _vertices[0], out s);
var b1 = Vector3.Dot(s, s1) * invDivisor;
if (b1 < 0 || b1 > 1)
{
return(false);
}
Vector3.Cross(ref s, ref e1, out s2);
var b2 = Vector3.Dot(ray.Direction, s2) * invDivisor;
if (b2 < 0 || (b1 + b2) > 1)
{
return(false);
}
var t = Vector3.Dot(e2, s2) * invDivisor;
if (t < ray.Start || t > ray.End)
{
return(false);
}
intersection.Point = ray.PointAtTime(t);
intersection.NormalVector = _planeNormal;
intersection.Distance = (ray.Origin - intersection.Point).Length;
Transformation.CoordinateSystem(ref intersection.NormalVector, out intersection.PointDifferentialOverU,
out intersection.PointDifferentialOverV);
return(true);
}
