protected override Intersections IntersectsInt(Ray r)
{
var dir_cross_e2 = Tuple.Cross(r.Direction, E2);
var det = Tuple.Dot(E1, dir_cross_e2);
if (Math.Abs(det) < EPSILON)
{
return(Intersections.EMPTY);
}
var f = 1.0 / det;
var p1_to_origin = r.Origin - P1;
var u = f * Tuple.Dot(p1_to_origin, dir_cross_e2);
if (u < 0 || u > 1)
{
return(Intersections.EMPTY);
}
var origin_cross_e1 = Tuple.Cross(p1_to_origin, E1);
var v = f * Tuple.Dot(r.Direction, origin_cross_e1);
if (v < 0 || (u + v) > 1)
{
return(Intersections.EMPTY);
}
var t = f * Tuple.Dot(E2, origin_cross_e1);
return(new Intersections(
new Intersection(t, this, u, v)));
}
public Triangle(Point p1, Point p2, Point p3)
{
P1 = p1;
P2 = p2;
P3 = p3;
E1 = (p2 - p1).ToVector();
E2 = (p3 - p1).ToVector();
Normal = Tuple.Cross(E2, E1).Normalize().ToVector();
}
public static Matrix View(Point from, Point to, Vector up)
{
var forward = (to - from).Normalize();
var left = Tuple.Cross(forward, up.Normalize());
var trueUp = Tuple.Cross(left, forward);
var orientation = new Matrix(new List <double> {
left.x, left.y, left.z, 0,
trueUp.x, trueUp.y, trueUp.z, 0,
-forward.x, -forward.y, -forward.z, 0,
0, 0, 0, 1
});
return(orientation * Transform.Translation(-from.x, -from.y, -from.z));
}