#include <stdio.h>
#include "triangle.h"

double intersect_triangle_ray(Ray & ray, vector3d& a,
							   vector3d& b, vector3d& c,
							  double & aa, double & bb)
{
	vector3d A = a-c;
	vector3d B = b-c;
	vector3d a_x_b = A.cross(B);
	vector3d c_o = c - ray.o;
	vector3d c_o_x_d = c_o.cross(ray.d);
	double den = a_x_b * ray.d;
	double t = a_x_b * c_o / den;
	aa = c_o_x_d * B / den;
	bb = -(c_o_x_d * A) / den;

	if(aa<0 || bb<0 || aa+bb>1) return -1.0;

//	if(t < 0.0) return -1.0;

	return t;
}