intersectsWithTriangle method

double intersectsWithTriangle (Triangle other)

Return the distance from the origin of this to the intersection with other if this intersects with other, or null if the don't intersect.

Implementation 

double intersectsWithTriangle(Triangle other) {
  const double EPSILON = 10e-6;

  final Vector3 point0 = other._point0;
  final Vector3 point1 = other._point1;
  final Vector3 point2 = other._point2;

  _e1
    ..setFrom(point1)
    ..sub(point0);
  _e2
    ..setFrom(point2)
    ..sub(point0);

  _direction.crossInto(_e2, _q);
  final double a = _e1.dot(_q);

  if (a > -EPSILON && a < EPSILON) {
    return null;
  }

  final double f = 1 / a;
  _s
    ..setFrom(_origin)
    ..sub(point0);
  final double u = f * (_s.dot(_q));

  if (u < 0.0) {
    return null;
  }

  _s.crossInto(_e1, _r);
  final double v = f * (_direction.dot(_r));

  if (v < -EPSILON || u + v > 1.0 + EPSILON) {
    return null;
  }

  final double t = f * (_e2.dot(_r));

  return t;
}