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 epsilon = 10e-6;

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

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

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

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

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

  if (u < 0.0) {
    return null;
  }

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

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

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

  return t;
}