public static void Intersects(ref Vector2 vertex1, ref Vector2 vertex2, ref Ray2D ray, out float result,
float tolerance = 0.0001f)
{
Vector2 tangent, normal;
float edgeMagnitude;
Vector2.Subtract(ref vertex1, ref vertex2, out tangent);
Vector2Helper.Normalize(ref tangent, out edgeMagnitude, out tangent);
Vector2Helper.RightPerp(ref tangent, out normal);
float dir;
Vector2.Dot(ref normal, ref ray.Direction, out dir);
if (MathF.Abs(dir) >= tolerance)
{
Vector2 originDiff;
Vector2.Subtract(ref ray.Origin, ref vertex2, out originDiff);
float actualDistance;
Vector2.Dot(ref normal, ref originDiff, out actualDistance);
var distanceFromOrigin = -(actualDistance / dir);
if (distanceFromOrigin >= 0)
{
Vector2 intersectPos;
Vector2.Multiply(ref ray.Direction, distanceFromOrigin, out intersectPos);
Vector2.Add(ref intersectPos, ref originDiff, out intersectPos);
float distanceFromSecond;
Vector2.Dot(ref intersectPos, ref tangent, out distanceFromSecond);
if (distanceFromSecond >= 0 && distanceFromSecond <= edgeMagnitude)
{ // Hit!
result = distanceFromOrigin;
return;
}
}
}
// No hit.
result = -1;
}