Question

So as I’ve been using XNA more and more, one thing really bothers me. X and Y can only be ints, which sucks when you want to use Vectors for character position, but want the intersection method of a rectangle.

So my question is what exactly happens in the Rectangle struct?

I’m probably over thinking this all, but thanks for any input in advance.

Answer 1

XNA’s lack of a 2D Axis-Aligned Bounding Box structure (that uses floating-point, unlike Rectangle) is slightly annoying. It has a 3D one, BoundingBox, which you can re-use if you simply ignore the Z axis.

Personally I write my own AABB structure and use that. Or, rather, I wrote it once, and it just gets copied between projects. It is not a difficult structure to write.

I’d post it for you here, except that you’ve asked specifically how Rectangle works (my own structure operates quite differently). So here’s one that I just threw together that should be similar to Rectangle:

public struct AABB
{
    public float X, Y, Width, Height;

    public static AABB Intersect(AABB a, AABB b)
    {
        AABB result;
        result.X = Math.Max(a.X, b.X);
        result.Y = Math.Max(a.Y, b.Y);
        result.Width = Math.Min(a.X + a.Width, b.X + b.Width) - result.X;
        result.Height = Math.Min(a.Y + a.Height, b.Y + b.Height) - result.Y;

        if(result.Width < 0 || result.Height < 0)
            return default(AABB);
        else
            return result;
    }
}

Being something that I just threw together, it’s not exactly well tested. And I’m not sure it will respond the same way as Rectangle when given negative widths/heights. But, as you can see, it’s not much code – so it should be fairly easy to modify.