bounds_side()? in Feature Requests

ID:814392
 
Jun 13 2012, 8:25 pm
Applies to:DM Language
Status: Open
Issue hasn't been assigned a status value.
I would like to see a new built-in feature that will allow me to determine what side of a bounding box is overlapping. This may be confusing, so here is an example:

Say X is a mob, and Y is something it is not supposed to be on. Now, if I run a check and see that X is overlapping Y via bounds_dist(), then I can catch X...but I can't do much about it. My first thought would be to modify it's step_x and step_y to shove it off, but I don't know which way to shove it. If X is overlapping Y's right side by 3 pixels, I want add 3 to X's step_x. I have no good way of figuring out that information, though.

This is why I would like something along the lines of bounds_side(a, b) (Although I'm not the best name-maker around), that will tell me which side of b a is overlapping.
#1 Jun 13 2012, 11:56 pm
Here is a quick example of a workaround for this, but it is much more bulky than need-be:
atom/proc
    shove_off(atom/b) // Shove src off of b.
        var/d = 0
        var/list/l
        var/atom/movable/a = src
        d = abs(bounds_dist(a, b)) // They are overlapping, which means bounds_dist() will be negative - lets make it positive

        l = obounds(a, d, 0) // check to the right (EAST)
        if(!(b in l))
            a.step_x += d
            return

        l = obounds(a, 0, d) // check up (NORTH)
        if(!(b in l))
            a.step_y += d
            return

        l = obounds(a, -d, 0) // check to the left (WEST)
        if(!(b in l))
            a.step_x -= d
            return

        l = obounds(a, 0, -d) // check down (SOUTH)
        if(!(b in l))
            a.step_y -= d
            return

        l = obounds(a, d, d) // check right and up (NORTHEAST)
        if(!(b in l))
            a.step_x += d
            a.step_y += d
            return

        l = obounds(a, -d, -d) // check left and down (SOUTHWEST)
        if(!(b in l))
            a.step_x -= d
            a.step_y -= d
            return

        l = obounds(a, -d, d) // check left and up (NORTHWEST)
        if(!(b in l))
            a.step_x -= d
            a.step_y += d
            return

        l = obounds(a, d, -d) // check right and down (SOUTHEAST)
        if(!(b in l))
            a.step_x += d
            a.step_y -= d
            return
#2 Jun 15 2012, 4:03 pm (Edited on Jun 15 2012, 4:24 pm)
It's only bulkier than need-be because of the way you're programming it. There's already a way easier and more clean way of going about this. Here's an incomplete example:
proc/bounds_side(atom/movable/case, atom/movable/check)

    if(check in obounds(case, case.bound_width, case.bound_height))

        var/real_x = check.real_x()
        if(global.in_between(case.real_x(), real_x, real_x + check.bound_width))
            . |= WEST
        // Etc...

        return .

    else return 0

atom/movable/proc

    // Assumes world.icon_size is a numeric literal.
    real_x() return src.x * world.icon_size + step_x
    real_y() return src.y * world.icon_size + step_y

proc
    in_between(x, min, max) return ((x >= min) && (x <= max))

I'd be more than happy to assist you, given you repost this in the Developers Help section. There just isn't a need for this feature, and I'd be more than happy to assist my skinny little buddy if you repost :). I'll even complete the code I've provided for you, if you repost. This information does belong in there, hence why I haven't posted a complete example; just a demonstration.
#3 Jun 16 2012, 1:28 pm
In response to Shanegirl (#2)
rofl...sorry, skinny little buddy?

hahahahahahahaha yup that's him