Like this:

if(mouse_x >= button_x &&
mouse_y >= button_y &&
mouse_x <= button_x+button_width &&
mouse_y <= button_y+button_height)

so there.

Just iterate through a list of buttons and check them. The time to check will increase as you add more buttons but it won't get noticeable unless you're using a LOT of buttons (And how many are you really going to need on screen at any time? Is this really going to be a speed bottleneck in your program?).

If you really want a method that doesn't increase as you add buttons, store a two dimensional array of ints that has the same dimensions as your window/viewing area. Set all those ints so that they correspond to the index of the appropriate button in an array/vector of buttons. When the user clicks the screen at coordinates (x,y), check the value of the two dimensional array at (x,y) and this will tell you the index of the button that was pressed.




That's pretty naive code of course, I'm just trying to illustrate what I mean.

Edit: I suck at teh C++

[edited by - Dobbs on July 27, 2002 4:46:01 PM]

[edited by - Dobbs on July 27, 2002 4:47:05 PM]

Now that we''re at it, why don''t we invent some kind of atom fusion system or a cure for cancer...

Even if you have a thousand buttons, checking each one every frame will not cost much, even on a prehistoric machine. So you could compare every button one by one at will, either by using some linked list or an array with the data you need (namely top, bottom, left and right coords). You''d probably use function pointers if you want an absoltuly generic data container, or simply use a bool flag which you''ll then consult on a later ocasion in the pipe line, if you want to keep the function simple (or you could just expand it out and write every single line of code the computer could ever imaginably run, mind you it might be a good idea to break or return as soon as you''ve found your target).

If you still want to do some kind of "sorting", then a simple quad-tree based thing will probably do all you want, cut the screen in 4 which then either point to 4 more rectangles or a array of triangle, as krez points out. Mind you, no matter how many compares you save, this will make you waste time writing and proofing more code.

No matter what your solution, don''t loose to much time on such a frivolous thing, concentrate on what you want the butttons to do...

If you want an introduction to testing a cursor click in 3d space, don''t forget to see the pick example in the DX sdk.

quote:Original post by krez
that''d be:
800 x 600 = 480,000 ints
480,000 x 4 = 1,920,000 bytes
almost 2 megs!

I never said it was a good idea, just that it has constant running time (in other words it was a joke). I''m well aware of how stupid it is, but you can use similar techniques in other situations to solve seemingly very complex problems.