detect overlap (collision) for 2D game

the game is simple:
object moving through a maze of walls by direction keys
this is 2D like the old 'Nibbles' game

The walls are made up of a textbox array (shaped in small squares) and my object moves around the screen in increments equal to the height and width of one piece of the wall.
So, it simplifies whether or not the object has collided since i loop through like:

for t = 1 to 10
if object.top = txtWall(t).Top then
if object.Left = txtWall(t).Left then
(collision)
exit for
end if
end if
next t

and that works. problem. as the map gets more intricate (more than say 50 pieces of wall squares) the game slows to a crawl.

Faster way?

Thanks
Wengang

You only have to check for collision with the tiles surrounding the object :)

but I won't know which 'tiles' are surrounding the object without going through them all in a loop

right?

depends on how you store your map.

If you have your map in one big map[x][y] array then it's really simple

I don't have a map. As I said, I just used a text box array

Try creating an array of Rects to represent your walls, looping through them will be faster. Also, use the With / End With statements to speed up the comparisons.

Well, I haven't done that before. But I'll try it out.
Thanks

I would stop using a textbox array immediately.

Your first step is to declare a simple 3D Array. Make this array's dimensions the size of your map.

Dim 3DArrayMap ( mapWidth , mapHeight ) as Integer

If you want to check to see if your graphic is touching an area with a wall you could just:

If 3DArrayMap ( object.X / widthOfOneTile , object.Y / heightOfOneTile ) = 1 (where 1 is a wall, and 0 is nothing) Then
'// Now you do what you would do if you were on a wall
End If

object.X / widthOfOneTile - this will end up giving you an x coordinate if object.X (for example:60) / widthOfOneTile (example:20) divide out evenly. In this example, they would come out with an x coord of 3.

(I'm not too sure about what will happen if you try to go to coordinate 3dArray ( 1.433 , 84.43 ) in terms of errors, but it wouldn't be to hard to fix.)

If you need me to clarify (assuming you understand/care at all) what I said, I'll be more than happy to make more sense.

That's a 2d array.............

YEah... That's a 2D array.... What's up with that?

omlesna said 3D array but described a 2d array...

textbox controls consume a ridiculous amount of resources, accessing COM objects is slow. Your nearest alternatives is the built in graphical functions line. Collisions with walls should best be detected on a raster of wall blocks, at the head only

on a piece of code I got from Megatron, getting the pixel color from the dc of the desktop window, I was able to do all collision detection by simply checking which color was on the screen at the location of the head of the snake. To make sure, I sent the snake to back so that the other objects would be in front of it.
Works very well.

If anybody else does the same type project in this fashion, one other piece of advice. Don't have all the boxes/objects moving in order by index number. Just move the last box in order to the second/first position and record the moves by manipulating a string variable that holds the position order of the boxes. This solved the biggest problem of all, the game was just crawling.
I have posted this game on my new website, where I'll be putting up some of my past projects.

http://www.geesoftsolutions.com

Kedaman, I'm not disregarding your advice. I'm aware that what you're saying is right. It's just that when the problem as it appears is solved, I don't feel the need to start making changes.

Thanks all.

no probs if it works for you :)