Help with Collision detection.

[recneps]

I am making a game, and im gonna have blocks, which if you try to go inside one, collision is true, and if its true then you cant move in. Got that? well heres my code, there something wrong. if you go "too far" in a wall, you get stuck. ive been over code like 50 times. Can anyone find the problem?

code:

setscreen ("graphics:300;300;nobuttonbar;Title:Game") setscreen ("offscreenonly") var chars : array char of boolean var x, y : int := 150 const left : char := KEY_LEFT_ARROW const right : char := KEY_RIGHT_ARROW const up : char := KEY_UP_ARROW const down : char := KEY_DOWN_ARROW const numblocks : int := 120 var xb, yb : array 0 .. numblocks of int var collision : boolean := false var num : int := 0 const charwidth : int := 5 var movex, movey : int := 0 procedure drawblock (x : int, y : int)     drawfillbox (x, y, x + 10, y + 10, blue) end drawblock procedure drawchar (x : int, y : int)     drawfilloval (x, y, charwidth, charwidth, red) end drawchar procedure checkcollision (x : int, y : int)     for i : 1 .. numblocks         if x <= xb (i) + 10 and x >= xb (i) and y <= yb (i) + 10 and y >= yb (i) then             collision := true         end if     end for end checkcollision procedure drawborder     num := 0     for a : 0 .. 30         xb (a) := 0         yb (a) := num * 10 %left wall coords         num += 1     end for     num := 0     for a : 31 .. 60         xb (a) := num * 10         yb (a) := 290 %draw top wall         num += 1     end for     num := 0     for a : 61 .. 90         xb (a) := 290         yb (a) := num * 10     %draw right wall         num += 1     end for     num := 0     for a : 91 .. 120         xb (a) := num * 10         yb (a) := 0     %draw bottom wall         num += 1     end for     for i : 0 .. numblocks         drawblock (xb (i), yb (i))     end for end drawborder var oldx, oldy := 0 loop     oldx := x     oldy := y     Input.KeyDown (chars)     cls     drawborder     drawchar (x, y)     if chars (up) then         y += 5     end if     if chars (down) then         y -= 5     end if     if chars (left) then         x -= 5     end if     if chars (right) then         x += 5     end if     if chars (chr (27)) then         return     end if     checkcollision (x, y)     if collision = true then         x := oldx         y := oldy     end if     View.Update     delay (25) end loop

[Paul]

I dunno, cause I can't figure out your code without looking at it closely, and I don't wanna do that, cause Im too tired, but I made the same kind of program, the only difference is using whatdotcolor instead of the coordinates.

[Tony]

i dont see collision := false anywhere in your program... once it is made to be true, it will always stay that way

instead you should make collisions into a function that returns true/false... such as

code:

function collide(x,y:int) :boolean for i:1..num  if x<=xb(i)+10 and...      result true  end if end for result false %if forloop has finished without returning true, it must be false end collide

and in the program you just use the function in your if statement

code:

if collide(myX, myY) then ...

[recneps]

Haha, im so stupid. Thanks tony ill get on fixing that. I knew it was a simple problem.