Flash sprite gets faster as time elapses - actionscript-3

Question

I am trying to make my first game in Flash, and it will be called Pedestrian Run. The rock here will come towards the player and it should be going at one consistent speed, however, every time it resets back to the starting point, it gets faster and faster. Is there any way to fix this, because I cannot for the life of me figure this out. Any help is appreciated. Here is the code on pastebin:
Pedestrian Run Code

Answer 1

I think the setTimeout in a recursive function is a very bad idea and it's what's probably causing your problem. Use the ENTER FRAME event for the game loop.

Answer 2

#Iansen is correct, your issue is caused by the setTimeout continually being called.
In your moveRock() you have a setTimeout to moveRock. Your setTimeouts are accumulating and that is why you are seeing the translation increase.
It would be best if you used a timer instead, like so:
In your class level variables:
private var moveTimer:Timer;
In your init() add this:
moveTimer = new Timer(25,0);
moveTimer.addEventListener( TimerEvent.TIMER, moveRock );
//you can call the moveTimer.start() anywhere you want, but this is fine
moveTimer.start();
Then your moveRock and spawnRock should look like this:
private function moveRock( e:TimerEvent ):void {
rock.x -= 15;
if (rock.x == char.x || rock.x == 0) {
removeChild(rock);
spawnRock();
}
}
private function spawnRock():void {
addChild(rock);
rock.x = 750;
rock.y = 520;
}
It also worth noting that the removeChild and addChild is pretty wasteful here in your current code and you'd be fine with just the moveRock() slightly altered:
private function moveRock( e:TimerEvent ):void {
rock.x -= 15;
if (rock.x == char.x || rock.x == 0) {
rock.x = 750;
rock.y = 520;
}
}

Answer 3

Don't use a constant value for your rock.x update. Use a variable and update it every time you "reset".
Notice in the example below, I'm updating after you despawn your previous rock.
private var speed:Number = 15;
function moveRock():void {
rock.x -= speed;
if (rock.x == char.x || rock.x == 0) {
this.removeChild(rock);
speed += 1;
spawnRock();
}
setTimeout(moveRock, 25);
}