Question

I am working on a game which has working similar to game monkey kick off. I have one ball bouncing on a place at the left side of screen and depending upon the position of the ball I apply linearImpulse to the ball on user touch so that it appears that the ball is kicked.
But what happens is when i apply impulse the ball goes out of the screen bounds. I dont want the ball to go out of the horizontal screen bounds whereas it can go out of the screen vertically.I tried using CCFollow but it doesn’t give the realistic feel to the game flow.
I tried THIS tutorial, but dint help much.I managed to scroll the background,Only this part remains.

Any Ideas on how the ball should not move out of the horizontal screen boundary..? but in case of vertical boundary on the other hand it can go out of the bounds.

Answer 1

If you’re not using physics, it’s a simple bounds check. Assuming the screen width is 320 points this will keep the ball inside the screen horizontally:

CGPoint ballPos = ball.position;
ball.position.x = fmaxf(0, fminf(320, ballPos.x));
ball.position = ballPos;

UPDATE: I noticed you mentioned linear impulse. So you’re using a physics engine. In that case, create a horizontal wall on both sides. See the cocos2d Box2D or Chipmunk templates how to enclose the screen with a collision border, then use only the left and right side borders in your game.