Comments on: How To Create A Breakout Game with Box2D and Cocos2D Tutorial: Part 2 http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22 Tutorials for iPhone / iOS Developers and Gamers Sun, 29 Jan 2012 06:07:20 +0000 hourly 1 http://wordpress.org/?v=3.1.2 By: Amol Chaudhari http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-8151 Amol Chaudhari Wed, 22 Dec 2010 05:46:14 +0000 http://www.raywenderlich.com/?p=505#comment-8151 Simply awesome tutorials.... i cant wait to start working on it... Thanx a lot :) Simply awesome tutorials…. i cant wait to start working on it…

Thanx a lot :)

]]> By: Ilja http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-7805 Ilja Wed, 15 Dec 2010 13:51:26 +0000 http://www.raywenderlich.com/?p=505#comment-7805 Ray, another thing i am worried about. I have slightly modified your code: added more blocks, made them smaller etc. I didn't introduce any randomness though. What I get every time I run the simulation is different behavior for the ball and (or) the blocks. The ball seems to hit the blocks by the slightly different angle every time I do restart, (or) the blocks move slightly different each time. I do believe it's not my modifications which causes it, i don't have any randomness in my code (no random stuff in your code either as far as i am concerned). What do you think it is? Round-off errors in core of Box2D? But why are they different each time? Ray,

another thing i am worried about. I have slightly modified your code: added more blocks, made them smaller etc. I didn’t introduce any randomness though. What I get every time I run the simulation is different behavior for the ball and (or) the blocks. The ball seems to hit the blocks by the slightly different angle every time I do restart, (or) the blocks move slightly different each time.

I do believe it’s not my modifications which causes it, i don’t have any randomness in my code (no random stuff in your code either as far as i am concerned). What do you think it is? Round-off errors in core of Box2D? But why are they different each time?

]]> By: guy http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-7743 guy Tue, 14 Dec 2010 20:34:33 +0000 http://www.raywenderlich.com/?p=505#comment-7743 Hi, thanks ray, thats what i did, just wanted to make sure its the right way and i'm not missing something :) Thanks again, Guy. Hi,

thanks ray, thats what i did, just wanted to make sure its the right way and i’m not missing something :)

Thanks again,

Guy.

]]> By: Ilja http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-7717 Ilja Tue, 14 Dec 2010 12:26:13 +0000 http://www.raywenderlich.com/?p=505#comment-7717 @Ray: yes it solves the problem and now I can add more blocks and it all looks good. Thank you for your help! @Ray: yes it solves the problem and now I can add more blocks and it all looks good. Thank you for your help!

]]> By: Ray Wenderlich http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-7674 Ray Wenderlich Tue, 14 Dec 2010 02:12:47 +0000 http://www.raywenderlich.com/?p=505#comment-7674 @Ilja: Whoops, nope that was my own mistake. When setting the Box2D position for the blocks, it should be this: <pre> blockBodyDef.position.Set(((float)xOffset)/PTM_RATIO, 250/PTM_RATIO); </pre> Before the xOffset was just an int, so it was having a rounding error. @Ilja: Whoops, nope that was my own mistake. When setting the Box2D position for the blocks, it should be this:

blockBodyDef.position.Set(((float)xOffset)/PTM_RATIO, 250/PTM_RATIO);

Before the xOffset was just an int, so it was having a rounding error.

]]> By: Ray Wenderlich http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-7671 Ray Wenderlich Tue, 14 Dec 2010 02:01:06 +0000 http://www.raywenderlich.com/?p=505#comment-7671 @guy: One way is to set a flag on a brick when the ball collides with it, but don't delete it till after the ball stops colliding with the brick (i.e. has bounced away). @guy: One way is to set a flag on a brick when the ball collides with it, but don’t delete it till after the ball stops colliding with the brick (i.e. has bounced away).

]]> By: Ilja http://www.raywenderlich.com/505/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-22#comment-7631 Ilja Tue, 14 Dec 2010 00:03:08 +0000 http://www.raywenderlich.com/?p=505#comment-7631 Hello Ray, and thank you for the tutorial! I am observing a strange thing while running your code. You create 4 blocks and you use a constant padding value to create a gap between them. What I see on the screen, this gap is not always of the same width! In particular, the 4th block is 2 gaps away from the 3rd block... My guess is Box2d causes this behavior. If I only create block sprites and place them on the screen and don't connect any bodies to the sprites, I get gaps of the same width between the blocks. Thanks! Greets from Latvia. Hello Ray, and thank you for the tutorial!

I am observing a strange thing while running your code. You create 4 blocks and you use a constant padding value to create a gap between them. What I see on the screen, this gap is not always of the same width! In particular, the 4th block is 2 gaps away from the 3rd block…

My guess is Box2d causes this behavior. If I only create block sprites and place them on the screen and don’t connect any bodies to the sprites, I get gaps of the same width between the blocks.

Thanks!
Greets from Latvia.

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