cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   jj0b
   Member

   If one can get away with using just CCSpriteFrameCache, CCSprite and CCSpriteFrame to make sprites and animations, what is the purpose of creating a CCSpriteSheet as is done in the programming guide example for working with sprites and animation?

   http://www.cocos2d-iphone.org/wiki/doku.php/prog_guide:animation

   These are the three lines in question:

   CCSpriteSheet *spritesheet = [CCSpriteSheet spriteSheetWithFile:@"animations/grossini.png"];
   [spritesheet addChild:sprite];
   [self addChild:spritesheet];

   The example works just fine without including these lines, so why would I ever need to create a CCSpriteSheet?

   Thanks

   Posted 1 year ago #
2. 

   randomtruth
   Member

   CCSpriteFrameCache and CCSpriteFrame are subclasses of CCSpriteSheet. So, whenever you create one of these, you are creating a CCSpriteSheet along with it. You would personally use it if you are upgrading from an older version of Cocos2d or need the marginal (almost non-existent) performance increase.

   Posted 1 year ago #
3. 

   jj0b
   Member

   OK, but why would you ever need to declare a CCSpriteSheet manually?

   The example works with or without creating the CCSpriteSheet so what benefit is gained by the extra three lines of code?

   If there is a good reason for doing this I want to know. Just trying to learn and understand the cocos2D way of doing things.

   Thanks!

   Posted 1 year ago #
4. 

   riq
   Key Master

   A CCSprite is an object that knows how to render it self. See CCSprite#draw
   If you have 50 CCSprite objects, then you will have 50 calls to CCSprite#draw, and CCSprite#draw calls 3 or 4 OpenGL calls. Very expensive!

   To avoid that, you can reparent all your 50 CCSprite objects to a CCSpriteSheet. The only requirement is that all the 50 CCSprite objects use the same texture.

   CCSpriteSheet will batch draws (instead of 50 draws, only 1 draw!), thus improving the performance. CCSprite#draw won't be called.

   CCSpriteFrame and CCSpriteFrameCache are different things.

   Please, for further info see: v0.99.0 release notes, and test/SpriteTest.m

   Posted 1 year ago #
5. 

   jj0b
   Member

   @rlq thank you. That makes sense.

   In the example they create an animation like this:

   NSMutableArray *animFrames = [NSMutableArray array];
   for(int i = 1; i < 15; i++) {
         CCSpriteFrame *frame = [[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName:[NSString            stringWithFormat:@"grossini_dance_%02d.png",i]];
        [animFrames addObject:frame];
   }
   CCAnimation *animation = [CCAnimation animationWithName:@"dance" delay:0.2f frames:animFrames];
   [sprite runAction:[CCRepeatForever actionWithAction: [CCAnimate actionWithAnimation:animation restoreOriginalFrame:NO] ]];

   I know that they added the sprite to the spritesheet in the previous code but wouldn't all the rest of the sprites in the animation NOT be in the spritesheet, and therefore be less efficient?

   Posted 1 year ago #
6. 

   riq
   Key Master

   @jj0b: If you have just 1 sprite, then the performance will be the same. Please, see the Performance Test in the wiki to understand how fast CCspriteSheet can be compared to non CCSpriteSheet.

   If the parent of the sprite is a CCSpriteSheet then it will render the sprite "batched".
   You can't add a CCSprite to a CCSpriteSheet if they don't share the same texture. It will raise an NSAssert. So, if you code works, and if you are using a CCSpriteSheet, it means that the sprite is batched.

   Posted 1 year ago #
7. 

   indy2005
   Member

   Hi,

   I understand the concept of CCSpriteSheet, but cant see how CCSpriteSheet is connected in any way to the animation frames or frame cache? Looks like each frame is coming from a different texture anyway?

   If the frames were created from CGRect offsets within the same texture as the CCSpriteSheet, would they automatically be batch called?

   Regards

   i

   Posted 1 year ago #
8. 

   riq
   Key Master

   @indy2005: if you have any of its ancestors is a CCSpriteSheet then it will be batched.

   Posted 1 year ago #
9. 

   indy2005
   Member

   @riq: still not sure I understand what we mean by ancestors, in terms of this example of using the sharedSpriteFrameCache.

   Sorry...bit slow today

   Posted 1 year ago #
10. 

    riq
    Key Master

    yes, what I wrote has no sense. I meant:

    @indy2005: if any of the sprite's ancestors is a CCSpriteSheet then it will be batched.

    ancestor = father (parent), or grand father, or grand grand father, etc...

    Posted 1 year ago #
11. 

    jj0b
    Member

    OK, I get CCSpriteSheet in general and see how much faster it is. I am changing my app to use them.

    In the example in Sprites.test all that they do is add one CCSprite to the CCSpriteSheet. After that they build the animation using the CCSpriteFrameCache to get CCSpriteFrame's and then that animation is run on the CCSprite that was added to the CCSpriteSheet.

    Are you saying that the fact that the animation is run on a CCSprite whose parent is a CCSpriteSheet that all the sprites in the animation will automatically be batched with that same spritesheet?

    That is fantastic if true. I just want to make sure I understand this correctly so that I can get the best performance out of my app.

    Posted 1 year ago #
12. 

    riq
    Key Master

    CCSpriteFrameCache is the cache of CCSpriteFrames... just that.

    And a CCSpriteFrame has:
    -> texture id
    -> rect

    And you can modify the frame of an CCSprite using setDisplayFrame (CCAnimation does that).

    But if the CCSprite has a CCSpriteSheet as an ancestor, then the "texture id" of the CCSpriteFrame, should be the same as the CCSpriteSheet. Otherwise it will raise an exception.

    @jj0b, @indy2005: Help us improve the API Reference ( http://www.cocos2d-iphone.org/api-ref/latest-stable/ )
    If you found this information useful, consider submitting a patch that improves the current API reference of CCSpriteFrame, CCSpriteFrameCache, CCSpriteSheet and CCSprite.

    How to submit a patch:
    -> Edit the CCSpriteSheet.h, CCSpriteFrameCache.h .... files
    -> and http://www.cocos2d-iphone.org/wiki/doku.php/faq#how_do_i_submit_a_patch

    Thanks.

    Posted 1 year ago #
13. 

    jj0b
    Member

    Thanks @riq I will do that today.

    Posted 1 year ago #
14. 

    indy2005
    Member

    @riq

    So - in the earlier code sample provided in this thread, you could never animate a CCSprite which was parented to a CCSpriteSheet, using the frames below, which all seem to come from different .png (so different textures)?

    NSMutableArray *animFrames = [NSMutableArray array];
    for(int i = 1; i < 15; i++) {
          CCSpriteFrame *frame = [[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName:[NSString            stringWithFormat:@"grossini_dance_%02d.png",i]];
         [animFrames addObject:frame];
    }
    CCAnimation *animation = [CCAnimation animationWithName:@"dance" delay:0.2f frames:animFrames];
    [sprite runAction:[CCRepeatForever actionWithAction: [CCAnimate actionWithAnimation:animation restoreOriginalFrame:NO] ]];

    Is this the case? Applying the above animation to a CCSprite parented to a CCSpriteSheet should fail as the frames dont share the same textureID?

    Regards

    i

    Posted 1 year ago #
15. 

    riq
    Key Master

    @indy2005: CCSpriteFrameCache#spriteFrameByName receives a frame name, not a image name. If the sample works, then the frames come from the same texture id.

    If the API reference was not clear, consider sending a patch to improve it. thanks.

    Posted 1 year ago #
16. 

    jj0b
    Member

    I added a patch to the Sprite vs. SpriteSheet Animation example in Sprite.test that clearly describes how CCSprite and CCSpriteSheet work with CCSpriteFrameCache and CCSpriteFrame when creating a CCAnimation.

    To whom it may concern I accidentally submitted the patch to the issue tracker as a defect instead of an enhancement. Sorry.

    Posted 1 year ago #
17. 

    riq
    Key Master

    @jjob: thanks

    Posted 1 year ago #
18. 

    indy2005
    Member

    Hi,

    Good work. Is there any way of seeing the contents of the diff file you updated?

    Regards

    i

    Posted 1 year ago #
19. 

    rwenderlich
    Member

    @indy - You can see @jjob's patch here: http://code.google.com/p/cocos2d-iphone/issues/detail?id=827

    Posted 1 year ago #
20. 

    indy2005
    Member

    Hello Ray,

    Fancy meeting you here ;-). Keep up the tutorials!!

    I found the patch, just not sure what I do with the diff file I downloaded to see the contents.

    Regards

    i

    Posted 1 year ago #
21. 

    indy2005
    Member

    opened it in xcode....ignore me!

    Can I ask - if a CCSprite isnt parented to a CCSpriteSheet, can a CCAnimation be from multiple texture ids? i.e. you can have 10 frames from 10 different png files if you want, if the CSprite is non batched?

    Regards

    i

    Posted 1 year ago #

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