Why are both AtlasSprite and AtlasSpriteManager needed?

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Why are both AtlasSprite and AtlasSpriteManager needed?

(4 posts) (3 voices)

Started 2 years ago by malphigian
Latest reply from malphigian

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malphigian
Member

I've gotten pretty comfortable with Cocos2d and I'm really happy with it. That said, something has been bugging me about my Atlas Animations and I feel like I'm missing how they are supposed to be used.

Can someone explain the rationale behind AtlasSpriteManager and AtlasSprite being separate classes that the client must create and manage?

In other words, is there ever a situation where you would use an AtlasSpriteManager without an AtlasSprite or vice versa? If so, what kind of situations would this be useful in? If not, why have both visible, why not just have AtlasSprite take care of creating a manager behind the scenes or vice versa?

It's not a big deal, I'm just curious why it's set up the way it is.

Posted 2 years ago #
riq
Key Master

AtlasSpriteManager is a class that renders multiples AtlasSprite in one batch call. This means it is MUCH faster than rendering each Sprite individually.

The AtlasSprite objects don't know how render themselves. They need someone who renders them.

AtlasSpriteManager only supports AtlasSprite objects (or subclasses) as children, and the only possible parent for the AtlasSprite objects is the AtlasSpriteManager (or a subclass of it).

Compare column 9 against column 10:
http://www.cocos2d-iphone.org/wiki/doku.php/perf_test:0_8#sprite_tests

Posted 2 years ago #
Clain
Member

It's set up this way to allow better performance. When you draw a regular Sprite in a Layer, you don't ask yourself why both the layer and the sprite have to be visible. Why is it a problem then when it comes to AtlasSprites ? If it helps, you can think of the AtlasSpriteManager as a Layer (it's not one, but conceptually, it's alike). It can only contain AtlasSprites, but the main advantage is that it batches openGL calls to draw the AtlasSprites. For approximately the same number of openGL calls used to draw a regular Sprite, you can draw as many AtlasSprites as you want.

A Sprite knows how to draw itself. An AtlasSprite doesn't. It's the role of the AtlasSpriteManager to draw its children. And thanks to that, it can batch the openGL calls and boost performance a lot compared to Sprites.

edit : riq replied faster ;)

Posted 2 years ago #
malphigian
Member

Thanks very much for taking the time to explain guys, I'm clear on the concept now. I think I confused myself because the current game I'm working on has some large character animations and I'm not reusing my atlas images for them.

Posted 2 years ago #

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