This document discusses cocos2d and how it handles loading textures asynchronously on iOS. It explains that cocos2d uses the CADisplayLink and RunLoop to synchronize drawing with the vertical refresh signal and maintain a framerate of 60 frames per second. It also describes how cocos2d uses the addImageAsync method and Grand Central Dispatch to load textures on background threads instead of blocking the main thread.

1. @splhack

2. cocos2d +

3. Loading

4. Loading.......

7. @yuroyuro: 31 May 2011
http://twitter.com/#!/yuroyoro/status/75399664496680960

8. cocos2d
RunLoop
cocos2d CADisplayLink
cocos2d RunLoop

9. CADisplayLink
RunLoop

10. VSYNC

11. VSYNC
VSYNC

12. VSYNC
Vertical Synchronizing signal

13. VRAM
VRAM

14. VSYNC
VSYNC
VRAM
iPhone

15. CADisplayLink
RunLoop VSYNC
CADisplayLink RunLoop VSYNC

16. CADisplayLink
iOS 1/60
60FPS
16.666
1 1/60

17. 1/60
VSYNC
1/60 → 2/60(1/30) → 3/60(1/20)
→ 4/60(1/15) → ...
1/60

18. RunLoop
(Blocking)
RunLoop

19. RunLoop
(Blocking)
RunLoop

20. RunLoop

21. cocos2d
CCTextureCache
- (void)addImageAsync:target:selector:
cocos2d

22. addImageAsync

23. addImageAsync
•
• GL API
(EAGLContext sharegroup)

24. addImageAsync
•
•OpenGL ES
•glTexImage2D
( GL )
OpenGL ES API

25. addImageAsync
•

26. “
RunLoop Main Queue
Global Queue Serial Queue ”
iOS 4

27. Grand Central Dispatch
GCD
iOS 4

28. Grand Central Dispatch
Global Queue
Serial Queue
addImageAsync

29. Grand Central Dispatch
iOS 4 5