FPS changed a lot sometimes when pause and resume app

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FPS changed a lot sometimes when pause and resume app

(8 posts) (3 voices)

Started 2 years ago by Yu Chao
Latest reply from Steve Oldmeadow

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Yu Chao
Member

I develop my game using cocos2d, I met issue that the fps changed a lot after I call

[[Director sharedDirector] pause];
[[Director sharedDirector] resume];

Say I started my app, the fps rate stays at 60 fps, after I click pause button twice which actually make the director paused and resumed, the fps rate may or may not changed to about 30-40. Not always but at some rate (60%?), the fps rate will jump between 60 and 30-40 when click pause and resume.

I don't have any clue about this, does anybody meet this?

Thanks in advance.

Posted 2 years ago #

Steve Oldmeadow
Administrator

Have a look at the code:

-(void) pause
{
	if( isPaused_ )
		return;

	oldAnimationInterval = animationInterval;

	// when paused, don't consume CPU
	[self setAnimationInterval:1/4.0];<----------- ??????
	isPaused_ = YES;
}

Posted 2 years ago #

Yu Chao
Member

@Steve

Sorry I didn't explain correctly in previous post, I revised it a bit. It's after click pause and then resume that the FPS rate may change, not click pause or resume singly.

Posted 2 years ago #
Steve Oldmeadow
Administrator
Do you mean the fps permanently drops after doing that? If so are you testing on a 3gs iPhone - if yes then use the display link director. Really, I'd advise everybody to use display link director otherwise you will have random fps drops on the 3gs (and I assume the latest iPods that use the same hardware).
```
if (![Director setDirectorType:CCDirectorTypeDisplayLink]) {
	[Director setDirectorType:CCDirectorTypeNSTimer];
}
```
Posted 2 years ago #
Yu Chao
Member

@Steve

Thanks very much, you saved me!

I was using cocos2d 0.8 version and upgraded it to 0.8.2 to use the CCDirectorTypeDisplayLink. Everything is just fine.

Posted 2 years ago #
Steve Oldmeadow
Administrator

Glad it fixed it for you. I forgot display link was only added to 0.8.2 - things change so fast around here.

Posted 2 years ago #
exorcyze
Member
I'm guessing that the display link type uses some hardware functions newly available on the 3gs? And that on 3gs phones it would still be better than using fast director?

IE, would the following be a good practice:
```
if (![Director setDirectorType:CCDirectorTypeDisplayLink]) {
	[Director setDirectorType:CCDirectorTypeMainLoop];
}
```
Posted 2 years ago #
Steve Oldmeadow
Administrator

Display link director uses the CADisplayLink class which became available in OS 3.1. CADisplayLink allows you to synchronise with the screen refresh rate so the limitation is that you can only uses tick rates that are fractions of the screen refresh rate (60 Hz). i.e. 60 ,30,15.... fps.

If you do not use the display link director you will get random fps drops on 3gs devices even with the latest firmware. For me it would usually be 60->40, there was also no apparent pattern to when it would happen.

So, my advice would be to try to use display link director and if you are running on an OS version older than 3.1 then fall back to whatever Director you would have used normally.

Posted 2 years ago #

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