Strange frame rate variation... « cocos2d for iPhone

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Strange frame rate variation...

(10 posts) (3 voices)

Started 1 year ago by Xou-Han
Latest reply from Xou-Han

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Xou-Han
Member

Hi there!

I'm working in a Cocos2D project. The project is nearly finished and it works well. However, since today (I didn't notice it before and I don't think it ever occurred) sometimes when the GameScene begin it runs at half the normal frame rate... The whole project runs at 60 fps, but sometimes (just sometimes and I think totally arbitrary) the game scene (once a level is selected in the menu) runs at 30 fps (regular 30 fps so it doesn't seem to be a performance problem because it never rises or falls from 30). Anyone knows what can be happening? The frame rate is just set once at the application initialization and it's never touched before...

It seems that the frame rate get to 30 fps when I show a CCSprite in front of the whole game scene (for example the pause screen, which is a black transparent layer), and when the CCSprite is set to invisible (and the game continues running) the fps return to 60 fps (however sometimes they keep at 30 fps)... I don't understand!

Thanks in advance! :)

Posted 1 year ago #
robodude666
Member

From what I've noticed, the game may drop to 30 FPS sometimes based on the activity on the screen. If you have a lot of particle effects, sprites, or actions going on at once it will drop. I find it interesting that it's either 60FPS or 30 FPS.. It's rarely ever in between.

Posted 1 year ago #

Xou-Han
Member

Hi there!

In fact I don't think it's due to screen activity... I'll explain: just when the level begins a 130/255 opacity layer is shown (and when you're ready to start the level you simply touch the screen then this layer is set to invisible and the game begins). What happens is that when this layer is shown FPS is EXACTLY 30, and when the layer isn't shown it usually raises to 60 FPS (but it doesn't goes around 60 or around 30, it is 30 or 60 exactly!)... When I pause the game the same layer is shown and again FPS goes to 30 (exactly), and then back to 60 when I un-pause it... Sometimes when the game begins (after the pre-game screen) FPS keep at 30, which is most unlikely... Here is the code I'm using, but I don't think it's something related to it because I've been using this code since men arrived on the moon and it always worked at 60 FPS without a problem...

// In the AppDelegate.m
- (void) applicationDidFinishLaunching:(UIApplication*)application
{
	[[UIApplication sharedApplication] setIdleTimerDisabled:YES];

	[FlurryAPI startSession:@"K4QRTGZ38WTLP9Z83K86"];

	window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

	[window setUserInteractionEnabled:YES];
	[window setMultipleTouchEnabled:YES];

	if( ! [CCDirector setDirectorType:CCDirectorTypeDisplayLink] )
		[CCDirector setDirectorType:CCDirectorTypeMainLoop];

	[[CCDirector sharedDirector] setPixelFormat:kPixelFormatRGBA8888];
	[CCTexture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGBA8888]; //Config DEFAULT

	[[CCDirector sharedDirector] setDeviceOrientation:CCDeviceOrientationLandscapeLeft];
	[[CCDirector sharedDirector] setAnimationInterval:1.0/60];  // Frames are set to 1/60...
	[[CCDirector sharedDirector] setDisplayFPS:YES];

	[[CCDirector sharedDirector] attachInView:window];
	[window makeKeyAndVisible];		

	[self initializeOpenfeint];

	[[CCDirector sharedDirector] runWithScene:[Game node]];
}

// In the GameScene.m
-(id) init
{
	if( (self=[super init])) {

		self.isTouchEnabled = YES;
		self.isAccelerometerEnabled = NO;

		cpInitChipmunk();
		space = cpSpaceNew();

		currentMap = 0;		

		[self schedule: @selector(step:)];
	}

	return self;
}

-(void) step: (ccTime) delta
{
	if ( !pause ) {

		int steps = (int)( delta / 0.01666 ) + 1;
		if (steps < 2) {
			steps = 2;
		}

		CGFloat dt = delta/(CGFloat)steps;

		for(int i=0; i<steps; i++){
			cpSpaceStep(space, dt);
		}	

		cpSpaceHashEach(space->activeShapes, &eachShape, nil);
		cpSpaceHashEach(space->staticShapes, &eachShape, nil);

		[self updateScene:delta];
	}
}

Does anyone knows what can be happening? It doesn't make sense that FPS are either 60 or 30 just when a semi-transparent layer is shown in front of the screen...

Thanks! :)

Posted 1 year ago #

Xou-Han
Member
Hey, I've found what is causing my problem (though I don't understand why):

I have a global CCSprite called "blackLayer" which I use to make a semi-transparent black layer in front of the game scene to pause the game and show statistics, for example, and if I try to print the pause screen without the black layer FPS keep at 60, but if I simply print the layer (without anything else) FPS drop to 30... However, I don't know why!
Here is how I create the layer:
```
blackLayer = [CCSprite spriteWithFile:@"blackLayer.png"];
	[blackLayer setPosition:CGPointMake(240, 160)];
	[blackLayer setOpacity:130];
	[blackLayer setVisible:FALSE];
	[self addChild:blackLayer z:2];
```
And when I touch the pause button I simply call:
[blackLayer setVisible:TRUE];

And to hide it:
[blackLayer setVisible:FALSE];

Why can this be happening? Is there any known bug with this? Does anybody knows how can I solve it?

Thanks in advance! :)
Posted 1 year ago #
robodude666
Member

That's weird... Shouldn't happen, and in fact the blackLayer sprite shows up fine with a constant 60FPS frame rate in my test scene class. I'm not doing anything else though.

Is blackLayer just a sprite, or is it part of an actual layer of its own? You could possibly be doing something else in the background that you might not be aware of. Do you have any schedulers going off, or actions?

Posted 1 year ago #
Xou-Han
Member
It's just a sprite as you've seen... I have plenty of sprites like this, but the frame rate only drops when showing this one (there's no problem with the others). And I'm sure there's no problem with actions or schedules, because it's that simple:

To show the layer:
```
[blackLayer setVisible:TRUE];
[labelNameLevel setVisible:TRUE];
startingLevel = TRUE;
```
To hide the label:
```
[blackLayer setVisible:FALSE];
                        [labelNameLevel setVisible:FALSE];
			startingLevel = FALSE;
```
I'm getting really mad with this... no explanation, no solution, it's really senseless... :S
Posted 1 year ago #
robodude666
Member

What is the image you are using in particular? Have you tried replacing the "blackLayer.png" filename in the creation process to another image, like say from your menu screen background? Or some other image you know works well? This particular blackLayer.png image might be corrupted in some way.

Posted 1 year ago #
Xou-Han
Member

Hi there!

I've tried this but didn't helped in anyway (the problem is still there)... I don't know what could have changed, but I've tried an older backup of my project (which I've saved like 15 days ago) and it doesn't show this problem (it keeps always at 60 FPS)... I've been using Flurry in my project (which is a free API to retrieve statistics) and it always worked well, but I've recently installed a new version (I'm sure it's not the problem, but)... I don't know what can I do because nothing seems to have sense with this... May I call the ghostbusters? ^_^

Thanks!

Posted 1 year ago #
JaSp
Member

I seem to have had the same kind of problems, particularly when using large semi-transparent sprites. My theory is that since it is large, the OpenGL blending function is more expensive as it covers more different objects to blend with, hence causing the slowdowns (but I'm not sure at all, I'm not a technical expert).

Anyway, if "blackLayer.png" is actually a fully black opaque image, you should try to replace your sprite with a black CCColorLayer.

Posted 1 year ago #
Xou-Han
Member

Hi there!

I've finally found what is happening (though I'm unable to solve and I don't know actually if there's someone who could) on this thread:
http://www.cocos2d-iphone.org/forum/topic/3507

It seems that at certain number of "big" images frames drops at a particular number... Fortunately I don't explicitly "need" all those images, so I've simply erased one of them and (thanks JaSp!) replaced another one by a CCColorLayer, and now FPS are always at 60...

Thanks both for your help! :)

Posted 1 year ago #

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