Huge FPS problems, 10-15 sprites all running of a single spritesheet

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Huge FPS problems, 10-15 sprites all running of a single spritesheet

(17 posts) (5 voices)

Started 1 year ago by Bongeh
Latest reply from Bongeh

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Bongeh
Member
Hi there,

i have an 8-bit, 1024 by 1024 png, it is 320kb on disc and has an alpha channel.

This sheet contains all my gfx for my entire game.

I have 3 sprites that are 480x320, these are my background and a paralax kind of background at the back. These sprites get there texture from the spritesheet.

I have a player sprite, that has a few CCAnimation's with all of the frames derived again from the spritesheet.

i have some various map objects, things you have to jump over, no more than 5 on screen at any one time, about 8-9 initialized into the scene all the time, however, if they are not on screen, i set the visibility to false so that openGL does not render them.

I am getting 45-50fps in quiet areas of my game, and once things get going, the fps bombs too about 30fps, the same happens when i try to initialize more sprites.

As far as i knew, it's possible to have hundreds of CCSprites running at a fairly acceptable fps, and yet my game seems so limited.

Does anyone have any ideas as to what could be causing my slowdown?
```
[[CCDirector sharedDirector] setPixelFormat:kTexture2DPixelFormat_Default];

	[CCTexture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGBA8888];
```
These two lines are the only place i set the texture format, they appear in my appDelegate.m in the order shown.

Any ideas?
Posted 1 year ago #
PhilM
Member

Its the large sprites that seem to cause that issue I think. Try hiding your background images to see what effect that has.

If your staying above 30fps, I wouldn't worry too much. Thats what we're doing, and have only recently started to run into a few issues where it drops below 30 (due to lots going on), and it starts to get a little noticeable. So I'm now looking at possible areas to optimise.

Theres some performance tests built into cocos2d you can run on your device to give you an idea of what it might be capable of running.

edit: it also helps if you can get away with loading your images in 16bit or less, rather than full 32bit. Depends on your graphics whether you can get it looking ok at lower formats.

Posted 1 year ago #
Bongeh
Member

thanks for the reply phil, is an 8-bit texture not half of a 16-bit one?

Yeah it does seem to be my 480 by 320 textures, however, i kinda need my backgrounds lol :), do you think building my background out of multiple sprites might help?

Personally i don't think it will as you are surely loading the same amount of texture onto the screen, but initializing lots more CCSprites?

As another note, I am using displayLink director and have thumbcode turned off.

Posted 1 year ago #
Bongeh
Member

for anyone following this post, ive managed to drastically improve my fps by spotting a fools error that i'd done myself.

i had 20+ chipmunk bodies sat off screen when they weren't being used. i now tell the objects to remove themselves from the gameSpace when they are not on the screen, and readd themselves when they come on. This means only 'active' sprites that are on the screen are being rehashed in my step: method.

This may seem like and obvious thing to do, but it didnt realise how much load i was putting onto chipmunk by having objects sat offscreen, doing what i thought was 'nothing'.

Other than that, i've consolidated all of my menu/button gfx into a single spritesheet to again reduce texture memory being used.

A question to anyone reading, does anyone know if its worth releasing the CCTexture2dCache when moving from my menu's into the game? or will replacing the current scene do this for me?

Posted 1 year ago #
greyhoundgames
Member

There is a function on the cache to release all textures that nobody is using. You can use that if you want.

Posted 1 year ago #
Bongeh
Member

my question was does replacing a scene, and thus releasing the one you've just exited, release the textures created in that scene? or do they sit in the cache?

Posted 1 year ago #
greyhoundgames
Member

You have to release it manually.

Posted 1 year ago #
Bongeh
Member

okay, thank you

Posted 1 year ago #
Bongeh
Member

hmmm after refining my logic and further testing i have managed to get up to 60 FPS on very hectic areas of my game.

However, this is areas when i have pads hovering over a background, logically, theres 8-9 schedulers running at this time. (my objects maintain themselves, when they move off screen they die, as do the schedulers)

If i have a 'floor' moving above the background, covering it entirely, the FPS hammers down to 45-50.

Logically, at times, there is alot less going on on areas with the 'floor' being present. I imagine this is because OpenGL is having to render 320x480 more of texture, but surely paralax has this same issue constantly?

Posted 1 year ago #
Bongeh
Member

okay, so i just instanciated 200 sprites during the part of my game where the 'floor' doesnt move over the background, just the sprites do. and it still held at 60fps!

Something major is going on with a 320x480 image being moved over teh top of another 320x480 image.

Is this a known openGL issue, or maybe i have a bug?

Posted 1 year ago #
Karl
Member

Bear in mind: using 8 bit PNGs buys you nothing. iPhone's OpenGL implementation only understands 16-bit and 32-bit textures (and PVRTC). There is an 8-bit mode, but it's for masking only.

You need to specify the format for cocos to convert your texture into at runtime.

Also, the iPhone's memory is SLOW. The bigger your texture data, the worse it will perform.

Posted 1 year ago #
abitofcode
Moderator

@Karl will probably be able to confirm if I have this right but I've always worked to textures being rounded up to the nearest power of 2 when in memory so 320 -> 512 and 480 -> 512.

Rather than move a 320 pixel high texture could you make it 256 pixels covering the gaps at the top/bottom with the background image. I do this in my game by having a blue bar at the bottom of my background image that continues into the bottom of each mountain sprite (which are 128x128 pixels), it seems to work down to 2G without lag (I've been told, not actually seen myself :)

Posted 1 year ago #
Karl
Member

As far as I know, moving a textured object shouldn't have a performance hit over the same object remaining stationary. OpenGL only cares about what it has to displayhere and now; it has no concept of motion. Cocos sends a render call for every visible object on every frame, even if technically it didn't need to be redrawn (even if it tried to optimize this step, if you have a background image and ANYTHING changes, it will need to redraw everything regardless).

And every render requires OpenGL to map pixels, which it does in slow main memory (there is no dedicated video memory on iPhone).

So basically, yes you'll get better performance with a 256 pixel high image than a 512 pixel high image, but you'll get worse performance if you replace a single 512 pixel high image with a 512 pixel high image AND a 256 pixel high image.

Posted 1 year ago #
Bongeh
Member

Thanks for the reply guys, i was under the impression that if all of my sprites were using a single CCSpriteSheet this would only be loading one 1024x1024 texture, and then all my sprites would be simply referencing that texture?

Are you saying that it would be more efficient to have say, 3 sprite files to make up a background rather than one that is the full size of the screen?

My spritesheet also has an alpha. Although certain areas of my texture do not require the alpha channel. If i had 2 spritesheets, with with alpha one without, both 1024x1024, do you think this would help openGL when rendering the background and floor (both non alpha textures in reality)

Posted 1 year ago #
Bongeh
Member

hmmm tried making a non alpha spritesheet for my larger bits of texture that dont need an alpha, it seems to have given me maybe 2-3more fps, but its still juddery.

Posted 1 year ago #
abitofcode
Moderator

btw you are testing this in release mode when looking at the fps?

Posted 1 year ago #
Bongeh
Member

yeah, cocos2d debug off, no NSlog's etc

I think im understanding what the issue is now.

I effectively have at certain points of my game

480x320
480x320
and maybe
7 or 8
200x100

thats

2360x1440 of texture being redrawn every tick

When testing, if i permanently make my background visible, i have solid 60FPS.

I need to cut up my background into strips and made the game hide the background sections when they are being covered.

That should solve it.

Posted 1 year ago #

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