GameLoop() vs Delegation - massive prformance boost

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GameLoop() vs Delegation - massive prformance boost

(14 posts) (10 voices)

Started 1 year ago by atman
Latest reply from liquidfire

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atman
Member

Hello,
First of all let me say that I'm fairly new to cocos2d, yet I just finished my first game and just submitted to apple for aproval. Its a simple space shooting game where obsticales come at the player and you shoot them. I used "traditional" approach using the gameloop() which is scheduled 60tps. On the final stages, I tried to implement particle FX and simply was unable to put more then two of them, due to massive performance loss. The framerate would drastically drop.

I know there is a way to setup pointers to objects which interact together, and send messages to them only when needed(instead of constant gameloop() callbacks) through delegation pattern. I tried searching an example code of this amazing technique online, but was unsuccessful(using objective c). I would die for an example code of a small game, just to see how its done.

I know there are many pros in this forum who know exactly what I'm talking about. I would like to start my new game using delegation instead of gameloop(). An example code would be greatly appreciated. Please help. Thank you :)

Posted 1 year ago #
MikeSz
Member

Ummm I'm certainly not a pro coder, though we have wrote games on the AppStore so we have some experience. In fact one of out games - geoFighter - is a dual-stick shooter. And my experience tells me, that unless you really have tons and tons of objects - nothing is wrong with a gameloop. We had 100 of enemies, each with an AI, explosions, several hundred of billboard particles (not a particle effect, they were all handled by us) and a lot, lot more - all at 60 fps. Furthermore - if we were to write this game today, with better knowdledge etc, results would be much much better still

So my belief is that you just have largely unoptimized code. There is no technical reason whatsoever to have any problems animating/moving/AIing well over 100 objects at a time

Posted 1 year ago #
indy2005
Member

Hi,

One question I always had, was that in a PC for example, the game loop runs hundreds of thousands of times a second potentially, and the output to the video card may happen at 60 fps. But in Cocos, we have to limit all of our code, AI logic in the 60 fps loop, rather than at a faster rate of the processor?

Is this a silly question? I cant imagine the Unreal engine for Gears of War 3, operating its AI and physics ticks just 60 times a second?

Regards

i

Posted 1 year ago #
abitofcode
Moderator

@atman Not quite what you're looking for but maybe in the right direction;

http://www.cocos2d-iphone.org/forum/topic/843

Posted 1 year ago #
mobilebros
Moderator

@atman I too am curious to what you're referring to? I don't see how the delegation pattern is going to help you, and since the whole cocos2d framework is based on a "gameloop" I'm not sure you'd be able to get it working.

Posted 1 year ago #
cublah
Member

@indy2005

Although the gameloop may run more times in a second, you are still limited by the scan rate of the display/system.

If you want the game to run in 60fps then all game logic, physics etc has to be done in a frame, that is why if your code is not efficient and it takes more than a frame to execute your framerate will drop.

Posted 1 year ago #
araker
Moderator

@indy you're right that the refresh rate and logic update rate can be decoupled in games on consoles and pc. A higher update rate than the refresh rate will mean more accurate physics, smoother animations and more responsive controls. To decouple it on the iPhone would be very power inefficient since the cpu would never be idle, while the benefits are minimal.

@atman, I'm also curious what you consider the benefits of using delegation instead of a game loop.

Posted 1 year ago #
jordo
Member

i've actually always wondered about this... I'm by no means an experienced game designer, but the first game i developed was in java, and I put rendering on one thread, and game updates on another... I then just had to 'synchronize' both threads around my 'game state' object...

I don't even know if this is the case, but it seems to me that because there's really no synchronization needed for any of the cocos stuff, that both the game loop and rendering are on the same thread?

Posted 1 year ago #
atman
Member

Thank you all for replies, perhaps i'm not releasing something sometime. my music in the game is caf file of 7mb, and sometimes during gameplay i get evryffin slowed down and even though its not noticable audibly, i "sence" its the music cashing. i use SimpleAudioEngline, and preload the track in constructor, however during playback i know fo shaw it stucks on music. i wonder if SimpleAudiEngline uses some sort of lazy loading for a caf file.
i use NSMutableArrays for all my obsticles and drop them in da garbage array once they outta screen coords then all gets released. everyffin looking good in terms of memory management. all sprites are 64x64px max, maybe around 30 prites at a time on the screen da most.
any efficency tricks would be appreciated :) Thanx

Posted 1 year ago #
crmagicxxx
Member

@atman

I am PC guy and totally unfamiliar with caf files (so I just avoid them by using mp3 and wav). So, are you sure that hardware is used to play your music if you use caf file? I am always using mp3 for background music and worked with even larger than 7mb files and never saw that "caching" lag you are referring to...

Posted 1 year ago #
araker
Moderator

Caf is just a container, what audio format is inside the caf? I'm also wondering if you have no music playing, is there no lag/slow downs?

@jordo, there is no need indeed to have the game loop and rendering on the same thread. In fact apple recommends doing the rendering in a second thread (WWDC session 414).

Posted 1 year ago #
liquidfire
Member

@crmagicxxx - Here is a paragraph from the documentation.

Preferred Audio Formats in iPhone OS
For uncompressed (highest quality) audio, use 16-bit, little endian, linear PCM audio data packaged in a CAF file. You can convert an audio file to this format in Mac OS X using the afconvert command-line tool, as shown here:

...

For compressed audio when playing one sound at a time, and when you don’t need to play audio simultaneously with the iPod application, use the AAC format packaged in a CAF or m4a file.

For less memory usage when you need to play multiple sounds simultaneously, use IMA4 (IMA/ADPCM) compression. This reduces file size but entails minimal CPU impact during decompression. As with linear PCM data, package IMA4 data in a CAF file.

Posted 1 year ago #
crmagicxxx
Member

@liquidfire

Thanks, but I still don't get a point of encapsulating everything in CAF file even if Apple says so. I am more settled when I see mp3 or wav in my resources because then I am sure what was my intended purpose for those files - effects or music...

Posted 1 year ago #
liquidfire
Member

Aside from that I guess it really doesn't matter. MP3 I know is hardware decoded. I have no idea about CAF though, not sure. Possibly yes, possibly no. I don't know audio.

Posted 1 year ago #

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