Retina FPS and iPhone 4 performance

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Retina FPS and iPhone 4 performance

(6 posts) (3 voices)

Started 9 months ago by cmcaleese34
Latest reply from cmcaleese34

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cmcaleese34
Member

I would like to start by thanking the cocos2d community as a whole for all the knowledge they have made available in this forum. I am about a week away from submitting my first game, and I wouldn't have made it nearly this far without all the great info on this site.

Anyway, on to the question:
My game uses box2d and follows a b2body moving fast through the world I created. In the world I have three background layers scrolling at different speeds for a parallax effect. The layers are .png images that I put in a sprite sheet with texture packer, as well as a CCLayerColor. Normally, when I run the application on my 3gs or in non-retina mode on the iPhone 4 everything runs smoothly at 60fps. However, as soon as I switch to retina my frame rate drops to 40fps.

I figured the drop was just because the hd graphics were taking up too much memory, but even when I turned the pixel format to RGBA4444 and tried using non-hd graphics scaled 200% I was getting 40fps. Also, in instruments, my cpu use is only at about 30% during the most tasking parts of the game. I have thumb turned off for armv6 and on for armv7. If I remove the CCLayerColor and one of the sprites my fps jumps up to 50, but I need both of those elements in my game and 50fps still isn't great. When I test the game on the iPad 2 (universal app) it never drops below 60fps and it uses most of the same -hd graphics that I am trying to use on the iPhone 4. Is the difference in performance really that great between the iPad 2 and iPhone 4?

Does anyone have any suggestions on how I could boost the frame rate in retina mode? Is there a build setting that I could be missing? I"m running in release mode, I did the stuff on the cocos2d best practices page... I am out of ideas at this point. Ideally I would just be able to switch retina mode off for this one scene because it would run smoothly if I could do that, but unfortunately as far as I know you have to commit to either having retina mode on or off. Using smaller images stretched 2x hasn't seemed to help much.

I'm so close to being finished but this fps problem is really vexing me. I never thought I would be having performance issues on the iPhone 4!

Thanks so much in advance for any suggestions!

Posted 9 months ago #
itlgames
Moderator

I had a similar issue, but not sure if its the same though:

http://www.cocos2d-iphone.org/forum/topic/17736

Basically my problem was the little hack to display SD graphics non blurry on retina devices (mag filter and content rect offset), and that was actually messing once I got the real HD graphics. Once removed, got back to 60fps stable.

Posted 9 months ago #
Birkemose
Moderator

To my understanding, enabling HD will also quadruple the pixels rendered by OpenGL.
Memory issues on 3G+ devices, really isnt a big problem, so cutting textures down to 4444, should have little or no effect unless you really are pushing it.

So if you simply are overloading the GPU, you would get exactly the result you describe.

Posted 9 months ago #
cmcaleese34
Member

Thanks for your replies. I never used that SD graphics hack, so unfortunately I couldn't remove that.

I think you are correct, Birkemose. So does that mean the only way to lighten the load on the GPU is to have fewer textures on screen? That would really be a downer since I can't reduce the number of items on the screen plus it runs at 60fps in standard definition. Is there anything else I can do or am I SOL?

thanks again

Posted 9 months ago #
Birkemose
Moderator

I am guessing that your game heavily relies on timing and physics.
My first try would be to lower physics updates and framerate to fixed 30. That would keep physics consistent.
If your gameplay needs responses quicker than that ( aka super-ninja-quick ), I guess your only option would be to reduce numbers of pixels drawn.

Posted 9 months ago #
cmcaleese34
Member

Ok, thanks. I'll switch the time step to 1/30 and see if that helps. When you say "reduce numbers of pixels drawn" that means fewer textures, right? In other words, there is no setting or hack I can use that would reduce the number? Sorry if that is a stupid question, but I am still pretty new to game development.

Posted 9 months ago #

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