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iPad 1 Performance (fill rate)

02-19-2012, 09:43 AM
#1
Joined: Jan 2012
Location: London, UK
Posts: 17
iPad 1 Performance (fill rate)

Hi guys,

I'm in the process of porting my iPhone Game to the iPad. Which supports a resolution with approx 5 times more pixels. While CPU load, and number of triangles to render should be roughly the same as running on an iPhone/iPod Touch when the game is zoomed out. The number of pixels to render will be 5 times more. I'm a little worried about this part.

I've seen my game run on a friend's iPad 1, running as an iPhone game with 2x zoom mode, and it runs no different, and again with the XCode Simulator running this way, is the same. But when I run it built as a proper 1024x768 iPad native app (without the scaling, and thus without the pixelation), it runs ridiculously slow on the simulator regardless of whether at 100% scale or 50% scale (2.53GHz Intel Core 2 Duo Mac OS X). Since I don't have my own iPad, I'm unable to test it, I'm contemplating buying one (or a 2nd hand one, just to gauge this performance). But it'd be great if I could just find some facts and figures to give me an idea of what to expect.

I'm a little worried that if I submit an update of my app, it may get rejected on the grounds that it runs too slow for the iPad.

To give an idea of how slow it goes. The only way to get full 60FPS performance on the simulator, is by disabling the background layer and foreground layer, so all that's rendered every frame are the turtles, the stars, and a bit of stats (so it smudges). As soon as I slap in a background layer it grinds to like 15 FPS (estimate). Is the iPad 1's GPU really this weak, or is it just the simulator. Can anyone with experience developing on the iPad shed some light?

I've got an idea how to optimise my engine (sacrificing the auto-scrolling of the background on some levels) which would make it run lighting fast on all devices, but I don't want to go that trouble if not necessary....
02-19-2012, 09:50 AM
#2
Get the iPad. Simulator does not simulate the performance.

02-19-2012, 02:39 PM
#3
Joined: Nov 2008
Location: Baltimore
Posts: 205
Quote:
Originally Posted by MrBlue View Post
Get the iPad. Simulator does not simulate the performance.
AAA+++

YOU HAVE TO GET REAL HARDWARE TO TEST ON!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The simulator runs at native speed of your macs CPU
the opengl layer is emulated using a jit for shaders
and accuracy but in no way tries to reflect real world performance.

So the parts of your app running on the CPU will be insanely faster then
the iPad, this includes disk i/o, physics etc.
and the opengl parts will most likely be insanely slower then the iPad.
Simulating OpenGL ES2 turns out to be a rather complicated problem
form what the apple GL team has told me.
02-19-2012, 06:35 PM
#4
Joined: Jan 2012
Location: London, UK
Posts: 17
I've submitted my App upgrade for review. When it's approved (fingers crossed lol), I'll visit a friend and try it on their iPad 1. My financial situation doesn't favour the investment in an iPad right this moment.
02-20-2012, 04:27 AM
#5
You could add your friend's iPad UDID as one of your 100 development devices and send them a pre-release profile build .app [and the corresponding provisioning profile] so they can test it before you submit to Apple.

If you get an 8GB iPod touch 4G (the latest retina one with A4 cpu like the iPhone 4) that will have fairly similar performance to an iPad 1 and they are only around 150 new. You'd still need to test on iPad for exact performance tests though as it does have 22% less pixels than iPad 1. So that might be a wise investment for development and means you can test retina iPhone too (which you should really be doing anyway).

Apps: Lead Wars (TA Thread) | Super Grav (TA Thread)
DemonStudios Ltd | Indie Game Dev
www.demonstudios.com
Follow: Facebook | Twitter
02-20-2012, 05:41 AM
#6
Memir despite having already submitted the app for approval I recommend doing what I suggest above now anyway (i.e. send your friend a build to test).

That way, if you find it doesn't run as well as you would like you could choose to reject the app yourself and stop that build being released. Then make any optimisations you need and submit a new binary (having re-tested of course).

Apple are very unlikely to reject an app for having framerate dropouts - they assume that you do your own performance tests so if it runs like a dog they will be OK with that as they assume you are happy with it. They just don't want crashes or for an app to break any of the terms.

Apps: Lead Wars (TA Thread) | Super Grav (TA Thread)
DemonStudios Ltd | Indie Game Dev
www.demonstudios.com
Follow: Facebook | Twitter
02-24-2012, 07:38 AM
#7
Joined: Jan 2012
Location: London, UK
Posts: 17
Too late, it's been approved. Don't know whether it runs like hell, or is normal.

If someone could check it out would be much appreciated. Ive asked a friend to try it this evening.

Thanks.
02-24-2012, 04:17 PM
#8
Joined: Jan 2012
Location: Warsaw, Poland
Posts: 34
Memir maybe you should think about QA pass?

I bet that you find bunch of testers at this forum, so maybe one of them would be able to give you a feedback daily (or even often).

Take a look at TestFlight platform and then (even without a "full" integration) you will be able to distribute build(s) easily.

I have simillar issue with iPad3 - I'm going to prepare my game for a new hardware but I won't get it for 2-3 months (I don't even know when iPad3 will be released in Poland ). So I'll find someone (from the US/UK?) who can help me with test on the real device.

-=Agnes=-

Last edited by AgnesDev; 02-24-2012 at 07:28 PM.
02-24-2012, 04:26 PM
#9
I tried the lite on my ipad 1st gen and it plays fine from what ive seen... nice app
02-25-2012, 05:38 AM
#10
Joined: Jan 2012
Location: London, UK
Posts: 17
Quote:
Originally Posted by Jack Shiels View Post
I tried the lite on my ipad 1st gen and it plays fine from what ive seen... nice app
Nice!

I'm tempted to buy an iPad to try it. As I think it should play better on the iPad than on the regular iPhone/iPod Touch, considering the nature of the game. I'll now have to release a new paid version with the new iPad support, along with some rebalancing of requirements for levels, and I'll throw in some more levels to the paid version.

While the iPhone/iPod Touch version can do the same thing, and zoom out to show (almost) the entire level (1024x680), it'll do so on a 480x320 res. While on the iPad it'll resize to the entire 1024x768, doing so on an actual 1024x768 res, which I think should make everything also a little bigger (132 ppi for iPad, vs 163 ppi for iPhone3, and 326ppi for iPhone 4).

iPhone Version


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iPad Version