Sharp textures for zoomed iPhone apps on the iPad

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Sharp textures for zoomed iPhone apps on the iPad

(19 posts) (5 voices)

Started 1 year ago by Daniel
Latest reply from amergill

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Daniel
Primary Feather
When you start a normal iPhone app on the iPad, the pixels are just scaled up, creating a blurry output. That is the case even when you created the app with HD textures for the retina display of iPhone4.

For "Go Usagi", I already helped Durrza change that for iOS 3.2: When you start the game on the iPad, it looks just like the retina version scaled up full-screen, with crisp and sharp textures. In iOS 3.2, however, it was a bit of a hack to accomplish that. Now, with iOS 4.2 finally available for the iPad, it was simple to add that feature to the Sparrow core.

If you grab the latest development version via SVN, you can see the feature in action in the demo application. If you want to have your games behave the same way, you just have to add the following code to you application delegate:
```
[SPStage setSupportHighResolutions:YES]; // that one's just like before

// force high resolution if we're on the iPad:
if ([[UIDevice currentDevice].model rangeOfString:@"iPad"].location == 0)
    [SPStage setContentScaleFactor:2.0f];
```
That's it!

On iOS 3.2 and non-retina devices, this code won't do anything. On the iPad with iOS 4.2, however, it will let your game run in high definition.

The only downside is that this code doesn't check if it runs in the simulator. The "model" property always returns "iPhone simulator". But on a real device, it will work fine =)

Take care, though: the iPad (revision 1) has only half the RAM of the iPhone4! So you'll have to take care that the HD textures fit into that space.

If anyone wants to test this feature, please be sure to come back here and post the results. Thanks in advance!

Daniel
Posted 1 year ago #
evilliam
Member

Hi Daniel,
I've checked out the latest version from the repository and this code works (in that it doesn't throw any errors)
However the app doesn't appear to work as I expected, it certainly doesn't appear to be displaying the scaled up textures at their larger size( they seem small )

I've tried changing the content scale factor to 1.0f instead, but no dice.

Is there anything else I can do to force the issue?

Cheers,
Liam

Posted 1 year ago #
Daniel
Primary Feather

Hm, that's weird ... have you tried the demo project, too? Does it work?
BTW, don't forget: this works only on iOS 4.2!

Posted 1 year ago #
evilliam
Member

Hi Daniel,
I'm using iOS 4.2 - and I've tried the demo project- which also doesn't work on my ipad (it stays small in the middle and offers me the 2x button that non-universal apps have)

This is a version I checked out of subversion today.

Any ideas?
I can hack around it but it won't work with any future version of Sparrow if I do.

Thanks all the same for your help.

Posted 1 year ago #
evilliam
Member

Ah- just noticed that clicking the '2x' button does in fact change the resolution for the demo (not just scale it up)

I'll take a look through that and see how it works (I don't want my app to have to scale up but will if I have to)

I'm actually using sparrow as part of a larger framework and actually init my app with the a frame that reflects the ipad size.
Perhaps this is the problem?

Posted 1 year ago #
evilliam
Member

Hmm - changing the frame with which I create the SPView instance doesn't seem to fix it (it just makes the fame small and sit in the top left hand corner, the graphic elements are still half-size) but their x & y values seem correct.
It's very weird indeed.

Is there any other way of *forcing* the SPTextures to be drawn at double scale? I've tried setting the SPStage contentScaleFactor to 4.0 and this just blows up.

Thanks for your time...
Liam

Posted 1 year ago #
freerunnering
Moderator

You wanted to have a universal app but this new code is for iPhone apps to force the iPad to use @2x graphics making them look better.

Posted 1 year ago #
evilliam
Member

I see...
I already had a universal app, but it doesn't seem to work anymore. I guess I'll have to hack around and double the scale sizes for the ipad version.

Posted 1 year ago #
Daniel
Primary Feather

Hi Liam,

as Freerunnering correctly pointed out, there's a small misunderstanding here: that new feature I talked about is just for conventional iPhone apps (*not* universal apps or iPad-only apps) to make them look good on the iPad.

For a real universal-app, that doesn't help you. In that case, you have different SPView sizes, depending on where the app is started:

- old iPhone: 480x320 with a scale factor of 1
- new iPhone: 480x320 with a scale factor of 2
- iPad: 1024x768 with a scale factor of 1

So you've got to handle 2 stage sizes: 480x320 or 1024x768, which have different aspect ratios as well.

For that case, I would create 2 sets of textures with a custom suffix (like "_hd"), and have all texture loading handled by a special class which gives you the HD textures on the iPad and the SD textures on the iPhone. The logic of deciding where to display which object with the different size and aspect ratio has be done manually, though. It's definitely more work, but that's the same that has to be done when you create a universal app with UIKit and the interface builder.

Posted 1 year ago #
evilliam
Member

Hi Daniel, I'm going through this now...
That all seems very cool, the trouble I seem to be having is that I can't seem to set the scale factor! Even when I force the app to use the @2x texture atlas it seems to draw the items at half-size.

I'm adding a category at runtime onto the SPDisplayObjects in my game to force them to scale up, and this seems to work for the most part (slightly furry fonts so I'll have to look into that)

but even when I set [SPStage setSupportHighResolutions:NO] for the ipad version the issue persists.
But it's no problem, won't take too long to hack around!

If I can ever help the Sparrow project out, let me know.

Posted 1 year ago #
evilliam
Member

Besides donating (WHICH I JUST DID, first open source project to ever get my fifty bucks)
I'd have given more but I don't get paid till this game gets on the app store.

Posted 1 year ago #
Daniel
Primary Feather

Hi Liam,

first of all: thanks A LOT for the donation!! It's really appreciated, and you help us a lot with that, honestly =)

Concerning the "@2x"-stuff: you're developing a universal app, right? Then, first of all, just forget all this scale factor stuff. Try to make your app work in 480x320 on the iPhone (ignore the retinga display right now), and in 1024x768 on the iPad.

Keep the following in mind: there are 2 things that define the size of your Sparrow stage:

1. the size of the SPView. It will be 480x320 or 1024x768.
2. the stage size. That can be a little confusing: it doesn't have to be the same size as the SPView -- it just defines the extent of the coordinate system. If you draw a quad at (x: stage.width-1, y: stage.height-1), it will be on the lower right corner of the SPView -- no matter how big the SPView is. To avoid confusion, I recommend you set the stage size to the same size as the SPView.

So you've got 2 different stage sizes and have to (manually) find a way to create your objects at the right positions and with the right textures so that it looks fine and makes sense.

Creating a universal app is definitely challenging, and more difficult than just having an iPhone app scale up. But I'm sure you'll find a way, and I'm here too to help you =)

You

Posted 1 year ago #
Daniel
Primary Feather

Hello again,

I had another idea that could make this a little easier. Have a look at this forum entry to find out more about it.

Posted 1 year ago #
humble
Moderator

Hi. I've downloaded the svn version and added the code, but I am fumbling a bit in the dark, since I do not actually have an iPad. Am I getting the correct behaviour when the simulator does not load the hd graphics or is something wrong?

Thanks..

ERik

Posted 1 year ago #
Daniel
Primary Feather

Hi Erik,

yes, as I wrote in the post, I have not found a way to find out at runtime that I'm running in the iPad simulator, so the code will only do something on the actual device. However, you can easily test it by hard-coding "2" as the scale factor before you launch it in the iPad simulator.

Keep in mind, though, that you shouldn't activate this feature in your application if you have not tested it on an actual device. The iPad has only half the memory of the iPhone4, so you need to be very careful with memory (especially texture memory) on that device.

Posted 1 year ago #
freerunnering
Moderator

The iPhone only has half the memory of the iPhone 4 yes but remember the iPod 4 also has the same ram as the iPad and is a retina device so that shouldn't be a problem or it'll be a problem on the iPod too and you need to fix it.

Posted 1 year ago #
humble
Moderator

Oh, sorry for my poor reading skills. Thanks for the advise guys! You are probably right about not doing something I haven't tested Daniel. Ah, well... I will do some testing on my iPod and see what happens i think... Thanks.

ERik

Posted 1 year ago #
Daniel
Primary Feather

Wow, thanks freerunnering, I was not aware of that! I always assumed that the latest iPod touch has the same amount of RAM as the iPhone4.

In that case, it's even more important to make sure to test HD apps at least on one of those devices (iPad with HD-feature turned on or iPod Touch 4).

Posted 1 year ago #
amergill
Member

Updated for iPad Detection.

[SPStage setSupportHighResolutions:YES];
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
[SPStage setContentScaleFactor:2.0f];
}

Posted 1 year ago #
undertake
Member

If you have not tested it on an actual device. The iPad has only half the memory of the iPhone4, so you need to be very careful with memory (especially texture memory) on that device.

Thanks

Posted 1 year ago #

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