Tag Archives: git

OpenGL ES 2.0 on iPhone OS 3.0

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Now that the NDA on the iPhone OS 3.0 SDK has been lifted (which happened much faster than what I thought it would take!) here’s my first contribution to the world of iPhone OS 3.0 open source code: sample code about how to use OpenGL ES 2.0 on the iPhone 3GS, something I announced in Twitter last week.

As you might know by now, one of the biggest enhancements (and yet, one of the most obscure) of the newly released iPhone 3GS is the new GPU chipset, which allows developers to create applications using Open GL ES 2.0 (together with Open GL 1.1, which was already available in the first two iterations of the iPhone). This is a major advance, invisible to the end user, which, coupled with the unprecedented performance boost of the iPhone 3GS, opens up the possibility to developers to create applications with new textures and effects, yet unforeseen on this platform.

Given that Xcode does not (yet) bring an Xcode template to play with, and that the OpenGL ES 2.0 Programming Guide book, by Aaftab Munshi, Dan Ginsburg and Dave Shreiner does not (obviously) bring iPhone examples, I have created a project in Github where I will be publishing the code samples in the book, as I progress in the lecture, ordered by chapter, ready to compile and play with.

Enjoy! I’m happy not having to use the word “[REDACTED]“ any more now (there’s the other OS, the bigger cat, but, oh well…)

Update, 2009-06-24: I just found this blog post by the folks of Black Pixel (Daniel Pasco‘s company) with benchmarks about OpenGL ES on the iPhone 3GS… and the first line says it all:

Holy crap, this thing is fast

Update, 2009-06-24: Jeff LaMarche just announced that the authors of the book have published iPhone – compatible code in the book website! That effectively renders this project useless :))

NIBs or code? Why not both? Here’s nib2objc.

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(Somehow this project seems to me so simple, that I’m sure someone has done this before. Anyway). This is my feeble attempt to bring an answer to the eternal dichotomy between those arguing about the relative benefits of creating user interfaces via Interface Builder or via pure Objective-C code: let me introduce nib2objc.

Unbeknown to most of us, the ibtool utility bundled with Interface Builder and Xcode allows us to inspect the contents of NIB files (or XIBs, for that matter) and get from them nice property lists XML streams, which I transform in NSDictionary instances, which I loop over and over util I get something that looks like this:

[source:c] UIView *view6 = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 460.0)]; view6.frame = CGRectMake(0.0, 0.0, 320.0, 460.0); view6.alpha = 1.000; view6.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; view6.backgroundColor = [UIColor colorWithWhite:0.750 alpha:1.000]; view6.clearsContextBeforeDrawing = NO; // …

UIButton *view9 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; view9.frame = CGRectMake(167.0, 65.0, 72.0, 37.0); view9.adjustsImageWhenDisabled = YES; view9.adjustsImageWhenHighlighted = YES; view9.alpha = 1.000; view9.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleBottomMargin; view9.clearsContextBeforeDrawing = NO; view9.clipsToBounds = NO; view9.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter; // … [view9 setTitleShadowColor:[UIColor colorWithWhite:0.000 alpha:1.000] forState:UIControlStateSelected];

// … [view6 addSubview:view9]; // … [/source]

Using this tool, I can now use IB for design, and then generate the code for those designs, in case I prefer to use a code-only approach (usually for UITableViewCells, as I explained before). For the moment it only works with UIKit classes, but I don’t think it might be a problem to extend it to AppKit classes as well.

I hope this project is useful to all of you! As usual, open source, public domain and on Github.

Update, 2009-04-09: This project has been featured in an article in Ars Technica by Erica Sadun!

That iPhone Keypad

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Finishing my series of copied flattered UIs, like that Facebook thingy or that Twitterriffic gadget, here’s Apple’s own iPhone keyboard, in a really sloppy implementation that has been blatantly and horribly copied, with awful sounds that pop when you tap the numbers and such. The Fring iPhone application uses a similar keyboard, but with a different color set.

This code, apart from showing the keyboard and playing those sounds, it doesn’t do anything else, even if a simple “tel:” URL call might suffice to turn it into a real dialer. As usual the code is on Github; feel free to play with it, extend it, and do what you want.

Asynchronous Loading of Images in a UITableView

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This is one of the most common scenarios for network- + UITableView-based applications; a UITableView instance whose contents come from the network; not only the text, but also the images! Somehow we all want to reproduce the behavior of the App Store (or of the iTunes) iPhone application, where the icons (or covers) of the apps (or songs) are downloaded one by one, as you scroll the table, without crashing nor opening 1000 simultaneous network connections.

My solution (there might be many others!) consists in the following key elements:

  • Avoid loading images right after the RSS feed is parsed; instead, use the -tableView:willDisplayCell:forRowAtIndexPath: delegate method in the controller to trigger the loading of the image for cells that become visible; this ensures that only the cells that are visible will receive the order to load images from the network;
  • Use a “model” class for each element of the table, and make the custom UITableViewCell subclass a delegate of this model object; then, the model object is responsible of loading its own image, and will tell the UITableViewCell when done;
  • Use the ASIHTTPRequest framework, with a shared download queue in the application delegate, so that all of the requests are properly queued, and network resources are properly used;
  • Show feedback to the user with scrolling wheels whenever and wherever appropriate;
  • Use the Reachability class from Apple’s own sample code to see if we’re really connected to Flickr, and otherwise show an error to the user.

I have created a sample project, as usual in Github, where I gather RSS data from Flickr’s public feed, and then I download synchronously the preview images of the feed. I even included a very simple Core Animation effect which reminds me of how the iTunes iPhone application allows us to hear previews of the songs we want to buy (the image flips and shows another view “behind”).

Feel free to contribute, fork, enjoy, read, use in your own projects, as you want. As I said, there might be many other (and most probably better) approaches to do this, so feel free to leave your comments below, as usual.

That Twitterriffic editor

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They say imitation is the best form of flattery. Well, here’s another attempt at doing that, after my “attack” on the Facebook iPhone app (decidedly I’m on a somewhat copying mood lately).

I use Twitterriffic a lot, both on the iPhone and on my Mac, and particularly in the iPhone version, I’ve always liked the little editor for tweets. It grows and shrinks as you type, it appears and disappears following the keyboard, and it provides a standard toolbar with many useful buttons (Actually, I wish the Mac version would have a similar text entry box, which would grow bigger as I type; it’s probably the only complaint I have about it!)

Well, here’s my own attempt at doing something similar, and after 1 hour of work, the result is published, ready for you to enjoy at Github. As usual, no strings attached, pure public domain stuff, so use it and play with it as you wish.

That Facebook strip

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No, not a comic strip nor anything else that uses the “strip” word. But rather this component which lately has appeared in many different iPhone applications (see below some screenshots from the Facebook, the LinkedIn and the TSRinfo ones), and which I simply reimplemented, and then posted the code to Github for everyone to enjoy and use.

Update, 2009-02-24: I have just been told via Twitter by enormego that two weeks ago they have released another “Facebook strip” in Github! You might want to check it out. Mine is much simpler as far as I’ve seen, in particular I don’t have a custom class for buttons… :)

Going Github

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This is something I’ve been looking forward to do for some time. After praising git back in 2007, now I’m moving many of my personal projects to Github, which has an absolutely brilliant service! For the moment I’m using the free account, but I will most probably switch to a paid account soon. The only thing it lacks, in my opinion, is a bug & issue tracker as you have in Google Code repositories, but other than that, it’s simply perfect.

So feel free to check out the projects I’ve moved there, and of course, to fork them and enjoy the code as you see fit.

git

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If you haven’t tried git, you should. Git is a “distributed version control” system, that is, similar to Subversion with the big difference that… you do not need a server. There are only clients, any of them, and you can pull and push changes to and from other repositories from your project colleagues. The git Wikipedia entry does a much better job than me to introduce the subject :)

In Mac OS X, I’ve just downloaded the source code tarball with the latest snapshot of the code, and it compiled out of the box. Just the classical operations:

./configure
make
sudo make install

Then I went through the tutorial, and frankly, I loved it. The Everyday GIT Guide is excellent too to understand the idea of this beautiful piece of code.

It’s too cool, really. Lightweight, and damn fast. No wonder why everyone’s talking about it lately!