Talk Funnel

If you’re developing an iPhone application that uses WiFi networking or the new Gaming Kit (Bluetooth) at some point you’ll want to test the code on two devices side-by-side. At this point you will realize that:

a) You can only run one instance of XCode on your machine at a time.

b) Debugging one device at a time is a royal PITA.

c) Your only option is to beg, borrow, or steal another Mac then install all of XCode and your code onto it just so you can do some debugging.

I’m here to tell you there’s a better way.

The solution is to use VMWare Fusion with Leopard or Snow Leopard server as a “guest OS.” (In VMWare-speak your regular machine is a host OS while each virtual OS instance running on it is a guest OS.)

The reason this works is because the latest version of VMWare allows you to run OS X Server as a guest OS on top of another OS X host OS. VMWare also allows you to assign specific USB devices to each VM instance so you can tell it that one iPhone/Touch belongs to the guest and the other to the host OS. Now I’ve only tried this with Snow Leopard Server so I’ll stick with that but VMWare says it can also install Leopard Server but I have’t tried that. Since Snow Leopard is still under NDA I’m not going to go into any specifics of the OS itself. Instead, I’ll show you how to set up VMWare so it can pull this off.

To start you’ll want the latest VMWare version (2.0.4 2.0.5 as of this writing). Earlier versions may not support OS X as a guest OS. To get access to the Snow Leopard releases you’ll need to be part of the Apple Mac Developer program. You’ll want the Server release. During WWDC 2009 some people were reporting having trouble installing Snow Leopard under VMWare from a disk image file so you might have to sacrifice a blank DVD and burn it to disc before installing it.

With the disc all you have to do is pop it in and it does the right thing. Or you can walk through and manually choose which versions you want to load.

Technically VMWare is only supposed to run Leopard/Snow Leopard Server which installs a lot of extra background services, etc. and needs a pretty hefty chunk of memory. If you Google around there are ways to patch the VMWare settings files to let it install Client. Far be it from me to suggest you do this, since it’s not certified and is not recommended for production use. All I’m saying is it might be less resource intensive and prevent your MacBook Pro from catching fire after the fans run on full-bore trying to cool down 100% loaded dual-core CPUs. But then again, YMMV.

So once you have VMWare and Leopard/Snow Leopard installed, you’ll want to install XCode (which comes on the OS install disk under “Extras,” or it can be downloaded separately from the Developer Connection website). Once that’s done you’ll also need the iPhone SDK. If you’re a member of the iPhone Developer Program (and really, who isn’t nowadays?) you’ll want to download and install the latest SDK (note that there are different downloads for Leopard and Snow Leopard).

Inside VMWare you’ll want to set up directory sharing. I won’t walk you through that here but if you have trouble getting the VMWare “folder-mapping” feature to work (like I did) one workaround is to turn on file-sharing in the host OS and mount the networked filesystem from the guest OS. If you do this, make sure you restrict access to only your own account on the shared volumes and turn it off for everyone else, otherwise all your pals at the coffee shop sitting on the WiFi and running Bonjour will have access to your source files.

Next you’ll want to end up with two separate projects, one for the host and the other for the guest OS. The reason for this is because each instance of XCode makes changes to the project settings each time you do a build. If you share the projects and load them from two XCode instances, you’ll end up with an endless litany of XCode warnings asking you if it should reload the project from disk. Save yourself a lot of headache. Just create separate projects but keep all your source and media files in the same shared folder. This way if you do actually make changes to the source code during debugging you only have to do it once from either side, otherwise it’s a nightmare keeping track of deltas.

(Handy tip: if you have dual monitors, install VMWare tools and put the guest OS on the second monitor then have it go full-screen. It’s like having two actual systems in one.)

So now comes the fun part: plugging in the actual devices. Make sure you’re not running XCode or any other app that accesses the USB devices behind the scenes. If you have iTunes set up to auto-run and sync when a device is plugged in you either haven’t done much real iPhone device debugging or you have a much higher tolerance for Annoyingly Intrusive Software. I turn off all auto-sync, auto-run, auto-whatever features that iTunes throws in to make itself the consumer-friendly app that it is. But that convenience gets in the way of debugging, so do yourself a favor and turn it all off. Manual sync mode is your friend.

iTunes also installs an iTunesHelper app that runs in the background. I personally take that out too by going into System Preferences > Accounts
then clicking on the “Login Items” tab button, finding “iTunesHelper” and hitting the ‘-’ button (or delete) to take it out. The point is, if iTunes snags your USB port before VMWare gets to it you won’t be able to switch it over.

So now we have the two devices plugged in. Do NOT give in to temptation and start XCode just yet. In VMWare bring up the “Virtual Machine Library” which lists all your VM instances (if it’s not already showing, go under Windows > Virtual Machine Library). Select your Leopard/Snow Leopard instance then push the “Settings” button.

Now go into the USB devices section. Note that you can only make changes to the guest OS once it’s powered up and running. So if the guest OS isn’t already running, boot it up. You’ll be faced with a list of all the USB devices on your host machine, something like this:

Unfortunately VMWare doesn’t actually show the device names as assigned through iTunes so there’s no way to tell which device is which. If you have two iPhones plugged in they both show up as Apple iPhone. You can always test an iPhone against a 2G touch (the Touch shows up as Apple iPod). Then again, if both devices are running the same code it may not really matter.

Turn on the checkbox next to the device you want assigned to the guest OS. If it doesn’t stick then it’s likely you’ve got some other app locking up your USB ports. Go back and re-check (might have to do a clean reboot). I should note that this was the most frustrating part of the whole exercise. The trick that made it work for me was to make sure XCode is not running until AFTER you’ve done your USB port assignments.

Once it’s checked, *now* start up XCode on both sides. The host OS should be seeing one device and the guest OS the other. Verify by loading up the XCode Organizer and seeing that each device shows up with a little green dot next it. If you haven’t done it yet, you’ll want to tell the XCode Organizer that the devices are to be used for Development.

Getting excited? Almost there. Now choose iPhone Device from your XCode Active SDK pop-up.

Ready to hit Build and Run?

Not so fast.

Your iPhone development certificate is only installed on your host OS. The guest OS is a whole other machine and it needs to be set up as if it was a brand new machine. Fortunately, it’s fairly straightforward to get the keys moved over.

Launch the Keychain Access application (in Applications > Utilities) on your host OS. If you followed the iPhone SDK instructions and created a provisioning profile for your application on the iTunes Connect site, you should have a private key certificate installed in your keychain. If you’re like me and have done this a number of times, you’ll have lots of similar looking keys floating around. The trick is to look for the private key with your name and a drop-down disclosure arrow next to it. Open those up and verify that they say iPhone Developer and/or iPhone Distribution next to them. If you’ve followed Apple guidelines you should have one for development and another for app-store or ad-hoc distribution.

While you’re there, it’s a good time to make sure the expiration date is in the future. I got bit once and boy, was it a pain to diagnose. Stuff that was working one minute magically stopped the next. So stay on top of your certificate expiration dates. If the date is pretty close or already gone by go back to iPhone developer site and follow instructions to regenerate new keys, then install them and come back when you’re done.

Command-select all the private certificates you want moved and export the lot of them (File menu > Export Items…) Make sure they go out as .p12 (Personal Information Exchange) files. You will be prompted for passwords. Pick something pithy but memorable and save the exported file to a shared folder you can get at from the guest OS. While you’re at it, you may also want to move over your app’s provisioning profiles just in case you need it later.

Back in the guest OS, double-click the exported certificate file, enter the password, and install it in your keychain. You’ll probably have to restart XCode so it picks up the changes. To verify that it worked, bring up the XCode project in the guest OS, do a Get Info on the target and make sure the Code Signing Identity is selected and is the same as the private key you just installed.

So NOW you’re ready to go. Select iPhone Device from the Active SDK on both sides, hit Build and Run, go grab a cup of coffee or an adult beverage, and wait until both instances come up side-by-side.

So, yay!

That wasn’t too bad, was it?

A few final thoughts: I ended up running Snow Leopard as both host and guest OS since I wanted to run XCode 3.2 with the latest goodies on both sides. You’ll definitely want separate project files if you want to run Leopard in host and Snow Leopard in guest OS. At this point it’s not clear if app-store submissions can be built using unreleased versions of XCode. So you might want to check on the developer forums before doing the crazy thing I did and upgrading everything everywhere to the new shiny version.

Also, there’s no reason this shouldn’t work for three or more devices (for group peer-to-peer or mass WiFi testing) but you’ll need a beefy Mac with a lot of CPU and memory. You’ll also be needing a USB hub (I ended up with this Belkin Ultra Mini model based on advice from @schwa on Twitter) if you run short on USB ports. All it takes is another VMWare instance and assigning the right device to the right OS instance. Lather, rinse, repeat.

Happy debugging!

Update: Make sure you read VMWare update release notes. In the latest release there are two known issues that directly impact this way of using VMWare:

• When being installed on a Mac running Mac OS X 10.6 (Snow Leopard), VMware Fusion does not install MacFUSE

  MacFUSE might cause the installer to fail or become non responsive, so the VMware Fusion installation process does not install it by default on a Mac with OS X 10.6.

• Selecting the Sleep option on a Mac OS X Server guest operating system causes it to stop responding
  The default setting for Mac OS X Server is for it to never sleep. However, if you change the setting or use Apple > Sleep, the virtual machine might stop responding.
  Workaround: Shut down the virtual machine and restart it, and make sure that in the Energy Saver window of Apple > System Preferences, the Put the computer to sleep when it is inactive for: slider is set to Never. Do not use Apple > Sleep.

You’ll definitely want to turn off Sleep mode as soon as you’ve installed the guest OS and before you walk away from the system for an extended length of time otherwise you’ll have to hard-reboot the VM instance. I even turn off the screen-saver. If the system is idle for any length of time the host OS should be the one doing the sleeping and screen blanking.

The first issue is also easily solved. You can manually download and install MacFUSE. It allows you to use not only third-party file systems on top of MacOS, but file systems on local disk, across the network etc. There are some issues with folder sharing across guest/host applications that clean install of MacFUSE might clear up.

I feel like things as they are have about as much awesomeness as they’re capable of having, and you can’t imbue awesomeness into something that actually sucks. And in its way, something that sucks full-bore sucking at me is a kind of honorable experience–it’s an honorable exchange.

Steve Albini — indie music producer interviewed on public radio’s The Sound of Young America.

Word came today that Apple’s WorldWide Developer Conference is going to be running from June 8-12 2009 in San Francisco.

Since Apple’s no longer going to be participating in MacWorld this is one of the few public conferences where Apple and its partners can make public product announcements. So now’s a good time to start floating outlandish rumors
predictions as to what’s going to be announced.

Since Apple already announced its intention to release iPhone 3.0 software around that time, a lot of products will be taking advantage of those features. One of them was access to the external USB port. The announcement demo featured a heart-monitor. My prediction is it will be totally upstaged by one of these:

One of the loudest complaints about the iPhone AppStore has been the lack of support for eval or demo applications. In the desktop world users can often download an application and use it for a period of time before deciding whether it’s worth paying for. But in the iPhone AppStore universe (where all transactions occur) there is no such support. Developers are then faced with the option of offering a lite version for free (or inexpensively) and a full version of their apps. The problem is that this still doesn’t allow the end-user to test out the full app and then choose to buy it if it fits their needs. And switching from a free to a full app involves installing an entirely independent application.

What we really need is a way to upgrade an eval app to the full version once the user decides the app is worth paying for.

Yesterday Apple publicly announced the developer release of iPhone 3.0 software (it won’t be publicly released until this Summer). To the dismay of many developers, there was — once again — no mention of support for eval applications among the 100 new features and “1000 new APIs.” So again, we are left without the option of letting users download an app, take it for a test run and then pay for it.

Or are we?

One of the features announced publicly was support for In App Purchases. This was presented as a way for users to obtain add-on levels or objects directly within games. The transaction (or more precisely, micro-transaction) still goes through the AppStore and gets charged to the same account. Despite public detractions I belive this is a Good Thing — especially since the feature can be used to legitimately support eval applications, even if the AppStore doesn’t officially support it yet.

Here’s how:

• Developer offers application for free on the app-store. This is a fully functional version (i.e. not lite or crippleware).
• User downloads and runs the application and is informed that the application is in eval mode and will stop working after a period of time.
• After the eval period (say, 1-4 weeks) the application puts up a notice indicating the eval period has expired. It can either stop working or drop into a degraded mode.
• At this point the user is given the option of performing an In App purchase of the full application.
• If user accepts, the application contacts the AppStore and purchases the add-on — which would be priced at what the full-price of the App would otherwise be. Once completed, the app downloads an add-on key indicating the app has been purchased.
• The presence of add-on indicates that the full app has been purchased and the timeout is taken out. All the application has to do each time it is launched is to look for the presence of this add-on.
• Everyone’s happy.

There’s a key assumption here — that the AppStore keeps track of already purchased In App purchases the same way it does with full applications today. In other words, if the user tries to re-download an In App purchase that they’ve already purchased with the same iTunes account, they shouldn’t be charged twice. If a user deletes the app or moves to a new phone, all they have to do is download the free version of the app, perform another In App purchase (for free this time) and off they go.

However, if this assumption is not true and In App purchases are tracked separately than full applications (or the application itself is responsible for keeping track of those transactions) then the developer will have to implement a way to track In App purchases that works across multiple app installs — most likely a simple web-server to keep track of eval vs. purchased apps. Let’s hope it doesn’t come to that (the documentation on the Store Kit is not out as of this writing and even if it was, developers under NDA won’t be able to talk about it publicly until the public release of the 3.0 software).

There are some other issues that need to be hashed out, mainly what happens if unscrupulous third-parties find out what this add-on looks like and make it available for free download? The iPhone application sandbox makes it a non-issue since only the application itself is allowed to write to its Documents directory or modify its user settings — unless the phone has been jailbroken, in which case the concerned developer may want to support more complex security (like cryptographic signing) for the add-on. Given that the AppStore DRM appears to be compromised using this technique does not significantly increase the risk of software piracy.

Another potential issue is the user who downloads the fully functional eval version, uses it for the full eval period, then deletes it, re-download and installs it so they can get another free eval period. If this is an area of concern, it can be handled through a simple web-service that keeps track of how many times the same user has installed an app. Personally, I don’t think it’s worth the hassle given that deleting an app also gets rid of all user-generated data. But that’s me.

Note also that when I’m talking about downlaoding something, I don’t mean literally downloading a chunk of code, but some sort of token that takes away the eval time limit. The whole operation can be performed very quickly once the In App transaction is completed.

I firmly believe having support for eval apps is critical for medium to high-priced applications to flourish on the AppStore. A user will hesitate to fork out a high price for a full-featured app without having the option to kick the tires beforehand. This method can easily solve the problem and let developers do eval apps as soon as the 3.0 software is officially released.

Fans of TV’s Seinfeld in the 1990’s will remember an episode where Elaine ponders whether someone is sponge-worthy:

JERRY: I thought you said it was imminent.

ELAINE: Yeah, it was, but then I just couldn’t decide if he was really sponge-worthy.

JERRY: Sponge-worthy?

ELAINE: Yeah, Jerry, I have to conserve these sponges.

JERRY: But you like this guy, isn’t that what the sponges are for?

ELAINE: Yes, yes - before they went off the market. I mean, now I’ve got to re-evaluate my whole screening process. I can’t afford to waste any of ‘em.

In this case, Elaine is in possession of a finite amount of discontinued Today contraceptive sponges and she wants to save her stash for someone really worth it.

There is a large number of blogs, twitterers, and web-sites out there vying for our attention and we have limited time in a given day to spend with them. So a few end up moving up to the top — the people, places, and things with which we have a steady, recurring relationship — in essence making them sponge-worthy.

If you’re a writer, publisher, or content-producer forget unique visitors, friends, or followers. Sponge-worthiness is the status to which you should aspire.

Almost all social networks today measure success and progress by assigning a numerical ‘friend’ or ‘follower’ rating — with the clear implication that the higher the number, the more {fill-in-the-blank attribute} you are. This is merely a form of popularity-based social dysfunction that ought to have been left behind in middle school but is now enshrined in the technologies we use today. The technology rewards quantity over quality (and my tinfoil-hat self blames it on a revenue model based on maximizing advertising pageviews).

The other thing is that such relationships are asymmetric by design. I can ‘follow’ you but that doesn’t mean you automatically ‘follow’ me. This is sold as a benefit, but its analog in real-life is unrequited love or hanging around with a person who is always talking about themselves. Ordinarily we’d be better off steering clear of these types of relationships, but again, our social networking technologies enshrine this in their code.

I like the term parasocial (coined in this post by Anaiis Flox) because it distinguishes between a real relationship (where you know and care about the other person and vice-versa) and a casual one. But I think we can go even farther.

In a project I was working on a couple years ago, we came up with the notion of circle of friends as a more fine-grain way to capture nuances in relationships. I’m thinking now that even that’s not good enough to really let us capture the nature of our relationships, because we have different types of connections to each other where each can have a magnitude and direction. For example, I may have a work relationship which I might designate as level 5/10 (whatever that means) with Mary, but a long-standing movie-going relationship of level 10/10 with Tom. Furthermore, I can have more than one kind of relationship with each of those individuals (i.e. I work with Mary but sometimes we go see movies together). Each of those links can also be further classified by duration and number of interactions.

I guess what I’m saying is there’s more to having a connection with someone and ‘follower’ and ‘friend’ counts don’t even come close to capturing that element, but so often we mistake one for the other.

When I see someone with a high follower/follow ratio (i.e. someone with a LOT more followers) on networks like Twitter or Facebook what that tells me is that this person is either:

• Not interested in learning about other people,
• Is overwhelmed and doesn’t have time to use the technology, or
• They would be better off in a more traditional one-way broadcasting or entertainment model.

In either case, it’s not likely any form of reciprocated relationship is likely to emanate from ‘friending’ them (as evidenced here). At that point, you can choose to follow them but with the understanding that you’re no more than a spectator in their personal amphitheater and really shouldn’t expect much more than that. Let’s be honest and not call it a social network but a micro fan-club.

If you check those with the highest number of followers on Twitter it will quickly become obvious that the majority are using the system as a unidirectional broadcast channel instead of two-way social interaction. This is what makes Eric Schmidt’s recent comment about Twitter being a ‘poor man’s email system’ that much more puzzling, because email is a bi-directional communication mechanism and far more ’social’ (in the relationship-building sense) than any of these so-called social networks.

If you’re debugging on the iPhone and encounter a lot of NSArray objects, you’ll notice that dumping out the contents doesn’t give you too much information. To help remedy this situation, I whipped out a quick-and-dirty ‘helper’ to show a bit more detail. As with the UIView helper all you have to do is include the NSArrayDebugExtras.m file in your project and build it. This works through the standard Objective-C category mechanism by adding an extra method to an existing class.

To use it, set a debugger breakpoint and enter:

(gdb) po array-variable-name


What you will get is a recursive dump of the array and its contents. If the array contains strings, labels, text fields, or text views, the actual text value is shown. If it contains other arrays, it recursively walks down the array of arrays and shows the contents.

Since there’s no garbage collection on the iPhone, probably the most useful information is the retainCount for each array and item.

If the array contains a lot of custom objects, of course, you’ll only see rudimentary information. In that case, I suggest you make a point of defining a debugDescription method for each object so the contents can be properly shown.

Of course, you’re welcome to tweak the display format to show whatever information makes sense to you, but this should give you a good starting point.

[ Download: NSArrayDebugExtras.zip ]

Almost overnight a lot of apps have popped-up for the iPhone and many of them are games. Quite a few of them look like they were developed by hobbyists over a weekend (not that there’s anything wrong with that). But developing a quality, professional game for the iPhone is still a time-consuming and difficult task.

Once you’ve settled on the game concept, you have to create the play logic, then generate the graphic assets and multimedia. And somewhere along the line you actually have to write the code to make it all happen.

To build a serious iPhone game you currently have several choices:

1. Create a custom one-off app in Objective-C (or C++): This gives you the most control but it means your game is pretty much going to stay on the iPhone. No desktop version. No Wii. Just iPhone. That might be fine, but if you’re investing tons of hours in content creation and game design, you may want to think hard about whether it makes business sense to leverage all that work and hit more platforms. Building a custom one-shot app also means that all your development effort is only for that one game. Instead, you may want to…
2. Develop a general-purpose iPhone gaming engine: Where the gaming logic and media content are kept separate and defined in configuration files. This way, you can get two, three, maybe even 100 bangs for your buck. Hopefully, the configuration language is expressive enough so you can build a whole class of apps, not just the same thing over and over. You should be mindful, however, that the iPhone SDK prohibits use of scripting languages, so you can’t embed a Javascript, Lua, or Python interpreter into your code. If you don’t have the know-how or are short on time, you may want to…
3. License a third-party gaming engine: This takes you away from the pleasure of writing raw Objective-C code (I’m not kidding — it actually is a lot of fun) but it also gives you support tools like 3D modelers, asset managers, physics engines, networking, etc. so you can focus on the high-level logic instead of low-level coding. Most also support some sort of scripting, but get around the SDK restriction by compiling it into executable code.

I have worked on several Objective-C-based iPhone apps so far and developed a custom animation engine for a client, so I have squarely followed options #1 and #2. But I also have ideas for quick, fun entertainment/game apps that I’d like to whip out quickly without spending months on building a custom animation engine. I’d rather spend my time on polishing the game logic and generating nice looking multimedia assets instead of working around iPhone Core Animation’s strange quirks (please, don’t get me started).

So I decided to look around and see what’s out there and came up with the following. To be fair, I haven’t had time to dig too deeply into each one, but as a public service I figured I’d share what I’ve found so far. If I’ve missed any other platforms or made any factual errors, please feel free to post a comment and I’ll issue an update.

Here they are (in alphabetic order):

		ShiVa (with the iPhone Authoring Tool) from StoneTrip.
		Torque Game Builder (with the iPhone SDK addition) from GarageGames.
		Unity iPhone.

In terms of features it’s hard to tell them apart from their spec sheets. They all feature 2D or 3D graphics, support a variety of media and content (including shaders, sound, movies, etc), handle physics and collision detection, and playback audio and video. On the iPhone, there’s also support for the accelerometer (for tilt moves). All three engines support server-based multi-user playing which requires licensing their servers (or their hosting services). It’s not clear at this point whether they support WiFi-based Bonjour peer-to-peer networking which the iPhone and Touch both support.

What differentiates the three engines is what other platforms they support and their pricing model, so let’s dig into that.

ShiVa

ShiVa comes in three versions, PLE, Advanced, and Unlimited (here’s the feature comparison table). The development platform runs under Windows (or Parallels on the Mac). The PLE version is free and allows you to create an application, but you can’t publish the output commercially. For publishing you’ll need the Advanced or Unlimited versions. Advanced costs €169 Euros (approximately $235 at today’s exchange rate) whereas Unlimited will set you back €1,499 Euros (approximately $2080).

The main difference between the two seems to be that the Unlimited edition has additional benchmarking and optimization tools and supports team development. There is no extra cost for output to iPhone (and it looks like they intend to support Windows Mobile and Symbian). You can also target your game so it can run in a browser, but it requires the user to download and install a plugin. A standalone desktop app generator lets you target Windows, Mac OS X, and Linux. However, you’ll likely need to repurpose your media to fit the different screen sizes.

As far as console platforms are concerned, not much there yet.

To support multi-player mode, you’ll need to license the Ston3D Server which comes in PLE, INDIE and PRO flavors. PLE is free but is limited to a single application and 6 simultaneous users. Clearly, it’s intended only for development and testing. The INDIE version runs on Windows, Ubuntu, and FreeBSD, but is limited to 64 sessions (game instances) and 4 sessions per server. It runs €359 Euros (approximately $500) and the PRO server without the session limitations runs €599 Euros (approximately $832).

There are also extra server-side features like managed hosting, payments module, and direct messaging to the user (via SMS, MMS, and email).

Torque

GarageGames offers a dizzying array of products and Torque variations, targeted at anything from simple 2D to networked 3D games. The basic 2D package is the Torque Game Builder which runs $100 for Indie apps (those earning less than $250K per year) or $495 for Commercial version. The Pro version also gives you access to the source code for both the engine and the editing tools ($250 for Indie, $1250 for Pro).

If you want 3D support then there’s Torque Game Engine ($150 Indie, $749 Commercial). In both cases, you get a lot of tools that support building levels, media, sprites, etc. and take care of a lot of the low-level grunt work for you.

But that’s not all, Bob. There’s also Torque Engine Advanced ($295 Indie, $1495 Commercial). This gets you all the tools to develop advanced 3D games for consoles and desktops. To deploy your game to a console, you’ll want to look at Torque Wii or Torque 360 (for the XBox 360). License fees for these have to be negotiated.

But it’s the iPhone we care about and to output there, you’ll want Torque for the iPhone. First you’ll need a license to one of the existing ‘builder’ tools (Tool Builder for 2D, or Engine for 3D). for the 2D version, you pay an additional $500 for an Indie license. That lets you publish a single iPhone title. Each additional title you want to publish requires an additional $100 license fee. You also have to show the GarageGames splash screen when the game starts and mention them in the game credits (and app web-site). 3D game support on the iPhone hasn’t been released yet so there’s no price listed.

Want server-based networking? The basic server is open-sourced under GPL. If you want to use it in a commercial app, however, the cost is $295 for Indies and $995 for Commercial apps (consoles are separate). This is for games delivered on Windows, Mac, or Linux. It’s not very clear if networking is supported on the current iPhone version, but I imagine it’ll be there soon.

Unity

Unity supports 2D and 3D content with a visual editor to help you develop and design your game content. The underlying scripting technology is based on C# and Javascript but their iPhone Publishing product spits out an XCode project that they claim ‘just works,’ compiling the scripting code into fast ARM assembler code (and thus avoiding the iPhone SDK’s edict against built-in scripting languages).

Under Unity, the Editor is the main point of creating apps. You visually adjust parameters and get live previews, then create scripts to handle game logic. In iPhone ‘preview’ mode, you adjust settings on your desktop screen inside the visual editor and watch it update live on the target test iPhone. It’s a very cool way to quickly adjust and position your objects and verify that they look right on the iPhone screen.

To develop Unity apps, you need the editing system ($199 for Indie developers earning $100K or less — with free 30-day eval, or $1499 for Pro) which lets you generate output for Mac, Windows, browser plugin, and OS X dashboard widget. To output to the iPhone you can got for the Basic iPhone license for $399 for Indie developers and requires showing the Unity splash screen, or $1499 for the Advanced license. Wii/WiiWare output is separate and carries a hefty license fee ($15K-$30K per title).

The Advanced edition also gets you .NET sockets. This means that you can write your own back-end server and aren’t locked into theirs, but you don’t necessarily get Bonjour/WiFi support. You can also stream assets on-demand (which requires an asset-server client license for $499) but I can’t imagine anyone wanting to stream assets unless the user was on WiFi.

Risks

There are inherent risks with using a third-party middleware. Will the platform continue to be supported? Are they actively fixing bugs? What happens if they go out of business and you want to continue developing your app? If these are concerns, then you may want to consider Torque’s Pro versions since they come with source code.

On a resource-restricted platform like an iPhone there’s also the matter of having a whole extra layer of runtime between your app and the OS. If your app is going to be pretty media-heavy you may want to roll your own and keep tight control over memory use.

Don’t be scared by these caveats. For certain classes of games these engines will amply make up for the risks by letting you concentrate on content instead of engine technology and getting your app out that much sooner. If used properly, they can also act as ‘force multipliers’ if you are an individual developer or a 2-3-person team. With these tools, you can rapidly create cool apps that would otherwise require a small army of coders and designers.

Which one?

Which one you choose will depend primarily on what features you need, so the first thing I suggest is to download and try out each package (here are direct download pages for ShiVa, Torque, and Unity). All three have free or eval versions and offer Indie pricing for small developers. If your app turns into a big hit and brings in enough revenue, it’s easy to justify the cost of the Pro or Advanced licenses.

If you intend to eventually move to the XBox then Torque is the only way to go. If Wii is where you might be heading, then it’s Torque vs. Unity. All three platforms support standalone desktop apps. I’m not sure with the prevalence of Flash in the browser if anyone’s willing to download and install a browser plugin just to run an application, so I’ll call web-based delivery a wash.

If licensing fees are a concern, then you may want to go with ShiVa. If you only need 2D support, then Torque may work for you (although their iPhone per-app licensing fee is a little too strange for my taste). Mac-only developers will want to look at Unity or Torque Engine Advanced . All others require Windows (but may work under Parallels or VMWare).

iPhone-only features

At this point, nobody seems to support peer-to-peer Bonjour-based networking on the iPhone. Quite a lot of games support that feature. Unlike a Nintendo-DS which allows two players to form an ad-hoc network just by sitting near each other, this only works when all the players are on the same WiFi subnet. It works pretty well when players are in the same room or dorm floor and doesn’t require going out to a central server. It’s especially handy in places where data access is metered and hitting a central server through the cell network can get expensive. Hopefully Bonjour support is something that will be supported soon.

All three engines appear to have decent support for the accelerometer but no mention yet of other iPhone-only features like multi-touch, GPS, or camera. One other thing to keep in mind is that all the license terms and prices listed apply to games only. If you want to develop a social networking or business app you may have to negotiate a separate license.

Bottom line

Which one will I use myself? My development environment is currently 100% Mac based and I have a lot of 3D, graphics, and sound production tools there so that will probably influence which way I go. That makes Unity a strong contender for me. However, I’ll defer final judgment until I’ve had a chance to seriously beat up each platform.

Remember that regardless of platform, you’ll need to sign-up separately for Apple’s iPhone development program (a $99 cost for individuals) to get a distribution certificate. You’ll also need to do the actual legwork of submitting the application to the app-store. And once the app is out, there’s the matter of marketing and promoting so your app stands out against all those other ones out there.

Ah yes, marketing. Let’s leave that for a future post…

Update: For those interested in going the open-source route, SIO2 and Oolong Game Engine are two 3D gaming engines for the iPhone/iPod Touch. (Many thanks to Justin Hall for the tip.)

Both look plenty capable for iPhone-only game development (NOTE: there’s no desktop or console output support). Based on a casual first-pass, it looks like SIO2’s tight integration with Blender 3D editor and support for Lua scripting makes it easier for those who want to focus on content-creation instead of low-level coding. Oolong, however, is targeted more at C++/Objective-C coders. According to the Oolong source code site it is the technology underlying Torque Game Builder for iPhone (see above).

Tilt shift photography is a technique where a photograph’s focus appears blurred and only the center of the subject is in focus (there’s more to it, but that’s the gist of it). You can simulate it in Photoshop but it’s probably easier (albeit more expensive) to use special tilt-shift lenses. The effect is pretty cool, as if you’re photographing a miniature set. Some background on the technique here and here and some beautiful examples here.

The effect is used to stunning effect in this time-lapse music video made entirely with a tilt-shift lens:

Metal Heart from Keith Loutit on Vimeo.

Be interesting to see what would result if you put together the amazing Canon EOS 5D Mark II HD and a decent TS lens…

The user interface of the iPhone is based on a series of nested UIView objects, arranged in a view-subview/parent-child relationship. When building a complex application with a lot of views, sometimes it’s handy to be able to see exactly what that relationship is.

But if you try to print out the value of a UIView in the debugger (or through an NSLog function) you’ll be sorely disappointed. In this example we have a variable called front that is derived from a UIView. Setting a breakpoint in the XCode debugger, I type in a po (print object) command to show what that variable contains:

(gdb) po _front
<BCCardSideView: 0×106b020>


What you see is that the variable is of type BCCardSideView and its hex address. Not very helpful.

One solution is to take advantage of the Objective-C dynamic runtime and override UIView’s default describe method. This is the method that is called every time you try to display the value of an object. Here we have just such an override that recursively walks the view tree and dumps out the values. The code is contained in a file called UIViewExtras.m. All you have to do to enable it is include the file in your XCode project. There are no explicit methods to call.

Here’s the same output after UIViewExtras.m is included in the project (the indentation is a little messed up because of the column width of this blog. In the debug window, it should look fine):

(gdb) po _front
+ BCCardSideView retain:3 - tag:0 - bgcolor:(r:0 g:0 b:0 a:1.00)
  bounds: x:0 y:0 w:130 h:80 - frame: x:5 y:5 w:130 h:80 - center: x:70, y:45
++ BCCardBackgroundView retain:4 - tag:0 - bgcolor:(r:255 g:255 b:0 a:1.00)
   bounds: x:0 y:0 w:130 h:80 - frame: x:5 y:5 w:130 h:80 - center: x:70, y:45
++ BCCardTextView retain:4 - tag:0 - bgcolor:(r:0 g:255 b:255 a:1.00)
   bounds: x:0 y:0 w:100 h:20 - frame: x:0 y:0 w:100 h:20 - center: x:50, y:10
   text (len:4 - color:r:0 g:255 b:0 a:0.00): ‘name’
++ BCCardTextView retain:4 - tag:0 - bgcolor:(r:255 g:255 b:0 a:0.00)
   bounds: x:0 y:0 w:100 h:20 - frame: x:0 y:20 w:100 h:20 - center: x:50, y:30
   text (len:5 - color:r:0 g:255 b:0 a:0.00): ‘title’
++ BCCardTextView retain:4 - tag:0 - bgcolor:(r:0 g:0 b:255 a:1.00)
   bounds: x:0 y:0 w:100 h:20 - frame: x:0 y:40 w:100 h:20 - center: x:50, y:50
   text (len:5 - color:r:0 g:255 b:0 a:0.00): ‘email’
++ BCCardTextView retain:4 - tag:0 - bgcolor:(r:255 g:0 b:0 a:1.00)
   bounds: x:0 y:0 w:60 h:20 - frame: x:0 y:60 w:60 h:20 - center: x:30, y:70
   text (len:7 - color:r:0 g:255 b:0 a:0.00): ‘phone.1′


For each view object you see:

• The retain count.
• The tag value (if specified).
• The background color value in RGBA. RGB values are scaled up to 0..255 and alpha is shown as a floating point value between 0 and 1.
• View bounds rectangle (x, y, width, height)
• View frame rectangle (x, y, width, height)
• View center (x, y)

If view is a UILabel or UITextField, you also get:

• - Length of text
• - RGB value for text itself (vs. the background)
• - Actual value of the ‘text’ inside the field.

Subviews are indented by multiple “+” (plus) signs. So the top-level has one ‘+’ all its subviews have two ‘+’ signs, *their* subviews will each have three ‘+’ signs etc.

I personally find this handy in debugging views — especially those created dynamically. I hope you do too.

[ Download: UIViewExtras.zip ] (Update: Link updated.)

I write software, stories, and half-truths. This is a place to hold some, all, or none of them.
P.S. If you have a burning need to reach me, you can try raminf on Twitter.