I didn’t have a handheld GPS, but I did have my iPhone.  I searched the App Store for “GPS Location” and there wasn’t an app with that name.  Huh?  I did find an app that gave me my coordinates, but they weren’t in the right format for what I needed.  So, I had to flip back & forth between the GPS app and the calculator to do the conversion myself.  Not cool.

So, here is GPS Location.  It’s super easy to use.  You launch the app and the GPS automatically fires up.  It figures out your location & shows your position on a map.  It displays your latitude & longitude in three different formats (DD.DDDDD, DD-MM.MMM and DD-MM-SS.S). If you scroll the map around, it updates the coordinates to match the center of the map.

I also needed time to the second.  You can’t get time to the second on the iPhone – huh!?  So, GPS Location also shows that too.  If you care about your lat/long, you probably care about the Greenwich Mean Time, so that’s what you get.  If you want to see the local time, just look in the status bar.

Check out GPS Location in the App Store.  Available soon.  Just $0.99.

With a little promo work & setting the dropdown menu to “Free” in iTunes Connect, Air Hockey had 87,000 downloads in 24 hours.  As you might expect, that’s the biggest single day for the paid version of Air Hockey.  Of course, all those downloads were free.  Air Hockey’s been in the App Store since Jul 31, 2008 and has sold well ever since.  In App Store terms, that’s ancient.  I’m pretty sure that’s about the time when dinosaurs roamed the Earth.

As best we can figure, Air Hockey’s done well because it has an easy to recognize name & icon, it’s super easy to learn, it’s average game length is only a few minutes at most, it looks good, and it’s gotten lots of features added over the last year and a half.  The importance of each of these could be argued.  It’s been featured by Apple a ton too.  That definitely doesn’t hurt.  There is a little bit of black magic in this software sales stuff too.

On a normal day, that many downloads would send about $61,000 our way.  So, did it cost us $61,000 to hold the promo?  Of course not.  Directly, it cost us the sales for one day.  Since nobody leaked that Air Hockey was going to be free, sales leading up to the free day were typical of what Air Hockey’s been doing.  Weekends bring in about 30-50% more money than week days.  Mondays are always slow.  Some people start their weekend early.

The real question is what will happen from here.  Since it was free yesterday, Air Hockey’s now lost it’s place on the paid charts.  The hope is that with all the press for yesterday’s promo, enough people will buy the game today to put it back where it was on the charts.  Well, the real hope is that it’ll end up higher on the charts than before.

Other developers have tried this same promo.  At least one posted sales figures from the Appvent Calendar.  From that sample size of one, it didn’t help much – if any.  So, we tried some things different.  As I’m sure Rana Sobhany (author of the soon-to-be released awesome book on iPhone marketing) would tell us, getting press is critical.  (She’d say it better than I did though.)  Instead of sending out a canned press release that everyone in the world would ignore, we sent personalized notes to important iPhone nodes around the internet.  Touch Arcade was the first to write about the promo, followed by Gizmodo, Geek.com, and several others.  Huge success.

In 24 hours of being free, Air Hockey raced up the charts to the #47 spot in the US, #13 spot in France, #17 in Italy, #52 in Japan, #66 in Canada, #67 in Germany and #99 in the UK.  According to Free App A Day, the next highest ranked app after a one day free promo was Reign of Sword at #60 in the US – Air Hockey made it 13 places higher.  In that 24 hours, 25,000 new people posted high scores to Air Hockey’s OpenFeint high score boards. We were very temped to leave the app free for a while longer.  Another day & it might have been in the top 10.  The world will never know.

The free promo is over.  Once again, the price of ownership is a mere $0.99.  Hit it!

The folks at Free App A Day and OpenFeint were outstanding to work with.  Many thanks to everyone that made this happen.

For one day only, our hit game Air Hockey is FREE!  We’re honored to be part of a combined Free App A Day and OpenFeint promotion.

Air Hockey was originally released in July 2008 – the very early days of the App Store.  Since then, Air Hockey’s been featured by Apple in nearly every category and hit the #1 paid game spot in September 2008.  Air Hockey was top ten staple for many months & has enjoyed living in the top 100 in several game categories.  Now you can have it for free!

So, what will happen over the next 24 hours…or the next month?  How many downloads will happen when the app is free?  Will it see a boost after the promo is over?  It currently averages 4 stars over 1 1/2 years of reviews…will that change?  We shall see!

Enough words.  If you don’t have Air Hockey, you’re wrong.  Get it now!

There have been lots of questions fired our way over the last couple weeks.  We can now spill the beans.

Why webOS?

We’re in the business of creating and selling great software.  Opportunities in nearly every platform are kicked around.  When Palm first announced their Mojo SDK, we applied to be a developer.  Palm has a long history of popular hardware (you had a Palm Pilot back in the day, right?) and the Pre was hardware worthy of some good apps.  They were only picking a handful of participants, so it seemed like a long shot.  As part of that application process, the questionnaire asked what app we would be developing.  We figured the best bet would be an established application instead of something new.  “Air Hockey” went in the app name section.  In the comments section (i.e. the “beg for approval” section), Air Hockey’s previous #1 paid game ranking in the iPhone App Store found it’s way onto our makeshift resume.  Couldn’t hurt.

While development was underway for Occurro! (for the iPhone), we got accepted into the beta developer program at Palm.  After all the signup was done, we realized that Palm had only announced plans for free applications.  Our development efforts were going full steam towards Occurro!’s release but without the option to actually sell apps, spending resources developing for webOS didn’t help our company grow.  Sure, free apps help build the brand.  Sure, apps could be supported by ads.  We looked at it.  It didn’t make sense.

Occurro! launched and was featured by Apple.  Starting a new iPhone project made sense.  Then they called.  Palm knew Air Hockey for webOS was at least somewhere in someone’s mind.  They asked how close the app was for release.  There wasn’t much to say besides “Ummmm…”

After dancing around a real status on the release date of Air Hockey for webOS, we talked for a while about why there wasn’t any progress.  There were several concerns, but #1 on the list was the lack of ability to recoup the cost of developing for webOS.  With roughly 300,000 Pres in circulation at the time (our best guesstimate), it would take multiple ad impressions per day from every Pre user to add up to much over the relatively short life of software.  To put food on the table, we had to be able to sell our apps.  Plain & simple.

“Uhhhh, we’ll call you back.”  After a few days, a non-disclosure agreement showed up.  I sent it back & we set up a meeting.  There was going to be a paid section App Catalog soon.  Oh yeah, and there’s a new device coming soon.  Palm wanted Air Hockey as a demo for the announcement of the new device.  It didn’t have a releasable name.  Just “new device.”  Things changed.

After meetings with product managers, engineers, vices of this, and chiefs of that, a demo of Air Hockey for webOS became #1 on the to-do list at Acceleroto.  We got to work with a very inside team to make the Air Hockey demo happen on time.  There wasn’t a “real” fast-motion game on the Pre yet, so there were a few hurdles.  We were invited to Palm to finish the development, but decided that timeline was so tight that the travel time to & from would actually impact the progress.  We had a Pre to test on & the SDK tools were in place to check for differences on the Pixi.  The demo for the Pixi launch was ready on time.  Next up, the paid version.

The demo version was very specific.  It was a technology demonstration to be used as part of the Pixi announcement.  The paid version needed more polish, more options, more features, etc.  The first 90% was done, but there was still 90% to go.  Through help straight from Palm and lots of sleepless nights, Air Hockey for webOS was ready the day Palm’s back end developer portal was ready to accept apps.

Did they pay you?

No.  No money made it our way from Palm for the development of Air Hockey (we didn’t ask though).  Palm keeps 30% of the sales.  We’ll get the other 70%.

How did you decide on that price?  It’s more than the iPhone version!?!

Economics 101.  It’s no secret that the iPhone version of Air Hockey has been $0.99 since it launched in July 2008.  When it launched, there were approximately 10 million iPhones & iPod touches that could run it.  At the launch of Air Hockey for webOS, there are something on the order of 1 million Pres that can run it (another guesstimate).  There’s more though.  There were about 3000 apps available when Air Hockey launched a couple weeks after the App Store opened.  At the time of writing, there are 125 apps available in Palm’s App Catalog.

No matter what the price, we don’t expect Air Hockey for webOS to bring in as many sales as the iPhone version.  Since we still need to make back our development resources, we have to charge a little more.  Economy of scale.  $1.99 made sense as our best guess for the sweet spot for Air Hockey.

Some people will think that’s too much.  Some people will not be able to afford it.  We know.  Some people will be very happy get Air Hockey for less than the cost of their morning cup of coffee.

How many sales do you have?

We’re still holding our breath.  After 24 hours, there were about 100 reviews for Air Hockey in the App Catalog.  Since you can write a review on your phone (instead of having to go back to a computer), we’re guessing the ratio of reviewers to purchasers is higher than it is on the iPhone.  We’re guessing sales are somewhere higher the number of reviews.  After that, we just don’t know.  Remember that the Palm developer program is still in beta?  They’re still finalizing the app sales stats stuff for us developers.  We’ll know soon.

How is webOS development compared to iPhone development?

Different. The actual hardware is remarkably similar between the iPhone & Pre.  The biggest difference is in the programming language & SDK.  iPhone development is centered around Objective-C.  WebOS development revolves around JavaScript, HTML & CSS.

The coding effort for the webOS & iPhone Air Hockey versions was tackled by Bryan Duke.  He knew C, C++, Objective-C, BASIC, FORTRAN, and even some ADA – but not a lick of JavaScript.  Thankfully JavaScript borrows from other languages so the nuts & bolts were quick to learn.  Objective-C (iPhone) programs are compiled to an executable binary.  JavaScript programs (webOS) are, well, scripts that are interpreted real time.  There’s an inherent difference in the execution speed of a given chunk of code.  Games require speed, so this’ll be a primary development concern for all you webOS devs out there.

Besides the language is the development environment.  The iPhone uses Xcode & webOS uses the Mojo SDK along with the Eclipse IDE.  Both work, but they’re different.  Intially getting your code onto a Pre is actually a whole day’s work easier than it was on the iPhone.  Bonus.  Debugging, however, is 1000x easier in Xcode.  Tradeoff.

What were the hurdles in development?

Speed.  We told Palm that we wouldn’t publish a game unless it ran at least 30 frames per second. Our webOS code is skinnied up from the iPhone version quite a bit to keep things fast.  After things were optimized, the single biggest time user is actually drawing everything to the screen.

Memory management (aka Garbage Collection).  WebOS is allows users to run multiple apps at once.  Users beg for multitasking.  You think it impacts game performance?  Absolutely.  Even if every app behaves nicely, they all consume memory.  Memory management is handled by the OS without any direct say of the individual applications.  Whenever the OS decides, it does a Garbage Collection.  Currently, this takes about 300ms (about a third of a second).  Air Hockey contains specific code to lessen the impact of these pauses, but developers can’t turn them off.  A lot of time was spent making sure objects weren’t needlessly allocated to minimize the frequency of the Garbage Collections, but you’ll see the pauses.  That may change in the future – we don’t know.

Touch handling.  WebOS runs apps basically as web pages.  So, touches are handled like mouse clicks in web pages.  Long story, but there are some specifics that equate to “touch neutral zones” in the OS.  If you look closely, you can tell that the touch response (drag your finger across the screen) isn’t as smooth as the background physics engine, puck & opponent movement.  We know & we’re working with Palm to make it better.

Sound.  The programming for sound is done, but there’s no sound currently in Air Hockey.  “WHY!?!?!” you’ve asked.  It’s not ready for this type of application.  The sounds work, but the ability to perfectly time them isn’t quite there.  If we included sounds, you’d be upset with them.  They’ll be included as soon as it makes sense to.

Timeline.  It happened quickly, but it was all-consuming.  Meeting the demo & paid timelines wasn’t trivial.  People are waiting on Occurro! and Air Hockey updates for the iPhone.  It’s time to get on that.  Oh yeah…and there’s another secret project starting soon.

Questions?

Leave a comment.  We look forward to hearing from you.

“The introduction of Pixi has also helped us demonstrate the scalability of Web OS and how applications can easily span our family of Web OS products. As an example, we invited Acceleroto, the developer of the popular mobile air hockey game, to build a Web OS app for demonstration at the Pixi announcement. Acceleroto’s application was built in weeks, not months. It runs on both Pre and Pixi and the developers never required access to an actual Pixi device during their development period. Acceleroto is just one of many partners already taking advantage of the speed, efficiency, and scalable environment offered by Web OS. We will be unveiling our full developer program this fall, including a commerce solution, support for application distribution, and an opening of the catalog to public submissions.”

Occurro! The Game of Stellar Combat was released on July 11, 2009.  A week later it was featured by Apple & it quickly rose into the top 50 paid apps in the App Store.  Take a minute & check out the trailer:

I shared some thoughts and ideas in a couple threads at the Cocos2D forum about little parts of the game, but never the overall design …or detail on things like explosions. This is some big-picture info on those topics.

Game Structure/Architecture
I started with one of the Cocos game skeletons in February ‘09. I stripped it down to the core and built Occurro! on top of it. Since then, I moved it from Cocos 0.5 to 0.6, then 0.7. A stripped down version of what I use currently is here: http://acceleroto.com/share/MultiTest.zip That file includes Cocos2D 0.7.3, so it really should be updated to the latest before you get going on a project with it. Otherwise, feel free to use it how you’d like.  (Caveat: if you compile that sample code & try to publish it in the App Store as a game, the entire world will make fun of you.)

Occurro! currently has 15 different Cocos layers that it can switch between, all in their own class. Each new “screen” that the user sees is a layer.  The game launches into a layer that does some pre-processing (is there a saved game?  what are the default options? etc.). From there it decides to go to the main menu or the resume menu. The main menu has several submenus that allow the user to do all the typical game setup stuff, see credits, and view high scores.

Occurro!’s high scores are handled by Geocade’s service. I display a UIWebView within a Cocos layer (just like in the above sample code). That layer handles all the location services, web requests, and keeps track of scores the user still needs to submit.

The main game is structured much the same as the above sample code – just much more complex. I set up a series of timers to handle various things in the game. My main game loop (called “step” in the code) is fired at 60Hz. I also use a gun firing timer, an enemy spawn generator timer, and a couple other housekeeping timers – all get fired at different rates.

When I start the game layer, all the initialization stuff is done. To speed things up during gameplay, I create a fairly big pile of each enemy, weapon & power up type and keep them around for the entire duration of the game.

After the initialization, I jump into the game loop & do this stuff:

• update the player ship based on player inputs & its physics
• update enemy positions based on each of their AI & physics
• update laser positions
• update and/or remove power ups
• check for collisions (lasers, enemies, power ups, etc)
• handle player death or other status changes if required
• kill enemies if required & generate explosions
• add points
• check for level ups and extra lives
• update the score board (if the player got any points)
• update other HUD indicators (if the player got any power ups or used weapons)
• update control indicators based on user inputs
• position & start sounds as required
• update the camera position

At the end of each game loop step, Cocos updates all the actual pixels on the screen using OpenGL.  After that, the game loop starts over again.

I tried to keep everything fairly compartmentalized in their own classes. I subclassed CocosNode to make the player, enemy, power up, and weapon classes.

Special Effects
My explosions are new classes that I made by copying and modifying Cocos2D’s ParticleExplosion class. Each one of my enemy explosions is made up of 2 different classes each with their own custom artwork. The first is the “flash” class – it shows a couple of initial flashes & picks between about 6 different art files for the flashes. The second is the flying particles of the explosion. When an enemy is killed, I start both of these particle systems at the same time. To make them look like I wanted, I just modified individual parameters within each class until they matched what I was thinking.

Touch Controls
The touch control system is fairly complicated & would take a couple pages to explain properly. In a nutshell, whenever a new touch is detected in a control zone (for example, one control zone is the area that I designate do control the lasers) it removes any old control on that control zone & sets the center of a new one at the touch location. After that, the touch location is compared to the initial position, some trig is done along with some other input shaping/calculations to determine what actual command is passed to the ship’s motion or laser system. When that touch ends, the corresponding input is stopped & that control indicator is removed from the screen.

This really just scratches the surface, but hopefully it helps get you thinking on the right track (or at least one of the right tracks).

For more information on Cocos2D iPhone, please visit http://www.cocos2d-iphone.org/

Also, please check out Occurro! in the App Store: http://bit.ly/occurro – just $0.99

We jumped on it.  That day we cooked up & tested a special version of Air Hockey made just for Apple.  It looks & feels almost exactly like our full version of Air Hockey with a few minor changes.  Since lots people would be playing it from the same device, all the options get reset to their default values every time the game launches.  Consistent user experience.  Instead of all 6 difficulty levels, it includes Kiddie, Easy & Medium games.  Medium is challenging enough to beat most people their first time playing the game.  With the 1 or 2-puck option, that will let pretty much anyone tailor a challenging experience for their first crack at Air Hockey.  Challenging, consistent, engaging…done.

There have been several sightings of Air Hockey in several Apple Stores in the US over the last week.  We have no idea exactly how many stores have installed Air Hockey, so do us a favor.  If you see Air Hockey installed in your local Apple Store (or any other iPod/iPhone retailer), send us a note.  Better yet, send us a photo.  Twitter works great (@GrouchoDuke or @acceleroto).  Leaving a comment here would also work well.

Over 500,000 people have downloaded Air Hockey & Air Hockey Free.  Now over 8 months since its launch, Air Hockey is still averaging 100 copies a day in sales.

So where’s the new game?  It’s on the way.  After going 10 rounds (and 4 months) with a game engine, we put an exciting project on the shelf until the technology matures.  Instead of releasing something we weren’t 100% happy with, we started an entirely new game a couple months ago.  It’ll be a fun, fast-paced shooter.  We’ll begin the beta testing process soon.  Stay tuned!

Get Air Hockey here: http://tinyurl.com/airhockey

On day 1, Feb 4, I announced it on twitter.  I don’t have a huge following there, but a few people retweeted my announcement.  A day or so later, I started a 36-hour PR-a-thon at Touch Arcade.  I announced Air Hockey Free and asked for private messages of those interested in a promo code for the full version of Air Hockey.  I got over 100 PMs & gave away 10 promo codes.  The thread had roughly 800 views and at quite a few of those downloaded the free version.  Several people PM’d me saying that they bought the full version after trying the free one.  Success?  Maybe.

About the time that the Touch Arcade promo was over, the first weekend happened.  I’ve known from my paid version over the last 5 months that weekends are the big money makers.  For free apps, there’s a download spike over weekends too.  That Sunday, roughly 3,000 people downloaded Air Hockey Free.  At that time, Air Hockey Free was in the top 100 arcade games and the top 100 kids games, but wasn’t in the top 100 games – not even close to the top 100 apps (all of these are US App Store rankings).  Visibility wasn’t huge, but better than nothing.

Monday’s have historically been the low point for sales each week.  The first Monday’s dip was about 30%.  Since then, I’ve just watched what Air Hockey Free would do by itself. A couple web pages reviewed Air Hockey Free and downloads increased throughout the week.

The next weekend caused another big jump in downloads.  By the second Monday morning, Air Hockey Free made it into the top 100 free games list.  A week later, the downloads per day had doubled again.  Yesterday roughly 9500 people downloaded Air Hockey Free for the first time.  As of today, more than 75,000 people have downloaded Air Hockey Free.

Air Hockey Free’s rankings in the US store have been fairly static over the past week.  The US downloads are still increasing, but the big push over the weekend was from somewhere else.  Germany.  I looked last night and again this morning – Air Hockey Free is the #3 app in Germany.  I love Germany.  (devs, to answer your question…no, I didn’t translate the app to German…it’s an air hockey table though – dead simple.)

I wish I’d been watching the story of the German App Store unfold.  Dang.  I’ll just have to watch it happen in the US.

If you don’t have Air Hockey Free, please download it here. Spread the word!

There’s more you devs want to know, right?  Does the free app generate full version sales?  Maybe.  The current “upgrade action” for Air Hockey Free users requires them to open the setup page while in a game, then click on a “Full Version” button.  I did this for a couple reasons.  First, I wanted the app to get approved by Apple.  The rules on what a free app can be are, well, how shall I say this, perhaps a bit open to reviewer interpretation.  Non-obtrusive design meant to me a better chance of the app making it to the App Store.  Second, I didn’t want to offend users by being to “in their face.”

Since its release, I’ve done some more research on how other free apps have touted their full versions.  I’ll just say, Air Hockey Free has the most non-offensive upgrade button I found.  A change of this strategy will likely increase full version sales.  We shall see!

Again, download Air Hockey Free.  Seriously.  Do it.  Now.

Not to get too excited yet, those numbers are just for games & that still places Air Hockey Free well outside the top 100 apps in the App Store. Today, the #46 game is the last free game in the top 100 overall.

We expect downloads take the normal Monday hit, but hopefully being in the top 100 games will combat that a little.  Stay tuned for more of the Air Hockey Free story!  Get it at the App Store link below.

After some serious App Store Top Free chart digging in just about every category, our best guesstimate showed Air Hockey Free to be in the number 300 spot out of all free applications by mid-day on the 6th. Now early morning on the 8th, Air Hockey Free is the number 40 spot in free Arcade games and the number 4 spot in free Kids games. Our Acceleroto Center for Supercomputing now estimates that based on the last 24 hour’s sales, Air Hockey Free is teetering just outside the top 100 free games in the App Store & isn’t too far from the top 100 of all free apps.

Date & Downloads
2/4/09 – 81
2/5/09 – 1894
2/6/09 – 1798
2/7/09 – 2658

Alright, so here’s the deal. Apple does not allow “demos” in their App Store. They do, however, allow “free” and “lite” apps. Users beg for demos. Air Hockey Free is not (officially) a demo. Do the math though. Much like many other free apps out there, Air Hockey Free is designed to show you just enough of the game so that you’ll figure out if you like it or not. If you like it and you want more options and harder difficulty settings, it’s time to think about upgrading. We’ve made it easy for you. Right there on the setup screen (double tap on the Acceleroto logo when you’re playing a game), there’s a button that takes you directly to the Air Hockey page on your iPhone or touch.

Air Hockey is just $0.99 and offers 4 more difficulty settings & more table color options. You haven’t beaten Air Hockey until you’ve won playing 2-puck INSANE!

It’s too early to tell a trend of conversions from Air Hockey Free to Air Hockey, but so far it looks like there’s about a 1% conversion rate. We’ll continue to post download numbers for Air Hockey & Air Hockey Free. Look for it soon in the top 100!

Download Air Hockey Free and spread the word!