Angry birds on Windows Phone 7

Angry Birds is not on an easy flight path with it's attempt to catapult itself onto the Windows Phone platform.

In promotional material for the WP7 launch Microsoft used the Angry Birds logo and upset developers Rovio - who had not committed to releasing their ubiquitous mobile game on the new platform. They spat out a few angry tweets and things were looking gloomy for those of us looking for an Angry Birds fix on our Windows Phones. Microsoft later admitted they had made a 'mistake' in the promo materials.

Fast forward a few months and two things have happened. Firstly, Rovio has now cheered up and confirmed Angry Birds for Windows Phone will now be released some time this year, and secondly, an unofficial clone called Chicks'n'Vixens has been released by independent developer Jabberworx. He was frustrated by Rovio's slowness at porting the game across to his favourite mobile platform and wrote his own version. Of this he said:

“If I were Rovio and had access to the art and knew about the 2D physics engines settings for the various objects (mass, physics, restitution, etc) I could get Angry Birds running on Windows Phone 7 in under a week.” Jabberworx

Ouch. Jabberworx must be a hell of a coder.

So why are people so bothered about being able to play Angry Birds on their Windows Phones? Surely there are better games out there? The thing is - it's turned into a status symbol for mobile platforms - any mobile ecosystem wanting to be a major player has to have it.

How well will the Windows Phone version run?

All current Windows Phone devices have good hardware specifications featuring a 1Ghz processor and decent graphics hardware sporting 2D and 3D acceleration. Exact comparisons with the iPhone are difficult but the hardware specification indicates that WP7 devices are in the same class performance-wise as the iPhone 4 except for slightly less powerful 3D graphics, but they should definitely be a step above the older 3GS model.

Angry Birds running on the original iPhone 3G with it's 400Mhz processor is a little slow to load with some stuttering sound on the menu pages but the game itself runs very well - sideways scrolling is fairly smooth  although not as fluid as you'd see on a real gaming device like a 1980's Amiga! Play the game on the 3GS and the extra power of the device translates into a higher frame rate and the game really starts to look great with super-smooth scrolling. This is even more so on the iPhone 4.

So you'd expect the Windows Phone version of the game to work very nicely but there is a potential problem. Microsoft designed the XNA gaming framework to lock games into rendering at an upper limit of 30 frames per second, which was apparently done to preserve battery life. This seems like a sensible compromise especially for graphically intensive 3D games but there is of course a trade-off in the ultimate smoothness of motion, which will negatively affect 2D games that make heavy use of full-screen scrolling. Results will quite likely be sub-par compared to current-model iOS devices which are probably pushing 60 frames per second. It could well be the case that Angry Birds on Windows Phone performs about the same as the iPhone 3G despite the superior hardware.

Only 30 fps on an otherwise top-notch smartphone - surely not?

Will Microsoft make changes to address this? They should definitely consider removing the frame limit for 2D games but the problem with that approach could be the difficulty of classifying games as many use a hybrid approach. But the question is - can the hardware do more than 30fps? John Carmack has proved the iPhone can with Rage - a full 3D game running at 60fps which looks stunning. Does the Windows Phone hardware support such a high refresh rate? There's conflicting information out there, some say the hardware cannot support it while other developers are saying it's purely an XNA framework limitation and the phone's main user interface and Silverlight apps can run at 60fps.

It will be interesting to find out how Angry Birds actually performs when it ships. Chicks'n'Vixens has a nice smooth screen update but it doesn't scroll around quite as energetically as Angry Birds. With the games I've tried so far, it seems a rule of thumb that 3D titles such as The Harvest and Rise of Glory can look very nice on Windows Phone 7 but 2D titles like Tiki Towers are disappointingly jerky.

Let's also hope that the Windows Phone version of Angry Birds is priced keenly, unlike some of the other titles in the Marketplace. The iPhone version was only £0.59p.