Xen Games started out developing for games for Pocket PC. Its first port to Symbian was the 2D Strategic Assault, implemented originally for the Sony Ericsson P800. This was followed by the 3D game Interstellar Flames 1, also first for the P800. The company is now transitioning its games to 3D using OpenGL ES.

Richard: How important is OpenGL ES and the hardware acceleration on Sony Ericsson's UIQ devices to porting your games?

Simon: When we ported Interstellar Flames 1 to UIQ 2 we used our own 3D rendering engine. Now OpenGL ES is becoming available, we are switching from our engine. This is because, combined with hardware acceleration, OpenGL ES is able to create far better graphics.

We originally did the work on porting to OpenGL ES for the ill fated Gizmondo device. Obviously the failure of that venture was a blow, but having done the work we looked for an alternative platform. We knew the graphic on the new version of Interstellar Flames needed hardware acceleration to work, so Sony Ericsson's UIQ 3 phones were an obvious choice. As we had worked with Sony Ericsson before, we knew their phones would be technically suitable for Interstellar Flames 2. The fact hardware accelerated graphics is available on all three of Sony Ericsson's UIQ 3 phones also helped the decision.

Richard: How much do you expect to use OpenGL ES in the future?

Simon: We are definitely moving to 3D and we don't see the point in using our own engine anymore, as the graphic won't be as good as those provided by hardware acceleration. Also, more and more phones will go the hardware accelerated route. As we concentrate on high quality games, which can take a year to write, we don't see any point in creating a game that is not Open GL ES 3D enabled. It makes no sense to write a game for a device with a 3D chip without using its features. To use the chip you need to use the standard APIs and OpenGL ES is the most widespread standard on phones.

Richard: Has Open GL ES other advantages beyond the quality of graphics?

Simon: The main advantage with OpenGL ES is its cross platform support.

Also, as it is modeled on the desktop OpenGL API, anyone familiar with the PC version can easily use OpenGL ES. Similarly many of the resources for OpenGL, such as tutorials on the Internet, apply to Open GL ES.

Richard: How useful have you found the tools and examples provided by Imagination Technologies through Sony Ericsson in your OpenGL ES development?

Simon: Beyond the texture compression we have not needed to make use of these tools and examples. We have a graphic artist, using something like 3D Studio Max, create the graphics for our games, we then use our own exporter application to convert the image map into our own geometry files while the textures are converted into Imagination Technologies compressed formats. We then write our own code to load that model into OpenGL ES.

The only change we have had to make for graphics handling, from the work we did for the Gizmondo version of Interstellar Flames 2, is for texture compression as the Gizmondo used an NVIDIA chip.

Richard: Given that OpenGL ES is a cross platform technology, how important is the UIQ platform to Xen Games?

Simon: Historically our sales on UIQ have not been impressive. I think this was mainly because the early UIQ phones were targeted at business users. Sony Ericsson clearly has given UIQ a more consumer orientation with W950 and we are expecting to see an improvement in sales.

From the point of view of a games developer, like us, the OS is not overly important. We don't make use of the UI, so porting a game is far more straightforward than porting a business application. We also avoid calls into the OS to make porting as easy as possible.

The more important factors in selecting platforms for our games are how suitable devices based on it are for games play and their sales volumes.

Sony Ericsson's UIQ phones measure up well against these criteria. In addition, Sony Ericsson's support for hardware acceleration as a standard feature seems quite aggressive. By contrast, on Pocket PC only the Dell X50v has such a chip. So as Interstellar Flames 2 requires the 3D chip, UIQ is the platform we have launched on.

Richard: So in the future you will support any platform where 3D acceleration chips are commonly available?

Simon: Yes. Porting a game using OpenGL ES is a small job compared to writing a game from scratch. So there are obvious benefits in supporting any platform in which graphics acceleration is widely available and where device volumes are likely to be high.

Richard: What sales channels are you using?

Simon: We are working with Sony Ericsson to get Interstellar Flames 2 into the online shop and hoping also to have it included as one of the try and buy applications loaded on new phones. Finding sales channels is however our biggest issue. Java applications already have good channels through operators, but advanced games for Symbian phones are an issue, mainly because of their size. It means we are at the leading edge when it comes to finding new sales outlets. However, I think the problem will be solved. After all companies like Sony Ericsson have a vested interest in encouraging operators to provide download channels for this type of application, as they are an important part of reason for investment in high end hardware.

Richard: So what about future games?

Simon: We certainly have a new game in the pipeline, but as we are a small company it will be sometime off from release, but it will be 3D and we hope it will be very exciting.

More information on OpenGL ES support on Sony Ericsson's UIQ 3 phones can be found on the Sony Ericsson Developer World Web site (developer.sonyericsson.com). The OpenGE ES SDK for UIQ 3 can be downloaded here (33.3 MB).

For more information on Xen Games see www.xengames.com.