Due to ship in early 2004, Gang Warfare is set to wow mobile gamers with great 3D graphics and immersive gameplay. Xen Games talks to Digit about the challenges of creating a 3D first-person-shooter game for the mobile platform.

XenArdent gamers of first-person-shooter (FPS) games such as Half-Life and Max Payne will soon be able to experience the same thrills on their mobile devices. That's the promise of mobile-games developer Xen Games, creator of mobile games such as Strategic Assault and Interstellar Flames, whose 3D first-person-shooter mobile game Gang Warfare ships in early 2004. Available on a range of mobile devices including PDAs (Palm and Pocket PC platforms) and Smartphones (Symbian and Windows Mobile platforms), Gang Warfare features a character-based storyline and a variety of gritty, urban locations in which the action takes place.

"While there's been attempts to adapt successful game genres to mobile devices, the end result often feels noticeably diluted due to the constraints of mobile games development," says Thameem Sheriffdeen, project lead on Gang Warfare. "Our approach with Gang Warfare differs in that our intention was essentially to identify the key aspects that people enjoy most in conventional desktop first-person-shooter games and refine them into a satisfying mobile games experience."

Xen 3D FPS
The game has been in development for almost two years - considerable longer than most mobile games - and key to its creation is Xen Games' development and use of its in-house 3D games engine called 4Sight.

"Handheld devices generally suffer from relatively poor performance compared to more conventional gaming platforms and also lack support for rendering 3D graphics," explains Sheriffdeen. "4Sight's internal real-time-rendering capabilities and features are quite extensive, yet the engine is designed and optimized specifically for mobile devices. This affords us the ability to create richer environments and graphical content than would otherwise be possible on handhelds, which Gang Warfare takes full advantage of."

The engine is also capable of special effects ranging from particles, reflections and transparencies, and offers several lighting models to work with - including radiosity-based lighting, explains Sheriffdeen. In addition, the engine provides other tools that aid games development including terrain generation and scripting of in-game gameplay sequences, he says.

The Xen Games team spent a long time experimenting with the 4Sight technology and trying out various ideas. Although this lengthened the development process, the team were then able to design the game to take full advantage of the underlying technology.

Xen 3D FPS
For example, explains Sheriffdeen, the team quickly realized that clever use of lighting could help introduce variation and visual depth into the game environments, which helped counteract a common problem with mobile games - namely dull and repetitive environments caused by the severe restrictions in texture usage that are imposed by mobile devices' limited memory.

Other limitations of mobile devices as a gaming platform had to be identified early on in the development process and solutions found. These limitations include restrictions on screen resolution, colour depth, and user controls - all of which can seriously affect the gameplay of mobile games.

To workaround users' inability to press more than one button at a time on mobile devices, Xen Games added options for auto firing when the player's weapon is focused on an enemy, thereby removing the need for the player to press two buttons to aim and shoot simultaneously.

As gamers tend to play mobile games in short bursts in contrast to lengthier sessions on consoles and PCs, care had to be taken with the type of levels used in Gang Warfare. Smaller maps of the levels were used in comparison with conventional PC FPS titles, as were clearer objectives that allow quicker immersion into the game and encourage replayability.

Xen 3D FPS
"As independent developers, we're very pleased with what we've achieved in Gang Warfare and feel that it sets a high standard as a unique and enjoyable mobile gaming experience. The game also succeeds in making the technical restrictions of mobile devices feel transparent to the end-user - something we feel particularly proud of," says Sheriffdeen.

Building the environments

The game is set in an urban landscape - loosely modelled on London. "It's a stylized version of London used to instill character into the games world," explains Sheriffdeen. "Although our intention was to create a believable gaming environment, realism was never a priority. Simulating urban warfare to any meaningful level of authenticity, in addition to being a fairly outlandish idea in itself, is far beyond the technical and practical considerations of current mobile devices."

Personality over realism was the aim of the game's designers, he explains, with every effort made to make the world of Gang Warfare feel tangible despite the technical limitations of the platform. "Simply put, a train station featured in the game should still be identifiable as a train station, even though the player is likely to be aware of the fact that they cannot actually commute to another city," he says.

Xen 3D FPS
Believable characters and a genuinely compelling plot were also key objectives of the game's designers. "We definitely tried to invoke some of the character and interaction inspired in some of the best examples of the action genre on conventional gaming platforms - games such as Half-Life or the Max Payne franchise," he explains.

Xen Games used Discreet 3DS Max and Character Studio to create the game, because of both packages' ability to scale the low-polygon models required says Sheriffdeen. The initial stages of a character's design revolved almost entirely around assembling the basic shape and optimizing it to an acceptable polycount with much of the character's detail achieved through its texture, rather than mesh complexity.

"Given the memory limitations on the use of textures, the advanced features of 3D Max's UV unwrapping was a great boon in maximizing the use of the character's texture skin, and we were able to mirror parts of his features as well as place more emphasis on the mesh sections that feature more prominently in the game such as 'face-on' views of a character," he says.

While optimization of the character models was essential, this had to be balanced with the need for enough complexity to allow for believable animation within Character Studio. "In the case of one of the enemy characters, we managed to get reduce the total number of polygons used to about 280, including his weapon. Paying particular attention to the areas of the model that are deformed most during the animation proved to be a key aspect of low-poly character animation," says Sheriffdeen.