The rise of cloud gaming services such as PlayStation Now may have ushered in a new era of convenience for blasting virtual aliens and monsters to smithereens, but on-demand play brings with it one huge unwanted drawback: the bandwidth required is astronomical. But researchers at Duke University and Microsoft Research think they have a solution that'll let gamers have their on-demand cake and eat it too. They have developed a tool called Kahawai (Hawaiian for stream), which splits the rendering calculations between your device and a remote server rather than offloading them all to the server.

The researchers claim that this collaborative rendering technique requires just one-sixth as much bandwidth as conventional cloud gaming setups for the same visual quality. The mobile or console device sketches out the key parts of each frame or the bulk of the image in a subset of the 60 frames displayed per second (at least six frames must be generated client side to be worthwhile), while the remote server does the heavy lifting and fills on all of the fine-grained details such as shadows, real-time lighting, and subtle changes in texture.

Kahawai was prototyped and integrated with open-source commercial gaming engine idTech 4, which powers games such as Doom 3 and Enemy Territory: Quake Wars. The researchers trialled it on 50 hardcore gamers playing Doom 3, with results that suggest no disadvantage for users of Kahawai versus a standard thin-client (i.e., server offloaded) streaming system. You can see a comparison of the performance and graphics in different scenarios in the video below.

Kahawai was also found to work offline, sans remote server connections, at lower graphical fidelity, which is great news for people on unstable networks (because play could continue uninterrupted) and for people with slow internet connections.

Kahawai may have applications beyond gaming, too. "Games are a natural place to start understanding how collaborative rendering can work," said study co-author and Duke computer scientist Landon Cox. "But any graphics-intensive application could potentially benefit from Kahawai, from 3-D medical imaging to computer-aided design software used by architects and engineers."

The researchers presented their findings at the 13th International Conference on Mobile Systems, Applications, and Services in Florence, Italy, on May 19. A paper describing the research is available to download directly from Duke University.