Bioshock Infinite is Irrational Game’s massive undertaking that has pushed the studio to rebuild its engine from scratch. As detailed by Irrational, the new engine which was built with the PS3’s architecture in mind also uses tech seen in Uncharted 2.
The studio decided that the engine used for Bioshock 1 and 2 was not powerful enough to build the floating city of Columbia. Chris Kline, technical director of Irrational Games recently wrote:
We started out by taking a look at the original BioShock engine, and very quickly realized that the tools in that engine were too underpowered and unwieldy for the depth and complexity of the gameplay and narrative we had planned —
The studio built a heavily modified version of the UE3 to fit their needs from scratch. In order to do this the studio looked at implementing tech based off Deferred Lighting which is used by many Sony first party games like Uncharted 2, Killzone 2, and inFAMOUS 2.
To meet the aesthetic goals of our art team, our rendering gurus had to write a whole new renderer for BioShock Infinite based on Deferred Lighting (a technique used in Uncharted 2, CryEngine3, and Killzone 2), and on top of that they’ve developed a proprietary per-pixel dynamic relighting scheme that allows characters and dynamic objects to receive global illumination.
According to Kline, Deferred Lighting allowed the team to move away from only utilizing the PS3’s GPU and onto the seven dedicated SPUs for rendering. Many of Sony’s first party studios have been using this strategy to offload most of the rendering aspects to the PS3’s SPUs on the Cell processor.
Kline quells any concerns over a sub-par PS3 port of Bioshock Infinite by revealing that the new development process is based off the PS3’s architecture. He also indicated that the engine has been optimized for the PS3 while giving a performance boost to the PC and Xbox 360.
So instead of declaring a "lead platform" and porting the game to the others, we’ve instead changed the game engine so that all platforms look (to a programmer) more like a PS3.
This means implementing a task-oriented task processor… that mimics the PPU/SPU split of the PS3. Writing code this way is more difficult for us, but has a key advantage: it’s both optimal for the PS3 *and* gives speed improvements on other platforms…
Kline finishes by stating, “I hope that gives you some confidence that we’re serious about making a great PS3 game.”
Clearly developing a game this way is much more difficult, but its also quite admirable that Irrational Games recognizes the technical benefits and have decided to take on this challenge head on. Other major third party studios and publishers such as EA have also gone this route by structuring their development process around the PS3’s architecture.