The Technical Difficulty In Porting a PS3 Game To the PS4 152
An anonymous reader writes "The Last of Us was one of the last major projects for the PlayStation 3. The code optimization done by development studio Naughty Dog was a real technical achievement — making graphics look modern and impressive on a 7-year-old piece of hardware. Now, they're in the process of porting it to the much more capable PS4, which will end up being a technical accomplishment in its own right. Creative director Neil Druckmann said, 'Just getting an image onscreen, even an inferior one with the shadows broken, lighting broken and with it crashing every 30 seconds that took a long time. These engineers are some of the best in the industry and they optimized the game so much for the PS3's SPUs specifically. It was optimized on a binary level, but after shifting those things over [to PS4] you have to go back to the high level, make sure the [game] systems are intact, and optimize it again. I can't describe how difficult a task that is. And once it's running well, you're running the [versions] side by side to make sure you didn't screw something up in the process, like physics being slightly off, which throws the game off, or lighting being shifted and all of a sudden it's a drastically different look. That's not 'improved' any more; that's different. We want to stay faithful while being better.'"
Re:Shitty code (Score:5, Interesting)
Re:PS3 Optimization: Parallelizing code 7 ways (Score:5, Interesting)
The PS3's Cell processor is, in simplified terms, a general purpose CPU and six special purpose coprocessors.
The "coprocessors" are decent general-purpose computers. The problem is that they only have 128K of RAM each. They can access main memory, with high latency but good bandwidth, through a DMA mechanism. (There's also a relatively conventional NVidia GPU on the back end, so the GPU part of the job isn't the big difference. This isn't about shaders.)
That 128K of RAM is too small for a frame. Too small for a level. Too small for any big part of game state. PS3 programming thus consists in turning a problem into some form of streaming process, where data is pumped into Cell processors, processed a bit, and pumped back out. This is a signal processing architecture. It's great for audio. Sucks for everything else.
The PS3 was a "build it and they will come" architecture. It was cheap to make, but large numbers of smart people spent years trying to figure out how to use the thing properly. (Sony basically gutted their US R&D group to beat on that problem.) In practice, a lot of games did most of their work in the main CPU (a MIPS machine) and the GPU, using the Cell processors only for audio, fire and explosions, particle systems, and other tasks that didn't have a lot of interconnected state.