Porting a game from one console to its predecessor is usually an easy endeavor. However, porting PlayStation 3 to PlayStation 4 is proving to be a daunting task, thanks to the move from the complex Cell processor architecture to the PC-like X86 processor architecture.
When they started working on The Last Of Us PS4 remake, Naughty Dog expected that to be a difficult task and it turned out to be harder than expected.
“I wish we had a button that was like ‘Turn On PS4 Mode’, but no,” said creative director Neil Druckmann. “We expected it to be Hell, and it was Hell. 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."
Problem is, the PlayStation 3 version of The Last Of Us was highly optimized for the console's Cell processor architecture in order to extract as much performance as possible. "[Naughty Dog]engineers are some of the best in the industry and they optimised the game so much for the PS3’s SPUs specifically," explained Druckmann. "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’ anymore; that’s different. We want to stay faithful while being better.”