The developers of Grand Theft Auto III's fanmade Dreamcast port may have already started work on bringing its sequel Vice City over to the Sega console.
However, that hasn't stopped them from doing some more incredible tinkering behind the scenes to further improve their previous efforts, and make sure the port is the best it can be.
Recently on Twitter, Falco Girgis, one of the many fan developers working on the project, revealed he has been working on a massive new update for the game that he has come to describe as a "[Pull Request] from hell". It features a large number of clever optimizations to the game's code that all work together to allow the port to run much more smoothly on the Sega console, with a smoother frame rate and significantly less pop-in.
"I went through all of the low-level common math infrastructure in both the engine and at the RenderWare driver layer and made numerous optimizations," Girgis said online, "before slowly working my way up to optimizing individual algorithms at the application layer using the new math routines.
He went on to outline some of the specific changes he made, such as the calculations for lighting and "collision intersection and contact resolution code", before demonstrating an actual hardware capture of the Dreamcast version running under a high load.
As he states, this would've "been a slideshow" on earlier versions of the port, with "the dynamic lighting from the sirens, the amount of rigid bodies in the physics simulation from the cars, and the high-speed chase placing high-demands on asset streaming". However, as you can see, the game runs a fairly stable framerate, with these optimizations clearly paying off.
According to Girgis, the update is currently only a draft and not yet available in a publicly available build, but the plan in the future is to eventually push it upstream to be reviewed, tested, and implemented when it is finished.