1994 Sega Saturn Pulls Off Real-Time Ray Tracing In Stunning Homebrew Demo

The Saturn was Sega's fifth generation fully-3D console, launched in 1994 to compete with the PlayStation 1 and Nintendo 64—and all these years later, homebrew developer XL2 has managed to create a functioning ray tracing demo on the hardware. The first video of the demo is a single room without any static lighting sources and all ray tracing done via Binary Space Partitioning (BSP). According to XL2, there's still room for improvement here, and room to have RT impact entities, include indirect lights, and have distance impact lighting. XL2 says "I just need to find a way to integrate it at a reasonable speed on the Saturn", but with the progress that's already been made, tech enthusiasts all over are seriously impressed.


The best-looking games on Sega Saturn were typically Sega-based arcade ports like Virtua Fighter 2 or titles uniquely optimized for the hardware, like PowerSlave or Panzer Dragoon. Fun fact for Quake fans: that game's acclaimed Saturn port was actually based on PowerSlave's Slavedriver engine. What XL2 has achieved here most strongly recalls PowerSlave's first-person gameplay and its dynamic lighting, though of course what we're seeing here is at a much higher fidelity than that. The confined size of the testing room does make one wonder just how expansive a Saturn game using this lighting could actually be—most RT demos on old hardware are fairly limited in scale, after all. But even this being achieved on 1994 hardware that was reportedly worse for 3D rendering than the original PlayStation is insane, so we have to be impressed either way.

The library of existing Sega Saturn games point toward Quake being at the higher end of impossible ports for Sega Saturn, so it's unlikely that XL2 can expand this single-room demo to a full game of similar scale, but we're still looking at an early brew here. Since the larger tech press was slow to pick up on this one, it's actually about two weeks old—and a newer, more advanced Saturn ray-tracing homebrew demo has already been uploaded.


But the second demo, which Tom's Hardware and a number of other outlets have yet to notice, is even more impressive, and starts making a Quake or Doom port with RT effects look feasible. The technical breakdown included in the second video's description indicates that this is "a new hybrid approach" that only tests rays against entities but still gets greatly enhanced dynamic shadows.

Now the multi-room demo is starting to look more like Amid Evil RTX, complete with stylized lighting and a killable enemy, than just some Quake-like test room. According to XL2, however, the mirror in the final room tanks framerate to 15 FPS from the usually-stable 30 FPS target on actual hardware, so he's left hoping that dynamic shadows "won't be too expensive" after he's made the rest of his optimizations. The possibilities are tantalizing, and will hopefully be playable for the larger public once development is complete. After all, a public release would give collectors another game to play, and invite modded Saturns to the party.