The big picture: Developers and modders have added intense path-traced lighting to several classic games from the 90s and early 00s over the last few years. Descent is the latest to receive a cutting-edge graphical overhaul. As stronger toolchains become available, expect to see more ray-traced retro games soon.

A group of game design students from Breda University of Applied Sciences in the Netherlands has released a free mod that adds path tracing to the classic 1995 first-person shooter Descent. It is only the latest shooter from that era to receive a remaster using the transformative and computationally expensive lighting technology.

DXX Raytracer is a fork of the Descent source port DXX Retro. It adds path-traced global illumination, updated textures, soft shadows, bloom, temporal anti-aliasing, motion blur, a 3D cockpit, and multiple post-processing features to the game. A debugging utility lets users tweak dynamic lights and materials to explore the mod's effects.

Although similar to Doom, Descent was one of the earliest first-person shooters to allow proper three-dimensional movement, letting players pilot a spaceship in all directions in a fully polygonal environment. It received two sequels and spawned the Freespace series. A spiritual successor, Overload, was released in 2018 to a generally positive reception.

Adding ray tracing to Descent creates an effect similar to the mods Sultim Tsyrendashiev released for other classic shooters like Doom, Quake, and the original Half-Life. Professional developers have also combined path tracing and low-end graphics in games like Portal, Quake II, and Minecraft.

Ray tracing is usually associated with the latest and most advanced titles. Ironically, adding RT to retro games better illustrates the difference it makes. The feature allows users with a relatively broad range of hardware to try path tracing while seeing older games in a new light (pun intended). Conversely, engaging the feature in Cyberpunk 2077 can make all but the most expensive graphics cards struggle.

Nvidia's upcoming RTX Remix suite will further modders' efforts to bring path tracing to even more classic titles, and experimentation has already begun. Although the company hasn't yet released the entire kit, the open-source runtime and the files from Portal RTX have created promising early results in games like Half-Life 2, Max Payne, SWAT 4, Need For Speed Underground 2, the original Splinter Cell, Call of Duty 2, Grand Theft Auto San Andreas, and others.