NVIDIA RTX-Remix 0.1 Released For Adding Path Tracing To Classic Games

In addition to releasing the GeForce RTX 4070 graphics card today (unfortunately, no launch day Linux review, still waiting on hardware...), NVIDIA has released as open-source the RTX Remix software for helping to add path tracing support to classic games.

RTX-Remix is a NVIDIA GameWorks initiative as a runtime to help provide path-tracing to classic games for better enjoying on NVIDIA's latest GeForce RTX graphics cards. initially this consists of DXVK-Remix and Bridge-Remix.

The initial NVIDIA RTX Remix Runtime v0.1 release overhauls the geometry hashing and processing system, a new sky handling system, CPU performance optimizations, and an assortment of other improvements. Prior to this now-public code, RTX-Remix is how NVIDIA went about adding path tracing support to Valve's Portal with Portal RTX.

As for how RTX Remix works, the Wiki page explains:

"You don’t have to be an expert in rendering to work with RTX Remix – the runtime and creator toolkit will take care of everything you need to create beautiful path traced mods. But understanding some of the key concepts and components and how they link together will make it easier to understand the workflow, and why the assets and captures are structured the way they are.

The RTX Remix runtime consists of two main parts: the Bridge, and the Renderer. The Bridge uses a d3d9.dll “interposer”, which when placed next to the game executable, captures the stream of rendering commands within the original 32-bit process of the game, and sends them to NvRemixBridge.exe, which is now a 64-bit process. This translation into a 64-bit instruction set gives you practically unlimited memory to play with, and better compatibility for modern ray tracing APIs.

The Bridge is only a pass-through however, feeding the d3d9 rendering commands as-is to another d3d9.dll, which contains the RTX Remix renderer. The Remix d3d9.dll is a fully-fledged path tracing rendering engine that takes the geometry, material and light information embedded in the d3d9 rendering commands and constructs a complete game scene with enhanced assets, materials and lights, and then proceeds to path trace it."

NVIDIA RTX-Remix is available in source form as well as Windows binaries. RTX-Remix is under an MIT license. More details on the open-source RTX-Remix via GitHub. More details on the RTX Remix tech is available from the NVIDIA feature page.