RTGI, not to be confused with NVIDIA’s RTXGI SDK which was recently updated to version 2.0, is Pascal Gilcher’s famous ReShade screen space ray tracing shader. The German graphics modder and former NVIDIA employee rose to fame when he released it in May 2019, providing PC gamers with an easy way to improve the lighting of older games at an acceptable performance cost.
Since then, countless ReShade presets powered by RTGI have been created for compatible PC games, many of which we’ve covered here on Wccftech. Meanwhile, Pascal Gilcher has continuously improved the shader for his Patreon backers. Three months after his latest update, Gilcher released a new version (0.51) of RTGI this past Thursday.
As usual, the modder also relayed some details on the latest improvements. According to him, there are lots of tweaks to the filtering and checkerboard rendering, which are much more motion-stable now. He also added the ability to disable diffuse or specular GI, in case users only want to use one of the two at any time. RTGI 0.51 also brings ray traced sky color back with a new method that Gilcher reckons should be relatively robust and won’t have a “toggle on” effect when the sky is first visible. He also mentioned ‘significant performance enhancements’ depending on the scene and provided an image comparison in Hogwarts Legacy.
However, RTGI is not the only ReShade ray tracing shader any longer. In late 2023, fellow modder NiceGuy released his own so-called Complete RT shader, which we have since covered in various showcases (Horizon Zero Dawn, Fallout 4, Skyrim, Red Dead Redemption 2, and even Zelda via emulator).
The Complete RT shader also received a major update (version 1.3) a few hours before RTGI. NiceGuy said he has now fully implemented a technique inspired by ReSTIR-GI; version 1.2 implemented the spatial part, whereas this new update adds the temporal dimension, providing a more accurate image and improved performance at once.
The Complete RT shader has also had its temporal upscaling performance improved; 1.3 allows not just the main ray tracing pass, but also the denoising passes to be upscaled. Temporal upscaling itself is also a quality improvement over the bilateral upscaling used in previous versions. Lastly, there’s a new diffuse illumination feature called Sky Lighting that helps users apply the color of the sky to the surroundings even if the sky itself is not visible on the screen. Sky Lighting automatically detects the sky color, but it is also fully customizable so users can change the tint, disable the automatic color detection, and fine-tune the intensity. You can watch the official demonstration of Complete RT 1.3 below.
Thanks to the two modders, I have access to both shaders, so I checked out these new releases in the MMORPG Guild Wars 2. Both updates boast performance improvements, and while it is true that RTGI 0.51 runs better than the previous version, Complete RT remains faster.
Granted, both shaders result in a major hit to frame rate in Guild Wars 2’s human capital of Divinity’s Reach from around 82 FPS to 46 FPS for Complete RT and 36 FPS for RTGI. However, Complete RT feels perceivably smoother and can actually be kept on even in intense combat situations if you have a G-Sync VRR display. I also prefer the look of Complete RT, both in the Plaza of Dwayna scene and in the Palace scene. Both support sky color, but NiceGuy’s shader seems to do a better job at diffuse illumination, perhaps because of its ReSTIR-GI-like implementation.
Interestingly, Complete RT works best combined with another shader made by Pascal Gilcher called Launchpad. This is a prepass shader equipped with a motion estimation algorithm that uses optical flow and should be pushed at the top of a user’s shader list in ReShade. Gilcher said the latest version of Launchpad features ‘greatly improved filtering and motion detection at no performance cost’.
Unfortunately, Gilcher didn’t provide an update on his groundbreaking ReShade path tracing solution that was first introduced in August 2023. You can read more about that ambitious project in my interview with the modder.
