RTGI and Complete RT Shaders Get Major Updates with Sky Color

While NVIDIA’s RTXGI SDK recently received an update to version 2.0, it should not be confused with RTGI, which is Pascal Gilcher’s renowned ReShade screen space ray tracing shader. This German graphics modder and former NVIDIA employee gained widespread recognition when he first released the shader in May 2019, offering PC gamers a simple solution to enhance the lighting in older games without sacrificing performance.

In the meantime, Pascal Gilcher has consistently enhanced the shader for his Patreon supporters. Just three months after his previous update, Gilcher recently unveiled a new version (0.51) of RTGI on Thursday.

As usual, the modder also shared some details about the latest improvements. According to him, there have been numerous tweaks made to the filtering and checkerboard rendering, resulting in a more stable motion. Additionally, the modder has now included the option to disable either the diffuse or specular GI, allowing users to choose which one to use at any given time. Furthermore, RTGI 0.51 reintroduces ray traced sky color through a new method that the modder believes is reliable and does not cause a sudden change in appearance when the sky is first visible. In addition, the modder has reported significant performance improvements in certain scenes and has provided a comparison image from Hogwarts Legacy.

Although RTGI used to be the sole ReShade ray tracing shader, it is no longer the case. In late 2023, another modder by the name of NiceGuy released their own version called Complete RT shader, which we have also featured in different showcases such as Horizon Zero Dawn, Fallout 4, Skyrim, Red Dead Redemption 2, and even Zelda through an emulator.

The Complete RT shader underwent a significant update (version 1.3) shortly before the release of RTGI. According to NiceGuy, the latest update has fully incorporated a technique influenced by ReSTIR-GI. While the previous version (1.2) only included the spatial component, this new update introduces the temporal dimension, resulting in a more precise image and enhanced performance simultaneously.

The temporal upscaling performance of the Complete RT shader has been enhanced, with version 1.3 now allowing for not only the main ray tracing pass, but also the denoising passes to be upscaled. This improvement in quality also surpasses the previous versions’ use of bilateral upscaling. Additionally, a new feature, called Sky Lighting, has been added which enables users to apply the color of the sky to the surrounding environment, even if the sky is not visible on the screen. This feature automatically detects the sky color but can also be fully customized, giving users the option to change the tint, disable automatic color detection, and adjust the intensity. An official demonstration of Complete RT 1.3 can be viewed below.

Thanks to the contributions of the two modders, I was able to obtain both shaders and test them out in the MMORPG Guild Wars 2. Both updates claim to have improved performance, and after my evaluation, I can confirm that RTGI 0.51 runs smoother than its previous version. However, Complete RT still maintains its title as the faster option.

While both shaders significantly decrease the frame rate in Guild Wars 2’s Divinity’s Reach, dropping from around 82 FPS to 46 FPS for Complete RT and 36 FPS for RTGI, I find that Complete RT provides a smoother experience and can even be used during intense combat with a G-Sync VRR display. Additionally, I personally prefer the visual effects of Complete RT in both the Plaza of Dwayna and the Palace scenes. Both shaders support sky color, but the implementation of ReSTIR-GI in NiceGuy’s shader seems to result in a better diffuse illumination.

Pascal Gilcher’s shader, Launchpad, is a valuable companion to Complete RT. This prepass shader utilizes an optical flow motion estimation algorithm and should be placed at the top of a user’s shader list in ReShade. According to Gilcher, the most recent version of Launchpad boasts enhanced filtering and motion detection without any impact on performance.

Unfortunately, Gilcher did not offer any updates on his revolutionary ReShade path tracing solution, which was initially introduced in August 2023.