RTGI Shader Adds Image Based Lighting, Extended Ray Length Multiplier


Pascal Gilcher, the creator of the RTGI shader we've often covered here on Wccftech, has released a new version (0.19) that adds image-based lighting and an extended ray length multiplier. The two features combined should provide quite the image quality boost, as demonstrated in the image below.

Gilcher also explained in his Discord channel how these new RTGI shader features work exactly.

The first one is the Extended Ray Length Multiplier, controlled via a new UI slider.
The way things worked before, you'd have to choose between small details or global illumination. If your radius is low, you have lighting around small details in the foreground, but in the background, you end up with shading that's just outlines of object edges, or you opt for real, global illumination and all the tiny details of the 3D models are gone. No more! The new setting allows you to increase the ray length with distance, so farther away areas now can have larger rays. The first 3 example pictures were taken with only 3 steps per ray.

The second new feature is my take on Image Based Lighting. You can enable it via preprocessor. It analyzes the scene (and past frames) to get a grasp of what lighting in which directions is going on in the scene and uses this information to refine the global illumination data where it's missing or rays reached their limit without finding an occluder. This results in bounce lighting that nicely melts together and it improves the overall feel of the scene. It costs little performance and in some cases drastically improves the visuals. It's a "enable and forget about it" feature that you will miss once it's disabled again.

There is a small caveat: you cannot use auto skycolor and image based lighting together at the moment on DirectX 9, as the shader hits the sampler limit. I thought this was fixed/workarounded by crosire, but apparently it is not. I made sure the errors only show up when actually enabling both, so you should be fine otherwise.

As a reminder, his RTGI shader is still in beta version and can only be accessed by subscribing to his Patreon at the 'Breakfast' level (€5) or above.