If not already available, sample the roughness from a specular map or derive from screen space normals variance.
float roughness = getRoughness(texCoord);
float stepSize = lerp(MIN_STEP, MAX_STEP, roughness);
One of the biggest complaints in previous RTGI versions (pre-0.17) was the "shimmering" or "boiling" effect on fine details, such as grass, chain-link fences, or distant foliage. Version 0.17.0.2 introduces a refined Temporal Anti-Aliasing (TAA) integration.
The algorithm now better differentiates between "new light information" and "temporal noise." Users will notice that static scenes look plastic-smooth, while moving objects retain a natural grain without the dancing pixels of older iterations.
RTGI (Ray Traced Global Illumination) version 0.17.0.2 is a shader for ReShade developed by Pascal Gilcher (Marty McFly) that adds realistic path-traced lighting and shadows to games. 1. Installation Prerequisites
ReShade with Add-on Support: You must install the "Add-on Support" version of ReShade to ensure the shader can access the game's depth buffer, which is required for ray tracing.
Shader Files: Place the RTGI.fx file in your game's reshade-shaders/Shaders folder and any associated textures into reshade-shaders/Textures. 2. Initial Configuration
Once in-game, open the ReShade menu (usually the Home key) and follow these steps: rtgi 0.17.0.2
Enable the Depth Buffer: Go to the Add-ons tab in ReShade and ensure "Generic Depth" is active. If you see a flickering or upside-down depth map, toggle "Copy depth buffer before clear operations" or "Reverse depth."
Activate RTGI: Search for RTGI in the shader list and check the box to enable it. 3. Key Settings in 0.17.0.2
The shader is highly customizable via the parameters at the bottom of the ReShade window:
Ray Length: Controls how far light bounces. Higher values look better in large outdoor areas but cost more performance. Amount: Adjusts the intensity of the illumination.
Z-Thickness: Essential for fixing "light leaking." It tells the shader how thick objects are so light doesn't bleed through thin walls.
Next-Gen Integration: Version 0.17.x improved temporal filtering. Ensure Temporal Accumulation is enabled to reduce noise/graininess while moving the camera. 4. Performance Tips If not already available, sample the roughness from
Resolution Scaling: Use the Render Scale setting (if available in your version) to run the ray tracing at a lower resolution (e.g., 0.5x) while keeping the game sharp.
Ray Count: Keep the Ray Count between 2 and 4 for general play. Values above 10 are typically for screenshots only. Troubleshooting Common Issues
Invisible Effect: If the shader does nothing, your depth buffer is likely not set up correctly. Check the DisplayDepth shader to see if you have a clear black-and-white view of the world.
Flickering: Disable in-game Anti-Aliasing (MSAA) and Ambient Occlusion (SSAO), as these often conflict with ReShade's depth access.
If you are using a specific game like GTA V or Skyrim, let me know so I can provide optimized preset values for those titles.
Built against Reshade 6.0+ SDK, this version supports the new addon event system. This means RTGI no longer conflicts with other popular shaders like MXAO or Clarity when loaded simultaneously. One of the biggest complaints in previous RTGI
Cyberpunk 2077 (no built-in RT):
Skyrim SE (ENB + RTGI hybrid):
GTA V:
RTGI 0.17.0.2 is likely the last major version in the "screen-space" paradigm. Martino has hinted at a 0.18 branch that will leverage neural radiance caching (similar to Nvidia's ReSTIR).
However, as of today, RTGI 0.17.0.2 represents the apex of what real-time post-process shaders can achieve. It narrows the gap between rasterized and path-traced visuals without requiring a $1,600 GPU.
Expect the community to port this shader to Reshade 6.5 and eventually RenderDoc for offline rendering workflows.
RTGI_BRDF.png (or similar texture) into reshade-shaders/Textures/Installing RTGI 0.17.0.2 requires Reshade and the shader files.