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Use Screen Space Global Illumination
The Screen Space Global Illumination (SSGI) override is a High Definition Render Pipeline (HDRP) feature that uses the depth and color buffer of the screen to calculate diffuse light bounces.
HDRP implements ray-traced global illumination (RTGI) on top of this override. This means that the properties visible in the Inspector change depending on whether you enable ray tracing.
SSGI and RTGI replace all lightmap and Light Probe data. If you enable this override on a Volume that affects the Camera, Light Probes and the ambient probe stop contributing to lighting for GameObjects.
Enable Screen Space Global Illumination
To enable SSGI:
- Open your HDRP Asset in the Inspector.
- Go to Lighting and enable Screen Space Global Illumination.
- Go to Edit > Project Settings > Graphics > Pipeline Specific Settings > HDRP > Frame Settings (Default Values) > Lighting and enable Screen Space Global Illumination.
Use Screen Space Global Illumination
HDRP uses the Volume framework to calculate SSGI, so to enable and modify SSGI properties, you must add a Screen Space Global Illumination override to a Volume in your Scene. To add Screen Space Global Illumination to a Volume:
- In the Scene or Hierarchy view, select a GameObject that contains a Volume component to view it in the Inspector.
- In the Inspector, go to Add Override > Lighting and select Screen Space Global Illumination. HDRP now calculates SSGI for any Camera this Volume affects.
Properties
To learn about SSGI properties, refer to Screen Space Global Illumination (SSGI) reference.
Limitations
- SSGI is not compatible with Reflection Probes.
- When you set Lit Shader mode to Deferred the Ambient Occlusion from Lit Shader will combine with Screen Space Ambient Occlusion and apply to the indirect lighting result where there is no Emissive contribution. This is similar behavior to rendering with Lit Shader mode set to Forward. If the Material has an emissive contribution then Ambient Occlusion is set to one.