Pipeline Integration
Metallic Indirect Fallback [URP]
Allows metals to be rendered as diffuse materials. This option is useful to prevent metals from appearing black when there is no source of reflections. It is identical to the Metallic Indirect Fallback checkbox in HDRP.
Performance impact: none
Ambient Override [URP]
Defines whether Unity's native ambient lighting should be removed from the frame before applying HTrace SSGI. In URP, it's not possible to automatically disable the native indirect lighting when a custom GI solution is enabled. So if we were to naively inject our SSGI output into the URP frame, we would just add it on top of the existing indirect lighting, not replace it, resulting in double-GI, which is obviously incorrect. Fortunately, GI in URP comes only in two forms: APV and Sky Ambient. We can reproduce each type on our side and subtract it from the frame, leaving only the direct lighting we want to work with. For example, if an APV was baked - HTrace reproduces its output and subtracts it from URP's Color Buffer (for opaque objects only), virtually removing its contribution to the frame. It can then be re-added through the Fallback option, the same way it's done in HDRP. However, this way it’s properly combined with whatever HTrace managed to gather from screen-space lighting, not just overlaid on top of it.
Performance impact: small
Multibounce [URP]
When enabled, HTrace SSGI calculates multiple "infinite" light bounces by using the previous frame's indirect lighting as input for the current frame. This results in brighter indirect lighting with more accurate color bleeding and less noise, but reduces the temporal responsiveness of GI, since multiple bounces take longer to update compared to a single bounce.
Performance impact: small
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