When using screen space post processing effects in Unity Passthrough will seem broken as the texture in the background will remain black even if Passthrough is activated. 

This is caused by Unity's post processing shaders not preserving the original alpha values of the rendered texture during the post processing steps. 

See Passthrough: Post-processing in combination with Passthrough for more information on Passthrough and post processing effects. 

This bug affects all Mixed Reality devices such as VRX and originates from the Unity post processing stack.


Affected Versions

Snapdragon Spaces Services

  • Any

Snapdragon Spaces Plugin

  • Any

Device and firmware versions

  •  Any Mixed Reality Device any firmware


There is no official workaround available at this time. Custom post processing effect shaders that preserve alpha can be used but remain within individual responsibility. 

Further Resources

Upvote the issue on Unity's product board Post-Processing - Alpha Preservation Setting - Unity Platform - Rendering & Visual Effects | Product Roadmap (