Paolo Leoncini

Thank you a lot Alex, now the picture is much clearer. For starting, in my OpenGL-based VR runtime I just added the fourth component to glClearColor(r, g, b, 0) and... le MR sont fait! On the Unreal side I'll need to go through an investigation since in an application using deferred rendering (and RT, I don't know if this matters), frames result in being fully filled by the passthrough video - maybe UE puts an invisible transparent envelope all around the scene that becomes an alpha = 0 for the MR passthrough. For now, just disable the MR flag in VBS. Paolo

I found this: The problem is that the MR passthrough gets mapped wherever alpha <> 0 (i.e. where all the semi-transparent surfaes gets rasterized and put alpha non zero into the framebuffer), not only on what we could agree to define "background".

In my Focus 3 I've just experienced an apparent issue related to video passthrough mapping over semi-transparent surfaces in VBS version 1.12.8, which 1.13.2 has "solved" (the MR passthrough UI flags in the Graphics tab now works). This was the opportunity to discover the MR video passthrough joys, which I kindly ask to explain in more detail - or point to explaining docs - in order to use it with awareness, especially along with the new XR Elite color passthrough. To my practicality in these days, MR passthrough - when enabled in VBS - got mapped in a sort of chromakey mode over transparent and semi-transparent parts of the 3D scene. Yet, I never got "pure" passthough, in what it was always mediated by the material props (diffuse/ambient/emissive values), and this is a mistery to me because as far as I understand VBS barely streams the PC app framebuffer, thus the link to 3D stuffs should have been lost in the rasterization. What is the best config for a pure MR passthrough mapping on wanted 3D scene surfaces? Thank a lot in advance for every explanation that would shed light on this behavior. Paolo