Forum Discussion
Passthrough + Bloom?
Has anyone had any luck getting Bloom+Mobile HDR working in a project with a passthrough layer? When I tried enabling it in my project that has passthrough none of my objects showed up.
Similar issue here. I'm on the same team with Stex at the Github issue: [5.3.2][v62]Passthrough not working with MobileHDR · Issue #409 · Oculus-VR/UnrealEngine (github.com)
We do wonder if Meta would be kind to do a quick fix, so this fabulous MobileHDR feature would also work under passthrough mode.
According to our further tests, the root cause of the issue is probably fairly simple: when Mobile HDR is on, the void background in the virtual scene editor is not omitted as it was in Passthrough when MobileHDR is off. Instead, the whole black void is rendered altogether with virtual objects, so laying it over the passthrough feed leads to not seeing actual passthrough environment.
It's such huge news for our team to learn that MobileHDR is supported in v62, and especially excited that it is compatible with Multi-view to enhance performance. We run some tests in VR usecase, the framerate is amazing with Quest 3's powerful XR2 Gen 2 Chip.
However when it comes to MR, the passthrough just doesn't work. We run some tests using only the simple official sample at Unreal-PassthroughSample. All we see is the visual objects in complete darkness, without actual passthrough background.
HDR on
So we did some further tests, slightly tweaking the official sample by laying the passthrough layer on top and play with opacity. Here are the results:
HDR on, PT layer on top, Opacity 0.02HDR on, PT layer on top, Opacity 0.11HDR on, PT layer on top, Opacity 0.62
Turns out passthrough layer was actually still there. It seems that the real problem is that, when MobileHDR is turned on, the rendering pass of the virtual scene didn't just render the objects, but also render the void scene in editor into black background. So when you lay the virtual layer over passthrough, it just cover the passthrough background up. While when MobileHDR is turned off, the rendering pass just works correctly, by only rendering the objects to add on the Passthrough Layer, while omitting the void black background in editor.