HDRP: UI often shows up in scene view instead of game view and gizmos don't show where ImGui is drawn.

[gwenvis]

I don't know if this happens in other pipelines as well - but in HDRP the UI often likes to show up in the scene view and not appear in the game view at all - unless fullscreen.

I'm posting this issue so other people could perhaps look at it - but right now I've remedied this by not using the custom pass volume the guide describes - but by using a component that subscribes to some events the scriptable render pipeline exposes. This seems to work well so far. I will attach the script I use for this in a gist.

https://gist.github.com/stepperman/45cb274e6a224455aaa421eb7a61dbb7

It's pretty untested - but seems to work well so far. It will still for some reason go to the scene view when the game view is maximised and then minimised but I feel this is barely a non-issue. The only gripe I have right now is that the UI renders over the Unity canvas, but for some reason Unity don't expose proper injection points for that unfortunately.

[psydack]

Hello there.

Could you share which version this is happening/reproduce?
Could you share some image / video of this happening ?

Thank you very much for sharing the snippet and using UImGui.

[iUltimateLP]

Wanted to comment on this, as we're experiencing the same issue. The Gist provided by @stepperman works just fine, although we noticed that it does screw with the alpha channel, making transparent windows way more transparent as they were previously.

Edit: we fixed that by switching the alpha mode to a seperate blend, add this to every pass in Resources/Shaders/DearImGui-Mesh.shader:

Blend SrcAlpha OneMinusSrcAlpha, One OneMinusSrcAlpha

[futurecreep-dev]

(UImGui 4.1.1, HDRP 15.0.6, 2023.1.6f1, Windows DX11, Custom Buffer Format R8G8B8A8 - did not test others)
The custom pass method makes UImGui display in Game view only if Gizmos are enabled; It's always visible in Scene view (while playing).
Even so, I found these other issues:

• Dynamic resolution makes UImGui rescale (at least visually, probably not technically).
• It has a smeared look as it is affected by TAA and (at least) bloom (custom pass set After Post Process).
• In builds UImGui is not visible at all.

Using the gist code instead (custom pass removed) it works and looks as expected, in builds included.
However, I modified the handler so it only runs for the main camera, otherwise UImGui flickers when on demand reflection probes get rendered (I think). It still has occasional 1-frame flickers in Editor but I don't mind for now.