Slate Performance Issues without Slate in VR

Development Programming & Scripting UI
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1

I’ve posted this in Using UE4, but it hasn’t gotten any attention there, so I decided to x-post here.

I’m working to optimize my game for HTC Vive, and I’m getting 4-6ms of Slate usage whenever I’m in VR (ocassionally it will be ~0.45ms for an entire play session but this is rare and inconsistent). It seems to occur even in a fresh blank project, and be related to VR. I’m working with the HTC Vive. In standalone the GPU Profiler shows 0.0 ms in Slate when outside of VR. As soon as I hit alt+enter and go into stereo I end up with 4-6ms of SlateUI in the profiler.

I can understand that there might be some if slate is being used as an overlay mask in the engine for whatever reason, but it doesn’t make sense that it would use up 4-6ms.

Here’s the original thread: Slate Performance Issues Without Slate - XR Development - Unreal Engine Forums

2

Are you doing your profiling in the editor or in a cooked build? Slate takes up a huge amount of time in the editor, because that’s what the editor uses. If you’re not using Slate in your game, there should be no time spent on it if you profile a cooked build.

3

It showed up in cooked builds too, but only when in VR

4

Huh, now that you mention it, I’m seeing that too. I happen to be doing some Vive profiling right now and I’m seeing around 2-3ms of time in the render thread with various Slate calls.