So… it turns out, it’s even easier, it just wasn’t really documented outside of the source code.
Console command:
Slate.DrawToVRRenderTarget 0
Calling this will stop slate viewport widgets from showing up in the HMD (world widgets still display just fine). So you can just call AddToViewport, and use widgets as normal.
You may also want/have to
- Make the window resizable so that viewport dimensions, and coordinates stay up to date.
- Set ShowMouseCursor to true on the playercontroller
But yeah… much easier than manually copying over Widget RenderTargets to the Spectator screen texture.