DX12 crashes when Forward Rendering + MSAA are enabled

Build Type: Binary and source build both exhibit this bug

Build version: 4.16.1 - 3466753

Description of the issue: Enabling Forward Rendering with MSAA with DX12 enabled causes an instant crash in the editor, caused by the Slate library.

Repro Steps

1. Create a new project

2. Set the project to use Forward Shading/Rendering and use MSAA for antialiasing

3. Restart the editor using the -DX12 option to force DirectX 12. The editor should instantly crash. The crash appears to occur most often in FViewport::Draw, although sometimes there are other assertion failures related to viewport rendering. They all appear to be triggered by code in Slate.

Frequency: 100%

Hey pseudoeric0,

I just attempted to reproduce this crash on my end but did reproduce the issue. Could you provide me with your full crash logs and your system’s ‘dxdiag’ so I can gather more information in order to report this crash.

Since I was unable to reproduce the issue on my end, perhaps try updating your GPU to be sure it is not a driver issue.

Let me know if you have further questions.

Cheers,

H.

hi pseudoeric0,

I had the same issue when trying to convert an existing project with forwarding rendering and MSAA enabled, the editor would crash on startup from the desktop shortcut with dx12 enabled. I created a youtube video showing this.

It seems to be caused by MSAA and not the forward rendering. changing the AA (Anti-aliasing) to temporal allows me to launch successfully with dx12.

Hope this helps,