v0.8.5-alpha: the one-frame black screen (exclusive fullscreen fix)

The black screen after exactly one frame was our bug, and my own install guide caused it. v0.8.5 fixes it and takes the decision away from you.

Thanks to the tester who sent a full log bundle on v0.8.4. It answered this in one read.

What was happening

The mod forces the game to render internally at 3840x2160 so the picture in the headset is sharp even from a 1080p desktop. That is fine in a window. It is not fine in exclusive fullscreen, where the buffer size is not just a buffer, it is a real display mode.

So on a 1920x1080 monitor, the mod was effectively asking the display for a 4K mode it does not have. The tester's log:

factory: ResizeBuffers 1920x1080 UPSIZED -> 3840x2160
windowed : NO (exclusive fullscreen)
hb 24  frames=1  (+0 in the last second)

One frame reached the headset, and then nothing, forever. In one of his sessions it also took the NVIDIA display driver down with it, an access violation inside nvwgf2umx.dll with no mod code anywhere on the stack.

And the reason he was in exclusive fullscreen at all is that my own INSTALL.txt told him to be. It said to use fullscreen, while the mod's own code was logging "VR needs WINDOWED" into a file nobody reads. He followed the instructions exactly and the instructions were wrong.

What v0.8.5 does

It declines exclusive fullscreen and keeps the game windowed by itself. You no longer have to know any of the above, or pick a window mode, or get it right.

This is not a compromise. Staying windowed avoids the display mode change and keeps the sharp 4K internal render at any desktop resolution. It is better on both counts. The desktop window is only a mirror of what you are already seeing in the headset.

If the game insists on fullscreen anyway, past eight attempts the mod gives up and lets it, and says so in the log. It will not sit there fighting the game.

There is a second, quieter fix behind it: the mod also refuses to resize the buffer to 4K while in exclusive fullscreen, which covers you if you turn the first fix off.

If you want the old behaviour

Set force_windowed = 0 in GRWVR\grwxr.cfg. If you do that and the headset goes black after one frame, also set upsize_width = 0 and upsize_height = 0.

Also worth knowing, and not our bug

Ubisoft posted on 7 August that they are aware of a CPU E-core issue and an issue affecting weapon attachments in the current game version, and that they have a workaround for the attachments. If your weapon behaves oddly, that is a candidate before you suspect this mod. The E-core part only affects Intel CPUs that have efficiency cores.

Being straight with you

I do not have a headset on the machine I build on, so v0.8.5 has not been confirmed in VR by me. The diagnosis came entirely from a tester's logs. v0.8.4's two fixes, by contrast, are now confirmed working on the machine that had been hanging, which is why this release is worth taking.

Reporting a problem

Double-click GRWVR\Collect-Logs.bat and attach the zip it makes. If you would rather do it by hand, please include:

1. GRWVR\grwxr.log, GRWVR\grwxr-prev.log, and every GRWVR\grwxr-<number>.log beside them. The game starts more than one process and the interesting one is often not the first.
2. Whether the game was running normally on your monitor, frozen, or gone from Task Manager.
3. Your headset and runtime (SteamVR, Virtual Desktop, Steam Link, Quest Link).