Savegame thumbnails are generated incorrectly

[Marisa the Magician]

Whenever the game is saved, the savepic.png comes out like this:


This is happening even after commit a0695cb (which I thought would fix it).
Looking through my savegames, it seems the most recent one with a correct thumbnail is from 2aee68d, which is about a month old. Might take pretty long to bisect this.

Edit: It seems that thumbnails are generated correctly on software renderers. Also, the screen resolution / scaling changes the size of the little square area (the lower the resolution, the bigger the square is).

[wildweasel]

I seem to recall someone else having this problem, ages ago - what screen resolution is GZDoom using?

[Marisa the Magician]

I run at 1920x1080 (native res). Sometimes with 0.5x scaling if I need extra FPS.

[drfrag]

Whatever it is it's not in my branch so it's a consequence of the refactor.

[_mental_]

Is it on Linux? I tested on Windows and macOS but with no scaling.

[Marisa the Magician]

Yes, this is on Linux.

[_mental_]

Cannot reproduce this on Ubuntu 16.04 VM. Could you please attach your .ini file?

[Marisa the Magician]

https://marisakirisa.me/tmp/gzdoom.ini

(refresh if it gave you a 403, seems like the permissions got a bit screwy when I uploaded the file)

[fakemai]

Thought I'd give it a go with your INI and a current Git build (2d50f535ff666a9cb0a0d3fe97c31f07e5a6f9a8) but couldn't reproduce. Am running Debian Stable, but also an ancient Intel GM45, so don't put too much faith in this. It could well be system-dependent though.

[_mental_]

I managed to reproduce this on Windows. Enable tone mapping (set gl_tonemap CVAR to true) and the bug will appear.

[Graf Zahl]

I cannot reproduce this with any tonemap (or other postprocessing) effect.

[_mental_]

It should be enough to have gl_tonemap 1 and everything else by default.
BTW tonemap and lens distortion give even more weird picture

savepic.png (67.07 KiB) Viewed 399 times

Screen resolution is 1440x900, thumbnail size is 216x162 and this corresponds to black rectangle in the corner.
This seems to be introduces with this commit and it's somehow related to switching of render buffers target textures.

[Graf Zahl]

I'll leave this to dpJudas then. Apparently I missed something important about the setup and I do not want to make it worse.

[dpJudas]

Okay, I'll take a look soon. Based on the screen shots, it probably has something to do with glViewport not being what the screenshot code reading from the back buffer expects.

[XxMiltenXx]

I also have a savegame thumbnail issue that might be related:

This happens under Windows 10 (build 10.0.16299.431) when FXAA is enabled. I used a new INI file and simply enabled FXAA (doesn't matter which quality setting)