[SOLVED] Increasing window size or toggling fullscreen shows unwanted grid lines at regular interval (bad 9-slice frame)

[komehara]

Hello,

When building a Renpy 8.1.3 game for web (always), and in standalone whenever I increase the window size beyond the base resolution 1080p, including when toggling fullscreen to my monitor native resolution 1440p, OR I shrink it to a lower resolution, I noticed glitchy grid lines appearing at regular intervals on my screen, as if splitting my textures into small rectangles.

At first I thought it was web-specific, then two users reported the same issue on standalone windows and mac builds (I could not repro on standalone Linux / Android).

See this screenshot:

Jasmine - Glitch grid lines on Mac - Screenshot_2024-01-03_at_7.01.04_PM.png

(3.17 MiB) Not downloaded yet

This is the first time it happens to me in a Renpy game. I cannot find any information on this looking for the words "grid lines".

I found https://www.renpy.org/doc/html/display_problems.html and apparently toggling fullscreen helps with standalone windows, but not web (unconfirmed on mac). Shift+G renderer could help too but couldn't test it myself as I don't have the issue on standalone.

Is there any existing Lemmasoft/GitHub thread on this? Is F / Shift+G enough to fix the issue? I can add a Troubleshooting section on the game page to help users, but what do you recommend me to write?

Finally, why is only my game causing the issue? I use 1920x1080 assets in webp and NVL mode.

I can try to extract a MWE with non-copyrighted assets for a repro, if I find the common factor.

EDIT: when switching web/standalone view to full monitor size 1440p, the grids are placed a regular intervals of 100px... must not be a coincidence.

Extra information:

- The lines do not appear on the main menu/game menu

[komehara]

So I found the cause to be a custom Frame image that surrounds the whole screen.

I defined it using custom Borders like this:

Code: Select all

define gui.ingame_frame_borders = Borders(43, 44, 43, 44)

to match *exactly* the size of the left/top/right/bottom edges of the 9-slice texture:

2024-01-03 Fix grid lines - add 1px to frame 3x.png (22.46 KiB) Viewed 13309 times

but it turns out it's bad when the algo rounds pixel positions to the nearest integer when stretching the window (with a non-integer multiple). So I added an extra pixel of safety:

Code: Select all

define gui.ingame_frame_borders = Borders(44, 45, 44, 45)

and the lines disappeared!

I'm not sure if it's a bug that the algo rounds the Borders this way, or just unavoidable, and it forces me to "lose" a good edge pixel at native resolution 1920x1080 when calculations are perfect. Either way, I remembered I had a similar issue in other engines and that it's safer to keep 1 or 2 px of margin when dealing with 9-slice frames.