gui_gridmenu arrows cause "Failed to load" errors

[rekterakathom]

Description

gui_gridmenu.lua uses two different unicode arrows, neither of which exist in the font the game uses (Exo2-SemiBold I believe?), so the glyph fails to load and this throws an on-screen error message. The arrows are also both in different styles, though you can't see this ingame because they fail to load

The broken glyphs are:

• Glyph 10229 ( ⟵ ) - arrow to the left - link to code

• Glyph 129050( 🠚 ) - arrow to the right - link to code

Error messages:

• [t=01:13:54.334499][f=0004406] [Font] Warning: [CFontTexture::LoadWantedGlyphs] Failed to load glyph 10229 after 5 font replacement attempts
• [t=01:38:32.439724][f=0048749] [Font] Warning: [CFontTexture::LoadWantedGlyphs] Failed to load glyph 129050 after 5 font replacement attempts

Expected Behaviour

Only supported unicode characters should be used to avoid errors.

Actual Behaviour

Unicode characters that are not supported by the font are being used and users receive errors about the missing glyphs.

Reproduction steps

• Glyph 10229 ( ⟵ ) - arrow to the left: Enter any submenu in the building menu. For example, at the start of a game enter the "Build" menu. Any building submenu that has the "Back" option will do.
• Glyph 129050( 🠚 ) - arrow to the right: Enter any submenu that has multiple pages. For example, place down T1 bot lab -> build cons bot -> place down T2 bot lab -> open build options for T2 bot lab -> error. Any building submenu that has multiple pages will do.

Other

Fix proposals:

1. Just remove the symbols completely. They don't work currently either and the menus look ok without them.
2. Use "less"- or "greater than" symbols. In my opinion this looks pretty crude and I personally prefer option 1. These symbols are supported by Exo2-SemiBold

[saurtron]

Can't the glyphs be added to the font or maybe some "extra glyphs" font?

[WatchTheFort]

beyond-all-reason/spring#537

[saurtron]

Looks like the arrows don't show up generally because of some fontconfig glitch.

I made an engine PR that both fixes fallbacks for linux and makes the arrows show both on windows and linux (as long as proper fonts are installed). Check PR for more info and windows testing log link.

Btw the left arrow looks bad for everyone it will need to be tweaked, the other looks fine imo.