Motivation / Problem

OpenGL video drivers now sometimes cause an 8bpp blitter to be used. These can't do font anti-alias.

Description

If any font should be anti-aliased, always use a 32bpp blitter.

Limitations

Most video drivers result in a 32bpp anyway, so no real change for non-OpenGL video drivers.

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker