UI Readability Investigation: Bitmap Font and HiDPI Improvements

[MichaelFisher1997]

Summary

Following the Vulkan optimization work in Issue #112 and branch feat/vulkan-graphics, the UI is now functional with automatic scaling based on screen resolution. However, further investigation and improvements are needed for optimal readability on high-resolution displays.

Current State

Implemented

• ✅ Automatic UI scaling based on screen height (ui_scale = screen_h / 720.0)
• ✅ Resolution setting in Settings menu (720p to 4K presets)
• ✅ Settings persistence to ~/.config/zigcraft/settings.json
• ✅ Proper Wayland support with SDL_GetWindowSizeInPixels() and SDL_SyncWindow()
• ✅ Anisotropic filtering for Vulkan textures

Known Limitations

• Bitmap font: Current font is a 5x7 pixel bitmap rendered as individual rectangles. When scaled up, it remains blocky/pixelated by design (retro aesthetic)
• No anti-aliasing on text: Each "pixel" of text is a solid rectangle
• Fixed aspect ratio glyphs: Characters don't adapt to ultra-wide resolutions

Areas to Investigate

1. Font Rendering Options

• Consider SDF (Signed Distance Field) fonts for smooth scaling
• Evaluate stb_truetype or FreeType integration for vector fonts
• Assess if current retro bitmap style is intentional or should be improved

2. UI Scale Refinements

• Add manual UI scale setting (0.5x to 2.0x multiplier)
• Test on various resolutions: 720p, 1080p, 1440p, 4K, ultrawide
• Ensure buttons and text remain clickable at all scales

3. HiDPI / Fractional Scaling

• Test with compositor scaling (e.g., 1.25x, 1.5x scale factors)
• Verify pixel-perfect rendering on scaled displays

4. In-Game HUD

• Apply same UI scaling to in-game debug overlay
• Scale pause menu and world map UI

Test Environment

• OS: NixOS 24.11 (Wayland/Hyprland)
• GPU: AMD Radeon RX 5700 XT
• Displays: 2560x1440 @ 144Hz, 2560x1080 @ 60Hz
• Scale: 1.0 (no HiDPI scaling)

Related

• Issue Vulkan Optimization: Fix Resolution, Add MSAA & Anisotropic Filtering #112 (Vulkan Optimization)
• Branch: feat/vulkan-graphics
• Commit: 44f478a