sgdk-ui

SGDK UI

Make the screen easy to read and the controls predictable. SGDK supplies text and VDP functions, not a ready-made menu or widget system. Keep menu state, controller navigation and drawing separate enough to test without a console. Use the game's existing structure rather than imposing a UI framework.

For NPC conversations, branching choices and portrait exchanges, use sgdk-dialogue when available. This skill covers the shared UI foundations.

Choose the right reference

• Fonts and text: glyph layout, bounded

strings, numbers, field widths and clearing old text.

• Menus and controls: focus, repeat,

pause, transitions and options.

• HUDs and budgets: Window, planes,

palettes, font tiles and transfer costs.

• Menu Lab: an original title/options/pause/results

example with a switchable font and fixed score HUD over a scrolling grid.

Build with ewrogers/sgdk:latest and pull before validation. Check unfamiliar calls in the selected image's inc/vdp_bg.h, src/vdp_bg.c, inc/vdp_tile.h, inc/vdp.h, inc/joy.h and bin/rescomp.txt. The references cite SGDK 2.11; verify differences when the image moves forward. Never invent menu, Unicode, wrapping or font APIs that the installed SDK does not provide.

Plan the screen before drawing

Agree on visible rows/columns, safe margins, glyphs, palette lines and which plane owns the HUD. Text coordinates are 8x8 cells. A 320x224 display has 40x28 visible cells, even if its backing plane is larger. Keep player-facing text inside the visible area; plane clipping alone is not screen clipping.

Reserve font and UI graphics tiles alongside the game's other art. A font normally replaces SGDK's font slots; it must not silently overwrite sprite or map storage. Decide who may change its palette during fades or transitions. Window replaces part of plane A; it is not an extra scrolling background.

Keep updates small and predictable

Sample cached input once per frame. Confirm/back are press edges; held cursor movement gets an explicit delay and repeat interval. Base menu repeat and countdowns on the project's region/timing policy, not assumed 60 Hz frames. Consume the action that opens a screen so it cannot also select its first item.

Use bounded buffers and field widths. Replace shorter text with a padded field so old glyphs do not remain; avoid visibly clearing it before drawing its replacement. Avoid formatting and rewriting unchanged HUD text every frame. The SDK's string conversion calls do not receive destination capacity. Check the selected implementation before choosing a convenience helper.

Test navigation, held buttons across transitions, changing options, pause, maximum numbers, shorter replacements and unsupported text bytes. Compile real font resources and verify glyph order, not just C syntax. Finish with an emulator checklist and say which checks still need console testing.