SD2-m2/docs/summary-v0.2.0.md

m2SDL summary — v0.2.0 (2026-09-23)

SDL2 bindings for GNU Modula-2 (gm2 16.0.1, SDL 2.32.4, Linux). All builds verified with make; tests also pass headless via SDL_VIDEODRIVER=dummy.

v0.1.0 (c4aa35b) — starter set

• src/SDL2.def — init/quit, GetError, delay, ticks, perf counter
• src/SDLVersion.def — SDLVersion record (CARDINAL8 fields), GetVersion, GetRevision
• src/SDLVideo.def — opaque WindowHandle, create/destroy, title, size, show/hide, window flag/position constants
• src/SDLEvents.def — opaque 56-byte event pump (PumpEvents, PollEvent, WaitEvent), quit/key/mouse type ids
• src/SDLRect.def/.mod — pure-M2 SDLPoint/SDLRect + helpers
• lib/SDLUtils.def/.mod — CStrToM2, GetErrorString
• tests/ — init, version, rect, window + run_tests.sh (4/4 green)
• examples/ — hello_window, version, event_loop
• Makefile — two-step gm2 build (-c helpers to .o, then link)

v0.2.0 — renderer + showcases

• src/SDLRender.def — SDL2 <SDL_render.h> subset: CreateRenderer, CreateWindowAndRenderer, draw color (CARDINAL8 = Uint8), clear/present, points/lines/rects in single (VAR) and array (ADR + count) forms, logical size
• lib/SDLUtils.DrainEvents — shared quit-event pump
• showcases/ — ports of SDL-main/examples/renderer/ (public domain): showcase_clear (01), showcase_rectangles (05), showcase_primitives (02); SDL3 to SDL2 adaptations in each header
• showcases/README.md — source map, build/run instructions
• Vendored SDL-main/ sources ignored via .gitignore (2543b44)

GM2 FFI rules learned (encoded in code)

1. DEFINITION MODULE FOR "C" + EXPORT UNQUALIFIED, link with -lSDL2.
2. No *) inside (* *) comments — C pointer spellings need a space.
3. CARDINAL <-> Uint32, INTEGER <-> int, opaque pointers = ADDRESS, ARRAY OF CHAR params = char *, VAR record params = T *.
4. Int-returning C procs need [ INTEGER ] to be called as statements.
5. Uint8 params must be SYSTEM.CARDINAL8 (16-bit SHORTCARD breaks ABI).
6. Same-size casts only: INTEGER(x) fails across sizes, use VAL.
7. Pure-M2 helpers compile with gm2 -c to .o, then link (passing .mod directly duplicates main).
8. gm2 sources must be 7-bit ASCII in practice (unicode confused it).

Next

Full SDL_Event variant record, renderer textures/surfaces, audio, joystick/gamepad, then SDL3 bindings alongside.