# m2SDL — SDL2 bindings for GNU Modula-2

Thin `DEFINITION MODULE FOR "C"` bindings of SDL2 for `gm2`
(GCC 16 / GNU Modula-2), starting with init, video, version,
timer, error and a minimal event pump.

## Status

Starter set, verified with gm2 + SDL 2.32.4 on Linux:

| Module | C header | Contents |
|---|---|---|
| `SDL2` | `<SDL.h>`, `<SDL_error.h>`, `<SDL_timer.h>` | init/quit, `GetError`, `Delay`, ticks, performance counter |
| `SDLVersion` | `<SDL_version.h>` | `SDLVersion` record, `GetVersion`, `GetRevision` |
| `SDLVideo` | `<SDL_video.h>` | window create/destroy, title, size, show/hide |
| `SDLEvents` | `<SDL_events.h>` | `PumpEvents`, `PollEvent`, `WaitEvent`, `PushEvent`, quit/key/mouse type ids (opaque buffer for now) |
| `SDLRect` | `<SDL_rect.h>` | pure-M2 `SDLPoint`/`SDLRect` + helpers |
| `SDLRender` | `<SDL_render.h>` | window+renderer creation, draw color, clear/present, points/lines/rects |
| `SDLKey` | `<SDL_keycode.h>` | pure-M2 keycode constants (arrows, Q/R, Escape...) |
| `SDLUtils` (`lib/`) | — | `CStrToM2()` + `GetErrorString()` helpers, `DrainEvents()` quit pump, `PollM2Event()` decoded poll |

Full `SDL_Event` union mapping, renderer, audio and gamepad come next.

## Layout

```text
m2SDL/
  src/        FOR "C" .def bindings (+ pure-M2 SDLRect)
  lib/        pure-M2 helpers built on the bindings (SDLUtils)
  tests/      gm2 smoke tests + run_tests.sh
  examples/   hello_window, version, event_loop
  showcases/  ports of SDL-main renderer examples (clear, rectangles, primitives)
  build/      generated binaries (git-ignored)
```

## Prerequisites

- `gm2` (tested: 16.0.1 experimental, `~/bin/Modula2/Gm2/bin/gm2`)
- SDL2 dev files (`pkg-config --cflags --libs sdl2`, tested: 2.32.4)

```sh
export PATH=$HOME/bin/Modula2/Gm2/bin:$PATH
```

## Build & test

```sh
make            # tests + examples + showcases -> build/
./tests/run_tests.sh
SDL_VIDEODRIVER=dummy ./tests/run_tests.sh   # headless
./build/examples/hello_window
./build/examples/version
./build/examples/event_loop
./build/showcases/showcase_clear   # or rectangles / primitives
```

`make check` is `make tests` + the runner script.

## Usage

```modula2
FROM SDL2 IMPORT SDL_Init, SDL_Quit, SDLInitVideo;
FROM SDLVideo IMPORT SDL_CreateWindow, SDL_DestroyWindow,
   WindowShown, WindowPosUndefined;
```

Compile your program with the binding search path and the C library:

```sh
gm2 -Isrc -Ilib myprog.mod src/SDLRect.mod lib/SDLUtils.mod -o myprog -lSDL2
```

Notes:

- `CARDINAL <-> Uint32`, `INTEGER <-> int` (see gm2 "Elementary data
  types" node); opaque `SDL_Window *` / `char *` travel as `ADDRESS`.
- `ARRAY OF CHAR` parameters map onto `char *`: string literals and
  `CHAR` arrays can be passed directly (see gm2 "Interface to C" node).
- `VAR` record parameters map onto `T *`: `SDL_GetVersion(v)`,
  `SDL_GetWindowSize(win, w, h)`.

## Roadmap

1. Full `SDL_Event` variant record + typed poll/wait.
2. Renderer + texture + surface subset.
3. Audio + joystick/gamepad subset.
4. SDL3 bindings alongside (sources at `../../SDL3-3.2.28`, not yet installed).