SD2-m2/examples/event_loop.mod

MODULE event_loop ;

(*
   m2SDL example: event loop until window close or 5 seconds.
   Uses the opaque SDLEvents subset: PollEvent over a raw buffer,
   first CARDINAL of SDL_Event is the Uint32 type - offset 0 on
   little and big endian alike.
*)

FROM SYSTEM IMPORT ADDRESS, ADR;
FROM SDL2 IMPORT SDL_Init, SDL_Quit, SDL_Delay,
   SDL_GetTicks64, SDLInitVideo, SDLInitEvents;
FROM SDLVideo IMPORT SDL_CreateWindow, SDL_DestroyWindow,
   WindowShown, WindowPosUndefined;
FROM SDLEvents IMPORT SDL_PollEvent, EventQuit, EventBufferBytes;
FROM libc IMPORT printf;

VAR
   win: ADDRESS;
   buf: ARRAY [0..EventBufferBytes-1] OF CHAR;
   evType: CARDINAL;
   start, now: LONGCARD;
   quit: BOOLEAN;

BEGIN
   IF SDL_Init(SDLInitVideo + SDLInitEvents) # 0 THEN
      printf("SDL_Init failed\n");
      HALT(1)
   END;
   win := SDL_CreateWindow("Close me, or wait 5s",
                           WindowPosUndefined, WindowPosUndefined,
                           640, 480, WindowShown);
   IF win = NIL THEN
      printf("CreateWindow failed\n");
      SDL_Quit;
      HALT(1)
   END;
   quit := FALSE;
   start := SDL_GetTicks64();
   WHILE NOT quit DO
      WHILE SDL_PollEvent(ADR(buf)) # 0 DO
         evType := 0;
         evType := VAL(CARDINAL, ORD(buf[0]))
                 + VAL(CARDINAL, ORD(buf[1])) * 256
                 + VAL(CARDINAL, ORD(buf[2])) * 65536;
         IF evType = EventQuit THEN quit := TRUE END
      END;
      now := SDL_GetTicks64();
      IF now - start > 5000 THEN quit := TRUE END;
      SDL_Delay(16)
   END;
   SDL_DestroyWindow(win);
   SDL_Quit;
   printf("bye\n")
END event_loop.