SD2-m2/showcases/showcase_rectangles.mod

MODULE showcase_rectangles ;

(*
   m2SDL showcase, ported from SDL-main
   examples/renderer/05-rectangles/rectangles.c (public domain).

   Draws animated rectangle outlines, a filled rectangle and a
   bar chart every frame; sizes breathe in and out over 2 seconds.

   SDL3 -> SDL2 adaptations
   - SDL_RenderRect/Rects/FillRect/FillRects become the SDL2
     SDL_RenderDrawRect(s) / SDL_RenderFillRect(s) spellings.
   - SDL_FRect floats become integer SDLRect; the -1.0..1.0 scale
     is kept as permille (-500..500) with integer arithmetic.
   - Rect arrays pass as ADR(rects) + count (see SDLRender docs).
   - Callback structure flattened into a main loop; auto-quit
     after 8 s so the showcase also terminates unattended.
*)

FROM SYSTEM IMPORT ADDRESS, ADR, CARDINAL8;
FROM SDL2 IMPORT SDL_Init, SDL_Quit, SDL_Delay,
   SDL_GetTicks, SDL_GetTicks64, SDLInitVideo;
FROM SDLVideo IMPORT WindowHandle, SDL_DestroyWindow, WindowResizable;
FROM SDLRender IMPORT RendererHandle,
   SDL_CreateWindowAndRenderer, SDL_DestroyRenderer,
   SDL_SetRenderDrawColor, SDL_RenderClear, SDL_RenderPresent,
   SDL_RenderSetLogicalSize,
   SDL_RenderDrawRect, SDL_RenderDrawRects,
   SDL_RenderFillRect, SDL_RenderFillRects;
FROM SDLRect IMPORT SDLRect, MakeRect;
FROM SDLUtils IMPORT DrainEvents;
FROM libc IMPORT printf;

CONST FrameMs = 16; MaxMs = 8000;
CONST WinW = 640; WinH = 480;

VAR
   win: WindowHandle;
   ren: RendererHandle;
   rects: ARRAY [0..15] OF SDLRect;
   quit: BOOLEAN;
   start: LONGCARD;
   now: CARDINAL;
   dir, sm, i, size, w, h: INTEGER;

BEGIN
   IF SDL_Init(SDLInitVideo) # 0 THEN
      printf("showcase_rectangles: SDL_Init failed\n");
      HALT(1)
   END;
   IF SDL_CreateWindowAndRenderer(WinW, WinH, WindowResizable,
                                  win, ren) # 0 THEN
      printf("showcase_rectangles: CreateWindowAndRenderer failed\n");
      SDL_Quit;
      HALT(1)
   END;
   SDL_RenderSetLogicalSize(ren, WinW, WinH);

   printf("showcase_rectangles: close window or wait 8s\n");
   quit := FALSE;
   start := SDL_GetTicks64();
   WHILE NOT quit DO
      DrainEvents(quit);
      now := SDL_GetTicks();
      (* breathe: +1 for one second, -1 for the next. *)
      IF VAL(INTEGER, now MOD 2000) >= 1000 THEN dir := 1 ELSE dir := -1 END;
      (* scale in permille, -500..500. *)
      sm := (VAL(INTEGER, now MOD 1000) - 500) * dir;

      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 0), VAL(CARDINAL8, 0),
                             VAL(CARDINAL8, 0), VAL(CARDINAL8, 255));
      SDL_RenderClear(ren);

      (* single outlined square, top left. *)
      rects[0] := MakeRect(100, 100, 100 + 100 * sm DIV 500,
                                    100 + 100 * sm DIV 500);
      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 255), VAL(CARDINAL8, 0),
                             VAL(CARDINAL8, 0), VAL(CARDINAL8, 255));
      SDL_RenderDrawRect(ren, rects[0]);

      (* three centered outlines at once. *)
      FOR i := 0 TO 2 DO
         size := (i + 1) * 50;
         w := size + size * sm DIV 500;
         rects[i] := MakeRect((WinW - w) DIV 2, (WinH - w) DIV 2, w, w)
      END;
      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 0), VAL(CARDINAL8, 255),
                             VAL(CARDINAL8, 0), VAL(CARDINAL8, 255));
      SDL_RenderDrawRects(ren, ADR(rects), 3);

      (* one filled rectangle. *)
      rects[0] := MakeRect(400, 50, 100 + 100 * sm DIV 500,
                                    50 + 50 * sm DIV 500);
      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 0), VAL(CARDINAL8, 0),
                             VAL(CARDINAL8, 255), VAL(CARDINAL8, 255));
      SDL_RenderFillRect(ren, rects[0]);

      (* white bar chart along the bottom. *)
      FOR i := 0 TO 15 DO
         w := WinW DIV 16;
         h := i * 8;
         rects[i] := MakeRect(i * w, WinH - h, w, h)
      END;
      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 255), VAL(CARDINAL8, 255),
                             VAL(CARDINAL8, 255), VAL(CARDINAL8, 255));
      SDL_RenderFillRects(ren, ADR(rects), 16);

      SDL_RenderPresent(ren);
      IF SDL_GetTicks64() - start > MaxMs THEN quit := TRUE END;
      SDL_Delay(FrameMs)
   END;

   SDL_DestroyRenderer(ren);
   SDL_DestroyWindow(win);
   SDL_Quit;
   printf("showcase_rectangles: bye\n")
END showcase_rectangles.