SDL3-m2/showcases/showcase_lines.mod

MODULE showcase_lines ;

(*
   m2SDL3 showcase, ported from SDL upstream
   examples/renderer/03-lines/lines.c (public domain).

   Draws brown house-like line segments, a green polyline batch
   and a 360-line multicolor circle every frame.

   Porting notes
   - SDL_RenderLine/RenderLines take SHORTREAL coordinates;
     REAL math (cos/sin) converts via VAL(SHORTREAL, ...).
   - SDL_rand(256) becomes libc rand() MOD 256.
   - 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 SDL3 IMPORT SDL_Init, SDL_Quit, SDL_Delay,
   SDL_GetTicks, SDLInitVideo;
FROM SDL3Video IMPORT WindowHandle, SDL_DestroyWindow, WindowResizable;
FROM SDL3Render IMPORT RendererHandle,
   SDL_CreateWindowAndRenderer, SDL_DestroyRenderer,
   SDL_SetRenderDrawColor, SDL_RenderClear, SDL_RenderPresent,
   SDL_SetRenderLogicalPresentation, LogicalLetterbox,
   SDL_RenderLine, SDL_RenderLines;
FROM SDL3Rect IMPORT SDLFPoint, MakeFPoint;
FROM SDL3Utils IMPORT DrainEvents;
FROM MathLib0 IMPORT cos, sin;
FROM libc IMPORT printf, rand, srand;

CONST FrameMs = 16; MaxMs = 8000;
CONST WinW = 640; WinH = 480;
CONST Pi = 3.141592653589793;

VAR
   win: WindowHandle;
   ren: RendererHandle;
   linePts: ARRAY [0..8] OF SDLFPoint;
   quit: BOOLEAN;
   start: LONGCARD;
   i: INTEGER;
   ang: REAL;
   cx, cy, ex, ey: SHORTREAL;

PROCEDURE F (v: REAL) : SHORTREAL;
BEGIN
   RETURN VAL(SHORTREAL, v)
END F;

PROCEDURE Col () : CARDINAL8;
BEGIN
   RETURN VAL(CARDINAL8, rand() MOD 256)
END Col;

BEGIN
   IF NOT SDL_Init(SDLInitVideo) THEN
      printf("showcase_lines: SDL_Init failed\n");
      HALT(1)
   END;
   IF NOT SDL_CreateWindowAndRenderer("m2SDL3 lines",
                                      WinW, WinH,
                                      VAL(LONGCARD, WindowResizable),
                                      win, ren) THEN
      printf("showcase_lines: CreateWindowAndRenderer failed\n");
      SDL_Quit;
      HALT(1)
   END;
   SDL_SetRenderLogicalPresentation(ren, WinW, WinH, LogicalLetterbox);
   srand(VAL(INTEGER, SDL_GetTicks()));

   linePts[0] := MakeFPoint(F(100.0), F(354.0));
   linePts[1] := MakeFPoint(F(220.0), F(230.0));
   linePts[2] := MakeFPoint(F(140.0), F(230.0));
   linePts[3] := MakeFPoint(F(320.0), F(100.0));
   linePts[4] := MakeFPoint(F(500.0), F(230.0));
   linePts[5] := MakeFPoint(F(420.0), F(230.0));
   linePts[6] := MakeFPoint(F(540.0), F(354.0));
   linePts[7] := MakeFPoint(F(400.0), F(354.0));
   linePts[8] := MakeFPoint(F(100.0), F(354.0));

   printf("showcase_lines: close window or wait 8s\n");
   quit := FALSE;
   start := SDL_GetTicks();
   WHILE NOT quit DO
      DrainEvents(quit);

      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 100), VAL(CARDINAL8, 100),
                             VAL(CARDINAL8, 100), VAL(CARDINAL8, 255));
      SDL_RenderClear(ren);

      (* brown house segments, one call per line. *)
      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 127), VAL(CARDINAL8, 49),
                             VAL(CARDINAL8, 32), VAL(CARDINAL8, 255));
      SDL_RenderLine(ren, F(240.0), F(450.0), F(400.0), F(450.0));
      SDL_RenderLine(ren, F(240.0), F(356.0), F(400.0), F(356.0));
      SDL_RenderLine(ren, F(240.0), F(356.0), F(240.0), F(450.0));
      SDL_RenderLine(ren, F(400.0), F(356.0), F(400.0), F(450.0));

      (* green polyline batch. *)
      SDL_SetRenderDrawColor(ren, VAL(CARDINAL8, 0), VAL(CARDINAL8, 255),
                             VAL(CARDINAL8, 0), VAL(CARDINAL8, 255));
      SDL_RenderLines(ren, ADR(linePts), 9);

      (* multicolor circle around (320, 80), radius 30. *)
      cx := F(320.0); cy := F(80.0);
      FOR i := 0 TO 359 DO
         ang := VAL(REAL, i) * (Pi / 180.0);
         ex := F(320.0 + cos(ang) * 30.0);
         ey := F(80.0 + sin(ang) * 30.0);
         SDL_SetRenderDrawColor(ren, Col(), Col(), Col(),
                                VAL(CARDINAL8, 255));
         SDL_RenderLine(ren, cx, cy, ex, ey)
      END;

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

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