(******************************************************************************)
(*                              POLYGONS.MOD                                  *)
(*                                                                            *)
(*    MetaWINDOW HOWTO: program series.  Demonstrates usage of polygons.      *)
(* Transcribed from POLYGONS.C METAGRAPHICS SOFTWARE CORPORATION (c) 1987-1989*)
(*                                                                            *)
(*  PSW 10/31/90 02:44am                                                      *)
(******************************************************************************)

MODULE Polygons;
(*
 *  Graphix
 *  Release 3.7
 *  (c) Copyright 1986-1992 PMI
 *  Green Bay, Wisconsin
 *  (414) 468-6040
 *  All rights reserved
 *
 *)

  IMPORT GrConst;
  IMPORT GrPorts;
  IMPORT Meta;
  IMPORT GrQry;
  IMPORT IO;

  FROM GrConst IMPORT rect, point, polyHead;

  CONST
    NUMPTS = 11;          (* how many points in polygon points array *)

  VAR
    GrafixCard,
    CommPort:   INTEGER;
    scrnR:      rect;
    i:          INTEGER;
    c:          CHAR;

  PROCEDURE DrawPoly();
    VAR
      x, y, z: INTEGER;
      p_pts: ARRAY[0..NUMPTS-1] OF point;   (* The polygon point series *)
      p_hdr: ARRAY[0..1] OF polyHead;     (* the polygon header array *)
  BEGIN
    x := scrnR.Xmax DIV 15;              (* obtain some scaling factors *)
    y := scrnR.Ymax DIV 12;

(* set up the first polygon header array - 8 points *)
    p_hdr[0].polyBgn  := 0;
    p_hdr[0].polyEnd  := 7;
    p_hdr[0].polyRect := scrnR;

(* set up the second polygon header array - 3 points *)
    p_hdr[1].polyBgn  := 8;
    p_hdr[1].polyEnd  := 10;
    p_hdr[1].polyRect := scrnR;

(* set up the polygon point series *)
     z := 0;

    p_pts[z].X := x*2;
    p_pts[z].Y := y*2;
    INC(z);

    p_pts[z].X := x*6;
    p_pts[z].Y := y*5;
    INC(z);

    p_pts[z].X := x*12;
    p_pts[z].Y := y*2;
    INC(z);

    p_pts[z].X := x*7;
    p_pts[z].Y := y*8;
    INC(z);

    p_pts[z].X := x*12;
    p_pts[z].Y := y*10;
    INC(z);

    p_pts[z].X := x*8;
    p_pts[z].Y := y*7;
    INC(z);

    p_pts[z].X := x*2;
    p_pts[z].Y := y*9;
    INC(z);

    p_pts[z].X := x*2;
    p_pts[z].Y := y*2;
    INC(z);

    p_pts[z].X := x*15;
    p_pts[z].Y := y*12;
    INC(z);

    p_pts[z].X := x*13;
    p_pts[z].Y := y*12;
    INC(z);

    p_pts[z].X := x*14;
    p_pts[z].Y := y*10;
    INC(z);

    Meta.PaintPoly(2, ADR(p_hdr), ADR(p_pts));     (* draw two polygons with one call *)
    c := IO.RdChar();

    Meta.ErasePoly(2,ADR(p_hdr),ADR(p_pts));
    c := IO.RdChar();

    Meta.FillPoly(2,ADR(p_hdr),ADR(p_pts),3);
    c := IO.RdChar();
  END DrawPoly;


BEGIN
  (* init the system *)

  GrQry.GrQuery(GrafixCard, CommPort);

  i := Meta.InitGrafix(-GrafixCard);

  IF (i # 0) THEN
    (* Display reason for no go *)
    GrQry.GrInitErr(GrafixCard, CommPort, i);
  END;

  Meta.SetDisplay(GrConst.GrafPg0);
  Meta.ScreenRect(scrnR);
  Meta.EraseRect(scrnR);
  DrawPoly();

  GrQry.GrQuit('', 0)
END Polygons.