program demo11;

{$I zglCustomConfig.cfg}
{$I zgl_config.cfg}

{$R *.res}

uses
  zgl_screen,
  zgl_window,
  zgl_timers,
  zgl_keyboard,
  zgl_fx,
  zgl_textures,
  zgl_textures_png,
  zgl_textures_jpg,
  zgl_grid_2d,
  zgl_font,
  zgl_text,
  zgl_math_2d,
  zgl_types,
  zgl_utils
  ;

var
  dirRes     : UTF8String {$IFNDEF MACOSX} = '../data/' {$ENDIF};
  fntMain    : LongWord;
  texBack    : zglPTexture;
  grid       : zglTGrid2D;
  wave       : Single;
  TimeStart  : LongWord;

procedure Init;
  var
    i, j: Integer;
begin
  texBack := tex_LoadFromFile(dirRes + 'back04.jpg');

  fntMain := font_LoadFromFile(dirRes + 'font.zfi');

  // RU: Инициализация сетки размером 21x16. Основная идея - каждый узел сетки это смещение относительно её верхнего левого угла.
  // EN: Initialization of grid with size 21x16. Main idea - every node of grid is an offset from the top left corner.
  grid.Cols := 21;
  grid.Rows := 16;
  SetLength(grid.Grid, grid.Cols, grid.Rows);
  for i := 0 to grid.Cols - 1 do
    for j := 0 to grid.Rows - 1 do
      begin
        grid.Grid[i, j].X := i * 40;
        grid.Grid[i, j].Y := j * 40;
      end;

  setFontTextScale(15, fntMain);
end;

procedure Draw;
begin
  // RU: Рендерим сетку в координатах 0,0.
  // EN: Render grid in coordinates 0,0.
  sgrid2d_Draw(texBack, 0, 0, @grid);

  text_Draw(fntMain, 0, 0, 'FPS: ' + u_IntToStr(zgl_Get(RENDER_FPS)));
end;

procedure Timer;
  var
    i, j: Integer;
    cwave, swave: Single;
begin
  wave  := wave + random(1000) / 10000;
  cwave := cos(wave);
  swave := sin(wave);

  // RU: Симуляция простого эффекта под водой.
  // EN: Simulation of simple underwater effect.
  for i := 1 to grid.Cols - 2 do
    for j := 1 to grid.Rows - 2 do
    begin
      if (i mod 2 = 0) and (j mod 2 = 0) Then
      begin
        grid.Grid[i, j].X := i * 40 + cwave;
        grid.Grid[i, j].Y := j * 40 + swave;
      end else
      begin
        grid.Grid[i, j].X := i * 40 - cwave;
        grid.Grid[i, j].Y := j * 40 - swave;
      end;
    end;
end;

Begin
  randomize();

  TimeStart := timer_Add(@Timer, 16, t_SleepToStart, 3);

  zgl_Reg(SYS_LOAD, @Init);
  zgl_Reg(SYS_DRAW, @Draw);

  wnd_SetCaption(utf8_Copy('11 - Grid'));

  zgl_Init();
End.