using System;

using sharpallegro;

namespace exdbuf
{
  unsafe class exdbuf : Allegro
  {
    static int Main()
    {
      // TODO: replace with BITMAP structure
      IntPtr buffer;
      int c;

      if (allegro_init() != 0)
        return 1;
      install_timer();
      install_keyboard();

      if (set_gfx_mode(GFX_AUTODETECT, 320, 200, 0, 0) != 0)
      {
        if (set_gfx_mode(GFX_SAFE, 320, 200, 0, 0) != 0)
        {
          set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
          allegro_message("Unable to set any graphic mode\n" + allegro_error);
          return 1;
        }
      }

      set_palette(desktop_palette);

      /* allocate the memory buffer */
      buffer = create_bitmap(SCREEN_W, SCREEN_H);

      /* First without any buffering...
       * Note use of the global retrace_counter to control the speed. We also
       * compensate screen size (GFX_SAFE) with a virtual 320 screen width.
       */
      clear_keybuf();
      c = retrace_count + 32;
      while (retrace_count - c <= 320 + 32)
      {
        acquire_screen();
        clear_to_color(screen, makecol(255, 255, 255));
        circlefill(screen, (retrace_count - c) * SCREEN_W / 320, SCREEN_H / 2, 32, makecol(0, 0, 0));
        textprintf_ex(screen, font, 0, 0, makecol(0, 0, 0), -1, "No buffering (" + gfx_driver.name + ")");
        release_screen();

        if (keypressed())
          break;
      }

      /* and now with a double buffer... */
      clear_keybuf();
      c = retrace_count + 32;
      while (retrace_count - c <= 320 + 32)
      {
        clear_to_color(buffer, makecol(255, 255, 255));
        circlefill(buffer, (retrace_count - c) * SCREEN_W / 320, SCREEN_H / 2, 32, makecol(0, 0, 0));
        textprintf_ex(buffer, font, 0, 0, makecol(0, 0, 0), -1, "Double buffered (" + gfx_driver.name + ")");
        blit(buffer, screen, 0, 0, 0, 0, SCREEN_W, SCREEN_H);

        if (keypressed())
          break;
      }

      destroy_bitmap(buffer);

      return 0;
    }
  }
}