src/libgame/system.c

/***********************************************************
* Artsoft Retro-Game Library                               *
*----------------------------------------------------------*
* (c) 1994-2006 Artsoft Entertainment                      *
*               Holger Schemel                             *
*               Detmolder Strasse 189                      *
*               33604 Bielefeld                            *
*               Germany                                    *
*               e-mail: info@artsoft.org                   *
*----------------------------------------------------------*
* system.c                                                 *
***********************************************************/

#include <string.h>
#include <signal.h>

#include "platform.h"

#if defined(PLATFORM_MSDOS)
#include <fcntl.h>
#endif

#include "system.h"
#include "image.h"
#include "sound.h"
#include "setup.h"
#include "joystick.h"
#include "misc.h"


/* ========================================================================= */
/* exported variables                                                        */
/* ========================================================================= */

struct ProgramInfo	program;
struct OptionInfo	options;
struct VideoSystemInfo	video;
struct AudioSystemInfo	audio;
struct GfxInfo		gfx;
struct ArtworkInfo	artwork;
struct JoystickInfo	joystick;
struct SetupInfo	setup;

LevelDirTree	       *leveldir_first_all = NULL;
LevelDirTree	       *leveldir_first = NULL;
LevelDirTree	       *leveldir_current = NULL;
int			level_nr;

Display		       *display = NULL;
Visual		       *visual = NULL;
int			screen = 0;
Colormap		cmap = None;

DrawWindow	       *window = NULL;
DrawBuffer	       *backbuffer = NULL;
DrawBuffer	       *drawto = NULL;

int			button_status = MB_NOT_PRESSED;
boolean			motion_status = FALSE;

int			redraw_mask = REDRAW_NONE;
int			redraw_tiles = 0;

int			FrameCounter = 0;


/* ========================================================================= */
/* init/close functions                                                      */
/* ========================================================================= */

void InitProgramInfo(char *argv0,
		     char *userdata_subdir, char *userdata_subdir_unix,
		     char *program_title, char *window_title, char *icon_title,
		     char *x11_icon_filename, char *x11_iconmask_filename,
		     char *sdl_icon_filename, char *msdos_cursor_filename,
		     char *cookie_prefix, char *filename_prefix,
		     int program_version)
{
  program.command_basepath = getBasePath(argv0);
  program.command_basename = getBaseName(argv0);

  program.userdata_subdir = userdata_subdir;
  program.userdata_subdir_unix = userdata_subdir_unix;
  program.userdata_path = getUserGameDataDir();

  program.program_title = program_title;
  program.window_title = window_title;
  program.icon_title = icon_title;

  program.x11_icon_filename = x11_icon_filename;
  program.x11_iconmask_filename = x11_iconmask_filename;
  program.sdl_icon_filename = sdl_icon_filename;
  program.msdos_cursor_filename = msdos_cursor_filename;

  program.cookie_prefix = cookie_prefix;
  program.filename_prefix = filename_prefix;

  program.version_major = VERSION_MAJOR(program_version);
  program.version_minor = VERSION_MINOR(program_version);
  program.version_patch = VERSION_PATCH(program_version);

  program.error_filename = getErrorFilename(ERROR_BASENAME);
  program.error_file = stderr;
}

void InitExitFunction(void (*exit_function)(int))
{
  program.exit_function = exit_function;

  /* set signal handlers to custom exit function */
  signal(SIGINT, exit_function);
  signal(SIGTERM, exit_function);

#if defined(TARGET_SDL)
  /* set exit function to automatically cleanup SDL stuff after exit() */
  atexit(SDL_Quit);
#endif
}

void InitPlatformDependentStuff(void)
{
#if defined(PLATFORM_MSDOS)
  _fmode = O_BINARY;
#endif

#if defined(PLATFORM_MACOSX)
  updateUserGameDataDir();
#endif

#if !defined(PLATFORM_UNIX) || defined(PLATFORM_MACOSX)
  openErrorFile();
#endif

#if defined(TARGET_SDL)
  if (SDL_Init(SDL_INIT_EVENTTHREAD | SDL_INIT_NOPARACHUTE) < 0)
    Error(ERR_EXIT, "SDL_Init() failed: %s", SDL_GetError());

  SDLNet_Init();
#endif
}

void ClosePlatformDependentStuff(void)
{
#if defined(PLATFORM_WIN32) || defined(PLATFORM_MSDOS)
  closeErrorFile();
#endif

#if defined(PLATFORM_MSDOS)
  dumpErrorFile();
#endif
}

void InitGfxFieldInfo(int sx, int sy, int sxsize, int sysize,
		      int real_sx, int real_sy,
		      int full_sxsize, int full_sysize,
		      Bitmap *field_save_buffer)
{
  gfx.sx = sx;
  gfx.sy = sy;
  gfx.sxsize = sxsize;
  gfx.sysize = sysize;
  gfx.real_sx = real_sx;
  gfx.real_sy = real_sy;
  gfx.full_sxsize = full_sxsize;
  gfx.full_sysize = full_sysize;

  gfx.field_save_buffer = field_save_buffer;

#if 0
  gfx.background_bitmap = NULL;
  gfx.background_bitmap_mask = REDRAW_NONE;
#endif

  SetDrawDeactivationMask(REDRAW_NONE);		/* do not deactivate drawing */
  SetDrawBackgroundMask(REDRAW_NONE);		/* deactivate masked drawing */
}

void InitGfxDoor1Info(int dx, int dy, int dxsize, int dysize)
{
  gfx.dx = dx;
  gfx.dy = dy;
  gfx.dxsize = dxsize;
  gfx.dysize = dysize;
}

void InitGfxDoor2Info(int vx, int vy, int vxsize, int vysize)
{
  gfx.vx = vx;
  gfx.vy = vy;
  gfx.vxsize = vxsize;
  gfx.vysize = vysize;
}

void InitGfxWindowInfo(int win_xsize, int win_ysize)
{
  gfx.win_xsize = win_xsize;
  gfx.win_ysize = win_ysize;

#if 1
  gfx.background_bitmap_mask = REDRAW_NONE;

  ReCreateBitmap(&gfx.background_bitmap, win_xsize, win_ysize, DEFAULT_DEPTH);
#endif
}

void InitGfxScrollbufferInfo(int scrollbuffer_width, int scrollbuffer_height)
{
  /* currently only used by MSDOS code to alloc VRAM buffer, if available */
  /* 2009-03-24: also (temporarily?) used for overlapping blit workaround */
  gfx.scrollbuffer_width = scrollbuffer_width;
  gfx.scrollbuffer_height = scrollbuffer_height;
}

void InitGfxClipRegion(boolean enabled, int x, int y, int width, int height)
{
  gfx.clipping_enabled = enabled;
  gfx.clip_x = x;
  gfx.clip_y = y;
  gfx.clip_width = width;
  gfx.clip_height = height;
}

void InitGfxDrawBusyAnimFunction(void (*draw_busy_anim_function)(void))
{
  gfx.draw_busy_anim_function = draw_busy_anim_function;
}

void InitGfxCustomArtworkInfo()
{
  gfx.override_level_graphics = FALSE;
  gfx.override_level_sounds = FALSE;
  gfx.override_level_music = FALSE;

  gfx.draw_init_text = TRUE;
}

void SetDrawDeactivationMask(int draw_deactivation_mask)
{
  gfx.draw_deactivation_mask = draw_deactivation_mask;
}

void SetDrawBackgroundMask(int draw_background_mask)
{
  gfx.draw_background_mask = draw_background_mask;
}

static void DrawBitmapFromTile(Bitmap *bitmap, Bitmap *tile,
			       int dest_x, int dest_y, int width, int height)
{
  int bitmap_xsize = width;
  int bitmap_ysize = height;
  int tile_xsize = tile->width;
  int tile_ysize = tile->height;
  int tile_xsteps = (bitmap_xsize + tile_xsize - 1) / tile_xsize;
  int tile_ysteps = (bitmap_ysize + tile_ysize - 1) / tile_ysize;
  int x, y;

  for (y = 0; y < tile_ysteps; y++)
  {
    for (x = 0; x < tile_xsteps; x++)
    {
      int draw_x = dest_x + x * tile_xsize;
      int draw_y = dest_y + y * tile_ysize;
      int draw_xsize = MIN(tile_xsize, bitmap_xsize - x * tile_xsize);
      int draw_ysize = MIN(tile_ysize, bitmap_ysize - y * tile_ysize);

      BlitBitmap(tile, bitmap, 0, 0, draw_xsize, draw_ysize, draw_x, draw_y);
    }
  }
}

void SetBackgroundBitmap(Bitmap *background_bitmap_tile, int mask)
{
  if (background_bitmap_tile != NULL)
    gfx.background_bitmap_mask |= mask;
  else
    gfx.background_bitmap_mask &= ~mask;

#if 0
  if (gfx.background_bitmap == NULL)
    gfx.background_bitmap = CreateBitmap(video.width, video.height,
					 DEFAULT_DEPTH);
#endif

  if (background_bitmap_tile == NULL)	/* empty background requested */
    return;

  if (mask == REDRAW_ALL)
    DrawBitmapFromTile(gfx.background_bitmap, background_bitmap_tile,
		       0, 0, video.width, video.height);
  else if (mask == REDRAW_FIELD)
    DrawBitmapFromTile(gfx.background_bitmap, background_bitmap_tile,
		       gfx.real_sx, gfx.real_sy,
		       gfx.full_sxsize, gfx.full_sysize);
  else if (mask == REDRAW_DOOR_1)
  {
    DrawBitmapFromTile(gfx.background_bitmap, background_bitmap_tile,
		       gfx.dx, gfx.dy,
		       gfx.dxsize, gfx.dysize);
  }
}

void SetWindowBackgroundBitmap(Bitmap *background_bitmap_tile)
{
  /* remove every mask before setting mask for window */
  /* (!!! TO BE FIXED: The whole REDRAW_* system really sucks! !!!) */
  SetBackgroundBitmap(NULL, 0xffff);		/* !!! FIX THIS !!! */
  SetBackgroundBitmap(background_bitmap_tile, REDRAW_ALL);
}

void SetMainBackgroundBitmap(Bitmap *background_bitmap_tile)
{
  /* remove window area mask before setting mask for main area */
  /* (!!! TO BE FIXED: The whole REDRAW_* system really sucks! !!!) */
  SetBackgroundBitmap(NULL, REDRAW_ALL);	/* !!! FIX THIS !!! */
  SetBackgroundBitmap(background_bitmap_tile, REDRAW_FIELD);
}

void SetDoorBackgroundBitmap(Bitmap *background_bitmap_tile)
{
  /* remove window area mask before setting mask for door area */
  /* (!!! TO BE FIXED: The whole REDRAW_* system really sucks! !!!) */
  SetBackgroundBitmap(NULL, REDRAW_ALL);	/* !!! FIX THIS !!! */
  SetBackgroundBitmap(background_bitmap_tile, REDRAW_DOOR_1);
}


/* ========================================================================= */
/* video functions                                                           */
/* ========================================================================= */

inline static int GetRealDepth(int depth)
{
  return (depth == DEFAULT_DEPTH ? video.default_depth : depth);
}

inline static void sysFillRectangle(Bitmap *bitmap, int x, int y,
			       int width, int height, Pixel color)
{
#if defined(TARGET_SDL)
  SDLFillRectangle(bitmap, x, y, width, height, color);
#else
  X11FillRectangle(bitmap, x, y, width, height, color);
#endif
}

inline static void sysCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
			       int src_x, int src_y, int width, int height,
			       int dst_x, int dst_y, int mask_mode)
{
#if defined(TARGET_SDL)
  SDLCopyArea(src_bitmap, dst_bitmap, src_x, src_y, width, height,
	      dst_x, dst_y, mask_mode);
#else
  X11CopyArea(src_bitmap, dst_bitmap, src_x, src_y, width, height,
	      dst_x, dst_y, mask_mode);
#endif
}

void InitVideoDisplay(void)
{
#if defined(TARGET_SDL)
  SDLInitVideoDisplay();
#else
  X11InitVideoDisplay();
#endif
}

void CloseVideoDisplay(void)
{
  KeyboardAutoRepeatOn();

#if defined(TARGET_SDL)
  SDL_QuitSubSystem(SDL_INIT_VIDEO);
#else
  if (display)
    XCloseDisplay(display);
#endif
}

void InitVideoBuffer(int width, int height, int depth, boolean fullscreen)
{
  video.width = width;
  video.height = height;
  video.depth = GetRealDepth(depth);

  video.fullscreen_available = FULLSCREEN_STATUS;
  video.fullscreen_enabled = FALSE;
#if 0
  video.fullscreen_mode_current = NULL;
  video.fullscreen_modes = NULL;
#endif

#if defined(TARGET_SDL)
  SDLInitVideoBuffer(&backbuffer, &window, fullscreen);
#else
  X11InitVideoBuffer(&backbuffer, &window);
#endif

  drawto = backbuffer;
}

inline static void FreeBitmapPointers(Bitmap *bitmap)
{
  if (bitmap == NULL)
    return;

#if defined(TARGET_SDL)
  SDLFreeBitmapPointers(bitmap);
#else
  X11FreeBitmapPointers(bitmap);
#endif

  checked_free(bitmap->source_filename);
  bitmap->source_filename = NULL;
}

inline static void TransferBitmapPointers(Bitmap *src_bitmap,
					  Bitmap *dst_bitmap)
{
  if (src_bitmap == NULL || dst_bitmap == NULL)
    return;

  FreeBitmapPointers(dst_bitmap);

  *dst_bitmap = *src_bitmap;
}

void FreeBitmap(Bitmap *bitmap)
{
  if (bitmap == NULL)
    return;

  FreeBitmapPointers(bitmap);

  free(bitmap);
}

Bitmap *CreateBitmapStruct(void)
{
#if defined(TARGET_SDL)
  return checked_calloc(sizeof(struct SDLSurfaceInfo));
#else
  return checked_calloc(sizeof(struct X11DrawableInfo));
#endif
}

Bitmap *CreateBitmap(int width, int height, int depth)
{
  Bitmap *new_bitmap = CreateBitmapStruct();
  int real_width  = MAX(1, width);	/* prevent zero bitmap width */
  int real_height = MAX(1, height);	/* prevent zero bitmap height */
  int real_depth  = GetRealDepth(depth);

#if defined(TARGET_SDL)
  SDLCreateBitmapContent(new_bitmap, real_width, real_height, real_depth);
#else
  X11CreateBitmapContent(new_bitmap, real_width, real_height, real_depth);
#endif

  new_bitmap->width  = real_width;
  new_bitmap->height = real_height;

  return new_bitmap;
}

void ReCreateBitmap(Bitmap **bitmap, int width, int height, int depth)
{
  Bitmap *new_bitmap = CreateBitmap(width, height, depth);

  if (*bitmap == NULL)
  {
    *bitmap = new_bitmap;
  }
  else
  {
    TransferBitmapPointers(new_bitmap, *bitmap);
    free(new_bitmap);
  }
}

void CloseWindow(DrawWindow *window)
{
#if defined(TARGET_X11)
  X11CloseWindow(window);
#endif
}

inline static boolean CheckDrawingArea(int x, int y, int width, int height,
				       int draw_mask)
{
  if (draw_mask == REDRAW_NONE)
    return FALSE;

  if (draw_mask & REDRAW_ALL)
    return TRUE;

  if ((draw_mask & REDRAW_FIELD) &&
      x >= gfx.real_sx && x < gfx.real_sx + gfx.full_sxsize)
    return TRUE;

  if ((draw_mask & REDRAW_DOOR_1) &&
      x >= gfx.dx && y < gfx.dy + gfx.dysize)
    return TRUE;

  if ((draw_mask & REDRAW_DOOR_2) &&
      x >= gfx.dx && y >= gfx.vy)
    return TRUE;

  return FALSE;
}

boolean DrawingDeactivated(int x, int y, int width, int height)
{
  return CheckDrawingArea(x, y, width, height, gfx.draw_deactivation_mask);
}

boolean DrawingOnBackground(int x, int y)
{
  return (CheckDrawingArea(x, y, 1, 1, gfx.background_bitmap_mask) &&
	  CheckDrawingArea(x, y, 1, 1, gfx.draw_background_mask));
}

static boolean InClippedRectangle(Bitmap *bitmap, int *x, int *y,
				  int *width, int *height, boolean is_dest)
{
#if 1
  int clip_x, clip_y, clip_width, clip_height;

  if (gfx.clipping_enabled && is_dest)	/* only clip destination bitmap */
  {
    clip_x = MIN(MAX(0, gfx.clip_x), bitmap->width);
    clip_y = MIN(MAX(0, gfx.clip_y), bitmap->height);
    clip_width = MIN(MAX(0, gfx.clip_width), bitmap->width - clip_x);
    clip_height = MIN(MAX(0, gfx.clip_height), bitmap->height - clip_y);
  }
  else
  {
    clip_x = 0;
    clip_y = 0;
    clip_width = bitmap->width;
    clip_height = bitmap->height;
  }

  /* skip if rectangle completely outside bitmap */

  if (*x + *width  <= clip_x ||
      *y + *height <= clip_y ||
      *x >= clip_x + clip_width ||
      *y >= clip_y + clip_height)
    return FALSE;

  /* clip if rectangle overlaps bitmap */

  if (*x < clip_x)
  {
    *width -= clip_x - *x;
    *x = clip_x;
  }
  else if (*x + *width > clip_x + clip_width)
  {
    *width = clip_x + clip_width - *x;
  }

  if (*y < clip_y)
  {
    *height -= clip_y - *y;
    *y = clip_y;
  }
  else if (*y + *height > clip_y + clip_height)
  {
    *height = clip_y + clip_height - *y;
  }

  return TRUE;

#else

  /* skip if rectangle completely outside bitmap */

  if (*x + *width <= 0 ||
      *y + *height <= 0 ||
      *x >= bitmap->width ||
      *y >= bitmap->height)
    return FALSE;

  /* clip if rectangle overlaps bitmap */

  if (*x < 0)
  {
    *width += *x;
    *x = 0;
  }
  else if (*x + *width > bitmap->width)
  {
    *width = bitmap->width - *x;
  }

  if (*y < 0)
  {
    *height += *y;
    *y = 0;
  }
  else if (*y + *height > bitmap->height)
  {
    *height = bitmap->height - *y;
  }

  return TRUE;
#endif
}

void BlitBitmap(Bitmap *src_bitmap, Bitmap *dst_bitmap,
		int src_x, int src_y, int width, int height,
		int dst_x, int dst_y)
{
  int dst_x_unclipped = dst_x;
  int dst_y_unclipped = dst_y;

  if (DrawingDeactivated(dst_x, dst_y, width, height))
    return;

#if 1
  if (!InClippedRectangle(src_bitmap, &src_x, &src_y, &width, &height, FALSE) ||
      !InClippedRectangle(dst_bitmap, &dst_x, &dst_y, &width, &height, TRUE))
    return;

  /* source x/y might need adjustment if destination x/y was clipped top/left */
  src_x += dst_x - dst_x_unclipped;
  src_y += dst_y - dst_y_unclipped;

#else
  /* skip if rectangle starts outside bitmap */
  if (src_x >= src_bitmap->width ||
      src_y >= src_bitmap->height ||
      dst_x >= dst_bitmap->width ||
      dst_y >= dst_bitmap->height)
    return;

  /* clip if rectangle overlaps bitmap */
  if (src_x + width > src_bitmap->width)
    width = src_bitmap->width - src_x;
  if (src_y + height > src_bitmap->height)
    height = src_bitmap->height - src_y;
  if (dst_x + width > dst_bitmap->width)
    width = dst_bitmap->width - dst_x;
  if (dst_y + height > dst_bitmap->height)
    height = dst_bitmap->height - dst_y;
#endif

#if 0
  /* !!! 2009-03-30: Fixed by using self-compiled, patched SDL.dll !!! */
  /* (This bug still exists in the actual (as of 2009-06-15) version 1.2.13,
     but is already fixed in SVN and should therefore finally be fixed with
     the next official SDL release, which is probably version 1.2.14.) */
#if 1
  /* !!! 2009-03-24: It seems that this problem still exists in 1.2.12 !!! */
#if defined(TARGET_SDL) && defined(PLATFORM_WIN32)
  if (src_bitmap == dst_bitmap)
  {
    /* !!! THIS IS A BUG (IN THE SDL LIBRARY?) AND SHOULD BE FIXED !!! */

    /* needed when blitting directly to same bitmap -- should not be needed with
       recent SDL libraries, but apparently does not work in 1.2.11 directly */

    static Bitmap *tmp_bitmap = NULL;
    static int tmp_bitmap_xsize = 0;
    static int tmp_bitmap_ysize = 0;

    /* start with largest static bitmaps for initial bitmap size ... */
    if (tmp_bitmap_xsize == 0 && tmp_bitmap_ysize == 0)
    {
      tmp_bitmap_xsize = MAX(gfx.win_xsize, gfx.scrollbuffer_width);
      tmp_bitmap_ysize = MAX(gfx.win_ysize, gfx.scrollbuffer_height);
    }

    /* ... and allow for later re-adjustments due to custom artwork bitmaps */
    if (src_bitmap->width > tmp_bitmap_xsize ||
	src_bitmap->height > tmp_bitmap_ysize)
    {
      tmp_bitmap_xsize = MAX(tmp_bitmap_xsize, src_bitmap->width);
      tmp_bitmap_ysize = MAX(tmp_bitmap_ysize, src_bitmap->height);

      FreeBitmap(tmp_bitmap);

      tmp_bitmap = NULL;
    }

    if (tmp_bitmap == NULL)
      tmp_bitmap = CreateBitmap(tmp_bitmap_xsize, tmp_bitmap_ysize,
				DEFAULT_DEPTH);

    sysCopyArea(src_bitmap, tmp_bitmap,
		src_x, src_y, width, height, dst_x, dst_y, BLIT_OPAQUE);
    sysCopyArea(tmp_bitmap, dst_bitmap,
		dst_x, dst_y, width, height, dst_x, dst_y, BLIT_OPAQUE);

    return;
  }
#endif
#endif
#endif

  sysCopyArea(src_bitmap, dst_bitmap,
	      src_x, src_y, width, height, dst_x, dst_y, BLIT_OPAQUE);
}

void FadeRectangle(Bitmap *bitmap_cross, int x, int y, int width, int height,
		   int fade_mode, int fade_delay, int post_delay,
		   void (*draw_border_function)(void))
{
#if 1
  /* (use destination bitmap "backbuffer" -- "bitmap_cross" may be undefined) */
  if (!InClippedRectangle(backbuffer, &x, &y, &width, &height, TRUE))
    return;
#endif

#if defined(TARGET_SDL)
  SDLFadeRectangle(bitmap_cross, x, y, width, height,
		   fade_mode, fade_delay, post_delay, draw_border_function);
#else
  X11FadeRectangle(bitmap_cross, x, y, width, height,
		   fade_mode, fade_delay, post_delay, draw_border_function);
#endif
}

void FillRectangle(Bitmap *bitmap, int x, int y, int width, int height,
		   Pixel color)
{
  if (DrawingDeactivated(x, y, width, height))
    return;

#if 1
  if (!InClippedRectangle(bitmap, &x, &y, &width, &height, TRUE))
    return;
#else
  /* skip if rectangle starts outside bitmap */
  if (x >= bitmap->width ||
      y >= bitmap->height)
    return;

  /* clip if rectangle overlaps bitmap */
  if (x + width > bitmap->width)
    width = bitmap->width - x;
  if (y + height > bitmap->height)
    height = bitmap->height - y;
#endif

  sysFillRectangle(bitmap, x, y, width, height, color);
}

void ClearRectangle(Bitmap *bitmap, int x, int y, int width, int height)
{
  FillRectangle(bitmap, x, y, width, height, BLACK_PIXEL);
}

void ClearRectangleOnBackground(Bitmap *bitmap, int x, int y,
				int width, int height)
{
  if (DrawingOnBackground(x, y))
    BlitBitmap(gfx.background_bitmap, bitmap, x, y, width, height, x, y);
  else
    ClearRectangle(bitmap, x, y, width, height);
}

void SetClipMask(Bitmap *bitmap, GC clip_gc, Pixmap clip_pixmap)
{
#if defined(TARGET_X11)
  if (clip_gc)
  {
    bitmap->clip_gc = clip_gc;
    XSetClipMask(display, bitmap->clip_gc, clip_pixmap);
  }
#endif
}

void SetClipOrigin(Bitmap *bitmap, GC clip_gc, int clip_x, int clip_y)
{
#if defined(TARGET_X11)
  if (clip_gc)
  {
    bitmap->clip_gc = clip_gc;
    XSetClipOrigin(display, bitmap->clip_gc, clip_x, clip_y);
  }
#endif
}

void BlitBitmapMasked(Bitmap *src_bitmap, Bitmap *dst_bitmap,
		      int src_x, int src_y, int width, int height,
		      int dst_x, int dst_y)
{
  if (DrawingDeactivated(dst_x, dst_y, width, height))
    return;

  sysCopyArea(src_bitmap, dst_bitmap, src_x, src_y, width, height,
	      dst_x, dst_y, BLIT_MASKED);
}

void BlitBitmapOnBackground(Bitmap *src_bitmap, Bitmap *dst_bitmap,
			    int src_x, int src_y, int width, int height,
			    int dst_x, int dst_y)
{
  if (DrawingOnBackground(dst_x, dst_y))
  {
    /* draw background */
    BlitBitmap(gfx.background_bitmap, dst_bitmap, dst_x, dst_y, width, height,
	       dst_x, dst_y);

    /* draw foreground */
    SetClipOrigin(src_bitmap, src_bitmap->stored_clip_gc,
		  dst_x - src_x, dst_y - src_y);
    BlitBitmapMasked(src_bitmap, dst_bitmap, src_x, src_y, width, height,
		     dst_x, dst_y);
  }
  else
    BlitBitmap(src_bitmap, dst_bitmap, src_x, src_y, width, height,
	       dst_x, dst_y);
}

void DrawSimpleBlackLine(Bitmap *bitmap, int from_x, int from_y,
			 int to_x, int to_y)
{
#if defined(TARGET_SDL)
  SDLDrawSimpleLine(bitmap, from_x, from_y, to_x, to_y, BLACK_PIXEL);
#else
  X11DrawSimpleLine(bitmap, from_x, from_y, to_x, to_y, BLACK_PIXEL);
#endif
}

void DrawSimpleWhiteLine(Bitmap *bitmap, int from_x, int from_y,
			 int to_x, int to_y)
{
#if defined(TARGET_SDL)
  SDLDrawSimpleLine(bitmap, from_x, from_y, to_x, to_y, WHITE_PIXEL);
#else
  X11DrawSimpleLine(bitmap, from_x, from_y, to_x, to_y, WHITE_PIXEL);
#endif
}

#if !defined(TARGET_X11_NATIVE)
void DrawLine(Bitmap *bitmap, int from_x, int from_y,
	      int to_x, int to_y, Pixel pixel, int line_width)
{
  int x, y;

  for (x = 0; x < line_width; x++)
  {
    for (y = 0; y < line_width; y++)
    {
      int dx = x - line_width / 2;
      int dy = y - line_width / 2;

      if ((x == 0 && y == 0) ||
	  (x == 0 && y == line_width - 1) ||
	  (x == line_width - 1 && y == 0) ||
	  (x == line_width - 1 && y == line_width - 1))
	continue;

#if defined(TARGET_SDL)
      SDLDrawLine(bitmap,
		  from_x + dx, from_y + dy, to_x + dx, to_y + dy, pixel);
#elif defined(TARGET_ALLEGRO)
      AllegroDrawLine(bitmap->drawable, from_x + dx, from_y + dy,
		      to_x + dx, to_y + dy, pixel);
#endif
    }
  }
}
#endif

void DrawLines(Bitmap *bitmap, struct XY *points, int num_points, Pixel pixel)
{
#if !defined(TARGET_X11_NATIVE)
  int line_width = 4;
  int i;

  for (i = 0; i < num_points - 1; i++)
    DrawLine(bitmap, points[i].x, points[i].y,
	     points[i + 1].x, points[i + 1].y, pixel, line_width);

  /*
  SDLDrawLines(bitmap->surface, points, num_points, pixel);
  */
#else
  XSetForeground(display, bitmap->line_gc[1], pixel);
  XDrawLines(display, bitmap->drawable, bitmap->line_gc[1],
	     (XPoint *)points, num_points, CoordModeOrigin);
#endif
}

Pixel GetPixel(Bitmap *bitmap, int x, int y)
{
  if (x < 0 || x >= bitmap->width ||
      y < 0 || y >= bitmap->height)
    return BLACK_PIXEL;

#if defined(TARGET_SDL)
  return SDLGetPixel(bitmap, x, y);
#elif defined(TARGET_ALLEGRO)
  return AllegroGetPixel(bitmap->drawable, x, y);
#else
  return X11GetPixel(bitmap, x, y);
#endif
}

Pixel GetPixelFromRGB(Bitmap *bitmap, unsigned int color_r,
		      unsigned int color_g, unsigned int color_b)
{
#if defined(TARGET_SDL)
  return SDL_MapRGB(bitmap->surface->format, color_r, color_g, color_b);
#elif defined(TARGET_ALLEGRO)
  return AllegroAllocColorCell(color_r << 8, color_g << 8, color_b << 8);
#else
  return X11GetPixelFromRGB(color_r, color_g, color_b);
#endif
}

Pixel GetPixelFromRGBcompact(Bitmap *bitmap, unsigned int color)
{
  unsigned int color_r = (color >> 16) & 0xff;
  unsigned int color_g = (color >>  8) & 0xff;
  unsigned int color_b = (color >>  0) & 0xff;

  return GetPixelFromRGB(bitmap, color_r, color_g, color_b);
}

/* execute all pending screen drawing operations */
void FlushDisplay(void)
{
#ifndef TARGET_SDL
  XFlush(display);
#endif
}

/* execute and wait for all pending screen drawing operations */
void SyncDisplay(void)
{
#ifndef TARGET_SDL
  XSync(display, FALSE);
#endif
}

void KeyboardAutoRepeatOn(void)
{
#if defined(TARGET_SDL)
  SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY / 2,
		      SDL_DEFAULT_REPEAT_INTERVAL / 2);
  SDL_EnableUNICODE(1);
#else
  if (display)
    XAutoRepeatOn(display);
#endif
}

void KeyboardAutoRepeatOff(void)
{
#if defined(TARGET_SDL)
  SDL_EnableKeyRepeat(0, SDL_DEFAULT_REPEAT_INTERVAL);
  SDL_EnableUNICODE(0);
#else
  if (display)
    XAutoRepeatOff(display);
#endif
}

boolean PointerInWindow(DrawWindow *window)
{
#if defined(TARGET_SDL)
  return TRUE;
#else
  Window root, child;
  int root_x, root_y;
  unsigned int mask;
  int win_x, win_y;

  /* if XQueryPointer() returns False, the pointer
     is not on the same screen as the specified window */
  return XQueryPointer(display, window->drawable, &root, &child,
		       &root_x, &root_y, &win_x, &win_y, &mask);
#endif
}

boolean SetVideoMode(boolean fullscreen)
{
#if defined(TARGET_SDL)
  return SDLSetVideoMode(&backbuffer, fullscreen);
#else
  boolean success = TRUE;

  if (fullscreen && video.fullscreen_available)
  {
    Error(ERR_WARN, "fullscreen not available in X11 version");

    /* display error message only once */
    video.fullscreen_available = FALSE;

    success = FALSE;
  }

  return success;
#endif
}

boolean ChangeVideoModeIfNeeded(boolean fullscreen)
{
#if defined(TARGET_SDL)
  if ((fullscreen && !video.fullscreen_enabled && video.fullscreen_available)||
      (!fullscreen && video.fullscreen_enabled))
    fullscreen = SetVideoMode(fullscreen);
#endif

  return fullscreen;
}

Bitmap *LoadImage(char *filename)
{
  Bitmap *new_bitmap;

#if defined(TARGET_SDL)
  new_bitmap = SDLLoadImage(filename);
#else
  new_bitmap = X11LoadImage(filename);
#endif

  if (new_bitmap)
    new_bitmap->source_filename = getStringCopy(filename);

  return new_bitmap;
}

Bitmap *LoadCustomImage(char *basename)
{
  char *filename = getCustomImageFilename(basename);
  Bitmap *new_bitmap;

  if (filename == NULL)
    Error(ERR_EXIT, "LoadCustomImage(): cannot find file '%s'", basename);

  if ((new_bitmap = LoadImage(filename)) == NULL)
    Error(ERR_EXIT, "LoadImage() failed: %s", GetError());

  return new_bitmap;
}

void ReloadCustomImage(Bitmap *bitmap, char *basename)
{
  char *filename = getCustomImageFilename(basename);
  Bitmap *new_bitmap;

  if (filename == NULL)		/* (should never happen) */
  {
    Error(ERR_WARN, "ReloadCustomImage(): cannot find file '%s'", basename);
    return;
  }

  if (strEqual(filename, bitmap->source_filename))
  {
    /* The old and new image are the same (have the same filename and path).
       This usually means that this image does not exist in this graphic set
       and a fallback to the existing image is done. */

    return;
  }

  if ((new_bitmap = LoadImage(filename)) == NULL)
  {
    Error(ERR_WARN, "LoadImage() failed: %s", GetError());
    return;
  }

  if (bitmap->width != new_bitmap->width ||
      bitmap->height != new_bitmap->height)
  {
    Error(ERR_WARN, "ReloadCustomImage: new image '%s' has wrong dimensions",
	  filename);
    FreeBitmap(new_bitmap);
    return;
  }

  TransferBitmapPointers(new_bitmap, bitmap);
  free(new_bitmap);
}

Bitmap *ZoomBitmap(Bitmap *src_bitmap, int zoom_width, int zoom_height)
{
  Bitmap *dst_bitmap = CreateBitmap(zoom_width, zoom_height, DEFAULT_DEPTH);

#if defined(TARGET_SDL)
  SDLZoomBitmap(src_bitmap, dst_bitmap);
#else
  X11ZoomBitmap(src_bitmap, dst_bitmap);
#endif

  return dst_bitmap;
}

static void CreateScaledBitmaps(Bitmap *old_bitmap, int zoom_factor,
				boolean create_small_bitmaps)
{
  Bitmap swap_bitmap;
  Bitmap *new_bitmap;
  Bitmap *tmp_bitmap_1;
  Bitmap *tmp_bitmap_2;
  Bitmap *tmp_bitmap_4;
  Bitmap *tmp_bitmap_8;
  Bitmap *tmp_bitmap_16;
  Bitmap *tmp_bitmap_32;
  int width_1, height_1;
  int width_2, height_2;
  int width_4, height_4;
  int width_8, height_8;
  int width_16, height_16;
  int width_32, height_32;
  int new_width, new_height;

  /* calculate new image dimensions for normal sized image */
  width_1  = old_bitmap->width  * zoom_factor;
  height_1 = old_bitmap->height * zoom_factor;

  /* get image with normal size (this might require scaling up) */
  if (zoom_factor != 1)
    tmp_bitmap_1 = ZoomBitmap(old_bitmap, width_1, height_1);
  else
    tmp_bitmap_1 = old_bitmap;

  /* this is only needed to make compilers happy */
  tmp_bitmap_2 = NULL;
  tmp_bitmap_4 = NULL;
  tmp_bitmap_8 = NULL;
  tmp_bitmap_16 = NULL;
  tmp_bitmap_32 = NULL;

  if (create_small_bitmaps)
  {
    /* calculate new image dimensions for small images */
    width_2  = width_1  / 2;
    height_2 = height_1 / 2;
    width_4  = width_1  / 4;
    height_4 = height_1 / 4;
    width_8  = width_1  / 8;
    height_8 = height_1 / 8;
    width_16  = width_1  / 16;
    height_16 = height_1 / 16;
    width_32  = width_1  / 32;
    height_32 = height_1 / 32;

    UPDATE_BUSY_STATE();

    /* get image with 1/2 of normal size (for use in the level editor) */
    if (zoom_factor != 2)
      tmp_bitmap_2 = ZoomBitmap(tmp_bitmap_1, width_1 / 2, height_1 / 2);
    else
      tmp_bitmap_2 = old_bitmap;

    UPDATE_BUSY_STATE();

    /* get image with 1/4 of normal size (for use in the level editor) */
    if (zoom_factor != 4)
      tmp_bitmap_4 = ZoomBitmap(tmp_bitmap_2, width_2 / 2, height_2 / 2);
    else
      tmp_bitmap_4 = old_bitmap;

    UPDATE_BUSY_STATE();

    /* get image with 1/8 of normal size (for use on the preview screen) */
    if (zoom_factor != 8)
      tmp_bitmap_8 = ZoomBitmap(tmp_bitmap_4, width_4 / 2, height_4 / 2);
    else
      tmp_bitmap_8 = old_bitmap;

    UPDATE_BUSY_STATE();

    /* get image with 1/16 of normal size (for use on the preview screen) */
    if (zoom_factor != 16)
      tmp_bitmap_16 = ZoomBitmap(tmp_bitmap_8, width_8 / 2, height_8 / 2);
    else
      tmp_bitmap_16 = old_bitmap;

    UPDATE_BUSY_STATE();

    /* get image with 1/32 of normal size (for use on the preview screen) */
    if (zoom_factor != 32)
      tmp_bitmap_32 = ZoomBitmap(tmp_bitmap_16, width_16 / 2, height_16 / 2);
    else
      tmp_bitmap_32 = old_bitmap;

    UPDATE_BUSY_STATE();
  }

#if 0
  /* if image was scaled up, create new clipmask for normal size image */
  if (zoom_factor != 1)
  {
#if defined(TARGET_X11)
    if (old_bitmap->clip_mask)
      XFreePixmap(display, old_bitmap->clip_mask);

    old_bitmap->clip_mask =
      Pixmap_to_Mask(tmp_bitmap_1->drawable, width_1, height_1);

    XSetClipMask(display, old_bitmap->stored_clip_gc, old_bitmap->clip_mask);
#else
    SDL_Surface *tmp_surface_1 = tmp_bitmap_1->surface;

    if (old_bitmap->surface_masked)
      SDL_FreeSurface(old_bitmap->surface_masked);

    SDL_SetColorKey(tmp_surface_1, SDL_SRCCOLORKEY,
		    SDL_MapRGB(tmp_surface_1->format, 0x00, 0x00, 0x00));
    if ((old_bitmap->surface_masked = SDL_DisplayFormat(tmp_surface_1)) ==NULL)
      Error(ERR_EXIT, "SDL_DisplayFormat() failed");
    SDL_SetColorKey(tmp_surface_1, 0, 0);	/* reset transparent pixel */
#endif
  }
#endif

  if (create_small_bitmaps)
  {
    new_width  = width_1;
    new_height = height_1 + (height_1 + 1) / 2;     /* prevent odd height */

    new_bitmap = CreateBitmap(new_width, new_height, DEFAULT_DEPTH);

    BlitBitmap(tmp_bitmap_1, new_bitmap, 0, 0, width_1, height_1, 0, 0);
    BlitBitmap(tmp_bitmap_2, new_bitmap, 0, 0, width_1 / 2, height_1 / 2,
	       0, height_1);
    BlitBitmap(tmp_bitmap_4, new_bitmap, 0, 0, width_1 / 4, height_1 / 4,
	       width_1 / 2, height_1);
    BlitBitmap(tmp_bitmap_8, new_bitmap, 0, 0, width_1 / 8, height_1 / 8,
	       3 * width_1 / 4, height_1);
    BlitBitmap(tmp_bitmap_16, new_bitmap, 0, 0, width_1 / 16, height_1 / 16,
	       7 * width_1 / 8, height_1);
    BlitBitmap(tmp_bitmap_32, new_bitmap, 0, 0, width_1 / 32, height_1 / 32,
	       15 * width_1 / 16, height_1);

    UPDATE_BUSY_STATE();
  }
  else
  {
    new_width  = width_1;
    new_height = height_1;

    new_bitmap = tmp_bitmap_1;	/* directly use tmp_bitmap_1 as new bitmap */
  }

  if (create_small_bitmaps)
  {
    /* if no small bitmaps created, tmp_bitmap_1 is used as new bitmap now */
    if (zoom_factor != 1)
      FreeBitmap(tmp_bitmap_1);

    if (zoom_factor != 2)
      FreeBitmap(tmp_bitmap_2);

    if (zoom_factor != 4)
      FreeBitmap(tmp_bitmap_4);

    if (zoom_factor != 8)
      FreeBitmap(tmp_bitmap_8);

    if (zoom_factor != 16)
      FreeBitmap(tmp_bitmap_16);

    if (zoom_factor != 32)
      FreeBitmap(tmp_bitmap_32);
  }

  /* replace image with extended image (containing 1/1, 1/2, 1/4, 1/8 size) */
#if defined(TARGET_SDL)
  swap_bitmap.surface = old_bitmap->surface;
  old_bitmap->surface = new_bitmap->surface;
  new_bitmap->surface = swap_bitmap.surface;
#else
  swap_bitmap.drawable = old_bitmap->drawable;
  old_bitmap->drawable = new_bitmap->drawable;
  new_bitmap->drawable = swap_bitmap.drawable;
#endif

  old_bitmap->width  = new_bitmap->width;
  old_bitmap->height = new_bitmap->height;

#if 1
  /* this replaces all blit masks created when loading -- maybe optimize this */
  {
#if defined(TARGET_X11)
    if (old_bitmap->clip_mask)
      XFreePixmap(display, old_bitmap->clip_mask);

    old_bitmap->clip_mask =
      Pixmap_to_Mask(old_bitmap->drawable, new_width, new_height);

    XSetClipMask(display, old_bitmap->stored_clip_gc, old_bitmap->clip_mask);
#else
    SDL_Surface *old_surface = old_bitmap->surface;

    if (old_bitmap->surface_masked)
      SDL_FreeSurface(old_bitmap->surface_masked);

    SDL_SetColorKey(old_surface, SDL_SRCCOLORKEY,
		    SDL_MapRGB(old_surface->format, 0x00, 0x00, 0x00));
    if ((old_bitmap->surface_masked = SDL_DisplayFormat(old_surface)) ==NULL)
      Error(ERR_EXIT, "SDL_DisplayFormat() failed");
    SDL_SetColorKey(old_surface, 0, 0);		/* reset transparent pixel */
#endif
  }
#endif

  UPDATE_BUSY_STATE();

  FreeBitmap(new_bitmap);	/* this actually frees the _old_ bitmap now */
}

void CreateBitmapWithSmallBitmaps(Bitmap *old_bitmap, int zoom_factor)
{
  CreateScaledBitmaps(old_bitmap, zoom_factor, TRUE);
}

void ScaleBitmap(Bitmap *old_bitmap, int zoom_factor)
{
  CreateScaledBitmaps(old_bitmap, zoom_factor, FALSE);
}


/* ------------------------------------------------------------------------- */
/* mouse pointer functions                                                   */
/* ------------------------------------------------------------------------- */

#if !defined(PLATFORM_MSDOS)
#define USE_ONE_PIXEL_PLAYFIELD_MOUSEPOINTER		0
/* XPM image definitions */
static const char *cursor_image_none[] =
{
  /* width height num_colors chars_per_pixel */
  "    16    16        3            1",

  /* colors */
  "X c #000000",
  ". c #ffffff",
  "  c None",

  /* pixels */
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",

  /* hot spot */
  "0,0"
};
#if USE_ONE_PIXEL_PLAYFIELD_MOUSEPOINTER
static const char *cursor_image_dot[] =
{
  /* width height num_colors chars_per_pixel */
  "    16    16        3            1",

  /* colors */
  "X c #000000",
  ". c #ffffff",
  "  c None",

  /* pixels */
  " X              ",
  "X.X             ",
  " X              ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",
  "                ",

  /* hot spot */
  "1,1"
};
static const char **cursor_image_playfield = cursor_image_dot;
#else
/* some people complained about a "white dot" on the screen and thought it
   was a graphical error... OK, let's just remove the whole pointer :-) */
static const char **cursor_image_playfield = cursor_image_none;
#endif

#if defined(TARGET_SDL)
static const int cursor_bit_order = BIT_ORDER_MSB;
#elif defined(TARGET_X11_NATIVE)
static const int cursor_bit_order = BIT_ORDER_LSB;
#endif

static struct MouseCursorInfo *get_cursor_from_image(const char **image)
{
  struct MouseCursorInfo *cursor;
  boolean bit_order_msb = (cursor_bit_order == BIT_ORDER_MSB);
  int header_lines = 4;
  int x, y, i;

  cursor = checked_calloc(sizeof(struct MouseCursorInfo));

  sscanf(image[0], " %d %d ", &cursor->width, &cursor->height);

  i = -1;
  for (y = 0; y < cursor->width; y++)
  {
    for (x = 0; x < cursor->height; x++)
    {
      int bit_nr = x % 8;
      int bit_mask = 0x01 << (bit_order_msb ? 7 - bit_nr : bit_nr );

      if (bit_nr == 0)
      {
        i++;
        cursor->data[i] = cursor->mask[i] = 0;
      }

      switch (image[header_lines + y][x])
      {
        case 'X':
	  cursor->data[i] |= bit_mask;
	  cursor->mask[i] |= bit_mask;
	  break;

        case '.':
	  cursor->mask[i] |= bit_mask;
	  break;

        case ' ':
	  break;
      }
    }
  }

  sscanf(image[header_lines + y], "%d,%d", &cursor->hot_x, &cursor->hot_y);

  return cursor;
}
#endif	/* !PLATFORM_MSDOS */

void SetMouseCursor(int mode)
{
#if !defined(PLATFORM_MSDOS)
  static struct MouseCursorInfo *cursor_none = NULL;
  static struct MouseCursorInfo *cursor_playfield = NULL;
  struct MouseCursorInfo *cursor_new;

  if (cursor_none == NULL)
    cursor_none = get_cursor_from_image(cursor_image_none);

  if (cursor_playfield == NULL)
    cursor_playfield = get_cursor_from_image(cursor_image_playfield);

  cursor_new = (mode == CURSOR_DEFAULT   ? NULL :
		mode == CURSOR_NONE      ? cursor_none :
		mode == CURSOR_PLAYFIELD ? cursor_playfield : NULL);

#if defined(TARGET_SDL)
  SDLSetMouseCursor(cursor_new);
#elif defined(TARGET_X11_NATIVE)
  X11SetMouseCursor(cursor_new);
#endif
#endif
}


/* ========================================================================= */
/* audio functions                                                           */
/* ========================================================================= */

void OpenAudio(void)
{
  /* always start with reliable default values */
  audio.sound_available = FALSE;
  audio.music_available = FALSE;
  audio.loops_available = FALSE;

  audio.sound_enabled = FALSE;
  audio.sound_deactivated = FALSE;

  audio.mixer_pipe[0] = audio.mixer_pipe[1] = 0;
  audio.mixer_pid = 0;
  audio.device_name = NULL;
  audio.device_fd = -1;

  audio.num_channels = 0;
  audio.music_channel = 0;
  audio.first_sound_channel = 0;

#if defined(TARGET_SDL)
  SDLOpenAudio();
#elif defined(PLATFORM_UNIX)
  UnixOpenAudio();
#elif defined(PLATFORM_MSDOS)
  MSDOSOpenAudio();
#endif
}

void CloseAudio(void)
{
#if defined(TARGET_SDL)
  SDLCloseAudio();
#elif defined(PLATFORM_UNIX)
  UnixCloseAudio();
#elif defined(PLATFORM_MSDOS)
  MSDOSCloseAudio();
#endif

  audio.sound_enabled = FALSE;
}

void SetAudioMode(boolean enabled)
{
  if (!audio.sound_available)
    return;

  audio.sound_enabled = enabled;
}


/* ========================================================================= */
/* event functions                                                           */
/* ========================================================================= */

void InitEventFilter(EventFilter filter_function)
{
#if defined(TARGET_SDL)
  /* set event filter to filter out certain events */
  SDL_SetEventFilter(filter_function);
#endif
}

boolean PendingEvent(void)
{
#if defined(TARGET_SDL)
  return (SDL_PollEvent(NULL) ? TRUE : FALSE);
#else
  return (XPending(display) ? TRUE : FALSE);
#endif
}

void NextEvent(Event *event)
{
#if defined(TARGET_SDL)
  SDLNextEvent(event);
#else
  XNextEvent(display, event);
#endif
}

void PeekEvent(Event *event)
{
#if defined(TARGET_SDL)
  SDL_PeepEvents(event, 1, SDL_PEEKEVENT, SDL_ALLEVENTS);
#else
  XPeekEvent(display, event);
#endif
}

Key GetEventKey(KeyEvent *event, boolean with_modifiers)
{
#if defined(TARGET_SDL)

#if 0
  printf("unicode == '%d', sym == '%d', mod == '0x%04x'\n",
	 (int)event->keysym.unicode,
	 (int)event->keysym.sym,
	 (int)SDL_GetModState());
#endif

  if (with_modifiers &&
      event->keysym.unicode > 0x0000 &&
      event->keysym.unicode < 0x2000)
    return event->keysym.unicode;
  else
    return event->keysym.sym;

#else

#if 0
  printf("with modifiers == '0x%04x', without modifiers == '0x%04x'\n",
	 (int)XLookupKeysym(event, event->state),
	 (int)XLookupKeysym(event, 0));
#endif

  if (with_modifiers)
    return XLookupKeysym(event, event->state);
  else
    return XLookupKeysym(event, 0);
#endif
}

KeyMod HandleKeyModState(Key key, int key_status)
{
  static KeyMod current_modifiers = KMOD_None;

  if (key != KSYM_UNDEFINED)	/* new key => check for modifier key change */
  {
    KeyMod new_modifier = KMOD_None;

    switch(key)
    {
      case KSYM_Shift_L:
	new_modifier = KMOD_Shift_L;
	break;
      case KSYM_Shift_R:
	new_modifier = KMOD_Shift_R;
	break;
      case KSYM_Control_L:
	new_modifier = KMOD_Control_L;
	break;
      case KSYM_Control_R:
	new_modifier = KMOD_Control_R;
	break;
      case KSYM_Meta_L:
	new_modifier = KMOD_Meta_L;
	break;
      case KSYM_Meta_R:
	new_modifier = KMOD_Meta_R;
	break;
      case KSYM_Alt_L:
	new_modifier = KMOD_Alt_L;
	break;
      case KSYM_Alt_R:
	new_modifier = KMOD_Alt_R;
	break;
      default:
	break;
    }

    if (key_status == KEY_PRESSED)
      current_modifiers |= new_modifier;
    else
      current_modifiers &= ~new_modifier;
  }

  return current_modifiers;
}

KeyMod GetKeyModState()
{
#if defined(TARGET_SDL)
  return (KeyMod)SDL_GetModState();
#else
  return HandleKeyModState(KSYM_UNDEFINED, 0);
#endif
}

KeyMod GetKeyModStateFromEvents()
{
  /* always use key modifier state as tracked from key events (this is needed
     if the modifier key event was injected into the event queue, but the key
     was not really pressed on keyboard -- SDL_GetModState() seems to directly
     query the keys as held pressed on the keyboard) -- this case is currently
     only used to filter out clipboard insert events from "True X-Mouse" tool */

  return HandleKeyModState(KSYM_UNDEFINED, 0);
}

boolean CheckCloseWindowEvent(ClientMessageEvent *event)
{
  if (event->type != EVENT_CLIENTMESSAGE)
    return FALSE;

#if defined(TARGET_SDL)
  return TRUE;		/* the only possible message here is SDL_QUIT */
#elif defined(PLATFORM_UNIX)
  if ((event->window == window->drawable) &&
      (event->data.l[0] == XInternAtom(display, "WM_DELETE_WINDOW", FALSE)))
    return TRUE;
#endif

  return FALSE;
}


/* ========================================================================= */
/* joystick functions                                                        */
/* ========================================================================= */

void InitJoysticks()
{
  int i;

#if defined(NO_JOYSTICK)
  return;	/* joysticks generally deactivated by compile-time directive */
#endif

  /* always start with reliable default values */
  joystick.status = JOYSTICK_NOT_AVAILABLE;
  for (i = 0; i < MAX_PLAYERS; i++)
    joystick.fd[i] = -1;		/* joystick device closed */

#if defined(TARGET_SDL)
  SDLInitJoysticks();
#elif defined(PLATFORM_UNIX)
  UnixInitJoysticks();
#elif defined(PLATFORM_MSDOS)
  MSDOSInitJoysticks();
#endif

#if 0
  for (i = 0; i < MAX_PLAYERS; i++)
    printf("::: Joystick for player %d: %d\n", i, joystick.fd[i]);
#endif
}

boolean ReadJoystick(int nr, int *x, int *y, boolean *b1, boolean *b2)
{
#if defined(TARGET_SDL)
  return SDLReadJoystick(nr, x, y, b1, b2);
#elif defined(PLATFORM_UNIX)
  return UnixReadJoystick(nr, x, y, b1, b2);
#elif defined(PLATFORM_MSDOS)
  return MSDOSReadJoystick(nr, x, y, b1, b2);
#endif
}