X-Git-Url: https://git.artsoft.org/?p=rocksndiamonds.git;a=blobdiff_plain;f=src%2Flibgame%2Fsdl.c;h=2e03378df85eb285caff378748294fed1ba59d41;hp=52766b17d600c54f88dad072c26e258b0ca91022;hb=2178db0a0652bc87717aa1a55c888258ad6701e5;hpb=39d01b9327d78c44d36894a0a442a7c45a19849f

diff --git a/src/libgame/sdl.c b/src/libgame/sdl.c
index 52766b17..2e03378d 100644
--- a/src/libgame/sdl.c
+++ b/src/libgame/sdl.c
@@ -1,15 +1,13 @@
-/***********************************************************
-* Artsoft Retro-Game Library                               *
-*----------------------------------------------------------*
-* (c) 1994-2006 Artsoft Entertainment                      *
-*               Holger Schemel                             *
-*               Detmolder Strasse 189                      *
-*               33604 Bielefeld                            *
-*               Germany                                    *
-*               e-mail: info@artsoft.org                   *
-*----------------------------------------------------------*
-* sdl.c                                                    *
-***********************************************************/
+// ============================================================================
+// Artsoft Retro-Game Library
+// ----------------------------------------------------------------------------
+// (c) 1995-2014 by Artsoft Entertainment
+//     		    Holger Schemel
+//		    info@artsoft.org
+//		    http://www.artsoft.org/
+// ----------------------------------------------------------------------------
+// sdl.c
+// ============================================================================
 
 #include "system.h"
 #include "sound.h"
@@ -17,8 +15,8 @@
 #include "misc.h"
 #include "setup.h"
 
+#define ENABLE_UNUSED_CODE	0	/* currently unused functions */
 
-#if defined(TARGET_SDL)
 
 /* ========================================================================= */
 /* video functions                                                           */
@@ -29,6 +27,9 @@
 static SDL_Window *sdl_window = NULL;
 static SDL_Renderer *sdl_renderer = NULL;
 static SDL_Texture *sdl_texture = NULL;
+static boolean fullscreen_enabled = FALSE;
+
+#define USE_RENDERER	TRUE
 #endif
 
 /* stuff needed to work around SDL/Windows fullscreen drawing bug */
@@ -38,29 +39,143 @@ static int fullscreen_xoffset;
 static int fullscreen_yoffset;
 static int video_xoffset;
 static int video_yoffset;
+static boolean limit_screen_updates = FALSE;
+
 
 /* functions from SGE library */
 void sge_Line(SDL_Surface *, Sint16, Sint16, Sint16, Sint16, Uint32);
 
+void SDLLimitScreenUpdates(boolean enable)
+{
+  limit_screen_updates = enable;
+}
+
 static void UpdateScreen(SDL_Rect *rect)
 {
-#if 1
+  static unsigned int update_screen_delay = 0;
+  unsigned int update_screen_delay_value = 50;		/* (milliseconds) */
   SDL_Surface *screen = backbuffer->surface;
 
-  SDL_UpdateTexture(sdl_texture, NULL, screen->pixels, screen->pitch);
+  if (limit_screen_updates &&
+      !DelayReached(&update_screen_delay, update_screen_delay_value))
+    return;
+
+  LimitScreenUpdates(FALSE);
+
+#if 0
+  {
+    static int LastFrameCounter = 0;
+    boolean changed = (FrameCounter != LastFrameCounter);
+
+    printf("::: FrameCounter == %d [%s]\n", FrameCounter,
+	   (changed ? "-" : "SAME FRAME UPDATED"));
+
+    LastFrameCounter = FrameCounter;
+
+    /*
+    if (FrameCounter % 2)
+      return;
+    */
+  }
+#endif
+
+#if USE_FINAL_SCREEN_BITMAP
+  if (gfx.final_screen_bitmap != NULL)	// may not be initialized yet
+  {
+    // !!! TEST !!!
+    // draw global animations using bitmaps instead of using textures
+    // to prevent texture scaling artefacts (this is potentially slower)
+
+    BlitBitmap(backbuffer, gfx.final_screen_bitmap, 0, 0,
+	       gfx.win_xsize, gfx.win_ysize, 0, 0);
+
+    // copy global animations to render target buffer, if defined (below border)
+    if (gfx.draw_global_anim_function != NULL)
+      gfx.draw_global_anim_function(DRAW_GLOBAL_ANIM_STAGE_1);
+
+    // copy global masked border to render target buffer, if defined
+    if (gfx.draw_global_border_function != NULL)
+      gfx.draw_global_border_function(DRAW_BORDER_TO_SCREEN);
+
+    // copy global animations to render target buffer, if defined (above border)
+    if (gfx.draw_global_anim_function != NULL)
+      gfx.draw_global_anim_function(DRAW_GLOBAL_ANIM_STAGE_2);
+
+    screen = gfx.final_screen_bitmap->surface;
+
+    // force full window redraw
+    rect = NULL;
+  }
+#endif
+
+#if defined(TARGET_SDL2)
+#if USE_RENDERER
+  if (rect)
+  {
+    int bytes_x = screen->pitch / video.width;
+    int bytes_y = screen->pitch;
+
+    if (video.fullscreen_enabled)
+      bytes_x = screen->pitch / fullscreen_width;
+
+    SDL_UpdateTexture(sdl_texture, rect,
+		      screen->pixels + rect->x * bytes_x + rect->y * bytes_y,
+		      screen->pitch);
+  }
+  else
+  {
+    SDL_UpdateTexture(sdl_texture, NULL, screen->pixels, screen->pitch);
+  }
+
+  // clear render target buffer
   SDL_RenderClear(sdl_renderer);
+
+  // copy backbuffer to render target buffer
   SDL_RenderCopy(sdl_renderer, sdl_texture, NULL, NULL);
+
+#if !USE_FINAL_SCREEN_BITMAP
+  // copy global animations to render target buffer, if defined (below border)
+  if (gfx.draw_global_anim_function != NULL)
+    gfx.draw_global_anim_function(DRAW_GLOBAL_ANIM_STAGE_1);
+
+  // copy global masked border to render target buffer, if defined
+  if (gfx.draw_global_border_function != NULL)
+    gfx.draw_global_border_function(DRAW_BORDER_TO_SCREEN);
+
+  // copy global animations to render target buffer, if defined (above border)
+  if (gfx.draw_global_anim_function != NULL)
+    gfx.draw_global_anim_function(DRAW_GLOBAL_ANIM_STAGE_2);
+#endif
+
+  // show render target buffer on screen
   SDL_RenderPresent(sdl_renderer);
+
 #else
+
   if (rect)
     SDL_UpdateWindowSurfaceRects(sdl_window, rect, 1);
   else
     SDL_UpdateWindowSurface(sdl_window);
 #endif
+
+#else	// TARGET_SDL
+  if (rect)
+    SDL_UpdateRects(screen, 1, rect);
+  else
+    SDL_UpdateRect(screen, 0, 0, 0, 0);
+#endif
 }
 
 static void setFullscreenParameters(char *fullscreen_mode_string)
 {
+#if defined(TARGET_SDL2)
+  fullscreen_width = video.width;
+  fullscreen_height = video.height;
+  fullscreen_xoffset = 0;
+  fullscreen_yoffset = 0;  
+
+#else
+
   struct ScreenModeInfo *fullscreen_mode;
   int i;
 
@@ -83,6 +198,7 @@ static void setFullscreenParameters(char *fullscreen_mode_string)
       break;
     }
   }
+#endif
 }
 
 static void SDLSetWindowIcon(char *basename)
@@ -121,15 +237,157 @@ static void SDLSetWindowIcon(char *basename)
 }
 
 #if defined(TARGET_SDL2)
-SDL_Surface *SDL_DisplayFormat(SDL_Surface *surface)
+
+static boolean equalSDLPixelFormat(SDL_PixelFormat *format1,
+				   SDL_PixelFormat *format2)
+{
+  return (format1->format	 == format2->format &&
+	  format1->BitsPerPixel	 == format2->BitsPerPixel &&
+	  format1->BytesPerPixel == format2->BytesPerPixel &&
+	  format1->Rmask	 == format2->Rmask &&
+	  format1->Gmask	 == format2->Gmask &&
+	  format1->Bmask	 == format2->Bmask &&
+	  format1->Amask	 == format2->Amask);
+}
+
+boolean SDLSetNativeSurface(SDL_Surface **surface)
 {
-  if (backbuffer == NULL ||
+  SDL_Surface *new_surface;
+
+  if (surface == NULL ||
+      *surface == NULL ||
+      backbuffer == NULL ||
       backbuffer->surface == NULL)
+    return FALSE;
+
+  // if pixel format already optimized for destination surface, do nothing
+  if (equalSDLPixelFormat((*surface)->format, backbuffer->surface->format))
+    return FALSE;
+
+  new_surface = SDL_ConvertSurface(*surface, backbuffer->surface->format, 0);
+
+  if (new_surface == NULL)
+    Error(ERR_EXIT, "SDL_ConvertSurface() failed: %s", SDL_GetError());
+
+  SDL_FreeSurface(*surface);
+
+  *surface = new_surface;
+
+  return TRUE;
+}
+
+SDL_Surface *SDLGetNativeSurface(SDL_Surface *surface)
+{
+  SDL_PixelFormat format;
+  SDL_Surface *new_surface;
+
+  if (surface == NULL)
     return NULL;
 
-  return SDL_ConvertSurface(surface, backbuffer->surface->format, 0);
+  if (backbuffer && backbuffer->surface)
+  {
+    format = *backbuffer->surface->format;
+    format.Amask = surface->format->Amask;	// keep alpha channel
+  }
+  else
+  {
+    format = *surface->format;
+  }
+
+  new_surface = SDL_ConvertSurface(surface, &format, 0);
+
+  if (new_surface == NULL)
+    Error(ERR_EXIT, "SDL_ConvertSurface() failed: %s", SDL_GetError());
+
+  return new_surface;
 }
+
+#else
+
+boolean SDLSetNativeSurface(SDL_Surface **surface)
+{
+  SDL_Surface *new_surface;
+
+  if (surface == NULL ||
+      *surface == NULL ||
+      !video.initialized)
+    return FALSE;
+
+  new_surface = SDL_DisplayFormat(*surface);
+
+  if (new_surface == NULL)
+    Error(ERR_EXIT, "SDL_DisplayFormat() failed: %s", SDL_GetError());
+
+  SDL_FreeSurface(*surface);
+
+  *surface = new_surface;
+
+  return TRUE;
+}
+
+SDL_Surface *SDLGetNativeSurface(SDL_Surface *surface)
+{
+  SDL_Surface *new_surface;
+
+  if (video.initialized)
+    new_surface = SDL_DisplayFormat(surface);
+  else
+    new_surface = SDL_ConvertSurface(surface, surface->format, SURFACE_FLAGS);
+
+  if (new_surface == NULL)
+    Error(ERR_EXIT, "%s() failed: %s",
+	  (video.initialized ? "SDL_DisplayFormat" : "SDL_ConvertSurface"),
+	  SDL_GetError());
+
+  return new_surface;
+}
+
+#endif
+
+#if defined(TARGET_SDL2)
+static SDL_Texture *SDLCreateTextureFromSurface(SDL_Surface *surface)
+{
+  SDL_Texture *texture = SDL_CreateTextureFromSurface(sdl_renderer, surface);
+
+  if (texture == NULL)
+    Error(ERR_EXIT, "SDL_CreateTextureFromSurface() failed: %s",
+	  SDL_GetError());
+
+  return texture;
+}
+#endif
+
+void SDLCreateBitmapTextures(Bitmap *bitmap)
+{
+#if defined(TARGET_SDL2)
+  if (bitmap == NULL)
+    return;
+
+  if (bitmap->texture)
+    SDL_DestroyTexture(bitmap->texture);
+  if (bitmap->texture_masked)
+    SDL_DestroyTexture(bitmap->texture_masked);
+
+  bitmap->texture        = SDLCreateTextureFromSurface(bitmap->surface);
+  bitmap->texture_masked = SDLCreateTextureFromSurface(bitmap->surface_masked);
+#endif
+}
+
+void SDLFreeBitmapTextures(Bitmap *bitmap)
+{
+#if defined(TARGET_SDL2)
+  if (bitmap == NULL)
+    return;
+
+  if (bitmap->texture)
+    SDL_DestroyTexture(bitmap->texture);
+  if (bitmap->texture_masked)
+    SDL_DestroyTexture(bitmap->texture_masked);
+
+  bitmap->texture = NULL;
+  bitmap->texture_masked = NULL;
 #endif
+}
 
 void SDLInitVideoDisplay(void)
 {
@@ -155,6 +413,7 @@ void SDLInitVideoDisplay(void)
 void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
 			boolean fullscreen)
 {
+#if !defined(TARGET_SDL2)
   static int screen_xy[][2] =
   {
     {  640, 480 },
@@ -162,7 +421,9 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
     { 1024, 768 },
     {   -1,  -1 }
   };
-  SDL_Rect **modes;
+#endif
+  SDL_Rect **modes = NULL;
+  boolean hardware_fullscreen_available = TRUE;
   int i, j;
 
   /* default: normal game window size */
@@ -171,6 +432,8 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
   fullscreen_xoffset = 0;
   fullscreen_yoffset = 0;
 
+#if !defined(TARGET_SDL2)
+  /* determine required standard fullscreen mode for game screen size */
   for (i = 0; screen_xy[i][0] != -1; i++)
   {
     if (screen_xy[i][0] >= video.width && screen_xy[i][1] >= video.height)
@@ -184,26 +447,52 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
 
   fullscreen_xoffset = (fullscreen_width  - video.width)  / 2;
   fullscreen_yoffset = (fullscreen_height - video.height) / 2;
+#endif
 
-#if 1
   checked_free(video.fullscreen_modes);
 
   video.fullscreen_modes = NULL;
   video.fullscreen_mode_current = NULL;
-#endif
 
-#if !defined(TARGET_SDL2)
+  video.window_scaling_percent = setup.window_scaling_percent;
+  video.window_scaling_quality = setup.window_scaling_quality;
+
+#if defined(TARGET_SDL2)
+  int num_displays = SDL_GetNumVideoDisplays();
+
+  if (num_displays > 0)
+  {
+    // currently only display modes of first display supported
+    int num_modes = SDL_GetNumDisplayModes(0);
+
+    if (num_modes > 0)
+    {
+      modes = checked_calloc((num_modes + 1) * sizeof(SDL_Rect *));
+
+      for (i = 0; i < num_modes; i++)
+      {
+	SDL_DisplayMode mode;
+
+	if (SDL_GetDisplayMode(0, i, &mode) < 0)
+	  break;
+
+	modes[i] = checked_calloc(sizeof(SDL_Rect));
+
+	modes[i]->w = mode.w;
+	modes[i]->h = mode.h;
+      }
+    }
+  }
+#else
   /* get available hardware supported fullscreen modes */
   modes = SDL_ListModes(NULL, SDL_FULLSCREEN | SDL_HWSURFACE);
-#else
-  // (for now, no display modes in SDL2 -- change this later)
-  modes = NULL;
 #endif
 
   if (modes == NULL)
   {
-    /* no screen modes available => no fullscreen mode support */
-    video.fullscreen_available = FALSE;
+    /* no hardware screen modes available => no fullscreen mode support */
+    // video.fullscreen_available = FALSE;
+    hardware_fullscreen_available = FALSE;
   }
   else if (modes == (SDL_Rect **)-1)
   {
@@ -222,7 +511,7 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
     /* in this case, a certain number of screen modes is available */
     int num_modes = 0;
 
-    for(i = 0; modes[i] != NULL; i++)
+    for (i = 0; modes[i] != NULL; i++)
     {
       boolean found_mode = FALSE;
 
@@ -257,23 +546,36 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
     if (num_modes == 0)
     {
       /* no appropriate screen modes available => no fullscreen mode support */
-      video.fullscreen_available = FALSE;
+      // video.fullscreen_available = FALSE;
+      hardware_fullscreen_available = FALSE;
     }
   }
 
-#if 0
-  /* set window icon */
-  SDLSetWindowIcon(program.sdl_icon_filename);
+  video.fullscreen_available = hardware_fullscreen_available;
+
+#if USE_DESKTOP_FULLSCREEN
+  // in SDL 2.0, there is always support for desktop fullscreen mode
+  // (in SDL 1.2, there is only support for "real" fullscreen mode)
+  video.fullscreen_available = TRUE;
+#endif
+
+#if defined(TARGET_SDL2)
+  if (modes)
+  {
+    for (i = 0; modes[i] != NULL; i++)
+      checked_free(modes[i]);
+
+    checked_free(modes);
+  }
 #endif
 
   /* open SDL video output device (window or fullscreen mode) */
   if (!SDLSetVideoMode(backbuffer, fullscreen))
     Error(ERR_EXIT, "setting video mode failed");
 
-#if 1
+  /* !!! SDL2 can only set the window icon if the window already exists !!! */
   /* set window icon */
-  SDLSetWindowIcon(program.sdl_icon_filename);
-#endif
+  SDLSetWindowIcon(program.icon_filename);
 
   /* set window and icon title */
 #if defined(TARGET_SDL2)
@@ -296,26 +598,174 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
      should never be drawn to directly, it would do no harm nevertheless. */
 
   /* create additional (symbolic) buffer for double-buffering */
-#if 1
   ReCreateBitmap(window, video.width, video.height, video.depth);
-#else
-  *window = CreateBitmap(video.width, video.height, video.depth);
-#endif
 }
 
-boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
+static SDL_Surface *SDLCreateScreen(DrawBuffer **backbuffer,
+				    boolean fullscreen)
 {
-  boolean success = TRUE;
+  SDL_Surface *new_surface = NULL;
+
 #if defined(TARGET_SDL2)
-  // int surface_flags_fullscreen = SURFACE_FLAGS | SDL_WINDOW_FULLSCREEN;
+  int surface_flags_window = SURFACE_FLAGS | SDL_WINDOW_RESIZABLE;
+#if USE_DESKTOP_FULLSCREEN
   int surface_flags_fullscreen = SURFACE_FLAGS | SDL_WINDOW_FULLSCREEN_DESKTOP;
-  int surface_flags_window = SURFACE_FLAGS;
 #else
-  int surface_flags_fullscreen = SURFACE_FLAGS | SDL_FULLSCREEN;
+  int surface_flags_fullscreen = SURFACE_FLAGS | SDL_WINDOW_FULLSCREEN;
+#endif
+
+#else
   int surface_flags_window = SURFACE_FLAGS;
+  int surface_flags_fullscreen = SURFACE_FLAGS | SDL_FULLSCREEN;
+#endif
+
+  int width  = (fullscreen ? fullscreen_width  : video.width);
+  int height = (fullscreen ? fullscreen_height : video.height);
+  int surface_flags = (fullscreen ? surface_flags_fullscreen :
+		       surface_flags_window);
+
+  // default window size is unscaled
+  video.window_width  = video.width;
+  video.window_height = video.height;
+
+#if defined(TARGET_SDL2)
+
+  // store if initial screen mode is fullscreen mode when changing screen size
+  video.fullscreen_initial = fullscreen;
+
+#if USE_RENDERER
+  float window_scaling_factor = (float)setup.window_scaling_percent / 100;
+#if !USE_DESKTOP_FULLSCREEN
+  float screen_scaling_factor = (fullscreen ? 1 : window_scaling_factor);
+#endif
+
+  video.window_width  = window_scaling_factor * width;
+  video.window_height = window_scaling_factor * height;
+
+  if ((*backbuffer)->surface)
+  {
+    SDL_FreeSurface((*backbuffer)->surface);
+    (*backbuffer)->surface = NULL;
+  }
+
+  if (sdl_texture)
+  {
+    SDL_DestroyTexture(sdl_texture);
+    sdl_texture = NULL;
+  }
+
+  if (!(fullscreen && fullscreen_enabled))
+  {
+    if (sdl_renderer)
+    {
+      SDL_DestroyRenderer(sdl_renderer);
+      sdl_renderer = NULL;
+    }
+
+    if (sdl_window)
+    {
+      SDL_DestroyWindow(sdl_window);
+      sdl_window = NULL;
+    }
+  }
+
+  if (sdl_window == NULL)
+    sdl_window = SDL_CreateWindow(program.window_title,
+				  SDL_WINDOWPOS_CENTERED,
+				  SDL_WINDOWPOS_CENTERED,
+#if USE_DESKTOP_FULLSCREEN
+				  video.window_width,
+				  video.window_height,
+#else
+				  (int)(screen_scaling_factor * width),
+				  (int)(screen_scaling_factor * height),
 #endif
+				  surface_flags);
+
+  if (sdl_window != NULL)
+  {
+#if 0
+    /* if SDL_CreateRenderer() is called from within a VirtualBox Windows VM
+     *without* enabling 2D/3D acceleration and/or guest additions installed,
+     it will crash if flags are *not* set to SDL_RENDERER_SOFTWARE (because
+     it will try to use accelerated graphics and apparently fails miserably) */
+    if (sdl_renderer == NULL)
+      sdl_renderer = SDL_CreateRenderer(sdl_window, -1, SDL_RENDERER_SOFTWARE);
+#else
+    if (sdl_renderer == NULL)
+      sdl_renderer = SDL_CreateRenderer(sdl_window, -1, 0);
+#endif
+
+    if (sdl_renderer != NULL)
+    {
+      SDL_RenderSetLogicalSize(sdl_renderer, width, height);
+      // SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
+      SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, setup.window_scaling_quality);
+
+      sdl_texture = SDL_CreateTexture(sdl_renderer,
+				      SDL_PIXELFORMAT_ARGB8888,
+				      SDL_TEXTUREACCESS_STREAMING,
+				      width, height);
+
+      if (sdl_texture != NULL)
+      {
+	// use SDL default values for RGB masks and no alpha channel
+	new_surface = SDL_CreateRGBSurface(0, width, height, 32, 0,0,0, 0);
+
+	if (new_surface == NULL)
+	  Error(ERR_WARN, "SDL_CreateRGBSurface() failed: %s",
+		SDL_GetError());
+      }
+      else
+      {
+	Error(ERR_WARN, "SDL_CreateTexture() failed: %s", SDL_GetError());
+      }
+    }
+    else
+    {
+      Error(ERR_WARN, "SDL_CreateRenderer() failed: %s", SDL_GetError());
+    }
+  }
+  else
+  {
+    Error(ERR_WARN, "SDL_CreateWindow() failed: %s", SDL_GetError());
+  }
+
+#else
+
+  if (sdl_window)
+    SDL_DestroyWindow(sdl_window);
+
+  sdl_window = SDL_CreateWindow(program.window_title,
+				SDL_WINDOWPOS_CENTERED,
+				SDL_WINDOWPOS_CENTERED,
+				width, height,
+				surface_flags);
+
+  if (sdl_window != NULL)
+    new_surface = SDL_GetWindowSurface(sdl_window);
+#endif
+
+#else
+  new_surface = SDL_SetVideoMode(width, height, video.depth, surface_flags);
+#endif
+
+#if defined(TARGET_SDL2)
+  // store fullscreen state ("video.fullscreen_enabled" may not reflect this!)
+  if (new_surface != NULL)
+    fullscreen_enabled = fullscreen;
+#endif
+
+  return new_surface;
+}
+
+boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
+{
+  boolean success = TRUE;
   SDL_Surface *new_surface = NULL;
 
+  SetWindowTitle();
+
   if (*backbuffer == NULL)
     *backbuffer = CreateBitmapStruct();
 
@@ -331,23 +781,7 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
     video_yoffset = fullscreen_yoffset;
 
     /* switch display to fullscreen mode, if available */
-#if defined(TARGET_SDL2)
-    sdl_window = SDL_CreateWindow(program.window_title,
-				  SDL_WINDOWPOS_CENTERED,
-				  SDL_WINDOWPOS_CENTERED,
-				  fullscreen_width, fullscreen_height,
-				  surface_flags_fullscreen);
-    if (sdl_window != NULL)
-    {
-      new_surface = SDL_GetWindowSurface(sdl_window);
-
-      // SDL_UpdateWindowSurface(sdl_window);	// immediately map window
-      UpdateScreen(NULL);	// immediately map window
-    }
-#else
-    new_surface = SDL_SetVideoMode(fullscreen_width, fullscreen_height,
-				   video.depth, surface_flags_fullscreen);
-#endif
+    new_surface = SDLCreateScreen(backbuffer, TRUE);
 
     if (new_surface == NULL)
     {
@@ -376,81 +810,7 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
     video_yoffset = 0;
 
     /* switch display to window mode */
-#if defined(TARGET_SDL2)
-
-#if 1
-    float scale_factor = 1;
-    int test_fullscreen = 0;
-    int surface_flags = (test_fullscreen ? surface_flags_fullscreen :
-			 surface_flags_window);
-
-    sdl_window = SDL_CreateWindow(program.window_title,
-				  SDL_WINDOWPOS_CENTERED,
-				  SDL_WINDOWPOS_CENTERED,
-				  (int)(scale_factor * video.width),
-				  (int)(scale_factor * video.height),
-				  surface_flags);
-
-    if (sdl_window != NULL)
-    {
-      sdl_renderer = SDL_CreateRenderer(sdl_window, -1, 0);
-
-      if (sdl_renderer != NULL)
-      {
-	SDL_RenderSetLogicalSize(sdl_renderer, video.width, video.height);
-	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
-
-	sdl_texture = SDL_CreateTexture(sdl_renderer,
-					SDL_PIXELFORMAT_ARGB8888,
-					SDL_TEXTUREACCESS_STREAMING,
-					video.width, video.height);
-
-	if (sdl_texture != NULL)
-	{
-	  new_surface = SDL_CreateRGBSurface(0, video.width, video.height, 32,
-					     0x00FF0000,
-					     0x0000FF00,
-					     0x000000FF,
-					     0xFF000000);
-
-	  if (new_surface == NULL)
-	    Error(ERR_WARN, "SDL_CreateRGBSurface() failed: %s",
-		  SDL_GetError());
-	}
-	else
-	{
-	  Error(ERR_WARN, "SDL_CreateTexture() failed: %s", SDL_GetError());
-	}
-      }
-      else
-      {
-	Error(ERR_WARN, "SDL_CreateRenderer() failed: %s", SDL_GetError());
-      }
-    }
-    else
-    {
-      Error(ERR_WARN, "SDL_CreateWindow() failed: %s", SDL_GetError());
-    }
-#else
-    sdl_window = SDL_CreateWindow(program.window_title,
-				  SDL_WINDOWPOS_CENTERED,
-				  SDL_WINDOWPOS_CENTERED,
-				  video.width, video.height,
-				  surface_flags_window);
-
-    if (sdl_window != NULL)
-    {
-      new_surface = SDL_GetWindowSurface(sdl_window);
-
-      // SDL_UpdateWindowSurface(sdl_window);	// immediately map window
-      UpdateScreen(NULL);	// immediately map window
-    }
-#endif
-
-#else
-    new_surface = SDL_SetVideoMode(video.width, video.height,
-				   video.depth, surface_flags_window);
-#endif
+    new_surface = SDLCreateScreen(backbuffer, FALSE);
 
     if (new_surface == NULL)
     {
@@ -464,49 +824,148 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
       (*backbuffer)->surface = new_surface;
 
       video.fullscreen_enabled = FALSE;
+      video.window_scaling_percent = setup.window_scaling_percent;
+      video.window_scaling_quality = setup.window_scaling_quality;
 
       success = TRUE;
     }
   }
 
-#if 1
-  SDL_EventState(SDL_SYSWMEVENT, SDL_ENABLE);
+#if defined(TARGET_SDL2)
+  SDLRedrawWindow();			// map window
+#endif
 
+#ifdef DEBUG
 #if defined(PLATFORM_WIN32)
+  // experimental drag and drop code
+
+  SDL_EventState(SDL_SYSWMEVENT, SDL_ENABLE);
+
   {
     SDL_SysWMinfo wminfo;
     HWND hwnd;
+    boolean wminfo_success = FALSE;
 
     SDL_VERSION(&wminfo.version);
-    SDL_GetWMInfo(&wminfo);
+#if defined(TARGET_SDL2)
+    if (sdl_window)
+      wminfo_success = SDL_GetWindowWMInfo(sdl_window, &wminfo);
+#else
+    wminfo_success = (SDL_GetWMInfo(&wminfo) == 1);
+#endif
 
-    hwnd = wminfo.window;
+    if (wminfo_success)
+    {
+#if defined(TARGET_SDL2)
+      hwnd = wminfo.info.win.window;
+#else
+      hwnd = wminfo.window;
+#endif
 
-    DragAcceptFiles(hwnd, TRUE);
+      DragAcceptFiles(hwnd, TRUE);
+    }
   }
 #endif
 #endif
 
-
   return success;
 }
 
-void SDLCreateBitmapContent(Bitmap *new_bitmap, int width, int height,
+void SDLSetWindowTitle()
+{
+#if defined(TARGET_SDL2)
+  SDL_SetWindowTitle(sdl_window, program.window_title);
+#else
+  SDL_WM_SetCaption(program.window_title, program.window_title);
+#endif
+}
+
+#if defined(TARGET_SDL2)
+void SDLSetWindowScaling(int window_scaling_percent)
+{
+  if (sdl_window == NULL)
+    return;
+
+  float window_scaling_factor = (float)window_scaling_percent / 100;
+  int new_window_width  = (int)(window_scaling_factor * video.width);
+  int new_window_height = (int)(window_scaling_factor * video.height);
+
+  SDL_SetWindowSize(sdl_window, new_window_width, new_window_height);
+
+  video.window_scaling_percent = window_scaling_percent;
+  video.window_width  = new_window_width;
+  video.window_height = new_window_height;
+
+  SetWindowTitle();
+}
+
+void SDLSetWindowScalingQuality(char *window_scaling_quality)
+{
+  if (sdl_texture == NULL)
+    return;
+
+  SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, window_scaling_quality);
+
+  SDL_Texture *new_texture = SDL_CreateTexture(sdl_renderer,
+					       SDL_PIXELFORMAT_ARGB8888,
+					       SDL_TEXTUREACCESS_STREAMING,
+					       video.width, video.height);
+
+  if (new_texture != NULL)
+  {
+    SDL_DestroyTexture(sdl_texture);
+
+    sdl_texture = new_texture;
+
+    SDLRedrawWindow();
+  }
+
+  video.window_scaling_quality = window_scaling_quality;
+}
+
+void SDLSetWindowFullscreen(boolean fullscreen)
+{
+  if (sdl_window == NULL)
+    return;
+
+#if USE_DESKTOP_FULLSCREEN
+  int flags = (fullscreen ? SDL_WINDOW_FULLSCREEN_DESKTOP : 0);
+#else
+  int flags = (fullscreen ? SDL_WINDOW_FULLSCREEN : 0);
+#endif
+
+  if (SDL_SetWindowFullscreen(sdl_window, flags) == 0)
+    video.fullscreen_enabled = fullscreen_enabled = fullscreen;
+
+  // if screen size was changed in fullscreen mode, correct desktop window size
+  if (!fullscreen && video.fullscreen_initial)
+  {
+    SDLSetWindowScaling(setup.window_scaling_percent);
+    SDL_SetWindowPosition(sdl_window,
+			  SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
+
+    video.fullscreen_initial = FALSE;
+  }
+}
+
+void SDLRedrawWindow()
+{
+  UpdateScreen(NULL);
+}
+#endif
+
+void SDLCreateBitmapContent(Bitmap *bitmap, int width, int height,
 			    int depth)
 {
-  SDL_Surface *surface_tmp, *surface_native;
+  SDL_Surface *surface =
+    SDL_CreateRGBSurface(SURFACE_FLAGS, width, height, depth, 0,0,0, 0);
 
-  if ((surface_tmp = SDL_CreateRGBSurface(SURFACE_FLAGS, width, height, depth,
-					  0, 0, 0, 0))
-      == NULL)
+  if (surface == NULL)
     Error(ERR_EXIT, "SDL_CreateRGBSurface() failed: %s", SDL_GetError());
 
-  if ((surface_native = SDL_DisplayFormat(surface_tmp)) == NULL)
-    Error(ERR_EXIT, "SDL_DisplayFormat() failed: %s", SDL_GetError());
-
-  SDL_FreeSurface(surface_tmp);
+  SDLSetNativeSurface(&surface);
 
-  new_bitmap->surface = surface_native;
+  bitmap->surface = surface;
 }
 
 void SDLFreeBitmapPointers(Bitmap *bitmap)
@@ -515,8 +974,19 @@ void SDLFreeBitmapPointers(Bitmap *bitmap)
     SDL_FreeSurface(bitmap->surface);
   if (bitmap->surface_masked)
     SDL_FreeSurface(bitmap->surface_masked);
+
   bitmap->surface = NULL;
   bitmap->surface_masked = NULL;
+
+#if defined(TARGET_SDL2)
+  if (bitmap->texture)
+    SDL_DestroyTexture(bitmap->texture);
+  if (bitmap->texture_masked)
+    SDL_DestroyTexture(bitmap->texture_masked);
+
+  bitmap->texture = NULL;
+  bitmap->texture_masked = NULL;
+#endif
 }
 
 void SDLCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
@@ -548,7 +1018,8 @@ void SDLCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
   dst_rect.w = width;
   dst_rect.h = height;
 
-  if (src_bitmap != backbuffer || dst_bitmap != window)
+  // if (src_bitmap != backbuffer || dst_bitmap != window)
+  if (!(src_bitmap == backbuffer && dst_bitmap == window))
     SDL_BlitSurface((mask_mode == BLIT_MASKED ?
 		     src_bitmap->surface_masked : src_bitmap->surface),
 		    &src_rect, real_dst_bitmap->surface, &dst_rect);
@@ -562,7 +1033,41 @@ void SDLCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
   }
 #else
   if (dst_bitmap == window)
-    SDL_UpdateRect(backbuffer->surface, dst_x, dst_y, width, height);
+  {
+    // SDL_UpdateRect(backbuffer->surface, dst_x, dst_y, width, height);
+    UpdateScreen(&dst_rect);
+  }
+#endif
+}
+
+void SDLBlitTexture(Bitmap *bitmap,
+		    int src_x, int src_y, int width, int height,
+		    int dst_x, int dst_y, int mask_mode)
+{
+#if defined(TARGET_SDL2)
+#if USE_RENDERER
+  SDL_Texture *texture;
+  SDL_Rect src_rect;
+  SDL_Rect dst_rect;
+
+  texture =
+    (mask_mode == BLIT_MASKED ? bitmap->texture_masked : bitmap->texture);
+
+  if (texture == NULL)
+    return;
+
+  src_rect.x = src_x;
+  src_rect.y = src_y;
+  src_rect.w = width;
+  src_rect.h = height;
+
+  dst_rect.x = dst_x;
+  dst_rect.y = dst_y;
+  dst_rect.w = width;
+  dst_rect.h = height;
+
+  SDL_RenderCopy(sdl_renderer, texture, &src_rect, &dst_rect);
+#endif
 #endif
 }
 
@@ -594,7 +1099,10 @@ void SDLFillRectangle(Bitmap *dst_bitmap, int x, int y, int width, int height,
   }
 #else
   if (dst_bitmap == window)
-    SDL_UpdateRect(backbuffer->surface, x, y, width, height);
+  {
+    // SDL_UpdateRect(backbuffer->surface, x, y, width, height);
+    UpdateScreen(&rect);
+  }
 #endif
 }
 
@@ -602,30 +1110,23 @@ void SDLFadeRectangle(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))
 {
-  static boolean initialization_needed = TRUE;
-  static SDL_Surface *surface_source = NULL;
-  static SDL_Surface *surface_target = NULL;
-  static SDL_Surface *surface_black = NULL;
+  SDL_Surface *surface_source = gfx.fade_bitmap_source->surface;
+  SDL_Surface *surface_target = gfx.fade_bitmap_target->surface;
+  SDL_Surface *surface_black  = gfx.fade_bitmap_black->surface;
   SDL_Surface *surface_screen = backbuffer->surface;
   SDL_Surface *surface_cross = (bitmap_cross ? bitmap_cross->surface : NULL);
   SDL_Rect src_rect, dst_rect;
-#if defined(TARGET_SDL2)
   SDL_Rect dst_rect2;
-#endif
   int src_x = x, src_y = y;
   int dst_x = x, dst_y = y;
   unsigned int time_last, time_current;
 
-  /* check if screen size has changed */
-  if (surface_source != NULL && (video.width  != surface_source->w ||
-				 video.height != surface_source->h))
-  {
-    SDL_FreeSurface(surface_source);
-    SDL_FreeSurface(surface_target);
-    SDL_FreeSurface(surface_black);
+  // store function for drawing global masked border
+  void (*draw_global_border_function)(int) = gfx.draw_global_border_function;
 
-    initialization_needed = TRUE;
-  }
+  // deactivate drawing of global border while fading, if needed
+  if (draw_border_function == NULL)
+    gfx.draw_global_border_function = NULL;
 
   src_rect.x = src_x;
   src_rect.y = src_y;
@@ -640,82 +1141,30 @@ void SDLFadeRectangle(Bitmap *bitmap_cross, int x, int y, int width, int height,
   dst_rect.w = width;		/* (ignored) */
   dst_rect.h = height;		/* (ignored) */
 
-#if defined(TARGET_SDL2)
   dst_rect2 = dst_rect;
-#endif
-
-  if (initialization_needed)
-  {
-#if defined(TARGET_SDL2)
-    unsigned int flags = 0;
-#else
-    unsigned int flags = SDL_SRCALPHA;
-
-    /* use same surface type as screen surface */
-    if ((surface_screen->flags & SDL_HWSURFACE))
-      flags |= SDL_HWSURFACE;
-    else
-      flags |= SDL_SWSURFACE;
-#endif
-
-    /* create surface for temporary copy of screen buffer (source) */
-    if ((surface_source =
-	 SDL_CreateRGBSurface(flags,
-			      video.width,
-			      video.height,
-			      surface_screen->format->BitsPerPixel,
-			      surface_screen->format->Rmask,
-			      surface_screen->format->Gmask,
-			      surface_screen->format->Bmask,
-			      surface_screen->format->Amask)) == NULL)
-      Error(ERR_EXIT, "SDL_CreateRGBSurface() failed: %s", SDL_GetError());
-
-    /* create surface for cross-fading screen buffer (target) */
-    if ((surface_target =
-	 SDL_CreateRGBSurface(flags,
-			      video.width,
-			      video.height,
-			      surface_screen->format->BitsPerPixel,
-			      surface_screen->format->Rmask,
-			      surface_screen->format->Gmask,
-			      surface_screen->format->Bmask,
-			      surface_screen->format->Amask)) == NULL)
-      Error(ERR_EXIT, "SDL_CreateRGBSurface() failed: %s", SDL_GetError());
-
-    /* create black surface for fading from/to black */
-    if ((surface_black =
-	 SDL_CreateRGBSurface(flags,
-			      video.width,
-			      video.height,
-			      surface_screen->format->BitsPerPixel,
-			      surface_screen->format->Rmask,
-			      surface_screen->format->Gmask,
-			      surface_screen->format->Bmask,
-			      surface_screen->format->Amask)) == NULL)
-      Error(ERR_EXIT, "SDL_CreateRGBSurface() failed: %s", SDL_GetError());
-
-    /* completely fill the surface with black color pixels */
-    SDL_FillRect(surface_black, NULL,
-		 SDL_MapRGB(surface_screen->format, 0, 0, 0));
-
-    initialization_needed = FALSE;
-  }
 
   /* copy source and target surfaces to temporary surfaces for fading */
   if (fade_mode & FADE_TYPE_TRANSFORM)
   {
     SDL_BlitSurface(surface_cross,  &src_rect, surface_source, &src_rect);
     SDL_BlitSurface(surface_screen, &dst_rect, surface_target, &src_rect);
+
+    draw_global_border_function(DRAW_BORDER_TO_FADE_SOURCE);
+    draw_global_border_function(DRAW_BORDER_TO_FADE_TARGET);
   }
   else if (fade_mode & FADE_TYPE_FADE_IN)
   {
     SDL_BlitSurface(surface_black,  &src_rect, surface_source, &src_rect);
     SDL_BlitSurface(surface_screen, &dst_rect, surface_target, &src_rect);
+
+    draw_global_border_function(DRAW_BORDER_TO_FADE_TARGET);
   }
   else		/* FADE_TYPE_FADE_OUT */
   {
     SDL_BlitSurface(surface_screen, &dst_rect, surface_source, &src_rect);
     SDL_BlitSurface(surface_black,  &src_rect, surface_target, &src_rect);
+
+    draw_global_border_function(DRAW_BORDER_TO_FADE_SOURCE);
   }
 
   time_current = SDL_GetTicks();
@@ -838,17 +1287,69 @@ void SDLFadeRectangle(Bitmap *bitmap_cross, int x, int y, int width, int height,
 	if (draw_border_function != NULL)
 	  draw_border_function();
 
-#if defined(TARGET_SDL2)
-	// SDL_UpdateWindowSurface(sdl_window);
-	// SDL_UpdateWindowSurfaceRects(sdl_window, &dst_rect2, 1);
 	UpdateScreen(&dst_rect2);
+      }
+    }
+  }
+  else if (fade_mode == FADE_MODE_CURTAIN)
+  {
+    float xx;
+    int xx_final;
+    int xx_size = width / 2;
+
+    SDL_BlitSurface(surface_target, &src_rect, surface_screen, &dst_rect);
+#if defined(TARGET_SDL2)
+    SDL_SetSurfaceBlendMode(surface_source, SDL_BLENDMODE_NONE);
 #else
-	SDL_UpdateRect(surface_screen, dst_x, dst_y, width, height);
+    SDL_SetAlpha(surface_source, 0, 0);		/* disable alpha blending */
 #endif
+
+    for (xx = 0; xx < xx_size;)
+    {
+      time_last = time_current;
+      time_current = SDL_GetTicks();
+      xx += xx_size * ((float)(time_current - time_last) / fade_delay);
+      xx_final = MIN(MAX(0, xx), xx_size);
+
+      src_rect.x = src_x;
+      src_rect.y = src_y;
+      src_rect.w = width;
+      src_rect.h = height;
+
+      dst_rect.x = dst_x;
+      dst_rect.y = dst_y;
+
+      /* draw new (target) image to screen buffer */
+      SDL_BlitSurface(surface_target, &src_rect, surface_screen, &dst_rect);
+
+      if (xx_final < xx_size)
+      {
+	src_rect.w = xx_size - xx_final;
+	src_rect.h = height;
+
+	/* draw old (source) image to screen buffer (left side) */
+
+	src_rect.x = src_x + xx_final;
+	dst_rect.x = dst_x;
+
+	SDL_BlitSurface(surface_source, &src_rect, surface_screen, &dst_rect);
+
+	/* draw old (source) image to screen buffer (right side) */
+
+	src_rect.x = src_x + xx_size;
+	dst_rect.x = dst_x + xx_size + xx_final;
+
+	SDL_BlitSurface(surface_source, &src_rect, surface_screen, &dst_rect);
       }
+
+      if (draw_border_function != NULL)
+	draw_border_function();
+
+      /* only update the region of the screen that is affected from fading */
+      UpdateScreen(&dst_rect2);
     }
   }
-  else
+  else		/* fading in, fading out or cross-fading */
   {
     float alpha;
     int alpha_final;
@@ -875,22 +1376,32 @@ void SDLFadeRectangle(Bitmap *bitmap_cross, int x, int y, int width, int height,
       if (draw_border_function != NULL)
 	draw_border_function();
 
-#if 1
       /* only update the region of the screen that is affected from fading */
-#if defined(TARGET_SDL2)
-      // SDL_UpdateWindowSurface(sdl_window);
-      // SDL_UpdateWindowSurfaceRects(sdl_window, &dst_rect, 1);
       UpdateScreen(&dst_rect);
-#else
-      SDL_UpdateRect(surface_screen, dst_x, dst_y, width, height);
-#endif
-#else
-      SDL_Flip(surface_screen);
-#endif
     }
   }
 
-  Delay(post_delay);
+  if (post_delay > 0)
+  {
+    unsigned int time_post_delay;
+
+    time_current = SDL_GetTicks();
+    time_post_delay = time_current + post_delay;
+
+    while (time_current < time_post_delay)
+    {
+      // do not wait longer than 10 ms at a time to be able to ...
+      Delay(MIN(10, time_post_delay - time_current));
+
+      // ... continue drawing global animations during post delay
+      UpdateScreen(NULL);
+
+      time_current = SDL_GetTicks();
+    }
+  }
+
+  // restore function for drawing global masked border
+  gfx.draw_global_border_function = draw_global_border_function;
 }
 
 void SDLDrawSimpleLine(Bitmap *dst_bitmap, int from_x, int from_y,
@@ -933,7 +1444,7 @@ void SDLDrawLine(Bitmap *dst_bitmap, int from_x, int from_y,
   sge_Line(dst_bitmap->surface, from_x, from_y, to_x, to_y, color);
 }
 
-#if 0
+#if ENABLE_UNUSED_CODE
 void SDLDrawLines(SDL_Surface *surface, struct XY *points,
 		  int num_points, Uint32 color)
 {
@@ -1018,7 +1529,7 @@ Pixel SDLGetPixel(Bitmap *src_bitmap, int x, int y)
 
 /* ========================================================================= */
 /* The following functions were taken from the SGE library                   */
-/* (SDL Graphics Extension Library) by Anders Lindström                      */
+/* (SDL Graphics Extension Library) by Anders Lindström                      */
 /* http://www.etek.chalmers.se/~e8cal1/sge/index.html                        */
 /* ========================================================================= */
 
@@ -1541,17 +2052,11 @@ int zoomSurfaceRGBA_scaleDownBy2(SDL_Surface *src, SDL_Surface *dst)
 {
   int x, y;
   tColorRGBA *sp, *csp, *dp;
-#if 0
-  int sgap;
-#endif
   int dgap;
 
   /* pointer setup */
   sp = csp = (tColorRGBA *) src->pixels;
   dp = (tColorRGBA *) dst->pixels;
-#if 0
-  sgap = src->pitch - src->w * 4;
-#endif
   dgap = dst->pitch - dst->w * 4;
 
   for (y = 0; y < dst->h; y++)
@@ -1596,11 +2101,9 @@ int zoomSurfaceRGBA_scaleDownBy2(SDL_Surface *src, SDL_Surface *dst)
 
 int zoomSurfaceRGBA(SDL_Surface *src, SDL_Surface *dst)
 {
-  int x, y, sx, sy, *sax, *say, *csax, *csay, csx, csy;
-  tColorRGBA *sp, *csp, *dp;
-#if 0
-  int sgap;
-#endif
+  int x, y, *sax, *say, *csax, *csay;
+  float sx, sy;
+  tColorRGBA *sp, *csp, *csp0, *dp;
   int dgap;
 
   /* use specialized zoom function when scaling down to exactly half size */
@@ -1609,40 +2112,23 @@ int zoomSurfaceRGBA(SDL_Surface *src, SDL_Surface *dst)
     return zoomSurfaceRGBA_scaleDownBy2(src, dst);
 
   /* variable setup */
-  sx = (int) (65536.0 * (float) src->w / (float) dst->w);
-  sy = (int) (65536.0 * (float) src->h / (float) dst->h);
+  sx = (float) src->w / (float) dst->w;
+  sy = (float) src->h / (float) dst->h;
 
   /* allocate memory for row increments */
-  sax = (int *)checked_malloc((dst->w + 1) * sizeof(Uint32));
-  say = (int *)checked_malloc((dst->h + 1) * sizeof(Uint32));
+  csax = sax = (int *)checked_malloc((dst->w + 1) * sizeof(Uint32));
+  csay = say = (int *)checked_malloc((dst->h + 1) * sizeof(Uint32));
 
   /* precalculate row increments */
-  csx = 0;
-  csax = sax;
   for (x = 0; x <= dst->w; x++)
-  {
-    *csax = csx;
-    csax++;
-    csx &= 0xffff;
-    csx += sx;
-  }
+    *csax++ = (int)(sx * x);
 
-  csy = 0;
-  csay = say;
   for (y = 0; y <= dst->h; y++)
-  {
-    *csay = csy;
-    csay++;
-    csy &= 0xffff;
-    csy += sy;
-  }
+    *csay++ = (int)(sy * y);
 
   /* pointer setup */
-  sp = csp = (tColorRGBA *) src->pixels;
+  sp = csp = csp0 = (tColorRGBA *) src->pixels;
   dp = (tColorRGBA *) dst->pixels;
-#if 0
-  sgap = src->pitch - src->w * 4;
-#endif
   dgap = dst->pitch - dst->w * 4;
 
   csay = say;
@@ -1658,7 +2144,7 @@ int zoomSurfaceRGBA(SDL_Surface *src, SDL_Surface *dst)
 
       /* advance source pointers */
       csax++;
-      sp += (*csax >> 16);
+      sp = csp + *csax;
 
       /* advance destination pointer */
       dp++;
@@ -1666,7 +2152,7 @@ int zoomSurfaceRGBA(SDL_Surface *src, SDL_Surface *dst)
 
     /* advance source pointer */
     csay++;
-    csp = (tColorRGBA *) ((Uint8 *) csp + (*csay >> 16) * src->pitch);
+    csp = (tColorRGBA *) ((Uint8 *) csp0 + *csay * src->pitch);
 
     /* advance destination pointers */
     dp = (tColorRGBA *) ((Uint8 *) dp + dgap);
@@ -1808,7 +2294,7 @@ SDL_Surface *zoomSurface(SDL_Surface *src, int dst_width, int dst_height)
   else
   {
     /* new source surface is 32 bit with a defined RGB ordering */
-    zoom_src = SDL_CreateRGBSurface(SDL_SWSURFACE, src->w, src->h, 32,
+    zoom_src = SDL_CreateRGBSurface(SURFACE_FLAGS, src->w, src->h, 32,
 				    0x000000ff, 0x0000ff00, 0x00ff0000, 0);
     SDL_BlitSurface(src, NULL, zoom_src, NULL);
     is_32bit = TRUE;
@@ -1819,7 +2305,7 @@ SDL_Surface *zoomSurface(SDL_Surface *src, int dst_width, int dst_height)
   if (is_32bit)
   {
     /* target surface is 32 bit with source RGBA/ABGR ordering */
-    zoom_dst = SDL_CreateRGBSurface(SDL_SWSURFACE, dst_width, dst_height, 32,
+    zoom_dst = SDL_CreateRGBSurface(SURFACE_FLAGS, dst_width, dst_height, 32,
 				    zoom_src->format->Rmask,
 				    zoom_src->format->Gmask,
 				    zoom_src->format->Bmask, 0);
@@ -1827,7 +2313,7 @@ SDL_Surface *zoomSurface(SDL_Surface *src, int dst_width, int dst_height)
   else
   {
     /* target surface is 8 bit */
-    zoom_dst = SDL_CreateRGBSurface(SDL_SWSURFACE, dst_width, dst_height, 8,
+    zoom_dst = SDL_CreateRGBSurface(SURFACE_FLAGS, dst_width, dst_height, 8,
 				    0, 0, 0, 0);
   }
 
@@ -1863,23 +2349,24 @@ SDL_Surface *zoomSurface(SDL_Surface *src, int dst_width, int dst_height)
   return zoom_dst;
 }
 
-void SDLZoomBitmap(Bitmap *src_bitmap, Bitmap *dst_bitmap)
+Bitmap *SDLZoomBitmap(Bitmap *src_bitmap, int dst_width, int dst_height)
 {
-  SDL_Surface *sdl_surface_tmp;
-  int dst_width = dst_bitmap->width;
-  int dst_height = dst_bitmap->height;
+  Bitmap *dst_bitmap = CreateBitmapStruct();
+  SDL_Surface **dst_surface = &dst_bitmap->surface;
 
-  /* throw away old destination surface */
-  SDL_FreeSurface(dst_bitmap->surface);
+  dst_width  = MAX(1, dst_width);	/* prevent zero bitmap width */
+  dst_height = MAX(1, dst_height);	/* prevent zero bitmap height */
+
+  dst_bitmap->width  = dst_width;
+  dst_bitmap->height = dst_height;
 
   /* create zoomed temporary surface from source surface */
-  sdl_surface_tmp = zoomSurface(src_bitmap->surface, dst_width, dst_height);
+  *dst_surface = zoomSurface(src_bitmap->surface, dst_width, dst_height);
 
   /* create native format destination surface from zoomed temporary surface */
-  dst_bitmap->surface = SDL_DisplayFormat(sdl_surface_tmp);
+  SDLSetNativeSurface(dst_surface);
 
-  /* free temporary surface */
-  SDL_FreeSurface(sdl_surface_tmp);
+  return dst_bitmap;
 }
 
 
@@ -1909,7 +2396,7 @@ Bitmap *SDLLoadImage(char *filename)
   UPDATE_BUSY_STATE();
 
   /* create native non-transparent surface for current image */
-  if ((new_bitmap->surface = SDL_DisplayFormat(sdl_image_tmp)) == NULL)
+  if ((new_bitmap->surface = SDLGetNativeSurface(sdl_image_tmp)) == NULL)
   {
     SetError("SDL_DisplayFormat(): %s", SDL_GetError());
 
@@ -1921,9 +2408,11 @@ Bitmap *SDLLoadImage(char *filename)
   UPDATE_BUSY_STATE();
 
   /* create native transparent surface for current image */
-  SDL_SetColorKey(sdl_image_tmp, SET_TRANSPARENT_PIXEL,
-		  SDL_MapRGB(sdl_image_tmp->format, 0x00, 0x00, 0x00));
-  if ((new_bitmap->surface_masked = SDL_DisplayFormat(sdl_image_tmp)) == NULL)
+  if (sdl_image_tmp->format->Amask == 0)
+    SDL_SetColorKey(sdl_image_tmp, SET_TRANSPARENT_PIXEL,
+		    SDL_MapRGB(sdl_image_tmp->format, 0x00, 0x00, 0x00));
+
+  if ((new_bitmap->surface_masked = SDLGetNativeSurface(sdl_image_tmp)) == NULL)
   {
     SetError("SDL_DisplayFormat(): %s", SDL_GetError());
 
@@ -2066,13 +2555,24 @@ void SDLNextEvent(Event *event)
 
 void SDLHandleWindowManagerEvent(Event *event)
 {
+#ifdef DEBUG
 #if defined(PLATFORM_WIN32)
+  // experimental drag and drop code
+
   SDL_SysWMEvent *syswmevent = (SDL_SysWMEvent *)event;
   SDL_SysWMmsg *syswmmsg = (SDL_SysWMmsg *)(syswmevent->msg);
 
+#if defined(TARGET_SDL2)
+  if (syswmmsg->msg.win.msg == WM_DROPFILES)
+#else
   if (syswmmsg->msg == WM_DROPFILES)
+#endif
   {
+#if defined(TARGET_SDL2)
+    HDROP hdrop = (HDROP)syswmmsg->msg.win.wParam;
+#else
     HDROP hdrop = (HDROP)syswmmsg->wParam;
+#endif
     int i, num_files;
 
     printf("::: SDL_SYSWMEVENT:\n");
@@ -2089,9 +2589,14 @@ void SDLHandleWindowManagerEvent(Event *event)
       printf("::: - '%s'\n", buffer);
     }
 
+#if defined(TARGET_SDL2)
+    DragFinish((HDROP)syswmmsg->msg.win.wParam);
+#else
     DragFinish((HDROP)syswmmsg->wParam);
+#endif
   }
 #endif
+#endif
 }
 
 
@@ -2230,5 +2735,3 @@ boolean SDLReadJoystick(int nr, int *x, int *y, boolean *b1, boolean *b2)
 
   return TRUE;
 }
-
-#endif /* TARGET_SDL */