From 3e3b2e2cbfb978e4a18276ddfe872eed61dc1d95 Mon Sep 17 00:00:00 2001
From: Holger Schemel <info@artsoft.org>
Date: Wed, 29 Jun 2016 20:32:20 +0200
Subject: [PATCH] changed zooming bitmaps to use masked surface for zooming

---
 src/libgame/sdl.c    | 30 ++++++++++++++++++++++++++++--
 src/libgame/system.c | 25 +------------------------
 2 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/src/libgame/sdl.c b/src/libgame/sdl.c
index 30ca1794..0e8945d5 100644
--- a/src/libgame/sdl.c
+++ b/src/libgame/sdl.c
@@ -2178,10 +2178,28 @@ SDL_Surface *zoomSurface(SDL_Surface *src, int dst_width, int dst_height)
   return zoom_dst;
 }
 
+static void SetOpaqueBitmapSurface(Bitmap *bitmap)
+{
+  if (bitmap == NULL)
+    return;
+
+  if (bitmap->surface)
+    SDL_FreeSurface(bitmap->surface);
+
+  if ((bitmap->surface = SDLGetNativeSurface(bitmap->surface_masked)) == NULL)
+    Error(ERR_EXIT, "SDL_DisplayFormat() failed");
+
+  /* remove alpha channel from native non-transparent surface, if defined */
+  SDLSetAlpha(bitmap->surface, FALSE, 0);
+
+  /* remove transparent color from native non-transparent surface, if defined */
+  SDL_SetColorKey(bitmap->surface, UNSET_TRANSPARENT_PIXEL, 0);
+}
+
 Bitmap *SDLZoomBitmap(Bitmap *src_bitmap, int dst_width, int dst_height)
 {
   Bitmap *dst_bitmap = CreateBitmapStruct();
-  SDL_Surface **dst_surface = &dst_bitmap->surface;
+  SDL_Surface **dst_surface = &dst_bitmap->surface_masked;
 
   dst_width  = MAX(1, dst_width);	/* prevent zero bitmap width */
   dst_height = MAX(1, dst_height);	/* prevent zero bitmap height */
@@ -2190,11 +2208,19 @@ Bitmap *SDLZoomBitmap(Bitmap *src_bitmap, int dst_width, int dst_height)
   dst_bitmap->height = dst_height;
 
   /* create zoomed temporary surface from source surface */
-  *dst_surface = zoomSurface(src_bitmap->surface, dst_width, dst_height);
+  *dst_surface = zoomSurface(src_bitmap->surface_masked, dst_width, dst_height);
 
   /* create native format destination surface from zoomed temporary surface */
   SDLSetNativeSurface(dst_surface);
 
+  /* set color key for zoomed surface from source surface, if defined */
+  if (SDLHasColorKey(src_bitmap->surface_masked))
+    SDL_SetColorKey(*dst_surface, SET_TRANSPARENT_PIXEL,
+		    SDLGetColorKey(src_bitmap->surface_masked));
+
+  /* create native non-transparent surface for opaque blitting */
+  SetOpaqueBitmapSurface(dst_bitmap);
+
   return dst_bitmap;
 }
 
diff --git a/src/libgame/system.c b/src/libgame/system.c
index 0e7169f4..d8c79937 100644
--- a/src/libgame/system.c
+++ b/src/libgame/system.c
@@ -977,32 +977,9 @@ void ReloadCustomImage(Bitmap *bitmap, char *basename)
   free(new_bitmap);
 }
 
-static void SetMaskedBitmapSurface(Bitmap *bitmap)
-{
-  if (bitmap == NULL)
-    return;
-
-  SDL_Surface *surface = bitmap->surface;
-
-  if (bitmap->surface_masked)
-    SDL_FreeSurface(bitmap->surface_masked);
-
-  SDL_SetColorKey(surface, SET_TRANSPARENT_PIXEL,
-		  SDL_MapRGB(surface->format, 0x00, 0x00, 0x00));
-
-  if ((bitmap->surface_masked = SDLGetNativeSurface(surface)) == NULL)
-    Error(ERR_EXIT, "SDL_DisplayFormat() failed");
-
-  SDL_SetColorKey(surface, UNSET_TRANSPARENT_PIXEL, 0);
-}
-
 static Bitmap *ZoomBitmap(Bitmap *src_bitmap, int zoom_width, int zoom_height)
 {
-  Bitmap *dst_bitmap = SDLZoomBitmap(src_bitmap, zoom_width, zoom_height);
-
-  SetMaskedBitmapSurface(dst_bitmap);
-
-  return dst_bitmap;
+  return SDLZoomBitmap(src_bitmap, zoom_width, zoom_height);
 }
 
 void ReCreateGameTileSizeBitmap(Bitmap **bitmaps)
-- 
2.34.1