From 6f3204f4481743b72bc918f4511f1afef0ac2989 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Tue, 25 Nov 2008 02:12:19 +0000
Subject: [PATCH] Fixed bug with converting colorkey surface to texture

---
 src/video/SDL_surface.c | 66 +++++++++++++++++++++++++++++++++++++++++
 src/video/SDL_video.c   |  4 +++
 2 files changed, 70 insertions(+)

diff --git a/src/video/SDL_surface.c b/src/video/SDL_surface.c
index 6102ce680..238302938 100644
--- a/src/video/SDL_surface.c
+++ b/src/video/SDL_surface.c
@@ -269,6 +269,72 @@ SDL_SetColorKey(SDL_Surface * surface, Uint32 flag, Uint32 key)
     return 0;
 }
 
+/* This is a fairly slow function to switch from colorkey to alpha */
+void
+SDL_ConvertColorkeyToAlpha(SDL_Surface *surface)
+{
+	int x, y;
+
+	if (!surface) {
+		return;
+	}
+
+	if (!(surface->map->info.flags & SDL_COPY_COLORKEY) ||
+	    !surface->format->Amask) {
+		return;
+	}
+
+	SDL_LockSurface(surface);
+
+	switch (surface->format->BytesPerPixel) {
+	case 2:
+		{
+			Uint16 *row, *spot;
+			Uint16 ckey = (Uint16)surface->map->info.colorkey;
+			Uint16 mask = (Uint16)(~surface->format->Amask);
+
+			row = (Uint16 *)surface->pixels;
+			for (y = surface->h; y--; ) {
+				spot = row;
+				for (x = surface->w; x--; ) {
+					if (*spot == ckey) {
+						*spot &= mask;
+					}
+					++spot;
+				}
+				row += surface->pitch / 2;
+			}
+		}
+		break;
+	case 3:
+		/* FIXME */
+		break;
+	case 4:
+		{
+			Uint32 *row, *spot;
+			Uint32 ckey = surface->map->info.colorkey;
+			Uint32 mask = ~surface->format->Amask;
+
+			row = (Uint32 *)surface->pixels;
+			for (y = surface->h; y--; ) {
+				spot = row;
+				for (x = surface->w; x--; ) {
+					if (*spot == ckey) {
+						*spot &= mask;
+					}
+					++spot;
+				}
+				row += surface->pitch / 4;
+			}
+		}
+		break;
+	}
+
+	SDL_UnlockSurface(surface);
+
+	SDL_SetColorKey(surface, 0, 0);
+}
+
 int
 SDL_SetSurfaceColorMod(SDL_Surface * surface, Uint8 r, Uint8 g, Uint8 b)
 {
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index 28eade9a0..b9bca0c0f 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -46,6 +46,9 @@
 #endif
 #endif /* SDL_VIDEO_OPENGL */
 
+/* From SDL_surface.c */
+extern void SDL_ConvertColorkeyToAlpha(SDL_Surface *surface);
+
 /* Available video drivers */
 static VideoBootStrap *bootstrap[] = {
 #if SDL_VIDEO_DRIVER_COCOA
@@ -1585,6 +1588,7 @@ SDL_CreateTextureFromSurface(Uint32 format, SDL_Surface * surface)
             }
             dst = SDL_ConvertSurface(surface, dst_fmt, 0);
             if (dst) {
+				SDL_ConvertColorkeyToAlpha(dst);
                 SDL_UpdateTexture(textureID, NULL, dst->pixels, dst->pitch);
                 SDL_FreeSurface(dst);
             }