Abstract operations on SDL_surface flags behind accessors

sc2/src/libs/graphics/sdl/sdl1_common.c

@@ -400,4 +400,57 @@ TFB_SetGamma (float gamma)
 	}
 }
 
+int
+TFB_GetSurfaceAlphaMod (SDL_Surface *surface, Uint8 *alpha)
+{
+	if (!surface || !surface->format || !alpha)
+	{
+		return -1;
+	}
+	if (surface->flags & SDL_SRCALPHA)
+	{
+		*alpha = surface->format->alpha;
+	}
+	else
+	{
+		*alpha = 255;
+	}
+	return 0;
+}
+
+int
+TFB_SetSurfaceAlphaMod (SDL_Surface *surface, Uint8 alpha)
+{
+	return SDL_SetAlpha (surface, SDL_SRCALPHA, alpha);
+}
+
+int
+TFB_DisableSurfaceAlphaMod (SDL_Surface *surface)
+{
+	return SDL_SetAlpha (surface, 0, 255);
+}
+
+int
+TFB_GetColorKey (SDL_Surface *surface, Uint32 *key)
+{
+	if (surface && surface->format && key &&
+			(surface->flags & SDL_SRCCOLORKEY))
+	{
+		*key = surface->format->colorkey;
+		return 0;
+	}
+	return -1;
+}
+
+int
+TFB_SetColorKey (SDL_Surface *surface, Uint32 key)
+{
+	return SDL_SetColorKey (surface, SDL_SRCCOLORKEY, key);
+}
+
+int
+TFB_DisableColorKey (SDL_Surface *surface)
+{
+	return SDL_SetColorKey (surface, 0, 0);
+}
 #endif

sc2/src/libs/graphics/sdl/sdl2_common.c

@@ -366,4 +366,56 @@ TFB_SetGamma (float gamma)
 	log_add (log_Warning, "Custom gamma correction is not available in the SDL2 engine.");
 }
 
+int
+TFB_GetSurfaceAlphaMod (SDL_Surface *surface, Uint8 *alpha)
+{
+	SDL_BlendMode blend_mode;
+	if (!surface || !alpha)
+	{
+		return -1;
+	}
+	if (SDL_GetSurfaceBlendMode (surface, &blend_mode) == 0)
+	{
+		return SDL_GetSurfaceAlphaMod (surface, alpha);
+	}
+	*alpha = 255;
+	return 0;
+}
+
+int
+TFB_SetSurfaceAlphaMod (SDL_Surface *surface, Uint8 alpha)
+{
+	int result = SDL_SetSurfaceBlendMode (surface, SDL_BLENDMODE_BLEND);
+	if (result == 0)
+	{
+		result = SDL_SetSurfaceAlphaMod (surface, alpha);
+	}
+	return result;
+}
+
+int
+TFB_DisableSurfaceAlphaMod (SDL_Surface *surface)
+{
+	SDL_SetSurfaceAlphaMod (surface, 255);
+	return SDL_SetSurfaceBlendMode (surface, SDL_BLENDMODE_NONE);
+}
+
+int
+TFB_GetColorKey (SDL_Surface *surface, Uint32 *key)
+{
+	return SDL_GetColorKey (surface, key);
+}
+
+int
+TFB_SetColorKey (SDL_Surface *surface, Uint32 key)
+{
+	return SDL_SetColorKey (surface, SDL_TRUE, key);
+}
+
+int
+TFB_DisableColorKey (SDL_Surface *surface)
+{
+	return SDL_SetColorKey (surface, SDL_FALSE, 0);
+}
+
 #endif

sc2/src/libs/graphics/sdl/sdl_common.h

@@ -45,5 +45,11 @@ extern SDL_Surface *SDL_Screens[TFB_GFX_NUMSCREENS];
 extern SDL_Surface *format_conv_surf;
 
 SDL_Surface* TFB_DisplayFormatAlpha (SDL_Surface *surface);
+int TFB_GetSurfaceAlphaMod (SDL_Surface *surface, Uint8 *alpha);
+int TFB_SetSurfaceAlphaMod (SDL_Surface *surface, Uint8 alpha);
+int TFB_DisableSurfaceAlphaMod (SDL_Surface *surface);
+int TFB_GetColorKey (SDL_Surface *surface, Uint32 *key);
+int TFB_SetColorKey (SDL_Surface *surface, Uint32 key);
+int TFB_DisableColorKey (SDL_Surface *surface);
 
 #endif