Florian Forster to sdl

in SDL 1.3 (revision 5508 from SVN), the method used to calculate the bits per pixel from a ?int format? differ between ?SDL_ListModes? (which always uses the ?SDL_BITSPERPIXEL? macro) and ?SDL_PixelFormatEnumTo- Masks? (which uses either ?SDL_BITSPERPIXEL? or ?SDL_BYTESPERPIXEL * 8?, depending on the value of ?SDL_BYTESPERPIXEL?). Because the values are later compared in ?SDL_ListModes? this may lead to some valid video modes not being returned. In my case the only mode returned by ?SDL_GetNumDisplayModes? was dismissed and NULL was returned. (This led to the calling application sticking its head in the sand.) The attached patch copies the method used within ?SDL_PixelFormatEnumTo- Masks? to ?SDL_ListModes?. This solved the problem for me though I don't fully understand the method used by ?SDL_PixelFormatEnumToMasks?.
libsdl-org · Jan 20, 2011 · e9259a1 · e9259a1
1 parent 5704341
commit e9259a1
Showing 1 changed file with 11 additions and 1 deletion.
diff --git a/src/SDL_compat.c b/src/SDL_compat.c
@@ -155,11 +155,21 @@ SDL_ListModes(const SDL_PixelFormat * format, Uint32 flags)
     modes = NULL;
     for (i = 0; i < SDL_GetNumDisplayModes(); ++i) {
         SDL_DisplayMode mode;
+        int bpp;
+
         SDL_GetDisplayMode(i, &mode);
         if (!mode.w || !mode.h) {
             return (SDL_Rect **) (-1);
         }
-        if (SDL_BITSPERPIXEL(mode.format) != format->BitsPerPixel) {
+
+        /* Copied from src/video/SDL_pixels.c:SDL_PixelFormatEnumToMasks */
+        if (SDL_BYTESPERPIXEL(mode.format) <= 2) {
+            bpp = SDL_BITSPERPIXEL(mode.format);
+        } else {
+            bpp = SDL_BYTESPERPIXEL(mode.format) * 8;
+        }
+
+        if (bpp != format->BitsPerPixel) {
             continue;
         }
         if (nmodes > 0 && modes[nmodes - 1]->w == mode.w