Date: Sat, 10 Apr 2004 02:25:33 -0400

From: Glenn Maynard
To: sdl@libsdl.org
Subject: [SDL] SDL_SetVideoMode() failing and not setting an error (patch)

Running an OpenGL SDL application off 1.2.7, at SDL_InitSubSystem(SDL_INIT_VIDEO) time:

Warning: Unable to initialize AAlib mouseUsing AAlib driver: Slang driver 1.0 (slang)

SDL_SetVideoMode then fails; SDL_GetError() returns "".

The installation problem is straightforward: X (the higher priority
driver) isn't running, so SDL is falling back on aalib.  However,
no error is being set when aalib fails to initialize.  This also
happens with the svgalib driver.

SDL_video.c line ~653 sets mode to NULL, since aalib didn't return an
OpenGL surface.  Line ~711 ("failed setting a video mode") returns NULL.
The attached patch sets an error.  It's a horrible, useless error
message--it should really say eg. "aalib does not support OpenGL"; this
should probably be done earlier in the individual drivers, too.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40884

src/video/SDL_video.c

@@ -661,6 +661,7 @@ SDL_Surface * SDL_SetVideoMode (int width, int height, int bpp, Uint32 flags)
 	    /* Sam - If we asked for OpenGL mode, and didn't get it, fail */
 	    if ( is_opengl && !(mode->flags & SDL_OPENGL) ) {
 		mode = NULL;
+		SDL_SetError("OpenGL not available");
 	    }
 	}
 	/*