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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.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 11 Apr 2004 19:54:40 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>SDL_Flip</TITLE
><META
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"><LINK
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TITLE="SDL Library Documentation"
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><HR
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><H1
><A
NAME="SDLFLIP"
></A
>SDL_Flip</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1426"
></A
><H2
>Name</H2
>SDL_Flip&nbsp;--&nbsp;Swaps screen buffers</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1429"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1430"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_Flip</B
></CODE
>(SDL_Surface *screen);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1436"
></A
><H2
>Description</H2
><P
>On hardware that supports double-buffering, this function sets up a flip
and returns.  The hardware will wait for vertical retrace, and then swap
video buffers before the next video surface blit or lock will return.
On hardware that doesn't support double-buffering, this is equivalent
to calling <A
HREF="sdlupdaterect.html"
>SDL_UpdateRect</A
><TT
CLASS="PARAMETER"
><I
>(screen, 0, 0, 0, 0)</I
></TT
></P
><P
>The <TT
CLASS="LITERAL"
>SDL_DOUBLEBUF</TT
> flag must have been passed to 
<A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>,
 when
setting the video mode for this function to perform hardware flipping.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1444"
></A
><H2
>Return Value</H2
><P
>This function returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> if successful, or 
<SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if there was an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1449"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>,
<A
HREF="sdlupdaterect.html"
><TT
CLASS="FUNCTION"
>SDL_UpdateRect</TT
></A
>,
<A
HREF="sdlsurface.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
></A
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