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view docs/html/sdlvideomodeok.html @ 883:50f5a29c6a17
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_VideoModeOK</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_ListModes" HREF="sdllistmodes.html"><LINK REL="NEXT" TITLE="SDL_SetVideoMode" HREF="sdlsetvideomode.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdllistmodes.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlsetvideomode.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLVIDEOMODEOK" ></A >SDL_VideoModeOK</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1202" ></A ><H2 >Name</H2 >SDL_VideoModeOK -- Check to see if a particular video mode is supported.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1205" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1206" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_VideoModeOK</B ></CODE >(int width, int height, int bpp, Uint32 flags);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1212" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_VideoModeOK</TT > returns <SPAN CLASS="RETURNVALUE" >0</SPAN > if the requested mode is not supported under any bit depth, or returns the bits-per-pixel of the closest available mode with the given width, height and requested <A HREF="sdlsurface.html" >surface</A > flags (see <A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >).</P ><P >The bits-per-pixel value returned is only a suggested mode. You can usually request and bpp you want when <A HREF="sdlsetvideomode.html" >setting</A > the video mode and SDL will emulate that color depth with a shadow video surface.</P ><P >The arguments to <TT CLASS="FUNCTION" >SDL_VideoModeOK</TT > are the same ones you would pass to <A HREF="sdlsetvideomode.html" >SDL_SetVideoMode</A ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1225" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >SDL_Surface *screen; Uint32 bpp; . . . printf("Checking mode 640x480@16bpp.\n"); bpp=SDL_VideoModeOK(640, 480, 16, SDL_HWSURFACE); if(!bpp){ printf("Mode not available.\n"); exit(-1); } printf("SDL Recommends 640x480@%dbpp.\n", bpp); screen=SDL_SetVideoMode(640, 480, bpp, SDL_HWSURFACE); . .</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1228" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >, <A HREF="sdlgetvideoinfo.html" ><TT CLASS="FUNCTION" >SDL_GetVideoInfo</TT ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdllistmodes.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlsetvideomode.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_ListModes</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_SetVideoMode</TD ></TR ></TABLE ></DIV ></BODY ></HTML >