Mercurial > sdl-ios-xcode
annotate docs/html/sdlglsetattribute.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 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_GL_SetAttribute</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Video" | |
| 14 HREF="video.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="SDL_GL_GetAttribute" | |
| 17 HREF="sdlglgetattribute.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_GL_SwapBuffers" | |
| 20 HREF="sdlglswapbuffers.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="REFENTRY" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
|
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31 SUMMARY="Header navigation table" |
| 0 | 32 WIDTH="100%" |
| 33 BORDER="0" | |
| 34 CELLPADDING="0" | |
| 35 CELLSPACING="0" | |
| 36 ><TR | |
| 37 ><TH | |
| 38 COLSPAN="3" | |
| 39 ALIGN="center" | |
| 40 >SDL Library Documentation</TH | |
| 41 ></TR | |
| 42 ><TR | |
| 43 ><TD | |
| 44 WIDTH="10%" | |
| 45 ALIGN="left" | |
| 46 VALIGN="bottom" | |
| 47 ><A | |
| 48 HREF="sdlglgetattribute.html" | |
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49 ACCESSKEY="P" |
| 0 | 50 >Prev</A |
| 51 ></TD | |
| 52 ><TD | |
| 53 WIDTH="80%" | |
| 54 ALIGN="center" | |
| 55 VALIGN="bottom" | |
| 56 ></TD | |
| 57 ><TD | |
| 58 WIDTH="10%" | |
| 59 ALIGN="right" | |
| 60 VALIGN="bottom" | |
| 61 ><A | |
| 62 HREF="sdlglswapbuffers.html" | |
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63 ACCESSKEY="N" |
| 0 | 64 >Next</A |
| 65 ></TD | |
| 66 ></TR | |
| 67 ></TABLE | |
| 68 ><HR | |
| 69 ALIGN="LEFT" | |
| 70 WIDTH="100%"></DIV | |
| 71 ><H1 | |
| 72 ><A | |
| 73 NAME="SDLGLSETATTRIBUTE" | |
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74 ></A |
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75 >SDL_GL_SetAttribute</H1 |
| 0 | 76 ><DIV |
| 77 CLASS="REFNAMEDIV" | |
| 78 ><A | |
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79 NAME="AEN2742" |
| 0 | 80 ></A |
| 81 ><H2 | |
| 82 >Name</H2 | |
| 83 >SDL_GL_SetAttribute -- Set a special SDL/OpenGL attribute</DIV | |
| 84 ><DIV | |
| 85 CLASS="REFSYNOPSISDIV" | |
| 86 ><A | |
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87 NAME="AEN2745" |
| 0 | 88 ></A |
| 89 ><H2 | |
| 90 >Synopsis</H2 | |
| 91 ><DIV | |
| 92 CLASS="FUNCSYNOPSIS" | |
| 93 ><A | |
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94 NAME="AEN2746" |
| 0 | 95 ></A |
| 96 ><P | |
| 97 ></P | |
| 98 ><PRE | |
| 99 CLASS="FUNCSYNOPSISINFO" | |
| 100 >#include "SDL.h"</PRE | |
| 101 ><P | |
| 102 ><CODE | |
| 103 ><CODE | |
| 104 CLASS="FUNCDEF" | |
| 105 >int <B | |
| 106 CLASS="FSFUNC" | |
| 107 >SDL_GL_SetAttribute</B | |
| 108 ></CODE | |
| 109 >(SDL_GLattr attr, int value);</CODE | |
| 110 ></P | |
| 111 ><P | |
| 112 ></P | |
| 113 ></DIV | |
| 114 ></DIV | |
| 115 ><DIV | |
| 116 CLASS="REFSECT1" | |
| 117 ><A | |
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118 NAME="AEN2752" |
| 0 | 119 ></A |
| 120 ><H2 | |
| 121 >Description</H2 | |
| 122 ><P | |
| 123 >Sets the OpenGL <A | |
| 124 HREF="sdlglattr.html" | |
| 125 >attribute</A | |
| 126 > <TT | |
| 127 CLASS="PARAMETER" | |
| 128 ><I | |
| 129 >attr</I | |
| 130 ></TT | |
| 131 > to <TT | |
| 132 CLASS="PARAMETER" | |
| 133 ><I | |
| 134 >value</I | |
| 135 ></TT | |
| 136 >. The attributes you set don't take effect until after a call to <A | |
| 137 HREF="sdlsetvideomode.html" | |
| 138 ><TT | |
| 139 CLASS="FUNCTION" | |
| 140 >SDL_SetVideoMode</TT | |
| 141 ></A | |
| 142 >. You should use <A | |
| 143 HREF="sdlglgetattribute.html" | |
| 144 ><TT | |
| 145 CLASS="FUNCTION" | |
| 146 >SDL_GL_GetAttribute</TT | |
| 147 ></A | |
| 148 > to check the values after a <TT | |
| 149 CLASS="FUNCTION" | |
| 150 >SDL_SetVideoMode</TT | |
| 151 > call.</P | |
| 152 ></DIV | |
| 153 ><DIV | |
| 154 CLASS="REFSECT1" | |
| 155 ><A | |
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156 NAME="AEN2763" |
| 0 | 157 ></A |
| 158 ><H2 | |
| 159 >Return Value</H2 | |
| 160 ><P | |
| 161 >Returns <SPAN | |
| 162 CLASS="RETURNVALUE" | |
| 163 >0</SPAN | |
| 164 > on success, or <SPAN | |
| 165 CLASS="RETURNVALUE" | |
| 166 >-1</SPAN | |
| 167 > on error.</P | |
| 168 ></DIV | |
| 169 ><DIV | |
| 170 CLASS="REFSECT1" | |
| 171 ><A | |
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172 NAME="AEN2768" |
| 0 | 173 ></A |
| 174 ><H2 | |
| 175 >Example</H2 | |
| 176 ><PRE | |
| 177 CLASS="PROGRAMLISTING" | |
| 178 >SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 ); | |
| 179 SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 ); | |
| 180 SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 ); | |
| 181 SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 ); | |
| 182 SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ); | |
| 183 if ( (screen=SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL )) == NULL ) { | |
| 184 fprintf(stderr, "Couldn't set GL mode: %s\n", SDL_GetError()); | |
| 185 SDL_Quit(); | |
| 186 return; | |
| 187 }</PRE | |
| 188 ><DIV | |
| 189 CLASS="NOTE" | |
| 190 ><BLOCKQUOTE | |
| 191 CLASS="NOTE" | |
| 192 ><P | |
| 193 ><B | |
| 194 >Note: </B | |
| 195 >The <TT | |
| 196 CLASS="LITERAL" | |
| 197 >SDL_DOUBLEBUF</TT | |
| 198 > flag is not required to enable double buffering when setting an OpenGL video mode. Double buffering is enabled or disabled using the SDL_GL_DOUBLEBUFFER attribute.</P | |
| 199 ></BLOCKQUOTE | |
| 200 ></DIV | |
| 201 ></DIV | |
| 202 ><DIV | |
| 203 CLASS="REFSECT1" | |
| 204 ><A | |
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205 NAME="AEN2774" |
| 0 | 206 ></A |
| 207 ><H2 | |
| 208 >See Also</H2 | |
| 209 ><P | |
| 210 ><A | |
| 211 HREF="sdlglgetattribute.html" | |
| 212 ><TT | |
| 213 CLASS="FUNCTION" | |
| 214 >SDL_GL_GetAttribute</TT | |
| 215 ></A | |
| 216 >, | |
| 217 <A | |
| 218 HREF="sdlglattr.html" | |
| 219 >GL Attributes</A | |
| 220 ></P | |
| 221 ></DIV | |
| 222 ><DIV | |
| 223 CLASS="NAVFOOTER" | |
| 224 ><HR | |
| 225 ALIGN="LEFT" | |
| 226 WIDTH="100%"><TABLE | |
|
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227 SUMMARY="Footer navigation table" |
| 0 | 228 WIDTH="100%" |
| 229 BORDER="0" | |
| 230 CELLPADDING="0" | |
| 231 CELLSPACING="0" | |
| 232 ><TR | |
| 233 ><TD | |
| 234 WIDTH="33%" | |
| 235 ALIGN="left" | |
| 236 VALIGN="top" | |
| 237 ><A | |
| 238 HREF="sdlglgetattribute.html" | |
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parents:
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239 ACCESSKEY="P" |
| 0 | 240 >Prev</A |
| 241 ></TD | |
| 242 ><TD | |
| 243 WIDTH="34%" | |
| 244 ALIGN="center" | |
| 245 VALIGN="top" | |
| 246 ><A | |
| 247 HREF="index.html" | |
|
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parents:
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248 ACCESSKEY="H" |
| 0 | 249 >Home</A |
| 250 ></TD | |
| 251 ><TD | |
| 252 WIDTH="33%" | |
| 253 ALIGN="right" | |
| 254 VALIGN="top" | |
| 255 ><A | |
| 256 HREF="sdlglswapbuffers.html" | |
|
803
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parents:
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257 ACCESSKEY="N" |
| 0 | 258 >Next</A |
| 259 ></TD | |
| 260 ></TR | |
| 261 ><TR | |
| 262 ><TD | |
| 263 WIDTH="33%" | |
| 264 ALIGN="left" | |
| 265 VALIGN="top" | |
| 266 >SDL_GL_GetAttribute</TD | |
| 267 ><TD | |
| 268 WIDTH="34%" | |
| 269 ALIGN="center" | |
| 270 VALIGN="top" | |
| 271 ><A | |
| 272 HREF="video.html" | |
|
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273 ACCESSKEY="U" |
| 0 | 274 >Up</A |
| 275 ></TD | |
| 276 ><TD | |
| 277 WIDTH="33%" | |
| 278 ALIGN="right" | |
| 279 VALIGN="top" | |
| 280 >SDL_GL_SwapBuffers</TD | |
| 281 ></TR | |
| 282 ></TABLE | |
| 283 ></DIV | |
| 284 ></BODY | |
| 285 ></HTML | |
| 286 > |