upstream-man-pages/man2/xhtml/glXChooseFBConfig.xml

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   3 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>glXChooseFBConfig</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glXChooseFBConfig"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glXChooseFBConfig — return a list of GLX frame buffer configurations that match the specified attributes</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">GLXFBConfig * <b class="fsfunc">glXChooseFBConfig</b>(</code></td><td>Display *  </td><td><var class="pdparam">dpy</var>, </td></tr><tr><td> </td><td>int  </td><td><var class="pdparam">screen</var>, </td></tr><tr><td> </td><td>const int *  </td><td><var class="pdparam">attrib_list</var>, </td></tr><tr><td> </td><td>int *  </td><td><var class="pdparam">nelements</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>dpy</code></em></span></dt><dd><p>
   4                     Specifies the connection to the X server.
   5                 </p></dd><dt><span class="term"><em class="parameter"><code>screen</code></em></span></dt><dd><p>
   6                     Specifies the screen number.
   7                 </p></dd><dt><span class="term"><em class="parameter"><code>attrib_list</code></em></span></dt><dd><p>
   8                     Specifies a list of attribute/value pairs.
   9                     The last attribute must be <code class="constant">None</code>.
  10                 </p></dd><dt><span class="term"><em class="parameter"><code>nelements</code></em></span></dt><dd><p>
  11                     Returns the number of elements in the list returned by <code class="function">glXChooseFBConfig</code>.
  12                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  13             <code class="function">glXChooseFBConfig</code> returns GLX frame buffer configurations that match the attributes
  14             specified in <em class="parameter"><code>attrib_list</code></em>, or <code class="constant">NULL</code> if no matches are found.
  15             If <em class="parameter"><code>attrib_list</code></em> is <code class="constant">NULL</code>, then <code class="function">glXChooseFBConfig</code> returns an array of GLX
  16             frame buffer configurations that are available on the specified screen.
  17             If an error occurs, no frame buffer configurations exist on the
  18             specified screen, or if no frame buffer configurations match the
  19             specified attributes, then <code class="constant">NULL</code> is returned.
  20             Use <code class="function">XFree</code> to free the memory returned by
  21             <code class="function">glXChooseFBConfig</code>.
  22         </p><p>
  23             All attributes in <em class="parameter"><code>attrib_list</code></em>, including boolean attributes, are
  24             immediately followed by the corresponding desired value. The list is
  25             terminated with <code class="constant">None</code>. If an attribute is not specified in <em class="parameter"><code>attrib_list</code></em>,
  26             then the default value (see below) is used (and the attribute is said to be
  27             specified implicitly). For example, if <code class="constant">GLX_STEREO</code> is not specified, then
  28             it is assumed to be <code class="constant">False</code>. For some attributes, the default is
  29             <code class="constant">GLX_DONT_CARE</code>, meaning that any value is OK for this attribute, so the
  30             attribute will not be checked.
  31         </p><p>
  32             Attributes are matched in an attribute-specific manner.
  33             Some of the attributes, such as <code class="constant">GLX_LEVEL</code>, must match the specified
  34             value exactly; others, such as, <code class="constant">GLX_RED_SIZE</code> must meet or exceed the
  35             specified minimum values. If more than one GLX frame buffer configuration is found,
  36             then a list of configurations, sorted
  37             according to the ``best'' match criteria, is returned. The match
  38             criteria for each attribute and the exact sorting order is
  39             defined below.
  40         </p><p>
  41             The interpretations of the various GLX visual attributes are as follows:
  42         </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GLX_FBCONFIG_ID</code></span></dt><dd><p>
  43                     </p><p>
  44                         Must be followed by a valid XID that indicates the desired GLX frame
  45                         buffer configuration. When a <code class="constant">GLX_FBCONFIG_ID</code> is specified, all
  46                         attributes are ignored. The default value is <code class="constant">GLX_DONT_CARE</code>.
  47                     </p></dd><dt><span class="term"><code class="constant">GLX_BUFFER_SIZE</code></span></dt><dd><p>
  48                     </p><p>
  49                         Must be followed by a nonnegative integer that indicates the desired
  50                         color index buffer size.
  51                         The smallest index buffer of at least the specified size is preferred.
  52                         This attribute is ignored if <code class="constant">GLX_COLOR_INDEX_BIT</code> is not set in
  53                         <code class="constant">GLX_RENDER_TYPE</code>. The default value is 0.
  54                     </p></dd><dt><span class="term"><code class="constant">GLX_LEVEL</code></span></dt><dd><p>
  55                     </p><p>
  56                         Must be followed by an integer buffer-level specification.
  57                         This specification is honored exactly.
  58                         Buffer level 0 corresponds to the default frame buffer of the display.
  59                         Buffer level 1 is the first overlay frame buffer, level two the second
  60                         overlay frame buffer, and so on.
  61                         Negative buffer levels correspond to underlay frame buffers.
  62                         The default value is 0.
  63                     </p></dd><dt><span class="term"><code class="constant">GLX_DOUBLEBUFFER</code></span></dt><dd><p>
  64                     </p><p>
  65                         Must be followed by <code class="constant">True</code> or <code class="constant">False</code>. If
  66                         <code class="constant">True</code> is specified, then
  67                         only double-buffered frame buffer configurations are considered;
  68                         if
  69                         <code class="constant">False</code> is specified, then
  70                         only single-buffered frame buffer configurations are considered.
  71                         The default value is <code class="constant">GLX_DONT_CARE</code>.
  72                     </p></dd><dt><span class="term"><code class="constant">GLX_STEREO</code></span></dt><dd><p>
  73                     </p><p>
  74                         Must be followed by <code class="constant">True</code> or <code class="constant">False</code>. If
  75                         <code class="constant">True</code> is specified, then
  76                         only stereo frame buffer configurations are considered;
  77                         if
  78                         <code class="constant">False</code> is specified, then
  79                         only monoscopic frame buffer configurations are considered.
  80                         The default value is <code class="constant">False</code>.
  81                     </p></dd><dt><span class="term"><code class="constant">GLX_AUX_BUFFERS</code></span></dt><dd><p>
  82                     </p><p>
  83                         Must be followed by a nonnegative integer that indicates the desired
  84                         number of auxiliary buffers.
  85                         Configurations with the
  86                         smallest number of auxiliary buffers that meet or exceed
  87                         the specified number are preferred.
  88                         The default value is 0.
  89                     </p></dd><dt><span class="term"><code class="constant">GLX_RED_SIZE</code>, <code class="constant">GLX_GREEN_SIZE</code>, <code class="constant">GLX_BLUE_SIZE</code>, <code class="constant">GLX_ALPHA_SIZE</code></span></dt><dd><p>
  90                     </p><p>
  91                         Each attribute, if present, must be followed by a nonnegative minimum size
  92                         specification or <code class="constant">GLX_DONT_CARE</code>.
  93                         The largest available total RGBA color buffer size (sum of <code class="constant">GLX_RED_SIZE</code>,
  94                         <code class="constant">GLX_GREEN_SIZE</code>, <code class="constant">GLX_BLUE_SIZE</code>, and <code class="constant">GLX_ALPHA_SIZE</code>)
  95                         of at least the minimum size specified for each color component is preferred.
  96                         If the requested number of bits for a color component is 0 or
  97                         <code class="constant">GLX_DONT_CARE</code>, it is not considered. The default value for each color
  98                         component is 0.
  99                     </p></dd><dt><span class="term"><code class="constant">GLX_DEPTH_SIZE</code></span></dt><dd><p>
 100                     </p><p>
 101                         Must be followed by a nonnegative minimum size specification.
 102                         If this value is zero,
 103                         frame buffer configurations with no depth buffer are preferred.
 104                         Otherwise, the largest available depth buffer of at least the minimum size
 105                         is preferred.
 106                         The default value is 0.
 107                     </p></dd><dt><span class="term"><code class="constant">GLX_STENCIL_SIZE</code></span></dt><dd><p>
 108                     </p><p>
 109                         Must be followed by a nonnegative integer that indicates the desired
 110                         number of stencil bitplanes.
 111                         The smallest stencil buffer of at least the specified size is preferred.
 112                         If the desired value is zero,
 113                         frame buffer configurations with no stencil buffer are preferred.
 114                         The default value is 0.
 115                     </p></dd><dt><span class="term"><code class="constant">GLX_ACCUM_RED_SIZE</code></span></dt><dd><p>
 116                     </p><p>
 117                         Must be followed by a nonnegative minimum size specification.
 118                         If this value is zero,
 119                         frame buffer configurations with no red accumulation buffer are preferred.
 120                         Otherwise, the largest possible red accumulation buffer
 121                         of at least the minimum size is preferred.
 122                         The default value is 0.
 123                     </p></dd><dt><span class="term"><code class="constant">GLX_ACCUM_GREEN_SIZE</code></span></dt><dd><p>
 124                     </p><p>
 125                         Must be followed by a nonnegative minimum size specification.
 126                         If this value is zero,
 127                         frame buffer configurations with no green accumulation buffer are preferred.
 128                         Otherwise, the largest possible green accumulation buffer
 129                         of at least the minimum size is preferred.
 130                         The default value is 0.
 131                     </p></dd><dt><span class="term"><code class="constant">GLX_ACCUM_BLUE_SIZE</code></span></dt><dd><p>
 132                     </p><p>
 133                         Must be followed by a nonnegative minimum size specification.
 134                         If this value is zero,
 135                         frame buffer configurations with no blue accumulation buffer are preferred.
 136                         Otherwise, the largest possible blue accumulation buffer
 137                         of at least the minimum size is preferred.
 138                         The default value is 0.
 139                     </p></dd><dt><span class="term"><code class="constant">GLX_ACCUM_ALPHA_SIZE</code></span></dt><dd><p>
 140                     </p><p>
 141                         Must be followed by a nonnegative minimum size specification.
 142                         If this value is zero,
 143                         frame buffer configurations with no alpha accumulation buffer are preferred.
 144                         Otherwise, the largest possible alpha accumulation buffer
 145                         of at least the minimum size is preferred.
 146                         The default value is 0.
 147                     </p></dd><dt><span class="term"><code class="constant">GLX_RENDER_TYPE</code></span></dt><dd><p>
 148                     </p><p>
 149                         Must be followed by a mask indicating which OpenGL rendering modes
 150                         the frame buffer configuration must support.
 151                         Valid bits are <code class="constant">GLX_RGBA_BIT</code> and
 152                         <code class="constant">GLX_COLOR_INDEX_BIT</code>. If the mask is
 153                         set to <code class="constant">GLX_RGBA_BIT</code> | <code class="constant">GLX_COLOR_INDEX_BIT</code>,
 154                         then only frame buffer configurations that can be bound to both
 155                         RGBA contexts and color index contexts will be considered.
 156                         The default value is <code class="constant">GLX_RGBA_BIT</code>.
 157                     </p></dd><dt><span class="term"><code class="constant">GLX_DRAWABLE_TYPE</code></span></dt><dd><p>
 158                     </p><p>
 159                         Must be followed by a mask indicating which GLX drawable types
 160                         the frame buffer configuration must support. Valid bits are
 161                         <code class="constant">GLX_WINDOW_BIT</code>,
 162                         <code class="constant">GLX_PIXMAP_BIT</code>, and <code class="constant">GLX_PBUFFER_BIT</code>.
 163                         For example, if mask is set to
 164                         <code class="constant">GLX_WINDOW_BIT</code> | <code class="constant">GLX_PIXMAP_BIT</code>,
 165                         only frame buffer configurations that support both windows and GLX pixmaps
 166                         will be considered.
 167                         The default value is <code class="constant">GLX_WINDOW_BIT</code>.
 168                     </p></dd><dt><span class="term"><code class="constant">GLX_X_RENDERABLE</code></span></dt><dd><p>
 169                     </p><p>
 170                         Must be followed by <code class="constant">True</code> or <code class="constant">False</code>.
 171                         If <code class="constant">True</code> is specified, then only frame buffer configurations that
 172                         have associated X visuals (and can be used to render to Windows and/or
 173                         GLX pixmaps) will be considered.
 174                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 175                     </p></dd><dt><span class="term"><code class="constant">GLX_X_VISUAL_TYPE</code></span></dt><dd><p>
 176                     </p><p>
 177                         Must be followed by one of
 178                         <code class="constant">GLX_TRUE_COLOR</code>,
 179                         <code class="constant">GLX_DIRECT_COLOR</code>,
 180                         <code class="constant">GLX_PSEUDO_COLOR</code>,
 181                         <code class="constant">GLX_STATIC_COLOR</code>,
 182                         <code class="constant">GLX_GRAY_SCALE</code>, or
 183                         <code class="constant">GLX_STATIC_GRAY</code>, indicating the desired X visual type.
 184                         Not all frame buffer configurations have an associated X visual. If
 185                         <code class="constant">GLX_DRAWABLE_TYPE</code> is specified in <em class="parameter"><code>attrib_list</code></em> and the
 186                         mask that follows does not have <code class="constant">GLX_WINDOW_BIT</code> set,
 187                         then this value is ignored. It is also ignored if
 188                         <code class="constant">GLX_X_RENDERABLE</code> is specified as <code class="constant">False</code>.
 189                         RGBA rendering may be supported for visuals of type
 190                         <code class="constant">GLX_TRUE_COLOR</code>,
 191                         <code class="constant">GLX_DIRECT_COLOR</code>,
 192                         <code class="constant">GLX_PSEUDO_COLOR</code>,
 193                         or <code class="constant">GLX_STATIC_COLOR</code>,
 194                         but color index rendering is only supported for visuals of type
 195                         <code class="constant">GLX_PSEUDO_COLOR</code> or <code class="constant">GLX_STATIC_COLOR</code>
 196                         (i.e., single-channel visuals).
 197                         The tokens <code class="constant">GLX_GRAY_SCALE</code> and <code class="constant">GLX_STATIC_GRAY</code> will
 198                         not match current OpenGL enabled visuals, but are included for future use.
 199                         The default value for <code class="constant">GLX_X_VISUAL_TYPE</code> is <code class="constant">GLX_DONT_CARE</code>.
 200                     </p></dd><dt><span class="term"><code class="constant">GLX_CONFIG_CAVEAT</code></span></dt><dd><p>
 201                     </p><p>
 202                         Must be followed by one of
 203                         <code class="constant">GLX_NONE</code>,
 204                         <code class="constant">GLX_SLOW_CONFIG</code>,
 205                         <code class="constant">GLX_NON_CONFORMANT_CONFIG</code>.
 206                         If <code class="constant">GLX_NONE</code> is specified, then only frame buffer configurations with
 207                         no caveats will be considered; if <code class="constant">GLX_SLOW_CONFIG</code>
 208                         is specified, then only slow frame buffer configurations will be considered; if
 209                         <code class="constant">GLX_NON_CONFORMANT_CONFIG</code> is specified, then only
 210                         nonconformant frame buffer configurations will be considered.
 211                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 212                     </p></dd><dt><span class="term"><code class="constant">GLX_TRANSPARENT_TYPE</code></span></dt><dd><p>
 213                     </p><p>
 214                         Must be followed by one of
 215                         <code class="constant">GLX_NONE</code>,
 216                         <code class="constant">GLX_TRANSPARENT_RGB</code>,
 217                         <code class="constant">GLX_TRANSPARENT_INDEX</code>.
 218                         If <code class="constant">GLX_NONE</code> is specified, then only opaque
 219                         frame buffer configurations will be considered; if <code class="constant">GLX_TRANSPARENT_RGB</code>
 220                         is specified, then only transparent
 221                         frame buffer configurations that support RGBA rendering will be considered;
 222                         if <code class="constant">GLX_TRANSPARENT_INDEX</code> is specified,
 223                         then only transparent frame buffer configurations that support color
 224                         index rendering will be considered.
 225                         The default value is <code class="constant">GLX_NONE</code>.
 226                     </p></dd><dt><span class="term"><code class="constant">GLX_TRANSPARENT_INDEX_VALUE</code></span></dt><dd><p>
 227                     </p><p>
 228                         Must be followed by an integer value indicating the transparent
 229                         index value; the value must be between 0 and the maximum
 230                         frame buffer value for indices.
 231                         Only frame buffer configurations that use the
 232                         specified transparent index value will be considered.
 233                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 234                         This attribute is ignored unless <code class="constant">GLX_TRANSPARENT_TYPE</code> is
 235                         included in <em class="parameter"><code>attrib_list</code></em> and specified as <code class="constant">GLX_TRANSPARENT_INDEX</code>.
 236                     </p></dd><dt><span class="term"><code class="constant">GLX_TRANSPARENT_RED_VALUE</code></span></dt><dd><p>
 237                     </p><p>
 238                         Must be followed by an integer value indicating the transparent
 239                         red value; the value must be between 0 and the maximum
 240                         frame buffer value for red.
 241                         Only frame buffer configurations that use the
 242                         specified transparent red value will be considered.
 243                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 244                         This attribute is
 245                         ignored unless <code class="constant">GLX_TRANSPARENT_TYPE</code> is included in
 246                         <em class="parameter"><code>attrib_list</code></em> and specified as <code class="constant">GLX_TRANSPARENT_RGB</code>.
 247                     </p></dd><dt><span class="term"><code class="constant">GLX_TRANSPARENT_GREEN_VALUE</code></span></dt><dd><p>
 248                     </p><p>
 249                         Must be followed by an integer value indicating the transparent
 250                         green value; the value must be between 0 and the maximum
 251                         frame buffer value for green.
 252                         Only frame buffer configurations that use the
 253                         specified transparent green value will be considered.
 254                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 255                         This attribute is
 256                         ignored unless <code class="constant">GLX_TRANSPARENT_TYPE</code> is included in
 257                         <em class="parameter"><code>attrib_list</code></em> and specified as <code class="constant">GLX_TRANSPARENT_RGB</code>.
 258                     </p></dd><dt><span class="term"><code class="constant">GLX_TRANSPARENT_BLUE_VALUE</code></span></dt><dd><p>
 259                     </p><p>
 260                         Must be followed by an integer value indicating the transparent
 261                         blue value; the value must be between 0 and the maximum
 262                         frame buffer value for blue.
 263                         Only frame buffer configurations that use the
 264                         specified transparent blue value will be considered.
 265                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 266                         This attribute is ignored unless <code class="constant">GLX_TRANSPARENT_TYPE</code> is included in
 267                         <em class="parameter"><code>attrib_list</code></em> and specified as <code class="constant">GLX_TRANSPARENT_RGB</code>.
 268                     </p></dd><dt><span class="term"><code class="constant">GLX_TRANSPARENT_ALPHA_VALUE</code></span></dt><dd><p>
 269                     </p><p>
 270                         Must be followed by an integer value indicating the transparent
 271                         alpha value; the value must be between 0 and the maximum
 272                         frame buffer value for alpha.
 273                         Only frame buffer configurations that use the
 274                         specified transparent alpha value will be considered.
 275                         The default value is <code class="constant">GLX_DONT_CARE</code>.
 276                     </p></dd></dl></div><p>
 277             When more than one GLX frame buffer configuration matches the specified attributes,
 278             a list of matching configurations is returned. The list is sorted
 279             according to the following precedence rules, which are applied in ascending
 280             order (i.e., configurations
 281             that are considered equal by a lower numbered rule are sorted by the higher
 282             numbered rule):
 283         </p><div class="variablelist"><dl><dt><span class="term">1.</span></dt><dd><p>
 284                         By <code class="constant">GLX_CONFIG_CAVEAT</code> where the precedence is <code class="constant">GLX_NONE</code>,
 285                         <code class="constant">GLX_SLOW_CONFIG</code>, and <code class="constant">GLX_NON_CONFORMANT_CONFIG</code>.
 286                     </p></dd><dt><span class="term">2.</span></dt><dd><p>
 287                          Larger total number of RGBA color components
 288                         (<code class="constant">GLX_RED_SIZE</code>, <code class="constant">GLX_GREEN_SIZE</code>, <code class="constant">GLX_BLUE_SIZE</code>,
 289                         plus <code class="constant">GLX_ALPHA_SIZE</code>)
 290                         that have higher number of bits. If the requested number of bits in
 291                         <em class="parameter"><code>attrib_list</code></em> is zero or <code class="constant">GLX_DONT_CARE</code> for a particular color
 292                         component, then the number of bits for that component is not considered.
 293                     </p></dd><dt><span class="term">3.</span></dt><dd><p>
 294                         Smaller <code class="constant">GLX_BUFFER_SIZE</code>.
 295                     </p></dd><dt><span class="term">4.</span></dt><dd><p>
 296                         Single buffered configuration (<code class="constant">GLX_DOUBLEBUFFER</code> being
 297                         <code class="constant">False</code> precedes a double buffered one.
 298                     </p></dd><dt><span class="term">5.</span></dt><dd><p>
 299                         Smaller <code class="constant">GLX_AUX_BUFFERS</code>.
 300                     </p></dd><dt><span class="term">6.</span></dt><dd><p>
 301                         Larger <code class="constant">GLX_DEPTH_SIZE</code>.
 302                     </p></dd><dt><span class="term">7.</span></dt><dd><p>
 303                         Smaller <code class="constant">GLX_STENCIL_SIZE</code>.
 304                     </p></dd><dt><span class="term">8.</span></dt><dd><p>
 305                         Larger total number of accumulation buffer color components
 306                         (<code class="constant">GLX_ACCUM_RED_SIZE</code>, <code class="constant">GLX_ACCUM_GREEN_SIZE</code>,
 307                         <code class="constant">GLX_ACCUM_BLUE_SIZE</code>, plus <code class="constant">GLX_ACCUM_ALPHA_SIZE</code>) that have
 308                         higher number of bits. If the requested number of bits in <em class="parameter"><code>attrib_list</code></em> is
 309                         zero or <code class="constant">GLX_DONT_CARE</code> for a particular color component, then the
 310                         number of bits for that component is not considered.
 311                     </p></dd><dt><span class="term">9.</span></dt><dd><p>
 312                         By <code class="constant">GLX_X_VISUAL_TYPE</code> where the precedence order is
 313                         <code class="constant">GLX_TRUE_COLOR</code>, <code class="constant">GLX_DIRECT_COLOR</code>, <code class="constant">GLX_PSEUDO_COLOR</code>,
 314                         <code class="constant">GLX_STATIC_COLOR</code>, <code class="constant">GLX_GRAY_SCALE</code>, <code class="constant">GLX_STATIC_GRAY</code>.
 315                     </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="examples"></a><h2>Examples</h2><p>
 316         </p><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>attrib_list</code></em> =</span></dt><dd><p>
 317                         {<code class="constant">GLX_RENDER_TYPE</code>, <code class="constant">GLX_RGBA_BIT</code>,
 318                         <code class="constant">GLX_RED_SIZE</code>, 4,
 319                         <code class="constant">GLX_GREEN_SIZE</code>, 4,
 320                         <code class="constant">GLX_BLUE_SIZE</code>, 4,
 321                         <code class="constant">None</code>};
 322                     </p></dd></dl></div><p>
 323             Specifies a frame buffer configuration that supports RGBA rendering
 324             and exists in the normal frame buffer,
 325             not an overlay or underlay buffer.
 326             The returned visual supports at least four bits each of red,
 327             green, and blue,
 328             and possibly no bits of alpha.
 329             It does not support stereo display.
 330             It may or may not have one or more auxiliary color buffers,
 331             a back buffer,
 332             a depth buffer,
 333             a stencil buffer,
 334             or an accumulation buffer.
 335         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 336             <code class="function">glXChooseFBConfig</code> is available only if the GLX version is 1.3 or greater.
 337         </p><p>
 338             If the GLX version is 1.1 or 1.0, the GL version must be 1.0.
 339             If the GLX version is 1.2, then the GL version must be 1.1.
 340             If the GLX version is 1.3, then the GL version must be 1.2.
 341         </p><p>
 342             <a class="citerefentry" href="glXGetFBConfigs.xml"><span class="citerefentry"><span class="refentrytitle">glXGetFBConfigs</span></span></a> and <a class="citerefentry" href="glXGetFBConfigAttrib.xml"><span class="citerefentry"><span class="refentrytitle">glXGetFBConfigAttrib</span></span></a> can
 343             be used to implement selection algorithms other than the generic
 344             one implemented by <code class="function">glXChooseFBConfig</code>. Call <code class="function">glXChooseFBConfig</code> to retrieve all the frame buffer configurations
 345             on a particular screen or, alternatively, all the frame buffer configurations with
 346             a particular set of attributes. Next, call <a class="citerefentry" href="glXGetFBConfigAttrib.xml"><span class="citerefentry"><span class="refentrytitle">glXGetFBConfigAttrib</span></span></a>
 347             to retrieve additional attributes for the frame buffer configurations and then
 348             select between them.
 349         </p><p>
 350             GLX implementations are strongly discouraged,
 351             but not proscribed,
 352             from changing the selection algorithm used by <code class="function">glXChooseFBConfig</code>.
 353             Therefore, selections may change from release to release
 354             of the client-side library.
 355         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 356             <code class="constant">NULL</code> is returned if an undefined GLX attribute is
 357             encountered in <em class="parameter"><code>attrib_list</code></em>, if <em class="parameter"><code>screen</code></em> is invalid, or if <em class="parameter"><code>dpy</code></em> does
 358             not support the GLX extension.
 359         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 360             <a class="citerefentry" href="glXGetFBConfigAttrib.xml"><span class="citerefentry"><span class="refentrytitle">glXGetFBConfigAttrib</span></span></a>,
 361             <a class="citerefentry" href="glXGetFBConfigs.xml"><span class="citerefentry"><span class="refentrytitle">glXGetFBConfigs</span></span></a>,
 362             <a class="citerefentry" href="glXGetVisualFromFBConfig.xml"><span class="citerefentry"><span class="refentrytitle">glXGetVisualFromFBConfig</span></span></a>
 363         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 364             Copyright <span class="trademark"></span>© 1991-2006
 365             Silicon Graphics, Inc. This document is licensed under the SGI
 366             Free Software B License. For details, see
 367             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 368         </p></div></div></body></html>