upstream-man-pages/man2/glXGetFBConfigAttrib.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="glXGetFBConfigAttrib">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glXGetFBConfigAttrib</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glXGetFBConfigAttrib</refname>
  17         <refpurpose>return information about a GLX frame buffer configuration</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>int <function>glXGetFBConfigAttrib</function></funcdef>
  23                 <paramdef>Display * <parameter>dpy</parameter></paramdef>
  24                 <paramdef>GLXFBConfig <parameter>config</parameter></paramdef>
  25                 <paramdef>int <parameter>attribute</parameter></paramdef>
  26                 <paramdef>int * <parameter>value</parameter></paramdef>
  27             </funcprototype>
  28         </funcsynopsis>
  29     </refsynopsisdiv>
  30     <!-- eqn: ignoring delim $$ -->
  31     <refsect1 id="parameters"><title>Parameters</title>
  32         <variablelist>
  33         <varlistentry>
  34             <term><parameter>dpy</parameter></term>
  35             <listitem>
  36                 <para>
  37                     Specifies the connection to the X server.
  38                 </para>
  39             </listitem>
  40         </varlistentry>
  41         <varlistentry>
  42             <term><parameter>config</parameter></term>
  43             <listitem>
  44                 <para>
  45                     Specifies the GLX frame buffer configuration to be queried.
  46                 </para>
  47             </listitem>
  48         </varlistentry>
  49         <varlistentry>
  50             <term><parameter>attribute</parameter></term>
  51             <listitem>
  52                 <para>
  53                     Specifies the attribute to be returned.
  54                 </para>
  55             </listitem>
  56         </varlistentry>
  57         <varlistentry>
  58             <term><parameter>value</parameter></term>
  59             <listitem>
  60                 <para>
  61                     Returns the requested value.
  62                 </para>
  63             </listitem>
  64         </varlistentry>
  65         </variablelist>
  66     </refsect1>
  67     <refsect1 id="description"><title>Description</title>
  68         <para>
  69             <function>glXGetFBConfigAttrib</function> sets <parameter>value</parameter> to the <parameter>attribute</parameter> value of GLX drawables
  70             created with respect to <parameter>config</parameter>.
  71             <function>glXGetFBConfigAttrib</function> returns an error code if it fails for any reason.
  72             Otherwise, <constant>Success</constant> is returned.
  73         </para>
  74         <para>
  75             <parameter>attribute</parameter> is one of the following:
  76         </para>
  77         <para>
  78         </para>
  79         <variablelist>
  80             <varlistentry>
  81                 <term><constant>GLX_FBCONFIG_ID</constant></term>
  82                 <listitem>
  83                     <para>
  84                         XID of the given GLXFBConfig.
  85                     </para>
  86                 </listitem>
  87             </varlistentry>
  88             <varlistentry>
  89                 <term><constant>GLX_BUFFER_SIZE</constant></term>
  90                 <listitem>
  91                     <para>
  92                     </para>
  93                     <para>
  94                         Number of bits per color buffer.
  95                         If the frame buffer configuration supports RGBA contexts, then
  96                         <constant>GLX_BUFFER_SIZE</constant> is the sum of
  97                         <constant>GLX_RED_SIZE</constant>,
  98                         <constant>GLX_GREEN_SIZE</constant>,
  99                         <constant>GLX_BLUE_SIZE</constant>, and
 100                         <constant>GLX_ALPHA_SIZE</constant>.
 101                         If the frame buffer configuration supports only color index contexts,
 102                         <constant>GLX_BUFFER_SIZE</constant> is the size of the
 103                         color indexes.
 104                     </para>
 105                 </listitem>
 106             </varlistentry>
 107             <varlistentry>
 108                 <term><constant>GLX_LEVEL</constant></term>
 109                 <listitem>
 110                     <para>
 111                     </para>
 112                     <para>
 113                         Frame buffer level of the configuration.
 114                         Level zero is the default frame buffer.
 115                         Positive levels correspond to frame buffers that overlay the default buffer,
 116                         and negative levels correspond to frame buffers that underlie the default
 117                         buffer.
 118                     </para>
 119                 </listitem>
 120             </varlistentry>
 121             <varlistentry>
 122                 <term><constant>GLX_DOUBLEBUFFER</constant></term>
 123                 <listitem>
 124                     <para>
 125                     </para>
 126                     <para>
 127                         <constant>True</constant> if color buffers exist in front/back pairs that can be swapped,
 128                         <constant>False</constant> otherwise.
 129                     </para>
 130                 </listitem>
 131             </varlistentry>
 132             <varlistentry>
 133                 <term><constant>GLX_STEREO</constant></term>
 134                 <listitem>
 135                     <para>
 136                     </para>
 137                     <para>
 138                         <constant>True</constant> if color buffers exist in left/right pairs,
 139                         <constant>False</constant> otherwise.
 140                     </para>
 141                 </listitem>
 142             </varlistentry>
 143             <varlistentry>
 144                 <term><constant>GLX_AUX_BUFFERS</constant></term>
 145                 <listitem>
 146                     <para>
 147                     </para>
 148                     <para>
 149                         Number of auxiliary color buffers that are available.
 150                         Zero indicates that no auxiliary color buffers exist.
 151                     </para>
 152                 </listitem>
 153             </varlistentry>
 154             <varlistentry>
 155                 <term><constant>GLX_RED_SIZE</constant></term>
 156                 <listitem>
 157                     <para>
 158                     </para>
 159                     <para>
 160                         Number of bits of red stored in each color buffer.
 161                         Undefined if RGBA contexts are not supported by the frame buffer configuration.
 162                     </para>
 163                 </listitem>
 164             </varlistentry>
 165             <varlistentry>
 166                 <term><constant>GLX_GREEN_SIZE</constant></term>
 167                 <listitem>
 168                     <para>
 169                     </para>
 170                     <para>
 171                         Number of bits of green stored in each color buffer.
 172                         Undefined if RGBA contexts are not supported by the frame buffer configuration.
 173                     </para>
 174                 </listitem>
 175             </varlistentry>
 176             <varlistentry>
 177                 <term><constant>GLX_BLUE_SIZE</constant></term>
 178                 <listitem>
 179                     <para>
 180                     </para>
 181                     <para>
 182                         Number of bits of blue stored in each color buffer.
 183                         Undefined if RGBA contexts are not supported by the frame buffer configuration.
 184                     </para>
 185                 </listitem>
 186             </varlistentry>
 187             <varlistentry>
 188                 <term><constant>GLX_ALPHA_SIZE</constant></term>
 189                 <listitem>
 190                     <para>
 191                     </para>
 192                     <para>
 193                         Number of bits of alpha stored in each color buffer.
 194                         Undefined if RGBA contexts are not supported by the frame buffer configuration.
 195                     </para>
 196                 </listitem>
 197             </varlistentry>
 198             <varlistentry>
 199                 <term><constant>GLX_DEPTH_SIZE</constant></term>
 200                 <listitem>
 201                     <para>
 202                     </para>
 203                     <para>
 204                         Number of bits in the depth buffer.
 205                     </para>
 206                 </listitem>
 207             </varlistentry>
 208             <varlistentry>
 209                 <term><constant>GLX_STENCIL_SIZE</constant></term>
 210                 <listitem>
 211                     <para>
 212                     </para>
 213                     <para>
 214                         Number of bits in the stencil buffer.
 215                     </para>
 216                 </listitem>
 217             </varlistentry>
 218             <varlistentry>
 219                 <term><constant>GLX_ACCUM_RED_SIZE</constant></term>
 220                 <listitem>
 221                     <para>
 222                     </para>
 223                     <para>
 224                         Number of bits of red stored in the accumulation buffer.
 225                     </para>
 226                 </listitem>
 227             </varlistentry>
 228             <varlistentry>
 229                 <term><constant>GLX_ACCUM_GREEN_SIZE</constant></term>
 230                 <listitem>
 231                     <para>
 232                     </para>
 233                     <para>
 234                         Number of bits of green stored in the accumulation buffer.
 235                     </para>
 236                 </listitem>
 237             </varlistentry>
 238             <varlistentry>
 239                 <term><constant>GLX_ACCUM_BLUE_SIZE</constant></term>
 240                 <listitem>
 241                     <para>
 242                     </para>
 243                     <para>
 244                         Number of bits of blue stored in the accumulation buffer.
 245                     </para>
 246                 </listitem>
 247             </varlistentry>
 248             <varlistentry>
 249                 <term><constant>GLX_ACCUM_ALPHA_SIZE</constant></term>
 250                 <listitem>
 251                     <para>
 252                     </para>
 253                     <para>
 254                         Number of bits of alpha stored in the accumulation buffer.
 255                     </para>
 256                 </listitem>
 257             </varlistentry>
 258             <varlistentry>
 259                 <term><constant>GLX_RENDER_TYPE</constant></term>
 260                 <listitem>
 261                     <para>
 262                     </para>
 263                     <para>
 264                         Mask indicating what type of GLX contexts can be made
 265                         current to the frame buffer configuration. Valid bits are
 266                         <constant>GLX_RGBA_BIT</constant> and
 267                         <constant>GLX_COLOR_INDEX_BIT</constant>.
 268                     </para>
 269                 </listitem>
 270             </varlistentry>
 271             <varlistentry>
 272                 <term><constant>GLX_DRAWABLE_TYPE</constant></term>
 273                 <listitem>
 274                     <para>
 275                     </para>
 276                     <para>
 277                         Mask indicating what drawable types the frame buffer configuration
 278                         supports. Valid bits are <constant>GLX_WINDOW_BIT</constant>,
 279                         <constant>GLX_PIXMAP_BIT</constant>, and <constant>GLX_PBUFFER_BIT</constant>.
 280                     </para>
 281                 </listitem>
 282             </varlistentry>
 283             <varlistentry>
 284                 <term><constant>GLX_X_RENDERABLE</constant></term>
 285                 <listitem>
 286                     <para>
 287                     </para>
 288                     <para>
 289                         <constant>True</constant> if drawables created with the
 290                         frame buffer configuration can be rendered to by X.
 291                     </para>
 292                 </listitem>
 293             </varlistentry>
 294             <varlistentry>
 295                 <term><constant>GLX_VISUAL_ID</constant></term>
 296                 <listitem>
 297                     <para>
 298                     </para>
 299                     <para>
 300                         XID of the corresponding visual, or zero
 301                         if there is no associated visual (i.e., if
 302                         <constant>GLX_X_RENDERABLE</constant> is <constant>False</constant> or
 303                         <constant>GLX_DRAWABLE_TYPE</constant> does not have the
 304                         <constant>GLX_WINDOW_BIT</constant> bit set).
 305                     </para>
 306                 </listitem>
 307             </varlistentry>
 308             <varlistentry>
 309                 <term><constant>GLX_X_VISUAL_TYPE</constant></term>
 310                 <listitem>
 311                     <para>
 312                     </para>
 313                     <para>
 314                         Visual type of associated visual. The returned value will be one of:
 315                         <constant>GLX_TRUE_COLOR</constant>, <constant>GLX_DIRECT_COLOR</constant>, <constant>GLX_PSEUDO_COLOR</constant>,
 316                         <constant>GLX_STATIC_COLOR</constant>, <constant>GLX_GRAY_SCALE</constant>, <constant>GLX_STATIC_GRAY</constant>,
 317                         or <constant>GLX_NONE</constant>, if there is no associated visual (i.e., if
 318                         <constant>GLX_X_RENDERABLE</constant> is <constant>False</constant> or
 319                         <constant>GLX_DRAWABLE_TYPE</constant> does not have the
 320                         <constant>GLX_WINDOW_BIT</constant> bit set).
 321                     </para>
 322                 </listitem>
 323             </varlistentry>
 324             <varlistentry>
 325                 <term><constant>GLX_CONFIG_CAVEAT</constant></term>
 326                 <listitem>
 327                     <para>
 328                     </para>
 329                     <para>
 330                         One of <constant>GLX_NONE</constant>,
 331                         <constant>GLX_SLOW_CONFIG</constant>, or
 332                         <constant>GLX_NON_CONFORMANT_CONFIG</constant>, indicating
 333                         that the frame buffer configuration has no caveats,
 334                         some aspect of the frame buffer configuration runs slower
 335                         than other frame buffer configurations, or some aspect of the
 336                         frame buffer configuration is nonconformant, respectively.
 337                     </para>
 338                 </listitem>
 339             </varlistentry>
 340             <varlistentry>
 341                 <term><constant>GLX_TRANSPARENT_TYPE</constant></term>
 342                 <listitem>
 343                     <para>
 344                     </para>
 345                     <para>
 346                         One of <constant>GLX_NONE</constant>,
 347                         <constant>GLX_TRANSPARENT_RGB</constant>,
 348                         <constant>GLX_TRANSPARENT_INDEX</constant>, indicating that
 349                         the frame buffer configuration is opaque, is transparent for particular
 350                         values of red, green, and blue, or is transparent for
 351                         particular index values, respectively.
 352                     </para>
 353                 </listitem>
 354             </varlistentry>
 355             <varlistentry>
 356                 <term><constant>GLX_TRANSPARENT_INDEX_VALUE</constant></term>
 357                 <listitem>
 358                     <para>
 359                     </para>
 360                     <para>
 361                         Integer value between 0 and the maximum
 362                         frame buffer value for indices, indicating the transparent
 363                         index value for the frame buffer configuration.
 364                         Undefined if <constant>GLX_TRANSPARENT_TYPE</constant>
 365                         is not <constant>GLX_TRANSPARENT_INDEX</constant>.
 366                     </para>
 367                 </listitem>
 368             </varlistentry>
 369             <varlistentry>
 370                 <term><constant>GLX_TRANSPARENT_RED_VALUE</constant></term>
 371                 <listitem>
 372                     <para>
 373                     </para>
 374                     <para>
 375                         Integer value between 0 and the maximum
 376                         frame buffer value for red, indicating the transparent
 377                         red value for the frame buffer configuration.
 378                         Undefined if <constant>GLX_TRANSPARENT_TYPE</constant>
 379                         is not <constant>GLX_TRANSPARENT_RGB</constant>.
 380                     </para>
 381                 </listitem>
 382             </varlistentry>
 383             <varlistentry>
 384                 <term><constant>GLX_TRANSPARENT_GREEN_VALUE</constant></term>
 385                 <listitem>
 386                     <para>
 387                     </para>
 388                     <para>
 389                         Integer value between 0 and the maximum
 390                         frame buffer value for green, indicating the transparent
 391                         green value for the frame buffer configuration.
 392                         Undefined if <constant>GLX_TRANSPARENT_TYPE</constant>
 393                         is not <constant>GLX_TRANSPARENT_RGB</constant>.
 394                     </para>
 395                 </listitem>
 396             </varlistentry>
 397             <varlistentry>
 398                 <term><constant>GLX_TRANSPARENT_BLUE_VALUE</constant></term>
 399                 <listitem>
 400                     <para>
 401                     </para>
 402                     <para>
 403                         Integer value between 0 and the maximum
 404                         frame buffer value for blue, indicating the transparent
 405                         blue value for the frame buffer configuration.
 406                         Undefined if <constant>GLX_TRANSPARENT_TYPE</constant>
 407                         is not <constant>GLX_TRANSPARENT_RGB</constant>.
 408                     </para>
 409                 </listitem>
 410             </varlistentry>
 411             <varlistentry>
 412                 <term><constant>GLX_TRANSPARENT_ALPHA_VALUE</constant></term>
 413                 <listitem>
 414                     <para>
 415                     </para>
 416                     <para>
 417                         Integer value between 0 and the maximum
 418                         frame buffer value for alpha, indicating the transparent
 419                         blue value for the frame buffer configuration.
 420                         Undefined if <constant>GLX_TRANSPARENT_TYPE</constant>
 421                         is not <constant>GLX_TRANSPARENT_RGB</constant>.
 422                     </para>
 423                 </listitem>
 424             </varlistentry>
 425             <varlistentry>
 426                 <term><constant>GLX_MAX_PBUFFER_WIDTH</constant></term>
 427                 <listitem>
 428                     <para>
 429                     </para>
 430                     <para>
 431                         The maximum width that can be specified to
 432                         <citerefentry><refentrytitle>glXCreatePbuffer</refentrytitle></citerefentry>.
 433                     </para>
 434                 </listitem>
 435             </varlistentry>
 436             <varlistentry>
 437                 <term><constant>GLX_MAX_PBUFFER_HEIGHT</constant></term>
 438                 <listitem>
 439                     <para>
 440                     </para>
 441                     <para>
 442                         The maximum height that can be specified to
 443                         <citerefentry><refentrytitle>glXCreatePbuffer</refentrytitle></citerefentry>.
 444                     </para>
 445                 </listitem>
 446             </varlistentry>
 447             <varlistentry>
 448                 <term><constant>GLX_MAX_PBUFFER_PIXELS</constant></term>
 449                 <listitem>
 450                     <para>
 451                     </para>
 452                     <para>
 453                         The maximum number of pixels (width times height) for a
 454                         pixel buffer. Note that this value may be less than
 455                         <constant>GLX_MAX_PBUFFER_WIDTH</constant> times
 456                         <constant>GLX_MAX_PBUFFER_HEIGHT</constant>. Also, this
 457                         value is static and assumes that no other pixel buffers
 458                         or X resources are contending for the frame buffer memory.
 459                         As a result, it may not be possible to allocate a pixel buffer of
 460                         the size given by <constant>GLX_MAX_PBUFFER_PIXELS</constant>.
 461                     </para>
 462                 </listitem>
 463             </varlistentry>
 464         </variablelist>
 465         <para>
 466             Applications should choose the frame buffer configuration that most closely
 467             meets their requirements.
 468             Creating windows, GLX pixmaps, or GLX pixel buffers with unnecessary buffers
 469             can result in
 470             reduced rendering performance as well as poor resource allocation.
 471         </para>
 472     </refsect1>
 473     <refsect1 id="notes"><title>Notes</title>
 474         <para>
 475             <function>glXGetFBConfigAttrib</function> is available only if the GLX version is 1.3 or greater.
 476         </para>
 477         <para>
 478             If the GLX version is 1.1 or 1.0, the GL version must be 1.0.
 479             If the GLX version is 1.2, then the GL version must be 1.1.
 480             If the GLX version is 1.3, then the GL version must be 1.2.
 481         </para>
 482     </refsect1>
 483     <refsect1 id="errors"><title>Errors</title>
 484         <para>
 485             <constant>GLX_NO_EXTENSION</constant> is returned if <parameter>dpy</parameter> does not support the GLX
 486             extension.
 487             <constant>GLX_BAD_ATTRIBUTE</constant> is returned if <parameter>attribute</parameter> is not a valid GLX attribute.
 488         </para>
 489     </refsect1>
 490     <refsect1 id="seealso"><title>See Also</title>
 491         <para>
 492             <citerefentry><refentrytitle>glXGetFBConfigs</refentrytitle></citerefentry>,
 493             <citerefentry><refentrytitle>glXChooseFBConfig</refentrytitle></citerefentry>,
 494             <citerefentry><refentrytitle>glXGetVisualFromFBConfig</refentrytitle></citerefentry>,
 495             <citerefentry><refentrytitle>glXGetConfig</refentrytitle></citerefentry>
 496         </para>
 497     </refsect1>
 498     <refsect1 id="Copyright"><title>Copyright</title>
 499         <para>
 500             Copyright <trademark class="copyright"></trademark> 1991-2006
 501             Silicon Graphics, Inc. This document is licensed under the SGI
 502             Free Software B License. For details, see
 503             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 504         </para>
 505     </refsect1>
 506 </refentry>