| 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="glXChooseFBConfig"> |
| 5 | <refmeta> |
| 6 | <refmetainfo> |
| 7 | <copyright> |
| 8 | <year>1991-2006</year> |
| 9 | <holder>Silicon Graphics, Inc.</holder> |
| 10 | </copyright> |
| 11 | </refmetainfo> |
| 12 | <refentrytitle>glXChooseFBConfig</refentrytitle> |
| 13 | <manvolnum>3G</manvolnum> |
| 14 | </refmeta> |
| 15 | <refnamediv> |
| 16 | <refname>glXChooseFBConfig</refname> |
| 17 | <refpurpose>return a list of GLX frame buffer configurations that match the specified attributes</refpurpose> |
| 18 | </refnamediv> |
| 19 | <refsynopsisdiv><title>C Specification</title> |
| 20 | <funcsynopsis> |
| 21 | <funcprototype> |
| 22 | <funcdef>GLXFBConfig * <function>glXChooseFBConfig</function></funcdef> |
| 23 | <paramdef>Display * <parameter>dpy</parameter></paramdef> |
| 24 | <paramdef>int <parameter>screen</parameter></paramdef> |
| 25 | <paramdef>const int * <parameter>attrib_list</parameter></paramdef> |
| 26 | <paramdef>int * <parameter>nelements</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>screen</parameter></term> |
| 43 | <listitem> |
| 44 | <para> |
| 45 | Specifies the screen number. |
| 46 | </para> |
| 47 | </listitem> |
| 48 | </varlistentry> |
| 49 | <varlistentry> |
| 50 | <term><parameter>attrib_list</parameter></term> |
| 51 | <listitem> |
| 52 | <para> |
| 53 | Specifies a list of attribute/value pairs. |
| 54 | The last attribute must be <constant>None</constant>. |
| 55 | </para> |
| 56 | </listitem> |
| 57 | </varlistentry> |
| 58 | <varlistentry> |
| 59 | <term><parameter>nelements</parameter></term> |
| 60 | <listitem> |
| 61 | <para> |
| 62 | Returns the number of elements in the list returned by <function>glXChooseFBConfig</function>. |
| 63 | </para> |
| 64 | </listitem> |
| 65 | </varlistentry> |
| 66 | </variablelist> |
| 67 | </refsect1> |
| 68 | <refsect1 id="description"><title>Description</title> |
| 69 | <para> |
| 70 | <function>glXChooseFBConfig</function> returns GLX frame buffer configurations that match the attributes |
| 71 | specified in <parameter>attrib_list</parameter>, or <constant>NULL</constant> if no matches are found. |
| 72 | If <parameter>attrib_list</parameter> is <constant>NULL</constant>, then <function>glXChooseFBConfig</function> returns an array of GLX |
| 73 | frame buffer configurations that are available on the specified screen. |
| 74 | If an error occurs, no frame buffer configurations exist on the |
| 75 | specified screen, or if no frame buffer configurations match the |
| 76 | specified attributes, then <constant>NULL</constant> is returned. |
| 77 | Use <function>XFree</function> to free the memory returned by |
| 78 | <function>glXChooseFBConfig</function>. |
| 79 | </para> |
| 80 | <para> |
| 81 | All attributes in <parameter>attrib_list</parameter>, including boolean attributes, are |
| 82 | immediately followed by the corresponding desired value. The list is |
| 83 | terminated with <constant>None</constant>. If an attribute is not specified in <parameter>attrib_list</parameter>, |
| 84 | then the default value (see below) is used (and the attribute is said to be |
| 85 | specified implicitly). For example, if <constant>GLX_STEREO</constant> is not specified, then |
| 86 | it is assumed to be <constant>False</constant>. For some attributes, the default is |
| 87 | <constant>GLX_DONT_CARE</constant>, meaning that any value is OK for this attribute, so the |
| 88 | attribute will not be checked. |
| 89 | </para> |
| 90 | <para> |
| 91 | Attributes are matched in an attribute-specific manner. |
| 92 | Some of the attributes, such as <constant>GLX_LEVEL</constant>, must match the specified |
| 93 | value exactly; others, such as, <constant>GLX_RED_SIZE</constant> must meet or exceed the |
| 94 | specified minimum values. If more than one GLX frame buffer configuration is found, |
| 95 | then a list of configurations, sorted |
| 96 | according to the ``best'' match criteria, is returned. The match |
| 97 | criteria for each attribute and the exact sorting order is |
| 98 | defined below. |
| 99 | </para> |
| 100 | <para> |
| 101 | The interpretations of the various GLX visual attributes are as follows: |
| 102 | </para> |
| 103 | <variablelist> |
| 104 | <varlistentry> |
| 105 | <term><constant>GLX_FBCONFIG_ID</constant></term> |
| 106 | <listitem> |
| 107 | <para> |
| 108 | </para> |
| 109 | <para> |
| 110 | Must be followed by a valid XID that indicates the desired GLX frame |
| 111 | buffer configuration. When a <constant>GLX_FBCONFIG_ID</constant> is specified, all |
| 112 | attributes are ignored. The default value is <constant>GLX_DONT_CARE</constant>. |
| 113 | </para> |
| 114 | </listitem> |
| 115 | </varlistentry> |
| 116 | <varlistentry> |
| 117 | <term><constant>GLX_BUFFER_SIZE</constant></term> |
| 118 | <listitem> |
| 119 | <para> |
| 120 | </para> |
| 121 | <para> |
| 122 | Must be followed by a nonnegative integer that indicates the desired |
| 123 | color index buffer size. |
| 124 | The smallest index buffer of at least the specified size is preferred. |
| 125 | This attribute is ignored if <constant>GLX_COLOR_INDEX_BIT</constant> is not set in |
| 126 | <constant>GLX_RENDER_TYPE</constant>. The default value is 0. |
| 127 | </para> |
| 128 | </listitem> |
| 129 | </varlistentry> |
| 130 | <varlistentry> |
| 131 | <term><constant>GLX_LEVEL</constant></term> |
| 132 | <listitem> |
| 133 | <para> |
| 134 | </para> |
| 135 | <para> |
| 136 | Must be followed by an integer buffer-level specification. |
| 137 | This specification is honored exactly. |
| 138 | Buffer level 0 corresponds to the default frame buffer of the display. |
| 139 | Buffer level 1 is the first overlay frame buffer, level two the second |
| 140 | overlay frame buffer, and so on. |
| 141 | Negative buffer levels correspond to underlay frame buffers. |
| 142 | The default value is 0. |
| 143 | </para> |
| 144 | </listitem> |
| 145 | </varlistentry> |
| 146 | <varlistentry> |
| 147 | <term><constant>GLX_DOUBLEBUFFER</constant></term> |
| 148 | <listitem> |
| 149 | <para> |
| 150 | </para> |
| 151 | <para> |
| 152 | Must be followed by <constant>True</constant> or <constant>False</constant>. If |
| 153 | <constant>True</constant> is specified, then |
| 154 | only double-buffered frame buffer configurations are considered; |
| 155 | if |
| 156 | <constant>False</constant> is specified, then |
| 157 | only single-buffered frame buffer configurations are considered. |
| 158 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 159 | </para> |
| 160 | </listitem> |
| 161 | </varlistentry> |
| 162 | <varlistentry> |
| 163 | <term><constant>GLX_STEREO</constant></term> |
| 164 | <listitem> |
| 165 | <para> |
| 166 | </para> |
| 167 | <para> |
| 168 | Must be followed by <constant>True</constant> or <constant>False</constant>. If |
| 169 | <constant>True</constant> is specified, then |
| 170 | only stereo frame buffer configurations are considered; |
| 171 | if |
| 172 | <constant>False</constant> is specified, then |
| 173 | only monoscopic frame buffer configurations are considered. |
| 174 | The default value is <constant>False</constant>. |
| 175 | </para> |
| 176 | </listitem> |
| 177 | </varlistentry> |
| 178 | <varlistentry> |
| 179 | <term><constant>GLX_AUX_BUFFERS</constant></term> |
| 180 | <listitem> |
| 181 | <para> |
| 182 | </para> |
| 183 | <para> |
| 184 | Must be followed by a nonnegative integer that indicates the desired |
| 185 | number of auxiliary buffers. |
| 186 | Configurations with the |
| 187 | smallest number of auxiliary buffers that meet or exceed |
| 188 | the specified number are preferred. |
| 189 | The default value is 0. |
| 190 | </para> |
| 191 | </listitem> |
| 192 | </varlistentry> |
| 193 | <varlistentry> |
| 194 | <term><constant>GLX_RED_SIZE</constant>, <constant>GLX_GREEN_SIZE</constant>, <constant>GLX_BLUE_SIZE</constant>, <constant>GLX_ALPHA_SIZE</constant></term> |
| 195 | <listitem> |
| 196 | <para> |
| 197 | </para> |
| 198 | <para> |
| 199 | Each attribute, if present, must be followed by a nonnegative minimum size |
| 200 | specification or <constant>GLX_DONT_CARE</constant>. |
| 201 | The largest available total RGBA color buffer size (sum of <constant>GLX_RED_SIZE</constant>, |
| 202 | <constant>GLX_GREEN_SIZE</constant>, <constant>GLX_BLUE_SIZE</constant>, and <constant>GLX_ALPHA_SIZE</constant>) |
| 203 | of at least the minimum size specified for each color component is preferred. |
| 204 | If the requested number of bits for a color component is 0 or |
| 205 | <constant>GLX_DONT_CARE</constant>, it is not considered. The default value for each color |
| 206 | component is 0. |
| 207 | </para> |
| 208 | </listitem> |
| 209 | </varlistentry> |
| 210 | <varlistentry> |
| 211 | <term><constant>GLX_DEPTH_SIZE</constant></term> |
| 212 | <listitem> |
| 213 | <para> |
| 214 | </para> |
| 215 | <para> |
| 216 | Must be followed by a nonnegative minimum size specification. |
| 217 | If this value is zero, |
| 218 | frame buffer configurations with no depth buffer are preferred. |
| 219 | Otherwise, the largest available depth buffer of at least the minimum size |
| 220 | is preferred. |
| 221 | The default value is 0. |
| 222 | </para> |
| 223 | </listitem> |
| 224 | </varlistentry> |
| 225 | <varlistentry> |
| 226 | <term><constant>GLX_STENCIL_SIZE</constant></term> |
| 227 | <listitem> |
| 228 | <para> |
| 229 | </para> |
| 230 | <para> |
| 231 | Must be followed by a nonnegative integer that indicates the desired |
| 232 | number of stencil bitplanes. |
| 233 | The smallest stencil buffer of at least the specified size is preferred. |
| 234 | If the desired value is zero, |
| 235 | frame buffer configurations with no stencil buffer are preferred. |
| 236 | The default value is 0. |
| 237 | </para> |
| 238 | </listitem> |
| 239 | </varlistentry> |
| 240 | <varlistentry> |
| 241 | <term><constant>GLX_ACCUM_RED_SIZE</constant></term> |
| 242 | <listitem> |
| 243 | <para> |
| 244 | </para> |
| 245 | <para> |
| 246 | Must be followed by a nonnegative minimum size specification. |
| 247 | If this value is zero, |
| 248 | frame buffer configurations with no red accumulation buffer are preferred. |
| 249 | Otherwise, the largest possible red accumulation buffer |
| 250 | of at least the minimum size is preferred. |
| 251 | The default value is 0. |
| 252 | </para> |
| 253 | </listitem> |
| 254 | </varlistentry> |
| 255 | <varlistentry> |
| 256 | <term><constant>GLX_ACCUM_GREEN_SIZE</constant></term> |
| 257 | <listitem> |
| 258 | <para> |
| 259 | </para> |
| 260 | <para> |
| 261 | Must be followed by a nonnegative minimum size specification. |
| 262 | If this value is zero, |
| 263 | frame buffer configurations with no green accumulation buffer are preferred. |
| 264 | Otherwise, the largest possible green accumulation buffer |
| 265 | of at least the minimum size is preferred. |
| 266 | The default value is 0. |
| 267 | </para> |
| 268 | </listitem> |
| 269 | </varlistentry> |
| 270 | <varlistentry> |
| 271 | <term><constant>GLX_ACCUM_BLUE_SIZE</constant></term> |
| 272 | <listitem> |
| 273 | <para> |
| 274 | </para> |
| 275 | <para> |
| 276 | Must be followed by a nonnegative minimum size specification. |
| 277 | If this value is zero, |
| 278 | frame buffer configurations with no blue accumulation buffer are preferred. |
| 279 | Otherwise, the largest possible blue accumulation buffer |
| 280 | of at least the minimum size is preferred. |
| 281 | The default value is 0. |
| 282 | </para> |
| 283 | </listitem> |
| 284 | </varlistentry> |
| 285 | <varlistentry> |
| 286 | <term><constant>GLX_ACCUM_ALPHA_SIZE</constant></term> |
| 287 | <listitem> |
| 288 | <para> |
| 289 | </para> |
| 290 | <para> |
| 291 | Must be followed by a nonnegative minimum size specification. |
| 292 | If this value is zero, |
| 293 | frame buffer configurations with no alpha accumulation buffer are preferred. |
| 294 | Otherwise, the largest possible alpha accumulation buffer |
| 295 | of at least the minimum size is preferred. |
| 296 | The default value is 0. |
| 297 | </para> |
| 298 | </listitem> |
| 299 | </varlistentry> |
| 300 | <varlistentry> |
| 301 | <term><constant>GLX_RENDER_TYPE</constant></term> |
| 302 | <listitem> |
| 303 | <para> |
| 304 | </para> |
| 305 | <para> |
| 306 | Must be followed by a mask indicating which OpenGL rendering modes |
| 307 | the frame buffer configuration must support. |
| 308 | Valid bits are <constant>GLX_RGBA_BIT</constant> and |
| 309 | <constant>GLX_COLOR_INDEX_BIT</constant>. If the mask is |
| 310 | set to <constant>GLX_RGBA_BIT</constant> | <constant>GLX_COLOR_INDEX_BIT</constant>, |
| 311 | then only frame buffer configurations that can be bound to both |
| 312 | RGBA contexts and color index contexts will be considered. |
| 313 | The default value is <constant>GLX_RGBA_BIT</constant>. |
| 314 | </para> |
| 315 | </listitem> |
| 316 | </varlistentry> |
| 317 | <varlistentry> |
| 318 | <term><constant>GLX_DRAWABLE_TYPE</constant></term> |
| 319 | <listitem> |
| 320 | <para> |
| 321 | </para> |
| 322 | <para> |
| 323 | Must be followed by a mask indicating which GLX drawable types |
| 324 | the frame buffer configuration must support. Valid bits are |
| 325 | <constant>GLX_WINDOW_BIT</constant>, |
| 326 | <constant>GLX_PIXMAP_BIT</constant>, and <constant>GLX_PBUFFER_BIT</constant>. |
| 327 | For example, if mask is set to |
| 328 | <constant>GLX_WINDOW_BIT</constant> | <constant>GLX_PIXMAP_BIT</constant>, |
| 329 | only frame buffer configurations that support both windows and GLX pixmaps |
| 330 | will be considered. |
| 331 | The default value is <constant>GLX_WINDOW_BIT</constant>. |
| 332 | </para> |
| 333 | </listitem> |
| 334 | </varlistentry> |
| 335 | <varlistentry> |
| 336 | <term><constant>GLX_X_RENDERABLE</constant></term> |
| 337 | <listitem> |
| 338 | <para> |
| 339 | </para> |
| 340 | <para> |
| 341 | Must be followed by <constant>True</constant> or <constant>False</constant>. |
| 342 | If <constant>True</constant> is specified, then only frame buffer configurations that |
| 343 | have associated X visuals (and can be used to render to Windows and/or |
| 344 | GLX pixmaps) will be considered. |
| 345 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 346 | </para> |
| 347 | </listitem> |
| 348 | </varlistentry> |
| 349 | <varlistentry> |
| 350 | <term><constant>GLX_X_VISUAL_TYPE</constant></term> |
| 351 | <listitem> |
| 352 | <para> |
| 353 | </para> |
| 354 | <para> |
| 355 | Must be followed by one of |
| 356 | <constant>GLX_TRUE_COLOR</constant>, |
| 357 | <constant>GLX_DIRECT_COLOR</constant>, |
| 358 | <constant>GLX_PSEUDO_COLOR</constant>, |
| 359 | <constant>GLX_STATIC_COLOR</constant>, |
| 360 | <constant>GLX_GRAY_SCALE</constant>, or |
| 361 | <constant>GLX_STATIC_GRAY</constant>, indicating the desired X visual type. |
| 362 | Not all frame buffer configurations have an associated X visual. If |
| 363 | <constant>GLX_DRAWABLE_TYPE</constant> is specified in <parameter>attrib_list</parameter> and the |
| 364 | mask that follows does not have <constant>GLX_WINDOW_BIT</constant> set, |
| 365 | then this value is ignored. It is also ignored if |
| 366 | <constant>GLX_X_RENDERABLE</constant> is specified as <constant>False</constant>. |
| 367 | RGBA rendering may be supported for visuals of type |
| 368 | <constant>GLX_TRUE_COLOR</constant>, |
| 369 | <constant>GLX_DIRECT_COLOR</constant>, |
| 370 | <constant>GLX_PSEUDO_COLOR</constant>, |
| 371 | or <constant>GLX_STATIC_COLOR</constant>, |
| 372 | but color index rendering is only supported for visuals of type |
| 373 | <constant>GLX_PSEUDO_COLOR</constant> or <constant>GLX_STATIC_COLOR</constant> |
| 374 | (i.e., single-channel visuals). |
| 375 | The tokens <constant>GLX_GRAY_SCALE</constant> and <constant>GLX_STATIC_GRAY</constant> will |
| 376 | not match current OpenGL enabled visuals, but are included for future use. |
| 377 | The default value for <constant>GLX_X_VISUAL_TYPE</constant> is <constant>GLX_DONT_CARE</constant>. |
| 378 | </para> |
| 379 | </listitem> |
| 380 | </varlistentry> |
| 381 | <varlistentry> |
| 382 | <term><constant>GLX_CONFIG_CAVEAT</constant></term> |
| 383 | <listitem> |
| 384 | <para> |
| 385 | </para> |
| 386 | <para> |
| 387 | Must be followed by one of |
| 388 | <constant>GLX_NONE</constant>, |
| 389 | <constant>GLX_SLOW_CONFIG</constant>, |
| 390 | <constant>GLX_NON_CONFORMANT_CONFIG</constant>. |
| 391 | If <constant>GLX_NONE</constant> is specified, then only frame buffer configurations with |
| 392 | no caveats will be considered; if <constant>GLX_SLOW_CONFIG</constant> |
| 393 | is specified, then only slow frame buffer configurations will be considered; if |
| 394 | <constant>GLX_NON_CONFORMANT_CONFIG</constant> is specified, then only |
| 395 | nonconformant frame buffer configurations will be considered. |
| 396 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 397 | </para> |
| 398 | </listitem> |
| 399 | </varlistentry> |
| 400 | <varlistentry> |
| 401 | <term><constant>GLX_TRANSPARENT_TYPE</constant></term> |
| 402 | <listitem> |
| 403 | <para> |
| 404 | </para> |
| 405 | <para> |
| 406 | Must be followed by one of |
| 407 | <constant>GLX_NONE</constant>, |
| 408 | <constant>GLX_TRANSPARENT_RGB</constant>, |
| 409 | <constant>GLX_TRANSPARENT_INDEX</constant>. |
| 410 | If <constant>GLX_NONE</constant> is specified, then only opaque |
| 411 | frame buffer configurations will be considered; if <constant>GLX_TRANSPARENT_RGB</constant> |
| 412 | is specified, then only transparent |
| 413 | frame buffer configurations that support RGBA rendering will be considered; |
| 414 | if <constant>GLX_TRANSPARENT_INDEX</constant> is specified, |
| 415 | then only transparent frame buffer configurations that support color |
| 416 | index rendering will be considered. |
| 417 | The default value is <constant>GLX_NONE</constant>. |
| 418 | </para> |
| 419 | </listitem> |
| 420 | </varlistentry> |
| 421 | <varlistentry> |
| 422 | <term><constant>GLX_TRANSPARENT_INDEX_VALUE</constant></term> |
| 423 | <listitem> |
| 424 | <para> |
| 425 | </para> |
| 426 | <para> |
| 427 | Must be followed by an integer value indicating the transparent |
| 428 | index value; the value must be between 0 and the maximum |
| 429 | frame buffer value for indices. |
| 430 | Only frame buffer configurations that use the |
| 431 | specified transparent index value will be considered. |
| 432 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 433 | This attribute is ignored unless <constant>GLX_TRANSPARENT_TYPE</constant> is |
| 434 | included in <parameter>attrib_list</parameter> and specified as <constant>GLX_TRANSPARENT_INDEX</constant>. |
| 435 | </para> |
| 436 | </listitem> |
| 437 | </varlistentry> |
| 438 | <varlistentry> |
| 439 | <term><constant>GLX_TRANSPARENT_RED_VALUE</constant></term> |
| 440 | <listitem> |
| 441 | <para> |
| 442 | </para> |
| 443 | <para> |
| 444 | Must be followed by an integer value indicating the transparent |
| 445 | red value; the value must be between 0 and the maximum |
| 446 | frame buffer value for red. |
| 447 | Only frame buffer configurations that use the |
| 448 | specified transparent red value will be considered. |
| 449 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 450 | This attribute is |
| 451 | ignored unless <constant>GLX_TRANSPARENT_TYPE</constant> is included in |
| 452 | <parameter>attrib_list</parameter> and specified as <constant>GLX_TRANSPARENT_RGB</constant>. |
| 453 | </para> |
| 454 | </listitem> |
| 455 | </varlistentry> |
| 456 | <varlistentry> |
| 457 | <term><constant>GLX_TRANSPARENT_GREEN_VALUE</constant></term> |
| 458 | <listitem> |
| 459 | <para> |
| 460 | </para> |
| 461 | <para> |
| 462 | Must be followed by an integer value indicating the transparent |
| 463 | green value; the value must be between 0 and the maximum |
| 464 | frame buffer value for green. |
| 465 | Only frame buffer configurations that use the |
| 466 | specified transparent green value will be considered. |
| 467 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 468 | This attribute is |
| 469 | ignored unless <constant>GLX_TRANSPARENT_TYPE</constant> is included in |
| 470 | <parameter>attrib_list</parameter> and specified as <constant>GLX_TRANSPARENT_RGB</constant>. |
| 471 | </para> |
| 472 | </listitem> |
| 473 | </varlistentry> |
| 474 | <varlistentry> |
| 475 | <term><constant>GLX_TRANSPARENT_BLUE_VALUE</constant></term> |
| 476 | <listitem> |
| 477 | <para> |
| 478 | </para> |
| 479 | <para> |
| 480 | Must be followed by an integer value indicating the transparent |
| 481 | blue value; the value must be between 0 and the maximum |
| 482 | frame buffer value for blue. |
| 483 | Only frame buffer configurations that use the |
| 484 | specified transparent blue value will be considered. |
| 485 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 486 | This attribute is ignored unless <constant>GLX_TRANSPARENT_TYPE</constant> is included in |
| 487 | <parameter>attrib_list</parameter> and specified as <constant>GLX_TRANSPARENT_RGB</constant>. |
| 488 | </para> |
| 489 | </listitem> |
| 490 | </varlistentry> |
| 491 | <varlistentry> |
| 492 | <term><constant>GLX_TRANSPARENT_ALPHA_VALUE</constant></term> |
| 493 | <listitem> |
| 494 | <para> |
| 495 | </para> |
| 496 | <para> |
| 497 | Must be followed by an integer value indicating the transparent |
| 498 | alpha value; the value must be between 0 and the maximum |
| 499 | frame buffer value for alpha. |
| 500 | Only frame buffer configurations that use the |
| 501 | specified transparent alpha value will be considered. |
| 502 | The default value is <constant>GLX_DONT_CARE</constant>. |
| 503 | </para> |
| 504 | </listitem> |
| 505 | </varlistentry> |
| 506 | </variablelist> |
| 507 | <para> |
| 508 | When more than one GLX frame buffer configuration matches the specified attributes, |
| 509 | a list of matching configurations is returned. The list is sorted |
| 510 | according to the following precedence rules, which are applied in ascending |
| 511 | order (i.e., configurations |
| 512 | that are considered equal by a lower numbered rule are sorted by the higher |
| 513 | numbered rule): |
| 514 | </para> |
| 515 | <variablelist> |
| 516 | <varlistentry> |
| 517 | <term>1.</term> |
| 518 | <listitem> |
| 519 | <para> |
| 520 | By <constant>GLX_CONFIG_CAVEAT</constant> where the precedence is <constant>GLX_NONE</constant>, |
| 521 | <constant>GLX_SLOW_CONFIG</constant>, and <constant>GLX_NON_CONFORMANT_CONFIG</constant>. |
| 522 | </para> |
| 523 | </listitem> |
| 524 | </varlistentry> |
| 525 | <varlistentry> |
| 526 | <term>2.</term> |
| 527 | <listitem> |
| 528 | <para> |
| 529 | Larger total number of RGBA color components |
| 530 | (<constant>GLX_RED_SIZE</constant>, <constant>GLX_GREEN_SIZE</constant>, <constant>GLX_BLUE_SIZE</constant>, |
| 531 | plus <constant>GLX_ALPHA_SIZE</constant>) |
| 532 | that have higher number of bits. If the requested number of bits in |
| 533 | <parameter>attrib_list</parameter> is zero or <constant>GLX_DONT_CARE</constant> for a particular color |
| 534 | component, then the number of bits for that component is not considered. |
| 535 | </para> |
| 536 | </listitem> |
| 537 | </varlistentry> |
| 538 | <varlistentry> |
| 539 | <term>3.</term> |
| 540 | <listitem> |
| 541 | <para> |
| 542 | Smaller <constant>GLX_BUFFER_SIZE</constant>. |
| 543 | </para> |
| 544 | </listitem> |
| 545 | </varlistentry> |
| 546 | <varlistentry> |
| 547 | <term>4.</term> |
| 548 | <listitem> |
| 549 | <para> |
| 550 | Single buffered configuration (<constant>GLX_DOUBLEBUFFER</constant> being |
| 551 | <constant>False</constant> precedes a double buffered one. |
| 552 | </para> |
| 553 | </listitem> |
| 554 | </varlistentry> |
| 555 | <varlistentry> |
| 556 | <term>5.</term> |
| 557 | <listitem> |
| 558 | <para> |
| 559 | Smaller <constant>GLX_AUX_BUFFERS</constant>. |
| 560 | </para> |
| 561 | </listitem> |
| 562 | </varlistentry> |
| 563 | <varlistentry> |
| 564 | <term>6.</term> |
| 565 | <listitem> |
| 566 | <para> |
| 567 | Larger <constant>GLX_DEPTH_SIZE</constant>. |
| 568 | </para> |
| 569 | </listitem> |
| 570 | </varlistentry> |
| 571 | <varlistentry> |
| 572 | <term>7.</term> |
| 573 | <listitem> |
| 574 | <para> |
| 575 | Smaller <constant>GLX_STENCIL_SIZE</constant>. |
| 576 | </para> |
| 577 | </listitem> |
| 578 | </varlistentry> |
| 579 | <varlistentry> |
| 580 | <term>8.</term> |
| 581 | <listitem> |
| 582 | <para> |
| 583 | Larger total number of accumulation buffer color components |
| 584 | (<constant>GLX_ACCUM_RED_SIZE</constant>, <constant>GLX_ACCUM_GREEN_SIZE</constant>, |
| 585 | <constant>GLX_ACCUM_BLUE_SIZE</constant>, plus <constant>GLX_ACCUM_ALPHA_SIZE</constant>) that have |
| 586 | higher number of bits. If the requested number of bits in <parameter>attrib_list</parameter> is |
| 587 | zero or <constant>GLX_DONT_CARE</constant> for a particular color component, then the |
| 588 | number of bits for that component is not considered. |
| 589 | </para> |
| 590 | </listitem> |
| 591 | </varlistentry> |
| 592 | <varlistentry> |
| 593 | <term>9.</term> |
| 594 | <listitem> |
| 595 | <para> |
| 596 | By <constant>GLX_X_VISUAL_TYPE</constant> where the precedence order is |
| 597 | <constant>GLX_TRUE_COLOR</constant>, <constant>GLX_DIRECT_COLOR</constant>, <constant>GLX_PSEUDO_COLOR</constant>, |
| 598 | <constant>GLX_STATIC_COLOR</constant>, <constant>GLX_GRAY_SCALE</constant>, <constant>GLX_STATIC_GRAY</constant>. |
| 599 | </para> |
| 600 | </listitem> |
| 601 | </varlistentry> |
| 602 | </variablelist> |
| 603 | </refsect1> |
| 604 | <refsect1 id="examples"><title>Examples</title> |
| 605 | <para> |
| 606 | </para> |
| 607 | <variablelist> |
| 608 | <varlistentry> |
| 609 | <term><parameter>attrib_list</parameter> =</term> |
| 610 | <listitem> |
| 611 | <para> |
| 612 | {<constant>GLX_RENDER_TYPE</constant>, <constant>GLX_RGBA_BIT</constant>, |
| 613 | <constant>GLX_RED_SIZE</constant>, 4, |
| 614 | <constant>GLX_GREEN_SIZE</constant>, 4, |
| 615 | <constant>GLX_BLUE_SIZE</constant>, 4, |
| 616 | <constant>None</constant>}; |
| 617 | </para> |
| 618 | </listitem> |
| 619 | </varlistentry> |
| 620 | </variablelist> |
| 621 | <para> |
| 622 | Specifies a frame buffer configuration that supports RGBA rendering |
| 623 | and exists in the normal frame buffer, |
| 624 | not an overlay or underlay buffer. |
| 625 | The returned visual supports at least four bits each of red, |
| 626 | green, and blue, |
| 627 | and possibly no bits of alpha. |
| 628 | It does not support stereo display. |
| 629 | It may or may not have one or more auxiliary color buffers, |
| 630 | a back buffer, |
| 631 | a depth buffer, |
| 632 | a stencil buffer, |
| 633 | or an accumulation buffer. |
| 634 | </para> |
| 635 | </refsect1> |
| 636 | <refsect1 id="notes"><title>Notes</title> |
| 637 | <para> |
| 638 | <function>glXChooseFBConfig</function> is available only if the GLX version is 1.3 or greater. |
| 639 | </para> |
| 640 | <para> |
| 641 | If the GLX version is 1.1 or 1.0, the GL version must be 1.0. |
| 642 | If the GLX version is 1.2, then the GL version must be 1.1. |
| 643 | If the GLX version is 1.3, then the GL version must be 1.2. |
| 644 | </para> |
| 645 | <para> |
| 646 | <citerefentry><refentrytitle>glXGetFBConfigs</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glXGetFBConfigAttrib</refentrytitle></citerefentry> can |
| 647 | be used to implement selection algorithms other than the generic |
| 648 | one implemented by <function>glXChooseFBConfig</function>. Call <function>glXChooseFBConfig</function> to retrieve all the frame buffer configurations |
| 649 | on a particular screen or, alternatively, all the frame buffer configurations with |
| 650 | a particular set of attributes. Next, call <citerefentry><refentrytitle>glXGetFBConfigAttrib</refentrytitle></citerefentry> |
| 651 | to retrieve additional attributes for the frame buffer configurations and then |
| 652 | select between them. |
| 653 | </para> |
| 654 | <para> |
| 655 | GLX implementations are strongly discouraged, |
| 656 | but not proscribed, |
| 657 | from changing the selection algorithm used by <function>glXChooseFBConfig</function>. |
| 658 | Therefore, selections may change from release to release |
| 659 | of the client-side library. |
| 660 | </para> |
| 661 | </refsect1> |
| 662 | <refsect1 id="errors"><title>Errors</title> |
| 663 | <para> |
| 664 | <constant>NULL</constant> is returned if an undefined GLX attribute is |
| 665 | encountered in <parameter>attrib_list</parameter>, if <parameter>screen</parameter> is invalid, or if <parameter>dpy</parameter> does |
| 666 | not support the GLX extension. |
| 667 | </para> |
| 668 | </refsect1> |
| 669 | <refsect1 id="seealso"><title>See Also</title> |
| 670 | <para> |
| 671 | <citerefentry><refentrytitle>glXGetFBConfigAttrib</refentrytitle></citerefentry>, |
| 672 | <citerefentry><refentrytitle>glXGetFBConfigs</refentrytitle></citerefentry>, |
| 673 | <citerefentry><refentrytitle>glXGetVisualFromFBConfig</refentrytitle></citerefentry> |
| 674 | </para> |
| 675 | </refsect1> |
| 676 | <refsect1 id="Copyright"><title>Copyright</title> |
| 677 | <para> |
| 678 | Copyright <trademark class="copyright"></trademark> 1991-2006 |
| 679 | Silicon Graphics, Inc. This document is licensed under the SGI |
| 680 | Free Software B License. For details, see |
| 681 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. |
| 682 | </para> |
| 683 | </refsect1> |
| 684 | </refentry> |