summaryrefslogtreecommitdiff
path: root/src/glx/mini/miniglx.c
blob: 25c7b9636242aa4bd22f873658ce95d029bd0ab9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
/**
 * \file miniglx.c
 * \brief Mini GLX interface functions.
 * \author Brian Paul
 *
 * The Mini GLX interface is a subset of the GLX interface, plus a
 * minimal set of Xlib functions.
 */

/*
 * Mesa 3-D graphics library
 * Version:  5.0
 *
 * Copyright (C) 1999-2003  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/* $Id: miniglx.c,v 1.1 2003/08/22 20:11:43 brianp Exp $ */

/**
 * \mainpage Mini GLX
 *
 * \section miniglxIntro Introduction
 *
 * The Mini GLX interface facilitates OpenGL rendering on embedded devices. The
 * interface is a subset of the GLX interface, plus a minimal set of Xlib-like
 * functions.
 *
 * Programs written to the Mini GLX specification should run unchanged
 * on systems with the X Window System and the GLX extension (after
 * recompilation). The intention is to allow flexibility for
 * prototyping and testing.
 *
 * The files in the src/miniglx/ directory are compiled to build the
 * libGL.so library.  This is the library which applications link with.
 * libGL.so in turn, loads the hardware-specific device driver.
 *
 *
 * \section miniglxDoxygen About Doxygen
 *
 * For a list of all files, select <b>File List</b>.  Choose a file from
 * the list for a list of all functions in the file.
 *
 * For a list of all functions, types, constants, etc.
 * select <b>File Members</b>.
 *
 *
 * \section miniglxReferences References
 *
 * - <A HREF="file:../../docs/MiniGLX.html">Mini GLX Specification</A>,
 *   Tungsten Graphics, Inc.
 * - OpenGL Graphics with the X Window System, Silicon Graphics, Inc.,
 *   ftp://ftp.sgi.com/opengl/doc/opengl1.2/glx1.3.ps
 * - Xlib - C Language X Interface, X Consortium Standard, X Version 11,
 *   Release 6.4, ftp://ftp.x.org/pub/R6.4/xc/doc/hardcopy/X11/xlib.PS.gz
 * - XFree86 Man pages, The XFree86 Project, Inc.,
 *   http://www.xfree86.org/current/manindex3.html
 *   
 */

/**
 * \page datatypes Notes on the XVisualInfo, Visual, and __GLXvisualConfig data types
 * 
 * -# X (unfortunately) has two (or three) data types which
 *    describe visuals.  Ideally, there would just be one.
 * -# We need the #__GLXvisualConfig type to augment #XVisualInfo and #Visual
 *    because we need to describe the GLX-specific attributes of visuals.
 * -# In this interface there is a one-to-one-to-one correspondence between
 *    the three types and they're all interconnected.
 * -# The #XVisualInfo type has a pointer to a #Visual.  The #Visual structure
 *    (aka MiniGLXVisualRec) has a pointer to the #__GLXvisualConfig.  The
 *    #Visual structure also has a pointer pointing back to the #XVisualInfo.
 * -# The #XVisualInfo structure is the only one who's contents are public.
 * -# The glXChooseVisual() and XGetVisualInfo() are the only functions that
 *    return #XVisualInfo structures.  They can be freed with XFree(), though
 *    there is a small memory leak.
 */


#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <linux/kd.h>
#include <linux/vt.h>

#include "miniglxP.h"
#include "dri.h"

#include "glapi.h"
#include "xf86drm.h"


/**
 * \brief Current GLX context.
 *
 * \sa glXGetCurrentContext().
 */
static GLXContext CurrentContext = NULL;



static Display *SignalDisplay = 0;

static void SwitchVT(int sig)
{
   fprintf(stderr, "SwitchVT %d dpy %p\n", sig, SignalDisplay);

   if (SignalDisplay) {
      SignalDisplay->vtSignalFlag = 1;
      switch( sig )
      {
      case SIGUSR1:                                /* vt has been released */
	 SignalDisplay->haveVT = 0;
	 break;
      case SIGUSR2:                                /* vt has been acquired */
	 SignalDisplay->haveVT = 1;
	 break;
      }
   }
}

/**********************************************************************/
/** \name Framebuffer device functions                                */
/**********************************************************************/
/*@{*/

/**
 * \brief Do the first part of setting up the framebuffer device.
 *
 * \param dpy the display handle.
 * \param use_vt use a VT for display or not
 *
 * \return GL_TRUE on success, or GL_FALSE on failure.
 * 
 * \sa This is called during XOpenDisplay().
 *
 * \internal
 * Gets the VT number, opens the respective console TTY device. Saves its state
 * to restore when exiting and goes into graphics mode.
 *
 * Opens the framebuffer device and make a copy of the original variable screen
 * information and gets the fixed screen information.  Maps the framebuffer and
 * MMIO region into the process address space.
 */
static GLboolean
OpenFBDev( Display *dpy, int use_vt )
{
   char ttystr[1000];
   int fd, vtnumber, ttyfd;

   assert(dpy);

   if (geteuid()) {
      fprintf(stderr, "error: you need to be root\n");
      return GL_FALSE;
   }
   
   if (use_vt) {
       
       /* open /dev/tty0 and get the VT number */
       if ((fd = open("/dev/tty0", O_WRONLY, 0)) < 0) {
	   fprintf(stderr, "error opening /dev/tty0\n");
	   return GL_FALSE;
       }
       if (ioctl(fd, VT_OPENQRY, &vtnumber) < 0 || vtnumber < 0) {
	   fprintf(stderr, "error: couldn't get a free vt\n");
	   return GL_FALSE;
       }
       
       fprintf(stderr, "*** got vt nr: %d\n", vtnumber);
       close(fd);
       
       /* open the console tty */
       sprintf(ttystr, "/dev/tty%d", vtnumber);  /* /dev/tty1-64 */
       dpy->ConsoleFD = open(ttystr, O_RDWR | O_NDELAY, 0);
       if (dpy->ConsoleFD < 0) {
	   fprintf(stderr, "error couldn't open console fd\n");
	   return GL_FALSE;
       }
       
       /* save current vt number */
       {
	   struct vt_stat vts;
	   if (ioctl(dpy->ConsoleFD, VT_GETSTATE, &vts) == 0)
	       dpy->OriginalVT = vts.v_active;
       }
       
       /* disconnect from controlling tty */
       ttyfd = open("/dev/tty", O_RDWR);
       if (ttyfd >= 0) {
	   ioctl(ttyfd, TIOCNOTTY, 0);
	   close(ttyfd);
       }
       
       /* some magic to restore the vt when we exit */
       {
	   struct vt_mode vt;
	   struct sigaction sig_tty;
	   
	   /* Set-up tty signal handler to catch the signal we request below */
	   SignalDisplay = dpy;
	   memset( &sig_tty, 0, sizeof( sig_tty ) );
	   sig_tty.sa_handler = SwitchVT;
	   sigemptyset( &sig_tty.sa_mask );
	   if( sigaction( SIGUSR1, &sig_tty, &dpy->OrigSigUsr1 ) ||
	       sigaction( SIGUSR2, &sig_tty, &dpy->OrigSigUsr2 ) )
	   {
	       fprintf(stderr, "error: can't set up signal handler (%s)",
		       strerror(errno) );
	       return GL_FALSE;
	   }
	   
	   
	   
	   vt.mode = VT_PROCESS;
	   vt.waitv = 0;
	   vt.relsig = SIGUSR1;
	   vt.acqsig = SIGUSR2;
	   if (ioctl(dpy->ConsoleFD, VT_SETMODE, &vt) < 0) {
	       fprintf(stderr, "error: ioctl(VT_SETMODE) failed: %s\n",
		       strerror(errno));
	       return GL_FALSE;
	   }
	   
	   
	   if (ioctl(dpy->ConsoleFD, VT_ACTIVATE, vtnumber) != 0)
	       printf("ioctl VT_ACTIVATE: %s\n", strerror(errno));
	   if (ioctl(dpy->ConsoleFD, VT_WAITACTIVE, vtnumber) != 0)
	       printf("ioctl VT_WAITACTIVE: %s\n", strerror(errno));
	   
	   if (ioctl(dpy->ConsoleFD, VT_GETMODE, &vt) < 0) {
	       fprintf(stderr, "error: ioctl VT_GETMODE: %s\n", strerror(errno));
	       return GL_FALSE;
	   }
	   
	   
	   
       }
       
       /* go into graphics mode */
       if (ioctl(dpy->ConsoleFD, KDSETMODE, KD_GRAPHICS) < 0) {
	   fprintf(stderr, "error: ioctl(KDSETMODE, KD_GRAPHICS) failed: %s\n",
		   strerror(errno));
	   return GL_FALSE;
       }
   }

   /* open the framebuffer device */
   dpy->FrameBufferFD = open(dpy->fbdevDevice, O_RDWR);
   if (dpy->FrameBufferFD < 0) {
      fprintf(stderr, "Error opening /dev/fb0: %s\n", strerror(errno));
      return GL_FALSE;
   }

  /* get the original variable screen info */
   if (ioctl(dpy->FrameBufferFD, FBIOGET_VSCREENINFO, &dpy->OrigVarInfo)) {
      fprintf(stderr, "error: ioctl(FBIOGET_VSCREENINFO) failed: %s\n",
              strerror(errno));
      return GL_FALSE;
   }

   /* make copy */
   dpy->VarInfo = dpy->OrigVarInfo;  /* structure copy */

   /* Turn off hw accels (otherwise mmap of mmio region will be
    * refused)
    */
   dpy->VarInfo.accel_flags = 0; 
   if (ioctl(dpy->FrameBufferFD, FBIOPUT_VSCREENINFO, &dpy->VarInfo)) {
      fprintf(stderr, "error: ioctl(FBIOPUT_VSCREENINFO) failed: %s\n",
	      strerror(errno));
      return GL_FALSE;
   }



   /* Get the fixed screen info */
   if (ioctl(dpy->FrameBufferFD, FBIOGET_FSCREENINFO, &dpy->FixedInfo)) {
      fprintf(stderr, "error: ioctl(FBIOGET_FSCREENINFO) failed: %s\n",
              strerror(errno));
      return GL_FALSE;
   }



   /* mmap the framebuffer into our address space */
   dpy->driverContext.FBStart = dpy->FixedInfo.smem_start;
   dpy->driverContext.FBSize = dpy->FixedInfo.smem_len;
   dpy->driverContext.shared.fbSize = dpy->FixedInfo.smem_len;
   dpy->driverContext.FBAddress = (caddr_t) mmap(0, /* start */
                                     dpy->driverContext.shared.fbSize, /* bytes */
                                     PROT_READ | PROT_WRITE, /* prot */
                                     MAP_SHARED, /* flags */
                                     dpy->FrameBufferFD, /* fd */
                                     0 /* offset */);
   if (dpy->driverContext.FBAddress == (caddr_t) - 1) {
      fprintf(stderr, "error: unable to mmap framebuffer: %s\n",
              strerror(errno));
      return GL_FALSE;
   }
	    
   /* mmap the MMIO region into our address space */
   dpy->driverContext.MMIOStart = dpy->FixedInfo.mmio_start;
   dpy->driverContext.MMIOSize = dpy->FixedInfo.mmio_len;
   dpy->driverContext.MMIOAddress = (caddr_t) mmap(0, /* start */
                                     dpy->driverContext.MMIOSize, /* bytes */
                                     PROT_READ | PROT_WRITE, /* prot */
                                     MAP_SHARED, /* flags */
                                     dpy->FrameBufferFD, /* fd */
                                     dpy->FixedInfo.smem_len /* offset */);
   if (dpy->driverContext.MMIOAddress == (caddr_t) - 1) {
      fprintf(stderr, "error: unable to mmap mmio region: %s\n",
              strerror(errno));
      return GL_FALSE;
   }

   fprintf(stderr, "got MMIOAddress %p offset %d\n",
           dpy->driverContext.MMIOAddress,
	   dpy->FixedInfo.smem_len);

   return GL_TRUE;
}




/**
 * \brief Setup up the desired framebuffer device mode.  
 *
 * \param dpy the display handle.
 * 
 * \return GL_TRUE on success, or GL_FALSE on failure.
 * 
 * \sa This is called during __miniglx_StartServer().
 *
 * \internal
 *
 * Bumps the size of the window the the next supported mode. Sets the
 * variable screen information according to the desired mode and asks
 * the driver to validate the mode. Certifies that a DirectColor or
 * TrueColor visual is used from the updated fixed screen information.
 * In the case of DirectColor visuals, sets up an 'identity' colormap to
 * mimic a TrueColor visual.
 *
 * Calls the driver hooks 'ValidateMode' and 'PostValidateMode' to
 * allow the driver to make modifications to the chosen mode according
 * to hardware constraints, or to save and restore videocard registers
 * that may be clobbered by the fbdev driver.
 *
 * \todo Timings are hard-coded in the source for a set of supported modes.
 */
static GLboolean
SetupFBDev( Display *dpy )
{
   int width, height;

   assert(dpy);

   width = dpy->driverContext.shared.virtualWidth;
   height = dpy->driverContext.shared.virtualHeight;
   
   /* Bump size up to next supported mode.
    */
   if (width <= 800 && height <= 600) {
      width = 800; height = 600; 
   }  
   else if (width <= 1024 && height <= 768) { 
      width = 1024; height = 768; 
   } 
   else if (width <= 768 && height <= 1024) {
      width = 768; height = 1024; 
   }  
   else if (width <= 1280 && height <= 1024) { 
      width = 1280; height = 1024; 
   } 


   dpy->driverContext.shared.virtualHeight = height;
   dpy->driverContext.shared.virtualWidth = width;
   dpy->driverContext.shared.fbStride = width * (dpy->driverContext.bpp / 8);
   
   /* set the depth, resolution, etc */
   dpy->VarInfo = dpy->OrigVarInfo;
   dpy->VarInfo.bits_per_pixel = dpy->driverContext.bpp;
   dpy->VarInfo.xres_virtual = dpy->driverContext.shared.virtualWidth;
   dpy->VarInfo.yres_virtual = dpy->driverContext.shared.virtualHeight;
   dpy->VarInfo.xres = width;
   dpy->VarInfo.yres = height;
   dpy->VarInfo.xoffset = 0;
   dpy->VarInfo.yoffset = 0;
   dpy->VarInfo.nonstd = 0;
   dpy->VarInfo.vmode &= ~FB_VMODE_YWRAP; /* turn off scrolling */

   if (dpy->VarInfo.bits_per_pixel == 32) {
      dpy->VarInfo.red.offset = 16;
      dpy->VarInfo.green.offset = 8;
      dpy->VarInfo.blue.offset = 0;
      dpy->VarInfo.transp.offset = 24;
      dpy->VarInfo.red.length = 8;
      dpy->VarInfo.green.length = 8;
      dpy->VarInfo.blue.length = 8;
      dpy->VarInfo.transp.length = 8;
   }
   else if (dpy->VarInfo.bits_per_pixel == 16) {
      dpy->VarInfo.red.offset = 11;
      dpy->VarInfo.green.offset = 5;
      dpy->VarInfo.blue.offset = 0;
      dpy->VarInfo.red.length = 5;
      dpy->VarInfo.green.length = 6;
      dpy->VarInfo.blue.length = 5;
      dpy->VarInfo.transp.offset = 0;
      dpy->VarInfo.transp.length = 0;
   }
   else {
      fprintf(stderr, "Only 32bpp and 16bpp modes supported at the moment\n");
      return 0;
   }

   if (!dpy->driver->validateMode( &dpy->driverContext )) {
      fprintf(stderr, "Driver validateMode() failed\n");
      return 0;
   }

   if (dpy->VarInfo.xres == 1280 && 
       dpy->VarInfo.yres == 1024) {
      /* timing values taken from /etc/fb.modes (1280x1024 @ 75Hz) */
      dpy->VarInfo.pixclock = 7408;
      dpy->VarInfo.left_margin = 248;
      dpy->VarInfo.right_margin = 16;
      dpy->VarInfo.upper_margin = 38;
      dpy->VarInfo.lower_margin = 1;
      dpy->VarInfo.hsync_len = 144;
      dpy->VarInfo.vsync_len = 3;
   }
   else if (dpy->VarInfo.xres == 1024 && 
	    dpy->VarInfo.yres == 768) {
      /* timing values taken from /etc/fb.modes (1024x768 @ 75Hz) */
      dpy->VarInfo.pixclock = 12699;
      dpy->VarInfo.left_margin = 176;
      dpy->VarInfo.right_margin = 16;
      dpy->VarInfo.upper_margin = 28;
      dpy->VarInfo.lower_margin = 1;
      dpy->VarInfo.hsync_len = 96;
      dpy->VarInfo.vsync_len = 3;
   }
   else if (dpy->VarInfo.xres == 800 &&
	    dpy->VarInfo.yres == 600) {
      /* timing values taken from /etc/fb.modes (800x600 @ 75Hz) */
      dpy->VarInfo.pixclock = 20203;
      dpy->VarInfo.left_margin = 160;
      dpy->VarInfo.right_margin = 16;
      dpy->VarInfo.upper_margin = 21;
      dpy->VarInfo.lower_margin = 1;
      dpy->VarInfo.hsync_len = 80;
      dpy->VarInfo.vsync_len = 3;
   }
   else if (dpy->VarInfo.xres == 768 &&
	    dpy->VarInfo.yres == 1024) {
      /* timing values for 768x1024 @ 75Hz */
      dpy->VarInfo.pixclock = 11993;
      dpy->VarInfo.left_margin = 136;
      dpy->VarInfo.right_margin = 32;
      dpy->VarInfo.upper_margin = 41;
      dpy->VarInfo.lower_margin = 1;
      dpy->VarInfo.hsync_len = 80;
      dpy->VarInfo.vsync_len = 3;
   }
   else {
      /* XXX need timings for other screen sizes */
      fprintf(stderr, "XXXX screen size %d x %d not supported at this time!\n",
	      dpy->VarInfo.xres, dpy->VarInfo.yres);
      return GL_FALSE;
   }

   fprintf(stderr, "[miniglx] Setting mode: visible %dx%d virtual %dx%dx%d\n",
	   dpy->VarInfo.xres, dpy->VarInfo.yres,
	   dpy->VarInfo.xres_virtual, dpy->VarInfo.yres_virtual,
	   dpy->VarInfo.bits_per_pixel);

   /* set variable screen info */
   if (ioctl(dpy->FrameBufferFD, FBIOPUT_VSCREENINFO, &dpy->VarInfo)) {
      fprintf(stderr, "error: ioctl(FBIOPUT_VSCREENINFO) failed: %s\n",
	      strerror(errno));
      return GL_FALSE;
   }

   /* get the variable screen info, in case it has been modified */
   if (ioctl(dpy->FrameBufferFD, FBIOGET_VSCREENINFO, &dpy->VarInfo)) {
      fprintf(stderr, "error: ioctl(FBIOGET_VSCREENINFO) failed: %s\n",
              strerror(errno));
      return GL_FALSE;
   }


   fprintf(stderr, "[miniglx] Readback mode: visible %dx%d virtual %dx%dx%d\n",
	   dpy->VarInfo.xres, dpy->VarInfo.yres,
	   dpy->VarInfo.xres_virtual, dpy->VarInfo.yres_virtual,
	   dpy->VarInfo.bits_per_pixel);

   /* Get the fixed screen info */
   if (ioctl(dpy->FrameBufferFD, FBIOGET_FSCREENINFO, &dpy->FixedInfo)) {
      fprintf(stderr, "error: ioctl(FBIOGET_FSCREENINFO) failed: %s\n",
              strerror(errno));
      return GL_FALSE;
   }

   if (dpy->FixedInfo.visual != FB_VISUAL_TRUECOLOR &&
       dpy->FixedInfo.visual != FB_VISUAL_DIRECTCOLOR) {
      fprintf(stderr, "non-TRUECOLOR visuals not supported.\n");
      return GL_FALSE;
   }

   if (dpy->FixedInfo.visual == FB_VISUAL_DIRECTCOLOR) {
      struct fb_cmap cmap;
      unsigned short red[256], green[256], blue[256];
      int rcols = 1 << dpy->VarInfo.red.length;
      int gcols = 1 << dpy->VarInfo.green.length;
      int bcols = 1 << dpy->VarInfo.blue.length;
      int i;

      cmap.start = 0;      
      cmap.len = gcols;
      cmap.red   = red;
      cmap.green = green;
      cmap.blue  = blue;
      cmap.transp = NULL;

      for (i = 0; i < rcols ; i++) 
         red[i] = (65536/(rcols-1)) * i;

      for (i = 0; i < gcols ; i++) 
         green[i] = (65536/(gcols-1)) * i;

      for (i = 0; i < bcols ; i++) 
         blue[i] = (65536/(bcols-1)) * i;
      
      if (ioctl(dpy->FrameBufferFD, FBIOPUTCMAP, (void *) &cmap) < 0) {
         fprintf(stderr, "ioctl(FBIOPUTCMAP) failed [%d]\n", i);
	 exit(1);
      }
   }

   /* May need to restore regs fbdev has clobbered:
    */
   if (!dpy->driver->postValidateMode( &dpy->driverContext )) {
      fprintf(stderr, "Driver postValidateMode() failed\n");
      return 0;
   }

   return GL_TRUE;
}


/**
 * \brief Restore the framebuffer device to state it was in before we started
 *
 * Undoes the work done by SetupFBDev().
 * 
 * \param dpy the display handle.
 *
 * \return GL_TRUE on success, or GL_FALSE on failure.
 * 
 * \sa Called from XDestroyWindow().
 *
 * \internal
 * Restores the original variable screen info.
 */
static GLboolean
RestoreFBDev( Display *dpy )
{
   /* restore original variable screen info */
   if (ioctl(dpy->FrameBufferFD, FBIOPUT_VSCREENINFO, &dpy->OrigVarInfo)) {
      fprintf(stderr, "ioctl(FBIOPUT_VSCREENINFO failed): %s\n",
              strerror(errno));
      return GL_FALSE;
   }
   dpy->VarInfo = dpy->OrigVarInfo;

   return GL_TRUE;
}


/**
 * \brief Close the framebuffer device.  
 *
 * \param dpy the display handle.
 * 
 * \sa Called from XCloseDisplay().
 *
 * \internal
 * Unmaps the framebuffer and MMIO region.  Restores the text mode and the
 * original virtual terminal. Closes the console and framebuffer devices.
 */
static void
CloseFBDev( Display *dpy )
{
   struct vt_mode VT;

   munmap(dpy->driverContext.FBAddress, dpy->driverContext.FBSize);
   munmap(dpy->driverContext.MMIOAddress, dpy->driverContext.MMIOSize);

   if (dpy->ConsoleFD) {
       /* restore text mode */
       ioctl(dpy->ConsoleFD, KDSETMODE, KD_TEXT);
       
       /* set vt */
       if (ioctl(dpy->ConsoleFD, VT_GETMODE, &VT) != -1) {
	   VT.mode = VT_AUTO;
	   ioctl(dpy->ConsoleFD, VT_SETMODE, &VT);
       }
       
       /* restore original vt */
       if (dpy->OriginalVT >= 0) {
	   ioctl(dpy->ConsoleFD, VT_ACTIVATE, dpy->OriginalVT);
	   dpy->OriginalVT = -1;
       }
       
       close(dpy->ConsoleFD);
   }
   close(dpy->FrameBufferFD);
}

/*@}*/


/**********************************************************************/
/** \name Misc functions needed for DRI drivers                       */
/**********************************************************************/
/*@{*/

/**
 * \brief Find the DRI screen dependent methods associated with the display.
 *
 * \param dpy a display handle, as returned by XOpenDisplay().
 * \param scrn the screen number. Not referenced.
 * 
 * \returns a pointer to a __DRIscreenRec structure.
 * 
 * \internal
 * Returns the MiniGLXDisplayRec::driScreen attribute.
 */
__DRIscreen *
__glXFindDRIScreen(Display *dpy, int scrn)
{
   (void) scrn;
   return dpy->driScreen;
}

/**
 * \brief Validate a drawable.
 *
 * \param dpy a display handle, as returned by XOpenDisplay().
 * \param draw drawable to validate.
 * 
 * \internal
 * Since Mini GLX only supports one window, compares the specified drawable with
 * the MiniGLXDisplayRec::TheWindow attribute.
 */
Bool
__glXWindowExists(Display *dpy, GLXDrawable draw)
{
   if (dpy->TheWindow == draw)
      return True;
   else
      return False;
}

/**
 * \brief Get current thread ID.
 *
 * \return thread ID.
 *
 * \internal
 * Always returns 0. 
 */
/*unsigned long
_glthread_GetID(void)
{
   return 0;
}*/

/*@}*/


/**
 * \brief Scan Linux /prog/bus/pci/devices file to determine hardware
 * chipset based on supplied bus ID.
 * 
 * \return probed chipset (non-zero) on success, zero otherwise.
 * 
 * \internal 
 */
static int get_chipset_from_busid( Display *dpy )
{
   char buf[0x200];
   FILE *file;
   const char *fname = "/proc/bus/pci/devices";
   int retval = 0;

   if (!(file = fopen(fname,"r"))) {
      fprintf(stderr, "couldn't open %s: %s\n", fname, strerror(errno));
      return 0;
   }

   while (fgets(buf, sizeof(buf)-1, file)) {
      unsigned int nr, bus, dev, fn, vendor, device, encode;
      nr = sscanf(buf, "%04x\t%04x%04x", &encode, 
		  &vendor, &device);
      
      bus = encode >> 16;
      dev = (encode & 0xFF) >> 3;
      fn = encode & 0x7;

      if (nr != 3)
	 break;

      if (bus == dpy->driverContext.pciBus &&
          dev == dpy->driverContext.pciDevice &&
          fn  == dpy->driverContext.pciFunc) {
	 retval = device;
	 break;
      }
   }

   fclose(file);

   if (retval)
      fprintf(stderr, "[miniglx] probed chipset 0x%x\n", retval);
   else
      fprintf(stderr, "[miniglx] failed to probe chipset\n");

   return retval;
}


/**
 * \brief Read settings from a configuration file.
 * 
 * The configuration file is usually "/etc/miniglx.conf", but can be overridden
 * with the MINIGLX_CONF environment variable. 
 *
 * The format consists in \code option = value \endcode lines. The option names 
 * corresponds to the fields in MiniGLXDisplayRec.
 * 
 * \param dpy the display handle as.
 *
 * \return non-zero on success, zero otherwise.
 * 
 * \internal 
 * Sets some defaults. Opens and parses the the Mini GLX configuration file and
 * fills in the MiniGLXDisplayRec field that corresponds for each option.
 */
static int __read_config_file( Display *dpy )
{
   FILE *file;
   const char *fname;

   /* Fallback/defaults
    */
   dpy->fbdevDevice = "/dev/fb0";
   dpy->clientDriverName = "fb_dri.so";
   dpy->driverContext.pciBus = 0;
   dpy->driverContext.pciDevice = 0;
   dpy->driverContext.pciFunc = 0;
   dpy->driverContext.chipset = 0;   
   dpy->driverContext.pciBusID = 0;
   dpy->driverContext.shared.virtualWidth = 1280;
   dpy->driverContext.shared.virtualHeight = 1024;
   dpy->driverContext.bpp = 32;
   dpy->driverContext.cpp = 4;
   dpy->rotateMode = 0;

   fname = getenv("MINIGLX_CONF");
   if (!fname) fname = "/etc/miniglx.conf";

   file = fopen(fname, "r");
   if (!file) {
      fprintf(stderr, "couldn't open config file %s: %s\n", fname, strerror(errno));
      return 0;
   }


   while (!feof(file)) {
      char buf[81], *opt = buf, *val, *tmp1, *tmp2;
      fgets(buf, sizeof(buf), file); 

      /* Parse 'opt = val' -- must be easier ways to do this.
       */
      while (isspace(*opt)) opt++;
      val = opt;
      if (*val == '#') continue; /* comment */
      while (!isspace(*val) && *val != '=' && *val) val++;
      tmp1 = val;
      while (isspace(*val)) val++;
      if (*val != '=') continue;
      *tmp1 = 0; 
      val++;
      while (isspace(*val)) val++;
      tmp2 = val;
      while (!isspace(*tmp2) && *tmp2 != '\n' && *tmp2) tmp2++;
      *tmp2 = 0;


      if (strcmp(opt, "fbdevDevice") == 0) 
	 dpy->fbdevDevice = strdup(val);
      else if (strcmp(opt, "clientDriverName") == 0)
	 dpy->clientDriverName = strdup(val);
      else if (strcmp(opt, "rotateMode") == 0)
	 dpy->rotateMode = atoi(val) ? 1 : 0;
      else if (strcmp(opt, "pciBusID") == 0) {
	 if (sscanf(val, "PCI:%d:%d:%d",
		    &dpy->driverContext.pciBus,
                    &dpy->driverContext.pciDevice,
                    &dpy->driverContext.pciFunc) != 3) {
	    fprintf(stderr, "malformed bus id: %s\n", val);
	    continue;
	 }
   	 dpy->driverContext.pciBusID = strdup(val);
      }
      else if (strcmp(opt, "chipset") == 0) {
	 if (sscanf(val, "0x%x", &dpy->driverContext.chipset) != 1)
	    fprintf(stderr, "malformed chipset: %s\n", opt);
      }
      else if (strcmp(opt, "virtualWidth") == 0) {
	 if (sscanf(val, "%d", &dpy->driverContext.shared.virtualWidth) != 1)
	    fprintf(stderr, "malformed virtualWidth: %s\n", opt);
      }
      else if (strcmp(opt, "virtualHeight") == 0) {
	 if (sscanf(val, "%d", &dpy->driverContext.shared.virtualHeight) != 1)
	    fprintf(stderr, "malformed virutalHeight: %s\n", opt);
      }
      else if (strcmp(opt, "bpp") == 0) {
	 if (sscanf(val, "%d", &dpy->driverContext.bpp) != 1)
	    fprintf(stderr, "malformed bpp: %s\n", opt);
	 dpy->driverContext.cpp = dpy->driverContext.bpp / 8;
      }
   }

   fclose(file);

   if (dpy->driverContext.chipset == 0 && dpy->driverContext.pciBusID != 0) 
      dpy->driverContext.chipset = get_chipset_from_busid( dpy );

   return 1;
}

static int InitDriver( Display *dpy )
{
   /*
    * Begin DRI setup.
    * We're kind of combining the per-display and per-screen information
    * which was kept separate in XFree86/DRI's libGL.
    */
   dpy->dlHandle = dlopen(dpy->clientDriverName, RTLD_NOW | RTLD_GLOBAL);
   if (!dpy->dlHandle) {
      fprintf(stderr, "Unable to open %s: %s\n", dpy->clientDriverName,
	      dlerror());
      return GL_FALSE;
   }

   /* Pull in Mini GLX specific hooks:
    */
   dpy->driver = (struct DRIDriverRec *) dlsym(dpy->dlHandle,
                                               "__driDriver");
   if (!dpy->driver) {
      fprintf(stderr, "Couldn't find __driDriver in %s\n",
              dpy->clientDriverName);
      dlclose(dpy->dlHandle);
      return GL_FALSE;
   }

   /* Pull in standard DRI client-side driver hooks:
    */
   dpy->createScreen = (driCreateScreenFunc*) dlsym(dpy->dlHandle,
                                                "__driCreateScreen");
   if (!dpy->createScreen) {
      fprintf(stderr, "Couldn't find __driCreateScreen in %s\n",
              dpy->clientDriverName);
      dlclose(dpy->dlHandle);
      return GL_FALSE;
   }

   return GL_TRUE;
}


/**********************************************************************/
/** \name Public API functions (Xlib and GLX)                         */
/**********************************************************************/
/*@{*/


/**
 * \brief Initialize the graphics system.
 * 
 * \param display_name currently ignored. It is recommended to pass it as NULL.
 * \return a pointer to a #Display if the function is able to initialize
 * the graphics system, NULL otherwise.
 * 
 * Allocates a MiniGLXDisplayRec structure and fills in with information from a
 * configuration file. 
 *
 * Calls OpenFBDev() to open the framebuffer device and calls
 * DRIDriverRec::initFBDev to do the client-side initialization on it.
 *
 * Loads the DRI driver and pulls in Mini GLX specific hooks into a
 * DRIDriverRec structure, and the standard DRI \e __driCreateScreen hook.
 * Asks the driver for a list of supported visuals.  Performs the per-screen
 * client-side initialization.  Also setups the callbacks in the screen private
 * information.
 *
 * Does the framebuffer device setup. Calls __miniglx_open_connections() to
 * serve clients.
 */
Display *
__miniglx_StartServer( const char *display_name )
{
   Display *dpy;
   int use_vt = 0;

   dpy = (Display *)calloc(1, sizeof(Display));
   if (!dpy)
      return NULL;

   dpy->IsClient = False;

   if (!__read_config_file( dpy )) {
      fprintf(stderr, "Couldn't get configuration details\n");
      free(dpy);
      return NULL;
   }

   /* Open the fbdev device
    */
   if (!OpenFBDev(dpy, use_vt)) {
      fprintf(stderr, "OpenFBDev failed\n");
      free(dpy);
      return NULL;
   }

   if (!InitDriver(dpy)) {
      fprintf(stderr, "InitDriver failed\n");
      free(dpy);
      return NULL;
   }

   /* Ask the driver for a list of supported configs:
   */
   dpy->driver->initContextModes( &dpy->driverContext, &dpy->numModes, &dpy->modes );

   /* Perform the initialization normally done in the X server 
    */
   if (!dpy->driver->initFBDev( &dpy->driverContext )) {
      fprintf(stderr, "%s: __driInitFBDev failed\n", __FUNCTION__);
      dlclose(dpy->dlHandle);
      return GL_FALSE;
   }

   /* do fbdev setup
    */
   if (!SetupFBDev(dpy)) {
      fprintf(stderr, "SetupFBDev failed\n");
      free(dpy);
      return NULL;
   }

   /* unlock here if not using VT -- JDS */
   if (!use_vt) {
       if (dpy->driver->restoreHardware)
	   dpy->driver->restoreHardware( &dpy->driverContext ); 
       DRM_UNLOCK( dpy->driverContext.drmFD,
		   dpy->driverContext.pSAREA,
		   dpy->driverContext.serverContext );
       dpy->hwActive = 1;
   }

   /* Ready for clients:
    */
   if (!__miniglx_open_connections(dpy)) {
      free(dpy);
      return NULL;
   }
      
   return dpy;
}


/**
 * \brief Initialize the graphics system.
 * 
 * \param display_name currently ignored. It is recommended to pass it as NULL.
 * \return a pointer to a #Display if the function is able to initialize
 * the graphics system, NULL otherwise.
 * 
 * Allocates a MiniGLXDisplayRec structure and fills in with information from a
 * configuration file. 
 *
 * Calls __miniglx_open_connections() to connect to the server.
 * 
 * Loads the DRI driver and pulls in Mini GLX specific hooks into a
 * DRIDriverRec structure, and the standard DRI \e __driCreateScreen hook.
 * Asks the driver for a list of supported visuals.  Performs the per-screen
 * client-side initialization.  Also setups the callbacks in the screen private
 * information.
 *
 * \todo
 *   - read config file
 *      - what about virtualWidth, etc?
 *   - determine dpy->driverClientMsgSize,
 *   - allocate dpy->driverClientMsg
 */
Display *
XOpenDisplay( const char *display_name )
{
   Display *dpy;

   dpy = (Display *)calloc(1, sizeof(Display));
   if (!dpy)
      return NULL;

   dpy->IsClient = True;

   /* read config file 
    */
   if (!__read_config_file( dpy )) {
      fprintf(stderr, "Couldn't get configuration details\n");
      free(dpy);
      return NULL;
   }

   /* Connect to the server and receive driverClientMsg
    */
   if (!__miniglx_open_connections(dpy)) {
      free(dpy);
      return NULL;
   }

   /* dlopen the driver .so file
    */
   if (!InitDriver(dpy)) {
      fprintf(stderr, "InitDriver failed\n");
      free(dpy);
      return NULL;
   }

   /* Ask the driver for a list of supported configs:
   */
   dpy->driver->initContextModes( &dpy->driverContext, &dpy->numModes, &dpy->modes );
   
   /* Perform the client-side initialization.  
    *
    * Clearly there is a limit of one on the number of windows in
    * existence at any time.
    *
    * Need to shut down DRM and free DRI data in XDestroyWindow(), too.
    */
   dpy->driScreen = (*dpy->createScreen)(dpy->driver,
					 &dpy->driverContext);
   if (!dpy->driScreen) {
      fprintf(stderr, "%s: __driCreateScreen failed\n", __FUNCTION__);
      dlclose(dpy->dlHandle);
      free(dpy);
      return NULL;
   }
   
   /* Anything more to do?
    */
   return dpy;
}


/**
 * \brief Release display resources.
 * 
 * When the application is about to exit, the resources associated with the
 * graphics system can be released by calling this function.
 * 
 * \param dpy display handle. It becomes invalid at this point.
 * 
 * Destroys the window if any, and destroys the per-screen
 * driver private information.
 * Calls __miniglx_close_connections().
 * 
 * If a server, puts the the framebuffer back into the initial state.
 *
 * Finally frees the display structure.
 */
void
XCloseDisplay( Display *dpy )
{
   glXMakeCurrent( dpy, NULL, NULL);

   if (dpy->NumWindows) 
      XDestroyWindow( dpy, dpy->TheWindow );

   /* As this is done in XOpenDisplay, need to undo it here:
    */
   (*dpy->driScreen->destroyScreen)(dpy->driScreen);

   __miniglx_close_connections( dpy );

   if (!dpy->IsClient) {
      /* put framebuffer back to initial state 
       */
      (*dpy->driver->haltFBDev)( &dpy->driverContext );
      RestoreFBDev(dpy);
      CloseFBDev(dpy);
   }

   dlclose(dpy->dlHandle);
   free(dpy);
}


/**
 * \brief Window creation.
 *
 * \param display a display handle, as returned by XOpenDisplay().
 * \param parent the parent window for the new window. For Mini GLX this should
 * be 
 * \code RootWindow(display, 0) \endcode
 * \param x the window abscissa. For Mini GLX, it should be zero.
 * \param y the window ordinate. For Mini GLX, it should be zero.
 * \param width the window width. For Mini GLX, this specifies the desired
 * screen width such as 1024 or 1280. 
 * \param height the window height. For Mini GLX, this specifies the desired
 * screen height such as 768 or 1024.
 * \param border_width the border width. For Mini GLX, it should be zero.
 * \param depth the window pixel depth. For Mini GLX, this should be the depth
 * found in the #XVisualInfo object returned by glXChooseVisual() 
 * \param class the window class. For Mini GLX this value should be
 * #InputOutput.
 * \param visual the visual type. It should be the visual field of the
 * #XVisualInfo object returned by glXChooseVisual().
 * \param valuemask which fields of the XSetWindowAttributes() are to be used.
 * For Mini GLX this is typically the bitmask 
 * \code CWBackPixel | CWBorderPixel | CWColormap \endcode
 * \param attributes initial window attributes. The
 * XSetWindowAttributes::background_pixel, XSetWindowAttributes::border_pixel
 * and XSetWindowAttributes::colormap fields should be set.
 *
 * \return a window handle if it succeeds or zero if it fails.
 * 
 * \note For Mini GLX, windows are full-screen; they cover the entire frame
 * buffer.  Also, Mini GLX imposes a limit of one window. A second window
 * cannot be created until the first one is destroyed.
 *
 * This function creates and initializes a ::MiniGLXWindowRec structure after
 * ensuring that there is no other window created.  Performs the per-drawable
 * client-side initialization calling the __DRIscreenRec::createDrawable
 * method.
 * 
 */
Window
XCreateWindow( Display *dpy, Window parent, int x, int y,
               unsigned int width, unsigned int height,
               unsigned int border_width, int depth, unsigned int class,
               Visual *visual, unsigned long valuemask,
               XSetWindowAttributes *attributes )
{
   Window win;

   /* ignored */
   (void) x;
   (void) y;
   (void) border_width;
   (void) depth;
   (void) class;
   (void) valuemask;
   (void) attributes;

   if (!dpy->IsClient) {
      fprintf(stderr, "Server process may not create windows (currently)\n");
      return NULL;
   }

   if (dpy->NumWindows > 0)
      return NULL;  /* only allow one window */

   assert(dpy->TheWindow == NULL);

   win = malloc(sizeof(struct MiniGLXWindowRec));
   if (!win)
      return NULL;

   /* In rotated mode, translate incoming x,y,width,height into
    * 'normal' coordinates.
    */
   if (dpy->rotateMode) {
      int tmp;
      tmp = width; width = height; height = tmp;
      tmp = x; x = y; y = tmp;
   }

   /* init other per-window fields */
   win->x = 0;
   win->y = 0;
   win->w = width;
   win->h = height;
   win->visual = visual;  /* ptr assignment */

   win->bytesPerPixel = dpy->driverContext.cpp;
   win->rowStride = dpy->driverContext.shared.virtualWidth * win->bytesPerPixel;
   win->size = win->rowStride * height; 
   win->frontStart = dpy->driverContext.FBAddress;
   win->frontBottom = (GLubyte *) win->frontStart + (height-1) * win->rowStride;

   /* This is incorrect: the hardware driver could put the backbuffer
    * just about anywhere.  These fields, including the above are
    * hardware dependent & don't really belong here.
    */
   if (visual->mode->doubleBufferMode) {
      win->backStart = (GLubyte *) win->frontStart +
	 win->rowStride * dpy->driverContext.shared.virtualHeight;
      win->backBottom = (GLubyte *) win->backStart
	 + (height - 1) * win->rowStride;
      win->curBottom = win->backBottom;
   }
   else {
      /* single buffered */
      win->backStart = NULL;
      win->backBottom = NULL;
      win->curBottom = win->frontBottom;
   }

   win->driDrawable = dpy->driScreen->createDrawable(dpy->driScreen, 
						     width, height, 
						     dpy->clientID, visual->mode);

   if (!win->driDrawable) {
      fprintf(stderr, "%s: dri.createDrawable failed\n", __FUNCTION__);
      free(win);
      return NULL;
   }

   dpy->NumWindows++;
   dpy->TheWindow = win;

   return win; 
}


/**
 * \brief Destroy window.
 *
 * \param display display handle.
 * \param w window handle.
 *
 * This function calls XUnmapWindow() and frees window \p w.
 * 
 * In case of destroying the current buffer first unbinds the GLX context
 * by calling glXMakeCurrent() with no drawable.
 */
void
XDestroyWindow( Display *display, Window win )
{
   if (display && display->IsClient && win) {
      /* check if destroying the current buffer */
      Window curDraw = glXGetCurrentDrawable();
      if (win == curDraw) {
         glXMakeCurrent( display, NULL, NULL);
      }

      XUnmapWindow( display, win );

      /* Destroy the drawable. */
      (*win->driDrawable->destroyDrawable)(win->driDrawable);
      free(win);
      
      /* unlink window from display */
      display->NumWindows--;
      assert(display->NumWindows == 0);
      display->TheWindow = NULL;
   }
}




/**
 * \brief Create color map structure.
 *
 * \param dpy the display handle as returned by XOpenDisplay().
 * \param w the window on whose screen you want to create a color map. This
 * parameter is ignored by Mini GLX but should be the value returned by the
 * \code RootWindow(display, 0) \endcode macro.
 * \param visual a visual type supported on the screen. This parameter is
 * ignored by Mini GLX but should be the XVisualInfo::visual returned by
 * glXChooseVisual().
 * \param alloc the color map entries to be allocated. This parameter is ignored
 * by Mini GLX but should be set to #AllocNone.
 *
 * \return the color map.
 * 
 * This function is only provided to ease porting.  Practically a no-op -
 * returns a pointer to a dynamically allocated chunk of memory (one byte).
 */
Colormap
XCreateColormap( Display *dpy, Window w, Visual *visual, int alloc )
{
   (void) dpy;
   (void) w;
   (void) visual;
   (void) alloc;
   return (Colormap) malloc(1);
}


/**
 * \brief Destroy color map structure.
 *
 * \param display The display handle as returned by XOpenDisplay().
 * \param colormap the color map to destroy.
 *
 * This function is only provided to ease porting.  Practically a no-op. 
 *
 * Frees the memory pointed by \p colormap.
 */
void
XFreeColormap( Display *display, Colormap colormap )
{
   (void) display;
   (void) colormap;
   free(colormap);
}


/**
 * \brief Free client data.
 *
 * \param data the data that is to be freed.
 *
 * Frees the memory pointed by \p data.
 */
void
XFree( void *data )
{
   free(data);
}


/**
 * \brief Query available visuals.
 *
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param vinfo_mask a bitmask indicating which fields of the \p vinfo_template
 * are to be matched.  The value must be \c VisualScreenMask.
 * \param vinfo_template a template whose fields indicate which visual
 * attributes must be matched by the results.  The XVisualInfo::screen field of
 * this structure must be zero.
 * \param nitens_return will hold the number of visuals returned.
 *
 * \return the address of an array of all available visuals.
 * 
 * An example of using XGetVisualInfo() to get all available visuals follows:
 * 
 * \code
 * XVisualInfo vinfo_template, *results;
 * int nitens_return;
 * Display *dpy = XOpenDisplay(NULL);
 * vinfo_template.screen = 0;
 * results = XGetVisualInfo(dpy, VisualScreenMask, &vinfo_template, &nitens_return);
 * \endcode
 * 
 * Returns the list of all ::XVisualInfo available, one per
 * ::__GLcontextMode stored in MiniGLXDisplayRec::modes.
 */
XVisualInfo *
XGetVisualInfo( Display *dpy, long vinfo_mask, XVisualInfo *vinfo_template, int *nitens_return )
{
   XVisualInfo *results;
   Visual *visResults;
   int i, n;

   ASSERT(vinfo_mask == VisualScreenMask);
   ASSERT(vinfo_template.screen == 0);

   n = dpy->numModes;
   results = (XVisualInfo *)calloc(1, n * sizeof(XVisualInfo));
   if (!results) {
      *nitens_return = 0;
      return NULL;
   }

   visResults = (Visual *)calloc(1, n * sizeof(Visual));
   if (!results) {
      free(results);
      *nitens_return = 0;
      return NULL;
   }

   for (i = 0; i < n; i++) {
      visResults[i].mode = dpy->modes + i;
      visResults[i].visInfo = results + i;
      visResults[i].dpy = dpy;

      if (dpy->driverContext.bpp == 32)
	 visResults[i].pixelFormat = PF_B8G8R8A8; /* XXX: FIX ME */
      else
	 visResults[i].pixelFormat = PF_B5G6R5; /* XXX: FIX ME */

      results[i].visual = visResults + i;
      results[i].visualid = i;
      results[i].class = TrueColor;
      results[i].depth = dpy->modes[i].redBits +
                         dpy->modes[i].redBits +
                         dpy->modes[i].redBits +
                         dpy->modes[i].redBits;
      results[i].bits_per_rgb = dpy->driverContext.bpp;
   }
   *nitens_return = n;
   return results;
}


/**
 * \brief Return a visual that matches specified attributes.
 *
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param screen the screen number. It is currently ignored by Mini GLX and
 * should be zero.
 * \param attribList a list of GLX attributes which describe the desired pixel
 * format. It is terminated by the token \c None. 
 *
 * The attributes are as follows:
 * \arg GLX_USE_GL:
 * This attribute should always be present in order to maintain compatibility
 * with GLX.
 * \arg GLX_RGBA:
 * If present, only RGBA pixel formats will be considered. Otherwise, only
 * color index formats are considered.
 * \arg GLX_DOUBLEBUFFER:
 * if present, only double-buffered pixel formats will be chosen.
 * \arg GLX_RED_SIZE \e n:
 * Must be followed by a non-negative integer indicating the minimum number of
 * bits per red pixel component that is acceptable.
 * \arg GLX_GREEN_SIZE \e n:
 * Must be followed by a non-negative integer indicating the minimum number of
 * bits per green pixel component that is acceptable.
 * \arg GLX_BLUE_SIZE \e n:
 * Must be followed by a non-negative integer indicating the minimum number of
 * bits per blue pixel component that is acceptable.
 * \arg GLX_ALPHA_SIZE \e n:
 * Must be followed by a non-negative integer indicating the minimum number of
 * bits per alpha pixel component that is acceptable.
 * \arg GLX_STENCIL_SIZE \e n:
 * Must be followed by a non-negative integer indicating the minimum number of
 * bits per stencil value that is acceptable.
 * \arg GLX_DEPTH_SIZE \e n:
 * Must be followed by a non-negative integer indicating the minimum number of
 * bits per depth component that is acceptable.
 * \arg None:
 * This token is used to terminate the attribute list.
 *
 * \return a pointer to an #XVisualInfo object which most closely matches the
 * requirements of the attribute list. If there is no visual which matches the
 * request, \c NULL will be returned.
 *
 * \note Visuals with accumulation buffers are not available.
 *
 * This function searches the list of available visual configurations in
 * MiniGLXDisplayRec::configs for a configuration which best matches the GLX
 * attribute list parameter.  A new ::XVisualInfo object is created which
 * describes the visual configuration.  The match criteria is described in the
 * specification.
 */
XVisualInfo*
glXChooseVisual( Display *dpy, int screen, int *attribList )
{
   Visual *vis;
   XVisualInfo *visInfo;
   const int *attrib;
   GLboolean rgbFlag = GL_FALSE, dbFlag = GL_FALSE, stereoFlag = GL_FALSE;
   GLint redBits = 0, greenBits = 0, blueBits = 0, alphaBits = 0;
   GLint indexBits = 0, depthBits = 0, stencilBits = 0;
   GLint numSamples = 0;
   int i;

   /*
    * XXX in the future, <screen> might be interpreted as a VT
    */
   ASSERT(dpy);
   ASSERT(screen == 0);

   vis = (Visual *)calloc(1, sizeof(Visual));
   if (!vis)
      return NULL;

   visInfo = (XVisualInfo *)malloc(sizeof(XVisualInfo));
   if (!visInfo) {
      free(vis);
      return NULL;
   }

   visInfo->visual = vis;
   vis->visInfo = visInfo;
   vis->dpy = dpy;

   /* parse the attribute list */
   for (attrib = attribList; attrib && *attrib != None; attrib++) {
      switch (attrib[0]) {
      case GLX_DOUBLEBUFFER:
         dbFlag = GL_TRUE;
         break;
      case GLX_RGBA:
         rgbFlag = GL_TRUE;
         break;
      case GLX_RED_SIZE:
         redBits = attrib[1];
         attrib++;
         break;
      case GLX_GREEN_SIZE:
         redBits = attrib[1];
         attrib++;
         break;
      case GLX_BLUE_SIZE:
         redBits = attrib[1];
         attrib++;
         break;
      case GLX_ALPHA_SIZE:
         redBits = attrib[1];
         attrib++;
         break;
      case GLX_STENCIL_SIZE:
         stencilBits = attrib[1];
         attrib++;
         break;
      case GLX_DEPTH_SIZE:
         depthBits = attrib[1];
         attrib++;
         break;
#if 0
      case GLX_ACCUM_RED_SIZE:
         accumRedBits = attrib[1];
         attrib++;
         break;
      case GLX_ACCUM_GREEN_SIZE:
         accumGreenBits = attrib[1];
         attrib++;
         break;
      case GLX_ACCUM_BLUE_SIZE:
         accumBlueBits = attrib[1];
         attrib++;
         break;
      case GLX_ACCUM_ALPHA_SIZE:
         accumAlphaBits = attrib[1];
         attrib++;
         break;
      case GLX_LEVEL:
         /* ignored for now */
         break;
#endif
      default:
         /* unexpected token */
         fprintf(stderr, "unexpected token in glXChooseVisual attrib list\n");
         free(vis);
         free(visInfo);
         return NULL;
      }
   }

   /* search screen configs for suitable visual */
   (void) numSamples;
   (void) indexBits;
   (void) redBits;
   (void) greenBits;
   (void) blueBits;
   (void) alphaBits;
   (void) stereoFlag;
   for (i = 0; i < dpy->numModes; i++) {
      const __GLcontextModes *mode = dpy->modes + i;
      if (mode->rgbMode == rgbFlag &&
          mode->redBits >= redBits &&
          mode->greenBits >= greenBits &&
          mode->blueBits >= blueBits &&
          mode->alphaBits >= alphaBits &&
          mode->depthBits >= depthBits &&
          mode->stencilBits >= stencilBits) {
         /* found it */
         visInfo->visualid = i;
         vis->mode = mode;
         break;
      }          
   }
   if (!vis->mode)
       return NULL;

   /* compute depth and bpp */
   if (rgbFlag) {
      /* XXX maybe support depth 16 someday */
      visInfo->class = TrueColor;
      visInfo->depth = dpy->driverContext.bpp;
      visInfo->bits_per_rgb = dpy->driverContext.bpp;
      if (dpy->driverContext.bpp == 32)
	 vis->pixelFormat = PF_B8G8R8A8;
      else
	 vis->pixelFormat = PF_B5G6R5;
   }
   else {
      /* color index mode */
      visInfo->class = PseudoColor;
      visInfo->depth = 8;
      visInfo->bits_per_rgb = 8;  /* bits/pixel */
      vis->pixelFormat = PF_CI8;
   }

   return visInfo;
}


/**
 * \brief Return information about GLX visuals.
 *
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param vis the visual to be queried, as returned by glXChooseVisual().
 * \param attrib the visual attribute to be returned.
 * \param value pointer to an integer in which the result of the query will be
 * stored.
 * 
 * \return zero if no error occurs, \c GLX_INVALID_ATTRIBUTE if the attribute
 * parameter is invalid, or \c GLX_BAD_VISUAL if the \p vis parameter is
 * invalid.
 *
 * Returns the appropriate attribute of ::__GLXvisualConfig pointed by
 * MiniGLXVisualRec::glxConfig of XVisualInfo::visual.
 *
 * \sa data types.
 */
int
glXGetConfig( Display *dpy, XVisualInfo *vis, int attrib, int *value )
{
   const __GLcontextModes *mode = vis->visual->mode;
   if (!mode) {
      *value = 0;
      return GLX_BAD_VISUAL;
   }

   switch (attrib) {
   case GLX_USE_GL:
      *value = True;
      return 0;
   case GLX_RGBA:
      *value = mode->rgbMode;
      return 0;
   case GLX_DOUBLEBUFFER:
      *value = mode->doubleBufferMode;
      return 0;
   case GLX_RED_SIZE:
      *value = mode->redBits;
      return 0;
   case GLX_GREEN_SIZE:
      *value = mode->greenBits;
      return 0;
   case GLX_BLUE_SIZE:
      *value = mode->blueBits;
      return 0;
   case GLX_ALPHA_SIZE:
      *value = mode->alphaBits;
      return 0;
   case GLX_DEPTH_SIZE:
      *value = mode->depthBits;
      return 0;
   case GLX_STENCIL_SIZE:
      *value = mode->stencilBits;
      return 0;
   default:
      *value = 0;
      return GLX_BAD_ATTRIBUTE;
   }
   return 0;
}


/**
 * \brief Create a new GLX rendering context.
 *
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param vis the visual that defines the frame buffer resources available to
 * the rendering context, as returned by glXChooseVisual().
 * \param shareList If non-zero, texture objects and display lists are shared
 * with the named rendering context. If zero, texture objects and display lists
 * will (initially) be private to this context. They may be shared when a
 * subsequent context is created.
 * \param direct whether direct or indirect rendering is desired. For Mini GLX
 * this value is ignored but it should be set to \c True.
 *
 * \return a ::GLXContext handle if it succeeds or zero if it fails due to
 * invalid parameter or insufficient resources.
 *
 * This function creates and initializes a ::MiniGLXContextRec structure and
 * calls the __DRIscreenRec::createContext method to initialize the client
 * private data.
 */ 
GLXContext
glXCreateContext( Display *dpy, XVisualInfo *vis,
                        GLXContext shareList, Bool direct )
{
   GLXContext ctx;
   void *sharePriv;

   ASSERT(vis);

   ctx = (struct MiniGLXContextRec *)calloc(1, sizeof(struct MiniGLXContextRec));
   if (!ctx)
      return NULL;

   ctx->vid = vis->visualid;
 
   if (shareList)
      sharePriv = shareList->driContext;
   else
      sharePriv = NULL;
   
   ctx->driContext = (*dpy->driScreen->createContext)(dpy->driScreen, 
						      vis->visual->mode,
						      sharePriv);
   if (!ctx->driContext) {
      free(ctx);
      return NULL;
   }

   return ctx;
}


/**
 * \brief Destroy a GLX context.
 *
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param ctx the GLX context to be destroyed.
 * 
 * This function frees the \p ctx parameter after unbinding the current context
 * by calling the __DRIcontextRec::bindContext method with zeros and calling
 * the __DRIcontextRec::destroyContext method.
 */
void
glXDestroyContext( Display *dpy, GLXContext ctx )
{
   GLXContext glxctx = glXGetCurrentContext();

   if (ctx) {
      if (glxctx == ctx) {
         /* destroying current context */
         (*ctx->driContext->bindContext)(dpy->driScreen, 0, 0);
	 CurrentContext = 0;
      }
      (*ctx->driContext->destroyContext)(ctx->driContext);
      free(ctx);
   }
}


/**
 * \brief Bind a GLX context to a window or a pixmap.
 *
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param drawable the window or drawable to bind to the rendering context.
 * This should be the value returned by XCreateWindow().
 * \param ctx the GLX context to be destroyed.
 *
 * \return \c True if it succeeds, \c False otherwise to indicate an invalid
 * display, window or context parameter.
 *
 * The current rendering context may be unbound by calling glXMakeCurrent()
 * with the window and context parameters set to zero.
 * 
 * An application may create any number of rendering contexts and bind them as
 * needed. Note that binding a rendering context is generally not a
 * light-weight operation.  Most simple OpenGL applications create only one
 * rendering context.
 *
 * This function first unbinds any old context via
 * __DRIcontextRec::unbindContext and binds the new one via
 * __DRIcontextRec::bindContext.
 *
 * If \p drawable is zero it unbinds the GLX context by calling
 * __DRIcontextRec::bindContext with zeros.
 */
Bool
glXMakeCurrent( Display *dpy, GLXDrawable drawable, GLXContext ctx)
{
   if (dpy && drawable && ctx) {
      GLXContext oldContext = glXGetCurrentContext();
      GLXDrawable oldDrawable = glXGetCurrentDrawable();
      /* unbind old */
      if (oldContext) {
         (*oldContext->driContext->unbindContext)(oldDrawable->driDrawable, oldContext->driContext);
      }
      /* bind new */
      CurrentContext = ctx;
      (*ctx->driContext->bindContext)(dpy->driScreen, drawable->driDrawable, ctx->driContext);
      ctx->drawBuffer = drawable;
      ctx->curBuffer = drawable;
   }
   else if (ctx && dpy) {
      /* unbind */
      (*ctx->driContext->bindContext)(dpy->driScreen, 0, 0);
   }
   else if (dpy) {
      CurrentContext = 0;	/* kw:  this seems to be intended??? */
   }

   return True;
}


/**
 * \brief Exchange front and back buffers.
 * 
 * \param dpy the display handle, as returned by XOpenDisplay().
 * \param drawable the drawable whose buffers are to be swapped.
 * 
 * Any pending rendering commands will be completed before the buffer swap
 * takes place.
 * 
 * Calling glXSwapBuffers() on a window which is single-buffered has no effect.
 *
 * This function just calls the __DRIdrawableRec::swapBuffers method to do the
 * work.
 */
void
glXSwapBuffers( Display *dpy, GLXDrawable drawable )
{
   if (!dpy || !drawable)
      return;

   (*drawable->driDrawable->swapBuffers)(drawable->driDrawable);
}


/**
 * \brief Return the current context
 *
 * \return the current context, as specified by glXMakeCurrent(), or zero if no
 * context is currently bound.
 *
 * \sa glXCreateContext(), glXMakeCurrent()
 *
 * Returns the value of the ::CurrentContext global variable.
 */
GLXContext
glXGetCurrentContext( void )
{
   return CurrentContext;
}


/**
 * \brief Return the current drawable.
 *
 * \return the current drawable, as specified by glXMakeCurrent(), or zero if
 * no drawable is currently bound.
 *
 * This function gets the current context via glXGetCurrentContext() and
 * returns the MiniGLXContextRec::drawBuffer attribute.
 */
GLXDrawable
glXGetCurrentDrawable( void )
{
   GLXContext glxctx = glXGetCurrentContext();
   if (glxctx)
      return glxctx->drawBuffer;
   else
      return NULL;
}


/**
 * \brief Query function address.
 *
 * The glXGetProcAddress() function will return the address of any available
 * OpenGL or Mini GLX function.
 * 
 * \param procName name of the function to be returned.
 *
 * \return If \p procName is a valid function name, a pointer to that function
 * will be returned.  Otherwise, \c NULL will be returned.
 *
 * The purpose of glXGetProcAddress() is to facilitate using future extensions
 * to OpenGL or Mini GLX. If a future version of the library adds new extension
 * functions they'll be accessible via glXGetProcAddress(). The alternative is
 * to hard-code calls to the new functions in the application but doing so will
 * prevent linking the application with older versions of the library.
 * 
 * Returns the function address by looking up its name in a static (name,
 * address) pair list.
 */
const void *
glXGetProcAddress( const GLubyte *procName )
{
   struct name_address {
      const char *name;
      const void *func;
   };
   static const struct name_address functions[] = {
      { "glXChooseVisual", (void *) glXChooseVisual },
      { "glXCreateContext", (void *) glXCreateContext },
      { "glXDestroyContext", (void *) glXDestroyContext },
      { "glXMakeCurrent", (void *) glXMakeCurrent },
      { "glXSwapBuffers", (void *) glXSwapBuffers },
      { "glXGetCurrentContext", (void *) glXGetCurrentContext },
      { "glXGetCurrentDrawable", (void *) glXGetCurrentDrawable },
      { "glXGetProcAddress", (void *) glXGetProcAddress },
      { "XOpenDisplay", (void *) XOpenDisplay },
      { "XCloseDisplay", (void *) XCloseDisplay },
      { "XCreateWindow", (void *) XCreateWindow },
      { "XDestroyWindow", (void *) XDestroyWindow },
      { "XMapWindow", (void *) XMapWindow },
      { "XCreateColormap", (void *) XCreateColormap },
      { "XFreeColormap", (void *) XFreeColormap },
      { "XFree", (void *) XFree },
      { "XGetVisualinfo", (void *) XGetVisualInfo },
      { NULL, NULL }
   };
   const struct name_address *entry;
   for (entry = functions; entry->name; entry++) {
      if (strcmp(entry->name, (const char *) procName) == 0) {
         return entry->func;
      }
   }
   return _glapi_get_proc_address((const char *) procName);
}


/**
 * \brief Query the Mini GLX version.
 *
 * \param dpy the display handle. It is currently ignored, but should be the
 * value returned by XOpenDisplay().
 * \param major receives the major version number of Mini GLX.
 * \param minor receives the minor version number of Mini GLX.
 *
 * \return \c True if the function succeeds, \c False if the function fails due
 * to invalid parameters.
 *
 * \sa #MINI_GLX_VERSION_1_0.
 * 
 * Returns the hard-coded Mini GLX version.
 */
Bool
glXQueryVersion( Display *dpy, int *major, int *minor )
{
   (void) dpy;
   *major = 1;
   *minor = 0;
   return True;
}


/*@}*/