summaryrefslogtreecommitdiff
path: root/src/mesa/drivers/x11/xm_api.c
blob: d5cc5f7d11179e8f992ae0533b45277a517e80da (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
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
/* $Id: xm_api.c,v 1.33 2002/03/01 04:28:32 brianp Exp $ */

/*
 * Mesa 3-D graphics library
 * Version:  4.1
 *
 * Copyright (C) 1999-2002  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.
 */
/* $XFree86: xc/extras/Mesa/src/X/xm_api.c,v 1.2 2002/02/26 23:37:31 tsi Exp $ */

/*
 * This file contains the implementations of all the XMesa* functions.
 *
 *
 * NOTES:
 *
 * The window coordinate system origin (0,0) is in the lower-left corner
 * of the window.  X11's window coordinate origin is in the upper-left
 * corner of the window.  Therefore, most drawing functions in this
 * file have to flip Y coordinates.
 *
 * Define USE_XSHM in the Makefile with -DUSE_XSHM if you want to compile
 * in support for the MIT Shared Memory extension.  If enabled, when you
 * use an Ximage for the back buffer in double buffered mode, the "swap"
 * operation will be faster.  You must also link with -lXext.
 *
 * Byte swapping:  If the Mesa host and the X display use a different
 * byte order then there's some trickiness to be aware of when using
 * XImages.  The byte ordering used for the XImage is that of the X
 * display, not the Mesa host.
 * The color-to-pixel encoding for True/DirectColor must be done
 * according to the display's visual red_mask, green_mask, and blue_mask.
 * If XPutPixel is used to put a pixel into an XImage then XPutPixel will
 * do byte swapping if needed.  If one wants to directly "poke" the pixel
 * into the XImage's buffer then the pixel must be byte swapped first.  In
 * Mesa, when byte swapping is needed we use the PF_TRUECOLOR pixel format
 * and use XPutPixel everywhere except in the implementation of
 * glClear(GL_COLOR_BUFFER_BIT).  We want this function to be fast so
 * instead of using XPutPixel we "poke" our values after byte-swapping
 * the clear pixel value if needed.
 *
 */

#ifdef __CYGWIN__
#undef WIN32
#undef __WIN32__
#endif

#include "glxheader.h"
#include "GL/xmesa.h"
#include "xmesaP.h"
#include "context.h"
#include "extensions.h"
#include "glthread.h"
#include "matrix.h"
#include "mem.h"
#include "mmath.h"
#include "mtypes.h"
#ifdef HAVE_CONFIG_H
#include "conf.h"
#endif
#include "macros.h"
#include "texformat.h"
#include "texstore.h"
#include "swrast/swrast.h"
#include "swrast_setup/swrast_setup.h"
#include "array_cache/acache.h"
#include "tnl/tnl.h"

#ifndef GLX_NONE_EXT
#define GLX_NONE_EXT 0x8000
#endif


/*
 * Global X driver lock
 */
_glthread_Mutex _xmesa_lock;



/*
 * Lookup tables for HPCR pixel format:
 */
static short hpcr_rgbTbl[3][256] = {
{
 16,  16,  17,  17,  18,  18,  19,  19,  20,  20,  21,  21,  22,  22,  23,  23,
 24,  24,  25,  25,  26,  26,  27,  27,  28,  28,  29,  29,  30,  30,  31,  31,
 32,  32,  33,  33,  34,  34,  35,  35,  36,  36,  37,  37,  38,  38,  39,  39,
 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
},
{
 16,  16,  17,  17,  18,  18,  19,  19,  20,  20,  21,  21,  22,  22,  23,  23,
 24,  24,  25,  25,  26,  26,  27,  27,  28,  28,  29,  29,  30,  30,  31,  31,
 32,  32,  33,  33,  34,  34,  35,  35,  36,  36,  37,  37,  38,  38,  39,  39,
 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
},
{
 32,  32,  33,  33,  34,  34,  35,  35,  36,  36,  37,  37,  38,  38,  39,  39,
 40,  40,  41,  41,  42,  42,  43,  43,  44,  44,  45,  45,  46,  46,  47,  47,
 48,  48,  49,  49,  50,  50,  51,  51,  52,  52,  53,  53,  54,  54,  55,  55,
 56,  56,  57,  57,  58,  58,  59,  59,  60,  60,  61,  61,  62,  62,  63,  63,
 64,  64,  65,  65,  66,  66,  67,  67,  68,  68,  69,  69,  70,  70,  71,  71,
 72,  72,  73,  73,  74,  74,  75,  75,  76,  76,  77,  77,  78,  78,  79,  79,
 80,  80,  81,  81,  82,  82,  83,  83,  84,  84,  85,  85,  86,  86,  87,  87,
 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
}
};



/**********************************************************************/
/*****                     X Utility Functions                    *****/
/**********************************************************************/


/*
 * X/Mesa error reporting function:
 */
static void error( const char *msg )
{
   (void)DitherValues;		/* Muffle compiler */

   if (getenv("MESA_DEBUG"))
      fprintf( stderr, "X/Mesa error: %s\n", msg );
}


/*
 * Return the host's byte order as LSBFirst or MSBFirst ala X.
 */
#ifndef XFree86Server
static int host_byte_order( void )
{
   int i = 1;
   char *cptr = (char *) &i;
   return (*cptr==1) ? LSBFirst : MSBFirst;
}
#endif


/*
 * Error handling.
 */
#ifndef XFree86Server
static int mesaXErrorFlag = 0;

static int mesaHandleXError( XMesaDisplay *dpy, XErrorEvent *event )
{
   (void) dpy;
   (void) event;
   mesaXErrorFlag = 1;
   return 0;
}
#endif


/*
 * Check if the X Shared Memory extension is available.
 * Return:  0 = not available
 *          1 = shared XImage support available
 *          2 = shared Pixmap support available also
 */
#ifndef XFree86Server
static int check_for_xshm( XMesaDisplay *display )
{
#ifdef USE_XSHM
   int major, minor, ignore;
   Bool pixmaps;

   if (XQueryExtension( display, "MIT-SHM", &ignore, &ignore, &ignore )) {
      if (XShmQueryVersion( display, &major, &minor, &pixmaps )==True) {
	 return (pixmaps==True) ? 2 : 1;
      }
      else {
	 return 0;
      }
   }
   else {
      return 0;
   }
#else
   /* Can't compile XSHM support */
   return 0;
#endif
}
#endif


/*
 * Return the width and height of the given drawable.
 */
static void get_drawable_size( XMesaDisplay *dpy, XMesaDrawable d,
                               unsigned int *width, unsigned int *height)
{
#ifdef XFree86Server
    (void) dpy;
    *width = d->width;
    *height = d->height;
#else
   Window root;
   int x, y;
   unsigned int bw, depth;

   _glthread_LOCK_MUTEX(_xmesa_lock);
   XGetGeometry( dpy, d, &root, &x, &y, width, height, &bw, &depth );
   _glthread_UNLOCK_MUTEX(_xmesa_lock);
#endif
}


/*
 * Apply gamma correction to an intensity value in [0..max].  Return the
 * new intensity value.
 */
static GLint gamma_adjust( GLfloat gamma, GLint value, GLint max )
{
   if (gamma == 1.0) {
      return value;
   }
   else {
      double x = (double) value / (double) max;
      return IROUND_POS((GLfloat) max * pow(x, 1.0F/gamma));
   }
}



/*
 * Return the true number of bits per pixel for XImages.
 * For example, if we request a 24-bit deep visual we may actually need/get
 * 32bpp XImages.  This function returns the appropriate bpp.
 * Input:  dpy - the X display
 *         visinfo - desribes the visual to be used for XImages
 * Return:  true number of bits per pixel for XImages
 */
#define GET_BITS_PER_PIXEL(xmv) bits_per_pixel(xmv)

#ifdef XFree86Server

static int bits_per_pixel( XMesaVisual xmv )
{
   XMesaVisualInfo visinfo = xmv->visinfo;
   const int depth = visinfo->nplanes;
   int i;
   for (i = 0; i < screenInfo.numPixmapFormats; i++) {
      if (screenInfo.formats[i].depth == depth)
         return screenInfo.formats[i].bitsPerPixel;
   }
   return depth;  /* should never get here, but this should be safe */
}

#else

static int bits_per_pixel( XMesaVisual xmv )
{
   XMesaDisplay *dpy = xmv->display;
   XMesaVisualInfo visinfo = xmv->visinfo;
   XMesaImage *img;
   int bitsPerPixel;
   /* Create a temporary XImage */
   img = XCreateImage( dpy, visinfo->visual, visinfo->depth,
		       ZPixmap, 0,           /*format, offset*/
		       (char*) MALLOC(8),    /*data*/
		       1, 1,                 /*width, height*/
		       32,                   /*bitmap_pad*/
		       0                     /*bytes_per_line*/
                     );
   assert(img);
   /* grab the bits/pixel value */
   bitsPerPixel = img->bits_per_pixel;
   /* free the XImage */
   FREE( img->data );
   img->data = NULL;
   XMesaDestroyImage( img );
   return bitsPerPixel;
}
#endif



/*
 * Determine if a given X window ID is valid (window exists).
 * Do this by calling XGetWindowAttributes() for the window and
 * checking if we catch an X error.
 * Input:  dpy - the display
 *         win - the window to check for existance
 * Return:  GL_TRUE - window exists
 *          GL_FALSE - window doesn't exist
 */
#ifndef XFree86Server
static GLboolean WindowExistsFlag;

static int window_exists_err_handler( XMesaDisplay* dpy, XErrorEvent* xerr )
{
   (void) dpy;
   if (xerr->error_code == BadWindow) {
      WindowExistsFlag = GL_FALSE;
   }
   return 0;
}

static GLboolean window_exists( XMesaDisplay *dpy, Window win )
{
   XWindowAttributes wa;
   int (*old_handler)( XMesaDisplay*, XErrorEvent* );
   WindowExistsFlag = GL_TRUE;
   old_handler = XSetErrorHandler(window_exists_err_handler);
   XGetWindowAttributes( dpy, win, &wa ); /* dummy request */
   XSetErrorHandler(old_handler);
   return WindowExistsFlag;
}
#endif



/**********************************************************************/
/*****                Linked list of XMesaBuffers                 *****/
/**********************************************************************/

static XMesaBuffer XMesaBufferList = NULL;


/* Allocate a new XMesaBuffer, add to linked list */
static XMesaBuffer alloc_xmesa_buffer(void)
{
   XMesaBuffer b = (XMesaBuffer) CALLOC_STRUCT(xmesa_buffer);
   if (b) {
      b->Next = XMesaBufferList;
      XMesaBufferList = b;
   }
   return b;
}


/*
 * Find an XMesaBuffer by matching X display and colormap but NOT matching
 * the notThis buffer.
 */
static XMesaBuffer find_xmesa_buffer(XMesaDisplay *dpy,
                                     XMesaColormap cmap,
                                     XMesaBuffer notThis)
{
   XMesaBuffer b;
   for (b=XMesaBufferList; b; b=b->Next) {
      if (b->display==dpy && b->cmap==cmap && b!=notThis) {
         return b;
      }
   }
   return NULL;
}


/*
 * Free an XMesaBuffer, remove from linked list, perhaps free X colormap
 * entries.
 */
static void free_xmesa_buffer(int client, XMesaBuffer buffer)
{
   XMesaBuffer prev = NULL, b;
   (void) client;
   for (b=XMesaBufferList; b; b=b->Next) {
      if (b==buffer) {
         /* unlink bufer from list */
         if (prev)
            prev->Next = buffer->Next;
         else
            XMesaBufferList = buffer->Next;
         /* Check to free X colors */
         if (buffer->num_alloced>0) {
            /* If no other buffer uses this X colormap then free the colors. */
            if (!find_xmesa_buffer(buffer->display, buffer->cmap, buffer)) {
#ifdef XFree86Server
               (void)FreeColors(buffer->cmap, client,
				buffer->num_alloced, buffer->alloced_colors,
				0);
#else
               XFreeColors(buffer->display, buffer->cmap,
                           buffer->alloced_colors, buffer->num_alloced, 0);
#endif
            }
         }

         _mesa_free_framebuffer_data(&buffer->mesa_buffer);
         FREE(buffer);

         return;
      }
      /* continue search */
      prev = b;
   }
   /* buffer not found in XMesaBufferList */
   _mesa_problem(NULL,"free_xmesa_buffer() - buffer not found\n");
}


/* Copy X color table stuff from one XMesaBuffer to another. */
static void copy_colortable_info(XMesaBuffer dst, const XMesaBuffer src)
{
   MEMCPY(dst->color_table, src->color_table, sizeof(src->color_table));
   MEMCPY(dst->pixel_to_r, src->pixel_to_r, sizeof(src->pixel_to_r));
   MEMCPY(dst->pixel_to_g, src->pixel_to_g, sizeof(src->pixel_to_g));
   MEMCPY(dst->pixel_to_b, src->pixel_to_b, sizeof(src->pixel_to_b));
   dst->num_alloced = src->num_alloced;
   MEMCPY(dst->alloced_colors, src->alloced_colors,
          sizeof(src->alloced_colors));
}



/**********************************************************************/
/*****                   Misc Private Functions                   *****/
/**********************************************************************/


/*
 * Return number of bits set in n.
 */
static int bitcount( unsigned long n )
{
   int bits;
   for (bits=0; n>0; n=n>>1) {
      if (n&1) {
         bits++;
      }
   }
   return bits;
}



/*
 * Allocate a shared memory XImage back buffer for the given XMesaBuffer.
 * Return:  GL_TRUE if success, GL_FALSE if error
 */
#ifndef XFree86Server
static GLboolean alloc_shm_back_buffer( XMesaBuffer b )
{
#ifdef USE_XSHM
   /*
    * We have to do a _lot_ of error checking here to be sure we can
    * really use the XSHM extension.  It seems different servers trigger
    * errors at different points if the extension won't work.  Therefore
    * we have to be very careful...
    */
   GC gc;
   int (*old_handler)( XMesaDisplay *, XErrorEvent * );

   b->backimage = XShmCreateImage( b->xm_visual->display,
                                   b->xm_visual->visinfo->visual,
                                   b->xm_visual->visinfo->depth,
				   ZPixmap, NULL, &b->shminfo,
				   b->width, b->height );
   if (b->backimage == NULL) {
      error("alloc_back_buffer: Shared memory error (XShmCreateImage), disabling.");
      b->shm = 0;
      return GL_FALSE;
   }

   b->shminfo.shmid = shmget( IPC_PRIVATE, b->backimage->bytes_per_line
			     * b->backimage->height, IPC_CREAT|0777 );
   if (b->shminfo.shmid < 0) {
      if (getenv("MESA_DEBUG"))
          perror("alloc_back_buffer");
      XDestroyImage( b->backimage );
      b->backimage = NULL;
      error("alloc_back_buffer: Shared memory error (shmget), disabling.");
      b->shm = 0;
      return GL_FALSE;
   }

   b->shminfo.shmaddr = b->backimage->data
                      = (char*)shmat( b->shminfo.shmid, 0, 0 );
   if (b->shminfo.shmaddr == (char *) -1) {
      if (getenv("MESA_DEBUG"))
          perror("alloc_back_buffer");
      XDestroyImage( b->backimage );
      shmctl( b->shminfo.shmid, IPC_RMID, 0 );
      b->backimage = NULL;
      error("alloc_back_buffer: Shared memory error (shmat), disabling.");
      b->shm = 0;
      return GL_FALSE;
   }

   b->shminfo.readOnly = False;
   mesaXErrorFlag = 0;
   old_handler = XSetErrorHandler( mesaHandleXError );
   /* This may trigger the X protocol error we're ready to catch: */
   XShmAttach( b->xm_visual->display, &b->shminfo );
   XSync( b->xm_visual->display, False );

   if (mesaXErrorFlag) {
      /* we are on a remote display, this error is normal, don't print it */
      XFlush( b->xm_visual->display );
      mesaXErrorFlag = 0;
      XDestroyImage( b->backimage );
      shmdt( b->shminfo.shmaddr );
      shmctl( b->shminfo.shmid, IPC_RMID, 0 );
      b->backimage = NULL;
      b->shm = 0;
      (void) XSetErrorHandler( old_handler );
      return GL_FALSE;
   }

   shmctl( b->shminfo.shmid, IPC_RMID, 0 ); /* nobody else needs it */

   /* Finally, try an XShmPutImage to be really sure the extension works */
   gc = XCreateGC( b->xm_visual->display, b->frontbuffer, 0, NULL );
   XShmPutImage( b->xm_visual->display, b->frontbuffer, gc,
		 b->backimage, 0, 0, 0, 0, 1, 1 /*one pixel*/, False );
   XSync( b->xm_visual->display, False );
   XFreeGC( b->xm_visual->display, gc );
   (void) XSetErrorHandler( old_handler );
   if (mesaXErrorFlag) {
      XFlush( b->xm_visual->display );
      mesaXErrorFlag = 0;
      XDestroyImage( b->backimage );
      shmdt( b->shminfo.shmaddr );
      shmctl( b->shminfo.shmid, IPC_RMID, 0 );
      b->backimage = NULL;
      b->shm = 0;
      return GL_FALSE;
   }

   if (b->backimage) {
      int height = b->backimage->height;
      /* Needed by PIXELADDR1 macro */
      b->ximage_width1 = b->backimage->bytes_per_line;
      b->ximage_origin1 = (GLubyte *) b->backimage->data
                        + b->ximage_width1 * (height-1);
      /* Needed by PIXELADDR2 macro */
      b->ximage_width2 = b->backimage->bytes_per_line / 2;
      b->ximage_origin2 = (GLushort *) b->backimage->data
                        + b->ximage_width2 * (height-1);
      /* Needed by PIXELADDR3 macro */
      b->ximage_width3 = b->backimage->bytes_per_line;
      b->ximage_origin3 = (GLubyte *) b->backimage->data
                        + b->ximage_width3 * (height-1);
      /* Needed by PIXELADDR4 macro */
      b->ximage_width4 = b->backimage->width;
      b->ximage_origin4 = (GLuint *) b->backimage->data
                        + b->ximage_width4 * (height-1);
   }

   return GL_TRUE;
#else
   /* Can't compile XSHM support */
   return GL_FALSE;
#endif
}
#endif



/*
 * Setup an off-screen pixmap or Ximage to use as the back buffer.
 * Input:  b - the X/Mesa buffer
 */
void xmesa_alloc_back_buffer( XMesaBuffer b )
{
   if (b->db_state==BACK_XIMAGE) {
      /* Deallocate the old backimage, if any */
      if (b->backimage) {
#if defined(USE_XSHM) && !defined(XFree86Server)
	 if (b->shm) {
	    XShmDetach( b->xm_visual->display, &b->shminfo );
	    XDestroyImage( b->backimage );
	    shmdt( b->shminfo.shmaddr );
	 }
	 else
#endif
	   XMesaDestroyImage( b->backimage );
	 b->backimage = NULL;
      }

      /* Allocate new back buffer */
#ifdef XFree86Server
      {
	 /* Allocate a regular XImage for the back buffer. */
	 b->backimage = XMesaCreateImage(b->xm_visual->BitsPerPixel,
					 b->width, b->height, NULL);
#else
      if (b->shm==0
	  || alloc_shm_back_buffer(b)==GL_FALSE
	  ) {
	 /* Allocate a regular XImage for the back buffer. */
	 b->backimage = XCreateImage( b->xm_visual->display,
                                      b->xm_visual->visinfo->visual,
                                      GET_VISUAL_DEPTH(b->xm_visual),
				      ZPixmap, 0,   /* format, offset */
				      NULL, b->width, b->height,
				      8, 0 );  /* pad, bytes_per_line */
#endif
	 if (!b->backimage) {
	    error("alloc_back_buffer: XCreateImage failed.");
	 }
         b->backimage->data = (char *) MALLOC( b->backimage->height
                                             * b->backimage->bytes_per_line );
         if (!b->backimage->data) {
            error("alloc_back_buffer: MALLOC failed.");
            XMesaDestroyImage( b->backimage );
            b->backimage = NULL;
         }
      }
      b->backpixmap = None;
   }
   else if (b->db_state==BACK_PIXMAP) {
      XMesaPixmap old_pixmap = b->backpixmap;
      /* Free the old back pixmap */
      if (b->backpixmap) {
	 XMesaFreePixmap( b->xm_visual->display, b->backpixmap );
      }
      /* Allocate new back pixmap */
      b->backpixmap = XMesaCreatePixmap( b->xm_visual->display, b->frontbuffer,
					 b->width, b->height,
					 GET_VISUAL_DEPTH(b->xm_visual) );
      b->backimage = NULL;
      /* update other references to backpixmap */
      if (b->buffer==(XMesaDrawable)old_pixmap) {
	 b->buffer = (XMesaDrawable)b->backpixmap;
      }
   }
}



/*
 * A replacement for XAllocColor.  This function should never
 * fail to allocate a color.  When XAllocColor fails, we return
 * the nearest matching color.  If we have to allocate many colors
 * this function isn't too efficient; the XQueryColors() could be
 * done just once.
 * Written by Michael Pichler, Brian Paul, Mark Kilgard
 * Input:  dpy - X display
 *         cmap - X colormap
 *         cmapSize - size of colormap
 * In/Out: color - the XColor struct
 * Output:  exact - 1=exact color match, 0=closest match
 *          alloced - 1=XAlloc worked, 0=XAlloc failed
 */
static void
noFaultXAllocColor( int client,
                    XMesaDisplay *dpy,
                    XMesaColormap cmap,
                    int cmapSize,
                    XMesaColor *color,
                    int *exact, int *alloced )
{
#ifdef XFree86Server
   Pixel *ppixIn;
   xrgb *ctable;
#else
   /* we'll try to cache ctable for better remote display performance */
   static Display *prevDisplay = NULL;
   static XMesaColormap prevCmap = 0;
   static int prevCmapSize = 0;
   static XMesaColor *ctable = NULL;
#endif
   XMesaColor subColor;
   int i, bestmatch;
   double mindist;       /* 3*2^16^2 exceeds long int precision. */

   (void) client;

   /* First try just using XAllocColor. */
#ifdef XFree86Server
   if (AllocColor(cmap,
		  &color->red, &color->green, &color->blue,
		  &color->pixel,
		  client) == Success) {
#else
   if (XAllocColor(dpy, cmap, color)) {
#endif
      *exact = 1;
      *alloced = 1;
      return;
   }

   /* Alloc failed, search for closest match */

   /* Retrieve color table entries. */
   /* XXX alloca candidate. */
#ifdef XFree86Server
   ppixIn = (Pixel *) MALLOC(cmapSize * sizeof(Pixel));
   ctable = (xrgb *) MALLOC(cmapSize * sizeof(xrgb));
   for (i = 0; i < cmapSize; i++) {
      ppixIn[i] = i;
   }
   QueryColors(cmap, cmapSize, ppixIn, ctable);
#else
   if (prevDisplay != dpy || prevCmap != cmap
       || prevCmapSize != cmapSize || !ctable) {
      /* free previously cached color table */
      if (ctable)
         FREE(ctable);
      /* Get the color table from X */
      ctable = (XMesaColor *) MALLOC(cmapSize * sizeof(XMesaColor));
      assert(ctable);
      for (i = 0; i < cmapSize; i++) {
         ctable[i].pixel = i;
      }
      XQueryColors(dpy, cmap, ctable, cmapSize);
      prevDisplay = dpy;
      prevCmap = cmap;
      prevCmapSize = cmapSize;
   }
#endif

   /* Find best match. */
   bestmatch = -1;
   mindist = 0.0;
   for (i = 0; i < cmapSize; i++) {
      double dr = 0.30 * ((double) color->red - (double) ctable[i].red);
      double dg = 0.59 * ((double) color->green - (double) ctable[i].green);
      double db = 0.11 * ((double) color->blue - (double) ctable[i].blue);
      double dist = dr * dr + dg * dg + db * db;
      if (bestmatch < 0 || dist < mindist) {
         bestmatch = i;
         mindist = dist;
      }
   }

   /* Return result. */
   subColor.red   = ctable[bestmatch].red;
   subColor.green = ctable[bestmatch].green;
   subColor.blue  = ctable[bestmatch].blue;
   /* Try to allocate the closest match color.  This should only
    * fail if the cell is read/write.  Otherwise, we're incrementing
    * the cell's reference count.
    */
#ifdef XFree86Server
   if (AllocColor(cmap,
		  &subColor.red, &subColor.green, &subColor.blue,
		  &subColor.pixel,
		  client) == Success) {
#else
   if (XAllocColor(dpy, cmap, &subColor)) {
#endif
      *alloced = 1;
   }
   else {
      /* do this to work around a problem reported by Frank Ortega */
      subColor.pixel = (unsigned long) bestmatch;
      subColor.red   = ctable[bestmatch].red;
      subColor.green = ctable[bestmatch].green;
      subColor.blue  = ctable[bestmatch].blue;
      subColor.flags = DoRed | DoGreen | DoBlue;
      *alloced = 0;
   }
#ifdef XFree86Server
   FREE(ppixIn);
   FREE(ctable);
#else
   /* don't free table, save it for next time */
#endif

   *color = subColor;
   *exact = 0;
}




/*
 * Do setup for PF_GRAYSCALE pixel format.
 * Note that buffer may be NULL.
 */
static GLboolean setup_grayscale( int client, XMesaVisual v,
                                  XMesaBuffer buffer, XMesaColormap cmap )
{
   if (GET_VISUAL_DEPTH(v)<4 || GET_VISUAL_DEPTH(v)>16) {
      return GL_FALSE;
   }

   if (buffer) {
      XMesaBuffer prevBuffer;

      if (!cmap) {
         return GL_FALSE;
      }

      prevBuffer = find_xmesa_buffer(v->display, cmap, buffer);
      if (prevBuffer &&
          (buffer->xm_visual->mesa_visual.rgbMode ==
           prevBuffer->xm_visual->mesa_visual.rgbMode)) {
         /* Copy colormap stuff from previous XMesaBuffer which uses same
          * X colormap.  Do this to avoid time spent in noFaultXAllocColor.
          */
         copy_colortable_info(buffer, prevBuffer);
      }
      else {
         /* Allocate 256 shades of gray */
         int gray;
         int colorsfailed = 0;
         for (gray=0;gray<256;gray++) {
            GLint r = gamma_adjust( v->RedGamma,   gray, 255 );
            GLint g = gamma_adjust( v->GreenGamma, gray, 255 );
            GLint b = gamma_adjust( v->BlueGamma,  gray, 255 );
            int exact, alloced;
            XMesaColor xcol;
            xcol.red   = (r << 8) | r;
            xcol.green = (g << 8) | g;
            xcol.blue  = (b << 8) | b;
            noFaultXAllocColor( client, v->display,
                                cmap, GET_COLORMAP_SIZE(v),
                                &xcol, &exact, &alloced );
            if (!exact) {
               colorsfailed++;
            }
            if (alloced) {
               assert(buffer->num_alloced<256);
               buffer->alloced_colors[buffer->num_alloced] = xcol.pixel;
               buffer->num_alloced++;
            }

            /*OLD
            assert(gray < 576);
            buffer->color_table[gray*3+0] = xcol.pixel;
            buffer->color_table[gray*3+1] = xcol.pixel;
            buffer->color_table[gray*3+2] = xcol.pixel;
            assert(xcol.pixel < 65536);
            buffer->pixel_to_r[xcol.pixel] = gray * 30 / 100;
            buffer->pixel_to_g[xcol.pixel] = gray * 59 / 100;
            buffer->pixel_to_b[xcol.pixel] = gray * 11 / 100;
            */
            buffer->color_table[gray] = xcol.pixel;
            assert(xcol.pixel < 65536);
            buffer->pixel_to_r[xcol.pixel] = gray;
            buffer->pixel_to_g[xcol.pixel] = gray;
            buffer->pixel_to_b[xcol.pixel] = gray;
         }

         if (colorsfailed && getenv("MESA_DEBUG")) {
            fprintf( stderr,
                  "Note: %d out of 256 needed colors do not match exactly.\n",
                  colorsfailed );
         }
      }
   }

   v->dithered_pf = PF_GRAYSCALE;
   v->undithered_pf = PF_GRAYSCALE;
   return GL_TRUE;
}



/*
 * Setup RGB rendering for a window with a PseudoColor, StaticColor,
 * or 8-bit TrueColor visual visual.  We try to allocate a palette of 225
 * colors (5 red, 9 green, 5 blue) and dither to approximate a 24-bit RGB
 * color.  While this function was originally designed just for 8-bit
 * visuals, it has also proven to work from 4-bit up to 16-bit visuals.
 * Dithering code contributed by Bob Mercier.
 */
static GLboolean setup_dithered_color( int client, XMesaVisual v,
                                       XMesaBuffer buffer, XMesaColormap cmap )
{
   if (GET_VISUAL_DEPTH(v)<4 || GET_VISUAL_DEPTH(v)>16) {
      return GL_FALSE;
   }

   if (buffer) {
      XMesaBuffer prevBuffer;

      if (!cmap) {
         return GL_FALSE;
      }

      prevBuffer = find_xmesa_buffer(v->display, cmap, buffer);
      if (prevBuffer &&
          (buffer->xm_visual->mesa_visual.rgbMode ==
           prevBuffer->xm_visual->mesa_visual.rgbMode)) {
         /* Copy colormap stuff from previous, matching XMesaBuffer.
          * Do this to avoid time spent in noFaultXAllocColor.
          */
         copy_colortable_info(buffer, prevBuffer);
      }
      else {
         /* Allocate X colors and initialize color_table[], red_table[], etc */
         int r, g, b, i;
         int colorsfailed = 0;
         for (r = 0; r < _R; r++) {
            for (g = 0; g < _G; g++) {
               for (b = 0; b < _B; b++) {
                  XMesaColor xcol;
                  int exact, alloced;
                  xcol.red  =gamma_adjust(v->RedGamma,   r*65535/(_R-1),65535);
                  xcol.green=gamma_adjust(v->GreenGamma, g*65535/(_G-1),65535);
                  xcol.blue =gamma_adjust(v->BlueGamma,  b*65535/(_B-1),65535);
                  noFaultXAllocColor( client, v->display,
                                      cmap, GET_COLORMAP_SIZE(v),
                                      &xcol, &exact, &alloced );
                  if (!exact) {
                     colorsfailed++;
                  }
                  if (alloced) {
                     assert(buffer->num_alloced<256);
                     buffer->alloced_colors[buffer->num_alloced] = xcol.pixel;
                     buffer->num_alloced++;
                  }
                  i = _MIX( r, g, b );
                  assert(i < 576);
                  buffer->color_table[i] = xcol.pixel;
                  assert(xcol.pixel < 65536);
                  buffer->pixel_to_r[xcol.pixel] = r * 255 / (_R-1);
                  buffer->pixel_to_g[xcol.pixel] = g * 255 / (_G-1);
                  buffer->pixel_to_b[xcol.pixel] = b * 255 / (_B-1);
               }
            }
         }

         if (colorsfailed && getenv("MESA_DEBUG")) {
            fprintf( stderr,
                  "Note: %d out of %d needed colors do not match exactly.\n",
                  colorsfailed, _R*_G*_B );
         }
      }
   }

   v->dithered_pf = PF_DITHER;
   v->undithered_pf = PF_LOOKUP;
   return GL_TRUE;
}


/*
 * Setup for Hewlett Packard Color Recovery 8-bit TrueColor mode.
 * HPCR simulates 24-bit color fidelity with an 8-bit frame buffer.
 * Special dithering tables have to be initialized.
 */
static void setup_8bit_hpcr( XMesaVisual v )
{
   /* HP Color Recovery contributed by:  Alex De Bruyn (ad@lms.be)
    * To work properly, the atom _HP_RGB_SMOOTH_MAP_LIST must be defined
    * on the root window AND the colormap obtainable by XGetRGBColormaps
    * for that atom must be set on the window.  (see also tkInitWindow)
    * If that colormap is not set, the output will look stripy.
    */

   /* Setup color tables with gamma correction */
   int i;
   double g;

   g = 1.0 / v->RedGamma;
   for (i=0; i<256; i++) {
      GLint red = IROUND_POS(255.0 * pow( hpcr_rgbTbl[0][i]/255.0, g ));
      v->hpcr_rgbTbl[0][i] = CLAMP( red, 16, 239 );
   }

   g = 1.0 / v->GreenGamma;
   for (i=0; i<256; i++) {
      GLint green = IROUND_POS(255.0 * pow( hpcr_rgbTbl[1][i]/255.0, g ));
      v->hpcr_rgbTbl[1][i] = CLAMP( green, 16, 239 );
   }

   g = 1.0 / v->BlueGamma;
   for (i=0; i<256; i++) {
      GLint blue = IROUND_POS(255.0 * pow( hpcr_rgbTbl[2][i]/255.0, g ));
      v->hpcr_rgbTbl[2][i] = CLAMP( blue, 32, 223 );
   }
   v->undithered_pf = PF_HPCR;  /* can't really disable dithering for now */
   v->dithered_pf = PF_HPCR;

   /* which method should I use to clear */
   /* GL_FALSE: keep the ordinary method  */
   /* GL_TRUE : clear with dither pattern */
   v->hpcr_clear_flag = getenv("MESA_HPCR_CLEAR") ? GL_TRUE : GL_FALSE;

   if (v->hpcr_clear_flag) {
      v->hpcr_clear_pixmap = XMesaCreatePixmap(v->display,
                                               DefaultRootWindow(v->display),
                                               16, 2, 8);
#ifndef XFree86Server
      v->hpcr_clear_ximage = XGetImage(v->display, v->hpcr_clear_pixmap,
                                       0, 0, 16, 2, AllPlanes, ZPixmap);
#endif
   }
}


/*
 * Setup RGB rendering for a window with a True/DirectColor visual.
 */
static void setup_truecolor( XMesaVisual v, XMesaBuffer buffer,
                             XMesaColormap cmap )
{
   unsigned long rmask, gmask, bmask;
   (void) buffer;
   (void) cmap;

   /* Compute red multiplier (mask) and bit shift */
   v->rshift = 0;
   rmask = GET_REDMASK(v);
   while ((rmask & 1)==0) {
      v->rshift++;
      rmask = rmask >> 1;
   }

   /* Compute green multiplier (mask) and bit shift */
   v->gshift = 0;
   gmask = GET_GREENMASK(v);
   while ((gmask & 1)==0) {
      v->gshift++;
      gmask = gmask >> 1;
   }

   /* Compute blue multiplier (mask) and bit shift */
   v->bshift = 0;
   bmask = GET_BLUEMASK(v);
   while ((bmask & 1)==0) {
      v->bshift++;
      bmask = bmask >> 1;
   }

   /*
    * Compute component-to-pixel lookup tables and dithering kernel
    */
   {
      static GLubyte kernel[16] = {
          0*16,  8*16,  2*16, 10*16,
         12*16,  4*16, 14*16,  6*16,
          3*16, 11*16,  1*16,  9*16,
         15*16,  7*16, 13*16,  5*16,
      };
      GLint rBits = bitcount(rmask);
      GLint gBits = bitcount(gmask);
      GLint bBits = bitcount(bmask);
      GLint maxBits;
      GLuint i;

      /* convert pixel components in [0,_mask] to RGB values in [0,255] */
      for (i=0; i<=rmask; i++)
         v->PixelToR[i] = (unsigned char) ((i * 255) / rmask);
      for (i=0; i<=gmask; i++)
         v->PixelToG[i] = (unsigned char) ((i * 255) / gmask);
      for (i=0; i<=bmask; i++)
         v->PixelToB[i] = (unsigned char) ((i * 255) / bmask);

      /* convert RGB values from [0,255] to pixel components */

      for (i=0;i<256;i++) {
         GLint r = gamma_adjust(v->RedGamma,   i, 255);
         GLint g = gamma_adjust(v->GreenGamma, i, 255);
         GLint b = gamma_adjust(v->BlueGamma,  i, 255);
         v->RtoPixel[i] = (r >> (8-rBits)) << v->rshift;
         v->GtoPixel[i] = (g >> (8-gBits)) << v->gshift;
         v->BtoPixel[i] = (b >> (8-bBits)) << v->bshift;
      }
      /* overflow protection */
      for (i=256;i<512;i++) {
         v->RtoPixel[i] = v->RtoPixel[255];
         v->GtoPixel[i] = v->GtoPixel[255];
         v->BtoPixel[i] = v->BtoPixel[255];
      }

      /* setup dithering kernel */
      maxBits = rBits;
      if (gBits > maxBits)  maxBits = gBits;
      if (bBits > maxBits)  maxBits = bBits;
      for (i=0;i<16;i++) {
         v->Kernel[i] = kernel[i] >> maxBits;
      }

      v->undithered_pf = PF_TRUECOLOR;
      v->dithered_pf = (GET_VISUAL_DEPTH(v)<24) ? PF_TRUEDITHER : PF_TRUECOLOR;
   }

   /*
    * Now check for TrueColor visuals which we can optimize.
    */
   if (   GET_REDMASK(v)  ==0x0000ff
       && GET_GREENMASK(v)==0x00ff00
       && GET_BLUEMASK(v) ==0xff0000
       && CHECK_BYTE_ORDER(v)
       && v->BitsPerPixel==32
       && sizeof(GLuint)==4
       && v->RedGamma==1.0 && v->GreenGamma==1.0 && v->BlueGamma==1.0) {
      /* common 32 bpp config used on SGI, Sun */
      v->undithered_pf = v->dithered_pf = PF_8A8B8G8R;
   }
   else if (GET_REDMASK(v)  ==0xff0000
       &&   GET_GREENMASK(v)==0x00ff00
       &&   GET_BLUEMASK(v) ==0x0000ff
       && CHECK_BYTE_ORDER(v)
       && v->BitsPerPixel==32
       && sizeof(GLuint)==4
       && v->RedGamma==1.0 && v->GreenGamma==1.0 && v->BlueGamma==1.0) {
      /* common 32 bpp config used on Linux, HP, IBM */
      v->undithered_pf = v->dithered_pf = PF_8R8G8B;
   }
   else if (GET_REDMASK(v)  ==0xff0000
       &&   GET_GREENMASK(v)==0x00ff00
       &&   GET_BLUEMASK(v) ==0x0000ff
       && CHECK_BYTE_ORDER(v)
       && v->BitsPerPixel==24
       && sizeof(GLuint)==4
       && v->RedGamma==1.0 && v->GreenGamma==1.0 && v->BlueGamma==1.0) {
      /* common packed 24 bpp config used on Linux */
      v->undithered_pf = v->dithered_pf = PF_8R8G8B24;
   }
   else if (GET_REDMASK(v)  ==0xf800
       &&   GET_GREENMASK(v)==0x07e0
       &&   GET_BLUEMASK(v) ==0x001f
       && CHECK_BYTE_ORDER(v)
       && v->BitsPerPixel==16
       && sizeof(GLushort)==2
       && v->RedGamma==1.0 && v->GreenGamma==1.0 && v->BlueGamma==1.0) {
      /* 5-6-5 color weight on common PC VGA boards */
      v->undithered_pf = PF_5R6G5B;
      v->dithered_pf = PF_DITHER_5R6G5B;
   }
   else if (GET_REDMASK(v)  ==0xe0
       &&   GET_GREENMASK(v)==0x1c
       &&   GET_BLUEMASK(v) ==0x03
       && CHECK_FOR_HPCR(v)) {
      setup_8bit_hpcr( v );
   }
}



/*
 * Setup RGB rendering for a window with a monochrome visual.
 */
static void setup_monochrome( XMesaVisual v, XMesaBuffer b )
{
   (void) b;
   v->dithered_pf = v->undithered_pf = PF_1BIT;
   /* if black=1 then we must flip pixel values */
   v->bitFlip = (GET_BLACK_PIXEL(v) != 0);
}



/*
 * When a context is "made current" for the first time, we can finally
 * finish initializing the context's visual and buffer information.
 * Input:  v - the XMesaVisual to initialize
 *         b - the XMesaBuffer to initialize (may be NULL)
 *         rgb_flag - TRUE = RGBA mode, FALSE = color index mode
 *         window - the window/pixmap we're rendering into
 *         cmap - the colormap associated with the window/pixmap
 * Return:  GL_TRUE=success, GL_FALSE=failure
 */
static GLboolean initialize_visual_and_buffer( int client,
                                               XMesaVisual v,
                                               XMesaBuffer b,
                                               GLboolean rgb_flag,
                                               XMesaDrawable window,
                                               XMesaColormap cmap
                                             )
{
#ifndef XFree86Server
   XGCValues gcvalues;
#endif

   if (b) {
      assert(b->xm_visual == v);
   }

   /* Save true bits/pixel */
   v->BitsPerPixel = GET_BITS_PER_PIXEL(v);
   assert(v->BitsPerPixel > 0);


   if (rgb_flag==GL_FALSE) {
      /* COLOR-INDEXED WINDOW:
       * Even if the visual is TrueColor or DirectColor we treat it as
       * being color indexed.  This is weird but might be useful to someone.
       */
      v->dithered_pf = v->undithered_pf = PF_INDEX;
      v->index_bits = GET_VISUAL_DEPTH(v);
   }
   else {
      /* RGB WINDOW:
       * We support RGB rendering into almost any kind of visual.
       */
      int xclass;
      xclass = GET_VISUAL_CLASS(v);
      if (xclass==TrueColor || xclass==DirectColor) {
	 setup_truecolor( v, b, cmap );
      }
      else if (xclass==StaticGray && GET_VISUAL_DEPTH(v)==1) {
	 setup_monochrome( v, b );
      }
      else if (xclass==GrayScale || xclass==StaticGray) {
         if (!setup_grayscale( client, v, b, cmap )) {
            return GL_FALSE;
         }
      }
      else if ((xclass==PseudoColor || xclass==StaticColor)
               && GET_VISUAL_DEPTH(v)>=4 && GET_VISUAL_DEPTH(v)<=16) {
	 if (!setup_dithered_color( client, v, b, cmap )) {
            return GL_FALSE;
         }
      }
      else {
	 error("XMesa: RGB mode rendering not supported in given visual.");
	 return GL_FALSE;
      }
      v->index_bits = 0;

      if (getenv("MESA_NO_DITHER")) {
	 v->dithered_pf = v->undithered_pf;
      }
   }


   /*
    * If MESA_INFO env var is set print out some debugging info
    * which can help Brian figure out what's going on when a user
    * reports bugs.
    */
   if (getenv("MESA_INFO")) {
      fprintf(stderr, "X/Mesa visual = %p\n", (void *) v);
      fprintf(stderr, "X/Mesa dithered pf = %u\n", v->dithered_pf);
      fprintf(stderr, "X/Mesa undithered pf = %u\n", v->undithered_pf);
      fprintf(stderr, "X/Mesa level = %d\n", v->level);
      fprintf(stderr, "X/Mesa depth = %d\n", GET_VISUAL_DEPTH(v));
      fprintf(stderr, "X/Mesa bits per pixel = %d\n", v->BitsPerPixel);
   }

   if (b && window) {
      /* Do window-specific initializations */

      /* Window dimensions */
      unsigned int w, h;
      get_drawable_size( v->display, window, &w, &h );
      b->width = w;
      b->height = h;

      b->frontbuffer = window;

      /* Setup for single/double buffering */
      if (v->mesa_visual.doubleBufferMode) {
         /* Double buffered */
#ifndef XFree86Server
         b->shm = check_for_xshm( v->display );
#endif
         xmesa_alloc_back_buffer( b );
         if (b->db_state==BACK_PIXMAP) {
            b->buffer = (XMesaDrawable)b->backpixmap;
         }
         else {
            b->buffer = XIMAGE;
         }
      }
      else {
         /* Single Buffered */
         b->buffer = b->frontbuffer;
      }

      /* X11 graphics contexts */
#ifdef XFree86Server
      b->gc = CreateScratchGC(v->display, window->depth);
#else
      b->gc = XCreateGC( v->display, window, 0, NULL );
#endif
      XMesaSetFunction( v->display, b->gc, GXcopy );

      /* cleargc - for glClear() */
#ifdef XFree86Server
      b->cleargc = CreateScratchGC(v->display, window->depth);
#else
      b->cleargc = XCreateGC( v->display, window, 0, NULL );
#endif
      XMesaSetFunction( v->display, b->cleargc, GXcopy );

      /*
       * Don't generate Graphics Expose/NoExpose events in swapbuffers().
       * Patch contributed by Michael Pichler May 15, 1995.
       */
#ifdef XFree86Server
      b->swapgc = CreateScratchGC(v->display, window->depth);
      {
	  CARD32 v[1];
	  v[0] = FALSE;
	  dixChangeGC(NullClient, b->swapgc, GCGraphicsExposures, v, NULL);
      }
#else
      gcvalues.graphics_exposures = False;
      b->swapgc = XCreateGC( v->display, window,
                              GCGraphicsExposures, &gcvalues);
#endif
      XMesaSetFunction( v->display, b->swapgc, GXcopy );
      /*
       * Set fill style and tile pixmap once for all for HPCR stuff
       * (instead of doing it each time in clear_color_HPCR_pixmap())
       * Initialize whole stuff
       * Patch contributed by Jacques Leroy March 8, 1998.
       */
      if (v->hpcr_clear_flag && b->buffer!=XIMAGE) {
	int i;
	for (i=0; i<16; i++)
        {
	   XMesaPutPixel(v->hpcr_clear_ximage, i, 0, 0);
	   XMesaPutPixel(v->hpcr_clear_ximage, i, 1, 0);
        }
        XMesaPutImage(b->display, (XMesaDrawable)v->hpcr_clear_pixmap,
		      b->cleargc, v->hpcr_clear_ximage, 0, 0, 0, 0, 16, 2);
	XMesaSetFillStyle( v->display, b->cleargc, FillTiled);
	XMesaSetTile( v->display, b->cleargc, v->hpcr_clear_pixmap );
      }

      /* Initialize the row buffer XImage for use in write_color_span() */
#ifdef XFree86Server
      b->rowimage = XMesaCreateImage(GET_VISUAL_DEPTH(v), MAX_WIDTH, 1,
				     (char *)MALLOC(MAX_WIDTH*4));
#else
      b->rowimage = XCreateImage( v->display,
                                  v->visinfo->visual,
                                  v->visinfo->depth,
                                  ZPixmap, 0,           /*format, offset*/
                                  (char*) MALLOC(MAX_WIDTH*4),  /*data*/
                                  MAX_WIDTH, 1,         /*width, height*/
                                  32,                   /*bitmap_pad*/
                                  0                     /*bytes_per_line*/ );
#endif
   }

   return GL_TRUE;
}



/*
 * Convert an RGBA color to a pixel value.
 */
unsigned long
xmesa_color_to_pixel( XMesaContext xmesa, GLubyte r, GLubyte g, GLubyte b, GLubyte a,
                      GLuint pixelFormat)
{
   switch (pixelFormat) {
      case PF_INDEX:
         return 0;
      case PF_TRUECOLOR:
         {
            unsigned long p;
            PACK_TRUECOLOR( p, r, g, b );
            return p;
         }
      case PF_8A8B8G8R:
         return PACK_8A8B8G8R( r, g, b, a );
      case PF_8R8G8B:
         /* fall through */
      case PF_8R8G8B24:
         return PACK_8R8G8B( r, g, b );
      case PF_5R6G5B:
         return PACK_5R6G5B( r, g, b );
      case PF_DITHER:
         {
            DITHER_SETUP;
            return DITHER( 1, 0, r, g, b );
         }
      case PF_1BIT:
         /* 382 = (3*255)/2 */
         return ((r+g+b) > 382) ^ xmesa->xm_visual->bitFlip;
      case PF_HPCR:
         return DITHER_HPCR(1, 1, r, g, b);
      case PF_LOOKUP:
         {
            LOOKUP_SETUP;
            return LOOKUP( r, g, b );
         }
      case PF_GRAYSCALE:
         return GRAY_RGB( r, g, b );
      case PF_TRUEDITHER:
         /* fall through */
      case PF_DITHER_5R6G5B:
         {
            unsigned long p;
            PACK_TRUEDITHER(p, 1, 0, r, g, b);
            return p;
         }
      default:
         _mesa_problem(NULL, "Bad pixel format in xmesa_color_to_pixel");
   }
   return 0;
}


/**********************************************************************/
/*****                       Public Functions                     *****/
/**********************************************************************/


/*
 * Create a new X/Mesa visual.
 * Input:  display - X11 display
 *         visinfo - an XVisualInfo pointer
 *         rgb_flag - GL_TRUE = RGB mode,
 *                    GL_FALSE = color index mode
 *         alpha_flag - alpha buffer requested?
 *         db_flag - GL_TRUE = double-buffered,
 *                   GL_FALSE = single buffered
 *         stereo_flag - stereo visual?
 *         ximage_flag - GL_TRUE = use an XImage for back buffer,
 *                       GL_FALSE = use an off-screen pixmap for back buffer
 *         depth_size - requested bits/depth values, or zero
 *         stencil_size - requested bits/stencil values, or zero
 *         accum_red_size - requested bits/red accum values, or zero
 *         accum_green_size - requested bits/green accum values, or zero
 *         accum_blue_size - requested bits/blue accum values, or zero
 *         accum_alpha_size - requested bits/alpha accum values, or zero
 *         num_samples - number of samples/pixel if multisampling, or zero
 *         level - visual level, usually 0
 *         visualCaveat - ala the GLX extension, usually GLX_NONE_EXT
 * Return;  a new XMesaVisual or 0 if error.
 */
XMesaVisual XMesaCreateVisual( XMesaDisplay *display,
                               XMesaVisualInfo visinfo,
                               GLboolean rgb_flag,
                               GLboolean alpha_flag,
                               GLboolean db_flag,
                               GLboolean stereo_flag,
                               GLboolean ximage_flag,
                               GLint depth_size,
                               GLint stencil_size,
                               GLint accum_red_size,
                               GLint accum_green_size,
                               GLint accum_blue_size,
                               GLint accum_alpha_size,
                               GLint num_samples,
                               GLint level,
                               GLint visualCaveat )
{
   char *gamma;
   XMesaVisual v;
   GLint red_bits, green_bits, blue_bits, alpha_bits;

   /* For debugging only */
   if (getenv("MESA_XSYNC")) {
      /* This makes debugging X easier.
       * In your debugger, set a breakpoint on _XError to stop when an
       * X protocol error is generated.
       */
#ifdef XFree86Server
      /* NOT_NEEDED */
#else
      XSynchronize( display, 1 );
#endif
   }

   v = (XMesaVisual) CALLOC_STRUCT(xmesa_visual);
   if (!v) {
      return NULL;
   }

   /*
    * In the X server, NULL is passed in for the display.  It will have
    * to be set before using this visual.  See XMesaSetVisualDisplay()
    * below.
    */
   v->display = display;

   /* Save a copy of the XVisualInfo struct because the user may XFREE()
    * the struct but we may need some of the information contained in it
    * at a later time.
    */
#ifdef XFree86Server
   v->visinfo = visinfo;
#else
   v->visinfo = (XVisualInfo *) MALLOC(sizeof(*visinfo));
   if(!v->visinfo) {
      FREE(v);
      return NULL;
   }
   MEMCPY(v->visinfo, visinfo, sizeof(*visinfo));

   /* Save a copy of the pointer now so we can find this visual again
    * if we need to search for it in find_glx_visual().
    */
   v->vishandle = visinfo;
#endif

#ifdef XFree86Server
   /* Initialize the depth of the screen */
   {
       PixmapFormatRec *format;

       for (format = screenInfo.formats;
	    format->depth != display->rootDepth;
	    format++)
	   ;
       v->screen_depth = format->bitsPerPixel;
   }
#endif

   /* check for MESA_GAMMA environment variable */
   gamma = getenv("MESA_GAMMA");
   if (gamma) {
      v->RedGamma = v->GreenGamma = v->BlueGamma = 0.0;
      sscanf( gamma, "%f %f %f", &v->RedGamma, &v->GreenGamma, &v->BlueGamma );
      if (v->RedGamma<=0.0)    v->RedGamma = 1.0;
      if (v->GreenGamma<=0.0)  v->GreenGamma = v->RedGamma;
      if (v->BlueGamma<=0.0)   v->BlueGamma = v->RedGamma;
   }
   else {
      v->RedGamma = v->GreenGamma = v->BlueGamma = 1.0;
   }

   v->ximage_flag = ximage_flag;
   v->level = level;
   v->VisualCaveat = visualCaveat;

   (void) initialize_visual_and_buffer( 0, v, NULL, rgb_flag, 0, 0 );

   {
      int xclass;
      xclass = GET_VISUAL_CLASS(v);
      if (xclass==TrueColor || xclass==DirectColor) {
         red_bits   = bitcount(GET_REDMASK(v));
         green_bits = bitcount(GET_GREENMASK(v));
         blue_bits  = bitcount(GET_BLUEMASK(v));
         alpha_bits = 0;
      }
      else {
         /* this is an approximation */
         int depth;
         depth = GET_VISUAL_DEPTH(v);
         red_bits = depth / 3;
         depth -= red_bits;
         green_bits = depth / 2;
         depth -= green_bits;
         blue_bits = depth;
         alpha_bits = 0;
         assert( red_bits + green_bits + blue_bits == GET_VISUAL_DEPTH(v) );
      }
   }

   if (alpha_flag && alpha_bits == 0)
      alpha_bits = 8;

   _mesa_initialize_visual( &v->mesa_visual,
                            rgb_flag, db_flag, stereo_flag,
                            red_bits, green_bits,
                            blue_bits, alpha_bits,
                            v->index_bits,
                            depth_size,
                            stencil_size,
                            accum_red_size, accum_green_size,
                            accum_blue_size, accum_alpha_size,
                            0 );
   return v;
}


void XMesaSetVisualDisplay( XMesaDisplay *dpy, XMesaVisual v )
{
    v->display = dpy;
}


void XMesaDestroyVisual( XMesaVisual v )
{
#ifndef XFree86Server
   FREE(v->visinfo);
#endif
   FREE(v);
}



/*
 * Create a new XMesaContext.
 * Input:  v - XMesaVisual
 *         share_list - another XMesaContext with which to share display
 *                      lists or NULL if no sharing is wanted.
 * Return:  an XMesaContext or NULL if error.
 */
XMesaContext XMesaCreateContext( XMesaVisual v, XMesaContext share_list )
{
   XMesaContext c;
   GLcontext *ctx;
   GLboolean direct = GL_TRUE; /* XXXX */
   /* NOT_DONE: should this be GL_FALSE??? */
   static GLboolean firstTime = GL_TRUE;

   if (firstTime) {
      _glthread_INIT_MUTEX(_xmesa_lock);
      firstTime = GL_FALSE;
   }

   c = (XMesaContext) CALLOC_STRUCT(xmesa_context);
   if (!c) {
      return NULL;
   }

   ctx = c->gl_ctx = _mesa_create_context( &v->mesa_visual,
                      share_list ? share_list->gl_ctx : (GLcontext *) NULL,
                      (void *) c, direct );
   if (!c->gl_ctx) {
      FREE(c);
      return NULL;
   }

   _mesa_enable_sw_extensions(ctx);
   _mesa_enable_1_3_extensions(ctx);

   if (CHECK_BYTE_ORDER(v)) {
      c->swapbytes = GL_FALSE;
   }
   else {
      c->swapbytes = GL_TRUE;
   }

   c->xm_visual = v;
   c->xm_buffer = NULL;   /* set later by XMesaMakeCurrent */
   c->display = v->display;
   c->pixelformat = v->dithered_pf;      /* Dithering is enabled by default */

   ctx->Driver.UpdateState = xmesa_update_state;

   /* Initialize the software rasterizer and helper modules.
    */
   _swrast_CreateContext( ctx );
   _ac_CreateContext( ctx );
   _tnl_CreateContext( ctx );
   _swsetup_CreateContext( ctx );

   xmesa_register_swrast_functions( ctx );

   /* Set up some constant pointers:
    */
   xmesa_init_pointers( ctx );


   /* Run the config file
    */
   _mesa_read_config_file( ctx );


   return c;
}




void XMesaDestroyContext( XMesaContext c )
{
#ifdef FX
   if (c->xm_buffer && c->xm_buffer->FXctx)
      fxMesaDestroyContext(c->xm_buffer->FXctx);
#endif
   if (c->gl_ctx) {
      _swsetup_DestroyContext( c->gl_ctx );
      _swrast_DestroyContext( c->gl_ctx );
      _tnl_DestroyContext( c->gl_ctx );
      _ac_DestroyContext( c->gl_ctx );
      _mesa_destroy_context( c->gl_ctx );
   }

   /*
    * XXX This code should really go away because the ancilliary data
    * associated with a window/pixmap should not go away just because
    * a context is destroyed.
    */
#if 0
   /* Destroy any buffers which are using this context.  If we don't
    * we may have dangling references.  Hmm, maybe we should just
    * set the buffer's context pointer to NULL instead of deleting it?
    * Let's see if we get any bug reports...
    * This contributed by Doug Rabson <dfr@calcaphon.com>
    */
   {
      XMesaBuffer b, next;
      for (b = XMesaBufferList; b; b = next) {
         next = b->Next;
         if (!b->pixmap_flag) {
#ifndef XFree86Server
            XSync(b->display, False);
#endif
            if (b->xm_context == c) {
               /* found a context created for this context */
               XMesaDestroyBuffer( b );
            }
         }
      }
   }
#endif

   FREE( c );
}



/*
 * XXX this isn't a public function!  It's a hack for the 3Dfx driver.
 * Create a new XMesaBuffer from an X window.
 * Input:  v - the XMesaVisual
 *         w - the window
 *         c - the context
 * Return:  new XMesaBuffer or NULL if error
 */
XMesaBuffer XMesaCreateWindowBuffer2( XMesaVisual v, XMesaWindow w,
                                      XMesaContext c )
{
#ifndef XFree86Server
   XWindowAttributes attr;
#endif
#ifdef FX
   char *fxEnvVar;
#endif
   int client = 0;

   XMesaBuffer b = alloc_xmesa_buffer();
   if (!b) {
      return NULL;
   }

   (void) c;

#ifdef XFree86Server
   client = CLIENT_ID(((XMesaDrawable)w)->id);
#endif

   assert(v);

#ifdef XFree86Server
   if (GET_VISUAL_DEPTH(v) != ((XMesaDrawable)w)->depth) {
#else
   XGetWindowAttributes( v->display, w, &attr );

   if (GET_VISUAL_DEPTH(v) != attr.depth) {
#endif
      if (getenv("MESA_DEBUG")) {
         fprintf(stderr, "XMesaCreateWindowBuffer: depth mismatch between visual and window!\n");
      }
      return NULL;
   }

   b->xm_context = NULL; /* Associate no context with this buffer */

   b->xm_visual = v;
   b->pixmap_flag = GL_FALSE;
   b->display = v->display;
#ifdef XFree86Server
   b->cmap = (ColormapPtr)LookupIDByType(wColormap(w), RT_COLORMAP);
#else
   if (attr.colormap) {
      b->cmap = attr.colormap;
   }
   else {
      if (getenv("MESA_DEBUG")) {
         fprintf(stderr, "Window %u has no colormap!\n", (unsigned int) w);
      }
      /* this is weird, a window w/out a colormap!? */
      /* OK, let's just allocate a new one and hope for the best */
      b->cmap = XCreateColormap(v->display, w, attr.visual, AllocNone);
   }
#endif

   /* determine back buffer implementation */
   if (v->mesa_visual.doubleBufferMode) {
      if (v->ximage_flag) {
	 b->db_state = BACK_XIMAGE;
      }
      else {
	 b->db_state = BACK_PIXMAP;
      }
   }
   else {
      b->db_state = 0;
   }

   _mesa_initialize_framebuffer(&b->mesa_buffer,
                                &v->mesa_visual,
                                v->mesa_visual.depthBits > 0,
                                v->mesa_visual.stencilBits > 0,
                                v->mesa_visual.accumRedBits > 0,
                                v->mesa_visual.alphaBits > 0 );

   if (!initialize_visual_and_buffer( client, v, b, v->mesa_visual.rgbMode,
                                      (XMesaDrawable)w, b->cmap )) {
      free_xmesa_buffer(client, b);
      return NULL;
   }

#ifdef FX
   fxEnvVar = getenv("MESA_GLX_FX");
   if (fxEnvVar) {
     if (fxEnvVar[0]!='d') {
       int attribs[100];
       int numAttribs = 0;
       int hw;
       if (v->mesa_visual.depthBits > 0) {
	 attribs[numAttribs++] = FXMESA_DEPTH_SIZE;
	 attribs[numAttribs++] = 1;
       }
       if (v->mesa_visual.doubleBufferMode) {
	 attribs[numAttribs++] = FXMESA_DOUBLEBUFFER;
       }
       if (v->mesa_visual.accumRedBits > 0) {
	 attribs[numAttribs++] = FXMESA_ACCUM_SIZE;
	 attribs[numAttribs++] = v->mesa_visual.accumRedBits;
       }
       if (v->mesa_visual.stencilBits > 0) {
         attribs[numAttribs++] = FXMESA_STENCIL_SIZE;
         attribs[numAttribs++] = v->mesa_visual.stencilBits;
       }
       if (v->mesa_visual.alphaBits > 0) {
         attribs[numAttribs++] = FXMESA_ALPHA_SIZE;
         attribs[numAttribs++] = 1;
       }
       if (c->gl_ctx) {
#define FXMESA_SHARE_CONTEXT 990099  /* keep in sync with fxapi.c! */
         attribs[numAttribs++] = FXMESA_SHARE_CONTEXT;
         attribs[numAttribs++] = (int) c->gl_ctx;
       }
       attribs[numAttribs++] = FXMESA_NONE;

       if ((hw = fxQueryHardware())==GR_SSTTYPE_VOODOO) {
         b->FXctx = fxMesaCreateBestContext(0, b->width, b->height, attribs);
         if ((v->undithered_pf!=PF_INDEX) && (b->backimage)) {
	   b->FXisHackUsable = b->FXctx ? GL_TRUE : GL_FALSE;
	   if (fxEnvVar[0]=='w' || fxEnvVar[0]=='W')
	     b->FXwindowHack = b->FXctx ? GL_TRUE : GL_FALSE;
	   else
	     b->FXwindowHack = GL_FALSE;
         }
       }
       else {
         if (fxEnvVar[0]=='w' || fxEnvVar[0]=='W')
	   b->FXctx = fxMesaCreateContext(w, GR_RESOLUTION_NONE,
					  GR_REFRESH_75Hz, attribs);
         else
	   b->FXctx = fxMesaCreateBestContext(0, b->width, b->height, attribs);
         b->FXisHackUsable = GL_FALSE;
         b->FXwindowHack = GL_FALSE;
       }
       /*
       fprintf(stderr,
               "voodoo %d, wid %d height %d hack: usable %d active %d\n",
               hw, b->width, b->height, b->FXisHackUsable, b->FXwindowHack);
       */
     }
   }
   else {
      fprintf(stderr,"WARNING: This Mesa Library includes the Glide driver but\n");
      fprintf(stderr,"         you have not defined the MESA_GLX_FX env. var.\n");
      fprintf(stderr,"         (check the README.3DFX file for more information).\n\n");
      fprintf(stderr,"         you can disable this message with a 'export MESA_GLX_FX=disable'.\n");
   }
#endif

   return b;
}


XMesaBuffer XMesaCreateWindowBuffer( XMesaVisual v, XMesaWindow w )
{
   return XMesaCreateWindowBuffer2( v, w, NULL );
}


/*
 * Create a new XMesaBuffer from an X pixmap.
 * Input:  v - the XMesaVisual
 *         p - the pixmap
 *         cmap - the colormap, may be 0 if using a TrueColor or DirectColor
 *                visual for the pixmap
 * Return:  new XMesaBuffer or NULL if error
 */
XMesaBuffer XMesaCreatePixmapBuffer( XMesaVisual v,
				     XMesaPixmap p, XMesaColormap cmap )
{
   int client = 0;
   XMesaBuffer b = alloc_xmesa_buffer();
   if (!b) {
      return NULL;
   }


#ifdef XFree86Server
   client = CLIENT_ID(((XMesaDrawable)p)->id);
#endif

   assert(v);

   b->xm_context = NULL; /* Associate no context with this buffer */

   b->xm_visual = v;
   b->pixmap_flag = GL_TRUE;
   b->display = v->display;
   b->cmap = cmap;

   /* determine back buffer implementation */
   if (v->mesa_visual.doubleBufferMode) {
      if (v->ximage_flag) {
	 b->db_state = BACK_XIMAGE;
      }
      else {
	 b->db_state = BACK_PIXMAP;
      }
   }
   else {
      b->db_state = 0;
   }

   _mesa_initialize_framebuffer(&b->mesa_buffer,
                                &v->mesa_visual,
                                v->mesa_visual.depthBits > 0,
                                v->mesa_visual.stencilBits > 0,
                                v->mesa_visual.accumRedBits +
                                v->mesa_visual.accumGreenBits +
                                v->mesa_visual.accumBlueBits > 0,
                                v->mesa_visual.alphaBits > 0 );

   if (!initialize_visual_and_buffer(client, v, b, v->mesa_visual.rgbMode,
				     (XMesaDrawable)p, cmap)) {
      free_xmesa_buffer(client, b);
      return NULL;
   }

   return b;
}



#if 0 /* not done */
XMesaBuffer XMesaCreatePBuffer( XMesaVisual v, XMesaColormap cmap,
                                unsigned int width, unsigned int height )
{
   int client = 0;
   XMesaBuffer b = alloc_xmesa_buffer();
   if (!b) {
      return NULL;
   }

   b->xm_context = NULL; /* Associate no context with this buffer */

   b->xm_visual = v;
   b->pbuffer_flag = GL_TRUE;
   b->display = v->display;
   b->cmap = cmap;

   /* determine back buffer implementation */
   if (v->mesa_visual.doubleBufferMode) {
      if (v->ximage_flag) {
	 b->db_state = BACK_XIMAGE;
      }
      else {
	 b->db_state = BACK_PIXMAP;
      }
   }
   else {
      b->db_state = 0;
   }

   _mesa_initialize_framebuffer(&b->mesa_buffer,
                                &v->mesa_visual,
                                v->mesa_visual.depthBits > 0,
                                v->mesa_visual.stencilBits > 0,
                                v->mesa_visual.accumRedBits +
                                v->mesa_visual.accumGreenBits +
                                v->mesa_visual.accumBlueBits > 0,
                                v->mesa_visual.alphaBits > 0 );

   if (!initialize_visual_and_buffer(client, v, b, v->mesa_visual.rgbMode,
				     0, cmap)) {
      free_xmesa_buffer(client, b);
      return NULL;
   }

   return b;
}
#endif



/*
 * Deallocate an XMesaBuffer structure and all related info.
 */
void XMesaDestroyBuffer( XMesaBuffer b )
{
   int client = 0;

#ifdef XFree86Server
   if (b->frontbuffer)
       client = CLIENT_ID(b->frontbuffer->id);
#endif

   if (b->gc)  XMesaFreeGC( b->xm_visual->display, b->gc );
   if (b->cleargc)  XMesaFreeGC( b->xm_visual->display, b->cleargc );
   if (b->swapgc)  XMesaFreeGC( b->xm_visual->display, b->swapgc );

   if (b->backimage) {
#if defined(USE_XSHM) && !defined(XFree86Server)
       if (b->shm) {
	   XShmDetach( b->xm_visual->display, &b->shminfo );
	   XDestroyImage( b->backimage );
	   shmdt( b->shminfo.shmaddr );
       }
       else
#endif
	   XMesaDestroyImage( b->backimage );
   }
   if (b->backpixmap) {
      XMesaFreePixmap( b->xm_visual->display, b->backpixmap );
      if (b->xm_visual->hpcr_clear_flag) {
	XMesaFreePixmap( b->xm_visual->display,
			 b->xm_visual->hpcr_clear_pixmap );
	XMesaDestroyImage( b->xm_visual->hpcr_clear_ximage );
      }
   }
   if (b->rowimage) {
      FREE( b->rowimage->data );
      b->rowimage->data = NULL;
      XMesaDestroyImage( b->rowimage );
   }

   if (b->xm_context)
      b->xm_context->xm_buffer = NULL;

   free_xmesa_buffer(client, b);
}



/*
 * Bind buffer b to context c and make c the current rendering context.
 */
GLboolean XMesaMakeCurrent( XMesaContext c, XMesaBuffer b )
{
   return XMesaMakeCurrent2( c, b, b );
}


/*
 * Bind buffer b to context c and make c the current rendering context.
 */
GLboolean XMesaMakeCurrent2( XMesaContext c, XMesaBuffer drawBuffer,
                             XMesaBuffer readBuffer )
{
   if (c) {
      if (!drawBuffer || !readBuffer)
         return GL_FALSE;  /* must specify buffers! */

#ifdef FX
      if (drawBuffer->FXctx) {
         fxMesaMakeCurrent(drawBuffer->FXctx);

         /* Disassociate drawBuffer's current context from drawBuffer */
         if (drawBuffer->xm_context)
            drawBuffer->xm_context->xm_buffer = NULL;

         /* Disassociate old buffer from this context */
         if (c->xm_buffer)
            c->xm_buffer->xm_context = NULL;

         /* Associate the context with this buffer */
         drawBuffer->xm_context = c;

         c->xm_buffer = drawBuffer;
         c->xm_read_buffer = readBuffer;
         c->use_read_buffer = (drawBuffer != readBuffer);

         return GL_TRUE;
      }
#endif
      if (c->gl_ctx == _mesa_get_current_context()
          && c->xm_buffer == drawBuffer
          && c->xm_read_buffer == readBuffer
          && c->xm_buffer->wasCurrent) {
         /* same context and buffer, do nothing */
         return GL_TRUE;
      }

      /* Disassociate drawBuffer's current context from drawBuffer */
      if (drawBuffer->xm_context)
         drawBuffer->xm_context->xm_buffer = NULL;
 
      /* Disassociate old buffer with this context */
      if (c->xm_buffer)
	  c->xm_buffer->xm_context = NULL;

      drawBuffer->xm_context = c; /* Associate the context with this buffer */

      c->xm_buffer = drawBuffer;
      c->xm_read_buffer = readBuffer;
      c->use_read_buffer = (drawBuffer != readBuffer);

      _mesa_make_current2(c->gl_ctx,
                          &drawBuffer->mesa_buffer,
                          &readBuffer->mesa_buffer);

      if (c->gl_ctx->Viewport.Width == 0) {
	 /* initialize viewport to window size */
	 _mesa_Viewport( 0, 0, drawBuffer->width, drawBuffer->height );
	 c->gl_ctx->Scissor.Width = drawBuffer->width;
	 c->gl_ctx->Scissor.Height = drawBuffer->height;
      }

      if (c->xm_visual->mesa_visual.rgbMode) {
         /*
          * Must recompute and set these pixel values because colormap
          * can be different for different windows.
          */
         c->clearpixel = xmesa_color_to_pixel( c,
                                               c->clearcolor[0],
                                               c->clearcolor[1],
                                               c->clearcolor[2],
                                               c->clearcolor[3],
                                               c->xm_visual->undithered_pf);
         XMesaSetForeground(c->display, c->xm_buffer->cleargc, c->clearpixel);
      }

      /* Solution to Stephane Rehel's problem with glXReleaseBuffersMESA(): */
      c->xm_buffer->wasCurrent = GL_TRUE;
   }
   else {
      /* Detach */
      _mesa_make_current2( NULL, NULL, NULL );
   }
   return GL_TRUE;
}


/*
 * Unbind the context c from its buffer.
 */
GLboolean XMesaUnbindContext( XMesaContext c )
{
   /* A no-op for XFree86 integration purposes */
   return GL_TRUE;
}


XMesaContext XMesaGetCurrentContext( void )
{
   GET_CURRENT_CONTEXT(ctx);
   if (ctx) {
      XMesaContext xmesa = (XMesaContext) ctx->DriverCtx;
      return xmesa;
   }
   else {
      return 0;
   }
}


XMesaBuffer XMesaGetCurrentBuffer( void )
{
   GET_CURRENT_CONTEXT(ctx);
   if (ctx) {
      XMesaContext xmesa = (XMesaContext) ctx->DriverCtx;
      return xmesa->xm_buffer;
   }
   else {
      return 0;
   }
}


/* New in Mesa 3.1 */
XMesaBuffer XMesaGetCurrentReadBuffer( void )
{
   GET_CURRENT_CONTEXT(ctx);
   if (ctx) {
      XMesaContext xmesa = (XMesaContext) ctx->DriverCtx;
      return xmesa->xm_buffer;
   }
   else {
      return 0;
   }
}


GLboolean XMesaForceCurrent(XMesaContext c)
{
   if (c) {
      if (c->gl_ctx != _mesa_get_current_context()) {
	 _mesa_make_current(c->gl_ctx, &c->xm_buffer->mesa_buffer);
      }
   }
   else {
      _mesa_make_current(NULL, NULL);
   }
   return GL_TRUE;
}


GLboolean XMesaLoseCurrent(XMesaContext c)
{
   (void) c;
   _mesa_make_current(NULL, NULL);
   return GL_TRUE;
}


/*
 * Switch 3Dfx support hack between window and full-screen mode.
 */
GLboolean XMesaSetFXmode( GLint mode )
{
#ifdef FX
   const char *fx = getenv("MESA_GLX_FX");
   if (fx && fx[0] != 'd') {
      GET_CURRENT_CONTEXT(ctx);
      GrHwConfiguration hw;
      if (!FX_grSstQueryHardware(&hw)) {
         /*fprintf(stderr, "!grSstQueryHardware\n");*/
         return GL_FALSE;
      }
      if (hw.num_sst < 1) {
         /*fprintf(stderr, "hw.num_sst < 1\n");*/
         return GL_FALSE;
      }
      if (ctx) {
         XMesaContext xmesa = (XMesaContext) ctx->DriverCtx;
         if (mode == XMESA_FX_WINDOW) {
	    if (xmesa->xm_buffer->FXisHackUsable) {
	       FX_grSstControl(GR_CONTROL_DEACTIVATE);
	       xmesa->xm_buffer->FXwindowHack = GL_TRUE;
	       return GL_TRUE;
	    }
	 }
	 else if (mode == XMESA_FX_FULLSCREEN) {
	    FX_grSstControl(GR_CONTROL_ACTIVATE);
	    xmesa->xm_buffer->FXwindowHack = GL_FALSE;
	    return GL_TRUE;
	 }
	 else {
	    /* Error: Bad mode value */
	 }
      }
   }
   /*fprintf(stderr, "fallthrough\n");*/
#else
   (void) mode;
#endif
   return GL_FALSE;
}



#ifdef FX
/*
 * Read image from VooDoo frame buffer into X/Mesa's back XImage.
 */
static void FXgetImage( XMesaBuffer b )
{
   static unsigned short pixbuf[MAX_WIDTH];
   GLuint x, y;
   int xpos, ypos;
   XMesaWindow root;
   unsigned int bw, depth, width, height;
   XMesaContext xmesa = (XMesaContext) b->xm_context->gl_ctx->DriverCtx;

   assert(xmesa->xm_buffer->FXctx);

#ifdef XFree86Server
   x = b->frontbuffer->x;
   y = b->frontbuffer->y;
   width = b->frontbuffer->width;
   height = b->frontbuffer->height;
   depth = b->frontbuffer->depth;
#else
   XGetGeometry( xmesa->xm_visual->display, b->frontbuffer,
                 &root, &xpos, &ypos, &width, &height, &bw, &depth);
#endif
   if (b->width != width || b->height != height) {
      b->width = MIN2((int)width, xmesa->xm_buffer->FXctx->width);
      b->height = MIN2((int)height, xmesa->xm_buffer->FXctx->height);
      if (b->width & 1)
         b->width--;  /* prevent odd width */
      xmesa_alloc_back_buffer( b );
   }

   grLfbWriteColorFormat(GR_COLORFORMAT_ARGB);
   if (xmesa->xm_visual->undithered_pf==PF_5R6G5B) {
      /* Special case: 16bpp RGB */
      grLfbReadRegion( GR_BUFFER_FRONTBUFFER,       /* src buffer */
                       0, xmesa->xm_buffer->FXctx->height - b->height,  /*pos*/
                       b->width, b->height,         /* size */
                       b->width * sizeof(GLushort), /* stride */
                       b->backimage->data);         /* dest buffer */
   }
   else if (xmesa->xm_visual->dithered_pf==PF_DITHER
	    && GET_VISUAL_DEPTH(xmesa->xm_visual)==8) {
      /* Special case: 8bpp RGB */
      for (y=0;y<b->height;y++) {
         GLubyte *ptr = (GLubyte*) xmesa->xm_buffer->backimage->data
                        + xmesa->xm_buffer->backimage->bytes_per_line * y;
         XDITHER_SETUP(y);

         /* read row from 3Dfx frame buffer */
         grLfbReadRegion( GR_BUFFER_FRONTBUFFER,
                          0, xmesa->xm_buffer->FXctx->height-(b->height-y),
                          b->width, 1,
                          0,
                          pixbuf );

         /* write to XImage back buffer */
         for (x=0;x<b->width;x++) {
            GLubyte r = (pixbuf[x] & 0xf800) >> 8;
            GLubyte g = (pixbuf[x] & 0x07e0) >> 3;
            GLubyte b = (pixbuf[x] & 0x001f) << 3;
            *ptr++ = XDITHER( x, r, g, b);
         }
      }
   }
   else {
      /* General case: slow! */
      for (y=0;y<b->height;y++) {
         /* read row from 3Dfx frame buffer */
         grLfbReadRegion( GR_BUFFER_FRONTBUFFER,
                          0, xmesa->xm_buffer->FXctx->height-(b->height-y),
                          b->width, 1,
                          0,
                          pixbuf );

         /* write to XImage back buffer */
         for (x=0;x<b->width;x++) {
            XMesaPutPixel(b->backimage,x,y,
			  xmesa_color_to_pixel(xmesa,
					       (pixbuf[x] & 0xf800) >> 8,
					       (pixbuf[x] & 0x07e0) >> 3,
					       (pixbuf[x] & 0x001f) << 3,
					       0xff, xmesa->pixelformat));
         }
      }
   }
   grLfbWriteColorFormat(GR_COLORFORMAT_ABGR);
}
#endif


/*
 * Copy the back buffer to the front buffer.  If there's no back buffer
 * this is a no-op.
 */
void XMesaSwapBuffers( XMesaBuffer b )
{
   GET_CURRENT_CONTEXT(ctx);

   /* If we're swapping the buffer associated with the current context
    * we have to flush any pending rendering commands first.
    */
   if (b->xm_context && b->xm_context->gl_ctx == ctx)
      _mesa_swapbuffers(ctx);

   if (b->db_state) {
#ifdef FX
      if (b->FXctx) {
         fxMesaSwapBuffers();

         if (b->FXwindowHack)
            FXgetImage(b);
         else
            return;
      }
#endif
     if (b->backimage) {
	 /* Copy Ximage from host's memory to server's window */
#if defined(USE_XSHM) && !defined(XFree86Server)
	 if (b->shm) {
            /*_glthread_LOCK_MUTEX(_xmesa_lock);*/
	    XShmPutImage( b->xm_visual->display, b->frontbuffer,
			  b->swapgc,
			  b->backimage, 0, 0,
			  0, 0, b->width, b->height, False );
            /*_glthread_UNLOCK_MUTEX(_xmesa_lock);*/
	 }
	 else
#endif
         {
            /*_glthread_LOCK_MUTEX(_xmesa_lock);*/
            XMesaPutImage( b->xm_visual->display, b->frontbuffer,
			   b->swapgc,
			   b->backimage, 0, 0,
			   0, 0, b->width, b->height );
            /*_glthread_UNLOCK_MUTEX(_xmesa_lock);*/
         }
      }
      else {
	 /* Copy pixmap to window on server */
         /*_glthread_LOCK_MUTEX(_xmesa_lock);*/
	 XMesaCopyArea( b->xm_visual->display,
			b->backpixmap,   /* source drawable */
			b->frontbuffer,  /* dest. drawable */
			b->swapgc,
			0, 0, b->width, b->height,  /* source region */
			0, 0                 /* dest region */
		      );
         /*_glthread_UNLOCK_MUTEX(_xmesa_lock);*/
      }
   }
#if !defined(XFree86Server)
   XSync( b->xm_visual->display, False );
#endif
}



/*
 * Copy sub-region of back buffer to front buffer
 */
void XMesaCopySubBuffer( XMesaBuffer b, int x, int y, int width, int height )
{
   GET_CURRENT_CONTEXT(ctx);

   /* If we're swapping the buffer associated with the current context
    * we have to flush any pending rendering commands first.
    */
   if (b->xm_context->gl_ctx == ctx)
      _mesa_swapbuffers(ctx);

   if (b->db_state) {
      int yTop = b->height - y - height;
#ifdef FX
      if (b->FXctx) {
         fxMesaSwapBuffers();
         if (b->FXwindowHack)
            FXgetImage(b);
         else
            return;
      }
#endif
      if (b->backimage) {
         /* Copy Ximage from host's memory to server's window */
#if defined(USE_XSHM) && !defined(XFree86Server)
         if (b->shm) {
            /* XXX assuming width and height aren't too large! */
            XShmPutImage( b->xm_visual->display, b->frontbuffer,
                          b->swapgc,
                          b->backimage, x, yTop,
                          x, yTop, width, height, False );
            /* wait for finished event??? */
         }
         else
#endif
         {
            /* XXX assuming width and height aren't too large! */
            XMesaPutImage( b->xm_visual->display, b->frontbuffer,
			   b->swapgc,
			   b->backimage, x, yTop,
			   x, yTop, width, height );
         }
      }
      else {
         /* Copy pixmap to window on server */
         XMesaCopyArea( b->xm_visual->display,
			b->backpixmap,           /* source drawable */
			b->frontbuffer,          /* dest. drawable */
			b->swapgc,
			x, yTop, width, height,  /* source region */
			x, yTop                  /* dest region */
                      );
      }
   }
}


/*
 * Return a pointer to the XMesa backbuffer Pixmap or XImage.  This function
 * is a way to get "under the hood" of X/Mesa so one can manipulate the
 * back buffer directly.
 * Output:  pixmap - pointer to back buffer's Pixmap, or 0
 *          ximage - pointer to back buffer's XImage, or NULL
 * Return:  GL_TRUE = context is double buffered
 *          GL_FALSE = context is single buffered
 */
GLboolean XMesaGetBackBuffer( XMesaBuffer b,
                              XMesaPixmap *pixmap,
                              XMesaImage **ximage )
{
   if (b->db_state) {
      if (pixmap)  *pixmap = b->backpixmap;
      if (ximage)  *ximage = b->backimage;
      return GL_TRUE;
   }
   else {
      *pixmap = 0;
      *ximage = NULL;
      return GL_FALSE;
   }
}


/*
 * Return the depth buffer associated with an XMesaBuffer.
 * Input:  b - the XMesa buffer handle
 * Output:  width, height - size of buffer in pixels
 *          bytesPerValue - bytes per depth value (2 or 4)
 *          buffer - pointer to depth buffer values
 * Return:  GL_TRUE or GL_FALSE to indicate success or failure.
 */
GLboolean XMesaGetDepthBuffer( XMesaBuffer b, GLint *width, GLint *height,
                               GLint *bytesPerValue, void **buffer )
{
   if (!b->mesa_buffer.DepthBuffer) {
      *width = 0;
      *height = 0;
      *bytesPerValue = 0;
      *buffer = 0;
      return GL_FALSE;
   }
   else {
      *width = b->mesa_buffer.Width;
      *height = b->mesa_buffer.Height;
      *bytesPerValue = sizeof(GLdepth);
      *buffer = b->mesa_buffer.DepthBuffer;
      return GL_TRUE;
   }
}


void XMesaFlush( XMesaContext c )
{
   if (c && c->xm_visual) {
#ifdef XFree86Server
      /* NOT_NEEDED */
#else
      XSync( c->xm_visual->display, False );
#endif
   }
}



const char *XMesaGetString( XMesaContext c, int name )
{
   (void) c;
   if (name==XMESA_VERSION) {
      return "3.5";
   }
   else if (name==XMESA_EXTENSIONS) {
      return "";
   }
   else {
      return NULL;
   }
}



XMesaBuffer XMesaFindBuffer( XMesaDisplay *dpy, XMesaDrawable d )
{
   XMesaBuffer b;
   for (b=XMesaBufferList; b; b=b->Next) {
      if (b->frontbuffer==d && b->display==dpy) {
         return b;
      }
   }
   return NULL;
}



/*
 * Look for XMesaBuffers whose X window has been destroyed.
 * Deallocate any such XMesaBuffers.
 */
void XMesaGarbageCollect( void )
{
   XMesaBuffer b, next;
   for (b=XMesaBufferList; b; b=next) {
      next = b->Next;
      if (b->display && b->frontbuffer && !b->pixmap_flag) {
#ifdef XFree86Server
	 /* NOT_NEEDED */
#else
         XSync(b->display, False);
         if (!window_exists( b->display, b->frontbuffer )) {
            /* found a dead window, free the ancillary info */
            XMesaDestroyBuffer( b );
         }
#endif
      }
   }
}


void XMesaReset( void )
{
    while (XMesaBufferList)
	XMesaDestroyBuffer(XMesaBufferList);

    XMesaBufferList = NULL;
}


unsigned long XMesaDitherColor( XMesaContext xmesa, GLint x, GLint y,
                                GLfloat red, GLfloat green,
                                GLfloat blue, GLfloat alpha )
{
   GLint r = (GLint) (red   * 255.0F);
   GLint g = (GLint) (green * 255.0F);
   GLint b = (GLint) (blue  * 255.0F);
   GLint a = (GLint) (alpha * 255.0F);

   switch (xmesa->pixelformat) {
      case PF_INDEX:
         return 0;
      case PF_TRUECOLOR:
         {
            unsigned long p;
            PACK_TRUECOLOR( p, r, g, b );
            return p;
         }
      case PF_8A8B8G8R:
         return PACK_8A8B8G8R( r, g, b, a );
      case PF_8R8G8B:
         return PACK_8R8G8B( r, g, b );
      case PF_5R6G5B:
         return PACK_5R6G5B( r, g, b );
      case PF_DITHER:
         {
            DITHER_SETUP;
            return DITHER( x, y, r, g, b );
         }
      case PF_1BIT:
         /* 382 = (3*255)/2 */
         return ((r+g+b) > 382) ^ xmesa->xm_visual->bitFlip;
      case PF_HPCR:
         return DITHER_HPCR(x, y, r, g, b);
      case PF_LOOKUP:
         {
            LOOKUP_SETUP;
            return LOOKUP( r, g, b );
         }
      case PF_GRAYSCALE:
         return GRAY_RGB( r, g, b );
      case PF_DITHER_5R6G5B:
         /* fall through */
      case PF_TRUEDITHER:
         {
            unsigned long p;
            PACK_TRUEDITHER(p, x, y, r, g, b);
            return p;
         }
      default:
         _mesa_problem(NULL, "Bad pixel format in XMesaDitherColor");
   }
   return 0;
}