This file is indexed.

/usr/include/Wt/WGLWidget is in libwt-dev 3.1.10-1ubuntu2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
// This may look like C code, but it's really -*- C++ -*-
/*
 * Copyright (C) 2010 Emweb bvba, Leuven, Belgium.
 *
 * See the LICENSE file for terms of use.
 */
#ifndef WGLWIDGET_H_
#define WGLWIDGET_H_

#include <Wt/WInteractWidget>
#include <Wt/WGenericMatrix>

namespace Wt {

#if 0
#define GLDEBUG do {js_ << "\n{var err = ctx.getError(); if(err != ctx.NO_ERROR) {alert('error " << __FUNCTION__ << ": ' + err); debugger;}}\n";} while(false)
//#define GLDEBUG do {js_ << "\n{var err = ctx.getError(); if(err != ctx.NO_ERROR) {debugger;}}\n";} while(false)
#else
#define GLDEBUG
#endif

class WHTML5Video;
class WImage;

// Incomplete implementation of the new webgl standard. This is to be
// considered as a technology preview, and we welcome comments regarding
// this interface.
// Expect this interface to change.
// TODO: provide a mechanism to write your own JavaScript

/*! \class WGLWidget Wt/WGLWidget Wt/WGLWidget
 *  \brief WebGL support class
 *
 * The WGLWidget class is an interface to the HTML5 WebGL infrastructure. Its
 * implementation started based on the working drafts of the Khronos group, and
 * will be updated as the standard stabilizes. To fully understand WebGL, it is
 * recommended to read the WebGL standard in addition to this documentation.
 *
 * The most recent version of the WebGL specification can be found here:
 * https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html
 *
 * This widget is work in progress. The API may change in the future because
 * of new features, reorganizations or changes in the WebGL draft.
 *
 * The goal of the WGLWidget class is to provide a method to render 3D
 * structures in the browser, where rendering and rerendering is normally
 * done at the client side in JavaScript without interaction from the server,
 * in order to obtain a smooth user interaction. Unless the scene requires
 * server-side updates, there is no communication with the server.
 *
 * The rendering interface resembles to OpenGL ES, the same standard as
 * WebGL is based on. This is a stripped down version of the normal OpenGL
 * as we usually find them on desktops. Many stateful OpenGL features are
 * not present in OpenGL ES: no modelview and camera transformation stacks,
 * no default lighting models, no support for other rendering methods than
 * through VBOs, ... Therefore much existing example code for OpenGL
 * applications and shaders will not work on WebGL without modifications.
 * The 'learning webgl' web site at http://learningwebgl.com/ is a good
 * starting point to get familiar with WebGL.
 *
 * To use a %WGLWidget, you must derive from it and reimplement
 * the painter methods. Usually, you will always need to implement
 * initializeGL() and paintGL(). Optionally, you may choose to implement
 * resizeGL() (if your widget does not have a fixed size), and updateGL().
 * If you need to modify the painting methods, a repaint is triggered by
 * calling the repaintGL() method. The default behaviour for any of these
 * four painting functions is to do nothing.
 *
 * The four painter methods (initializeGL(), resizeGL(), paintGL() and
 * updateGL()) all record JavaScript which is sent to the
 * browser. The JavaScript code of paintGL() is cached client-side, and
 * may be executed many times, e.g. to repaint a scene from different
 * viewpoints. The JavaScript code of initializeGL(), resizeGL() and
 * updateGL() are intended for OpenGL state updates, and is therefore
 * only executed once on the client and is then discarded.
 *
 * There are four painting methods that you may implement in a
 * specialization of this class. The purpose of these functions is
 * to register what JavaScript code has to be executed to render a
 * scene. Through invocations of the WebGL functions documented below,
 * Wt records the JavaScript calls that have to be invoked in the
 * browser.
 * <ul>
 * <li><b>initializeGL()</b>: this function is executed only once, right
 *     after the successful detection of WebGL in the browser. (note: in
 *     future versions, it may be re-executed when the webglcontextlost
 *     signal is fired, but this is currently not yet implemented). This
 *     is the ideal location to compose shader programs, send VBO's to
 *     the client, extract uniform and attribute locations, ... Due to
 *     the presence of VBO's, this function may generate a large amount
 *     of data to the client.
 * <li><b>resizeGL()</b>: this function is executed whenever the canvas
 *     dimensions change. A change in canvas size will require you to
 *     invoke the viewport() function again, as well as recalculate the
 *     projection matrices (especially when the aspect ratio has changed).
 *     The resizeGL() function is therefore the ideal location to set those
 *     properties.
 *     The resizeGL() function is invoked automatically on every resize,
 *     and after the first initializeGL() invocation. Additional invocations
 *     may be triggered by calling repaint() with the RESIZE_GL flag.
 * <li><b>paintGL()</b>: this is the main scene drawing function. Through
 *     its execution, Wt records what has to be done to render a scene,
 *     and it is executed every time that the scene is to be redrawn. You
 *     can use the VBO's and shaders prepared in the initializeGL() phase.
 *     Usually, this function sets uniforms and attributes, links
 *     attributes to VBO's, applies textures, and draws primitives.
 *     You may also create local programs, buffers, ... Remeber that this
 *     function is executed a lot of times, so every buffer/program created
 *     in this function should also be destroyed to avoid memory leaks.
 *     This function is transmitted once to the client, and is executed
 *     when the scene needs to be redrawn. Redraws may be triggered from
 *     mouse events, timer triggers, events on e.g. a video element, or
 *     whatever other event.
 *     The paintGL() function can be updated through invoking repaintGL()
 *     with the PAINT_GL flag.
 * <li><b>updateGL()</b>: VBO's, programs, uniforms, GL properties,
 *     or anything else set during intializeGL() are not necessarily
 *     immutable. If you want to change, add, remove or reconfigure those
 *     properties, the execution of an updateGL() function can be triggered
 *     by invoking repaintGL() with the UPDATE_GL flag. This signals that
 *     updateGL() needs to be evaluated - just once. It is possible that
 *     the paintGL() function also requires updates as consequence of the
 *     changes in the updateGL() function; in this case, you should also set
 *     the PAINT_GL flag of repaintGL().
 * </ul>
 *
 * The WebGL functions are intended to be used exclusively from within the
 * invocation of the four callback functions mentioned above. In order to
 * manually trigger the execution of these function, use the repaintGL().
 *
 * A WGLWidget must be given a size explicitly, or must be put inside a
 * layout manager that manages its width and height. The behaviour of a
 * WGLWidget that was not given a size is undefined.
 *
 * <h3>Client side matrices.</h3>
 *
 * The WGLWidget provides the WGLWidget::JavaScriptMatrix4x4 class as
 * a mechanism to use client-side modifiable matrices in the render
 * functions. These matrices can be used identically to the
 * 'constant', with the advantage that there is no need to have a
 * roundtrip to the server to redraw the scene when they are changed.
 * As such, they are ideal for mouse-based camera manipulations, timer
 * triggered animations, or object manipulations.
 *
 * Note: the client side matrices are currently not yet communicated back
 * to the server, but that is an implementation idea for the future.
 */
class WT_API WGLWidget: public WInteractWidget
{
public:
  typedef std::string Shader;
  typedef std::string Program;
  typedef std::string AttribLocation;
  typedef std::string Buffer;
  typedef std::string UniformLocation;
  typedef std::string Texture;

  /*! \brief A client-side JavaScript matrix
   *
   * A JavaScriptMatrix has methods that make it possible to do client-side
   * calculations on matrices.
   *
   * Important: only the jsRef() of the return value from a call to
   * WGLWidget::createJavaScriptMatrix() is a variable name that can be used 
   * in custom JavaScript to modify a matrix from external scripts.
   * The jsRef() of return values of operations refer to unnamed temporary
   * objects - rvalues in C++-lingo.
   */
  class WT_API JavaScriptMatrix4x4 {
  public:
    // Create an identity matrix
    JavaScriptMatrix4x4(const std::string &jsVariable);
    JavaScriptMatrix4x4();
    JavaScriptMatrix4x4(const JavaScriptMatrix4x4 &other);

    JavaScriptMatrix4x4 &operator=(const JavaScriptMatrix4x4 &rhs);

    std::string jsRef() const { return jsRef_; }

    JavaScriptMatrix4x4 inverted() const;
    JavaScriptMatrix4x4 transposed() const;

    JavaScriptMatrix4x4 operator*(const WGenericMatrix<double, 4, 4> &m) const;

  private:
    std::string jsRef_;
  };

  /*! \brief Construct a WebGL widget.
   *
   * Before the first rendering, you must apply a size to the WGLWidget.
   *
   * /code
   * /endcode
   */
  WGLWidget(WContainerWidget *parent);

  /*! \brief Destructor
   */
  ~WGLWidget();

  /*! \brief Initialize the WebGL state when the widget is first shown.
   *
   * initializeGL() is called once, when the widget is first rendered. It
   * usually creates most of the WebGL related state: shaders, VBOs,
   * uniform locations, ...
   *
   * If this state is to be updated during the lifetime of the widget,
   * you should specialize the updateGL() to accomodate for this.
   *
   * Note: in a future version, this method will probably also be invoked
   * on contextrestore events.
   */
  virtual void initializeGL();

  /*! \brief Act on resize events
   *
   * Usually, this method only contains functions to set the viewport
   * and the projection matrix (as this is aspect ration dependent).
   *
   * resizeGL() is rendered after initializeGL, and whenever widget is
   * resized. After this method finishes, the widget is repainted with
   * the cached client-side paint function.
   */
  virtual void resizeGL(int width, int height);

  /*! \brief Update the client-side painting function.
   *
   * This method is invoked client-side when a repaint is required,
   * i.e. when the repaintSlot() (a JavaScript-side JSlot) is triggered.
   * Typical examples are: after mouse-based camera movements, after
   * a timed update of a camera or an object's position, after
   * a resize event (resizeGL() will also be called then), after
   * an animation event, ... In many cases, this function will be
   * executed client-side many many times.
   *
   * Using the WebGL functions from this class, you construct a scene.
   * The implementation tracks all JavaScript calls that need to be
   * performed to draw the scenes, and will replay them verbatim on
   * every trigger of the repaintSlot(). There are a few mechanisms
   * that may be employed to change what is rendered without updating
   * the paintGL() cache:
   * <ul>
   * <li>Client-side matrices may be used to change camera viewpoints,
   *     manipilate separate object's model transformation matrices, ...
   *     </li>
   * <li>Shader sources can be updated without requiring the paint
   *     function to be renewed</li>
   * </ul>
   *
   * Updating the paintGL() cache is usually not too expensive; the VBOs,
   * which are large in many cases, are already at the client side, while
   * the paintGL() code only draws the VBOs. Of course, if you have to
   * draw many separate objects, the paintGL() JS code may become large
   * and updating is more expensive.
   *
   * In order to update the paintGL() cache, call repaintGL() with
   * the PAINT_GL parameter, which will cause the invocation of this
   * method.
   */
  virtual void paintGL();

  /*! \brief Update state set in initializeGL()
   *
   * Invoked when repaint is called with the UPDATE_GL call.
   *
   * This is intended to be executed when you want to change programs,
   * 'constant' uniforms, or even VBO's, ... without resending already
   * initialized data. It is a mechanism to make changes to what you've
   * set in intializeGL(). For every server-side invocation of this method,
   * the result will be rendered client-side exactly once.
   */
  virtual void updateGL();

  /*! \brief Specifies what WebGL function needs to be updated
   */
  enum ClientSideRenderer {PAINT_GL = 1,  //!< refresh paintGL()
                           RESIZE_GL = 2, //!< refresh resizeGL()
                           UPDATE_GL = 4  //!< refresh updateGL()
  };

  /*! \brief Request invocation of resizeGL, paintGL and/or updateGL.
   *
   * If invoked with PAINT_GL, the client-side cached paint function
   * is updated. If invoked with RESIZE_GL or UPDATE_GL, the code
   * will be executed once.
   *
   * If invoked with multiple flags set, the order of execution will be
   * updateGL(), resizeGL(), paintGL().
   */
  void repaintGL(WFlags<ClientSideRenderer> which);

  void resize(const WLength &width, const WLength &height);



  /*! \brief The enourmous GLenum
   *
   * This enum contains all numeric constants defined by the WebGL standard.
   */
  enum GLenum {
    /* ClearBufferMask */
    DEPTH_BUFFER_BIT               = 0x00000100,
    STENCIL_BUFFER_BIT             = 0x00000400,
    COLOR_BUFFER_BIT               = 0x00004000,
    
    /* BeginMode */
    POINTS                         = 0x0000,
    LINES                          = 0x0001,
    LINE_LOOP                      = 0x0002,
    LINE_STRIP                     = 0x0003,
    TRIANGLES                      = 0x0004,
    TRIANGLE_STRIP                 = 0x0005,
    TRIANGLE_FAN                   = 0x0006,
    
    /* AlphaFunction (not supported in ES20) */
    /*      NEVER */
    /*      LESS */
    /*      EQUAL */
    /*      LEQUAL */
    /*      GREATER */
    /*      NOTEQUAL */
    /*      GEQUAL */
    /*      ALWAYS */
    
    /* BlendingFactorDest */
    ZERO                           = 0,
    ONE                            = 1,
    SRC_COLOR                      = 0x0300,
    ONE_MINUS_SRC_COLOR            = 0x0301,
    SRC_ALPHA                      = 0x0302,
    ONE_MINUS_SRC_ALPHA            = 0x0303,
    DST_ALPHA                      = 0x0304,
    ONE_MINUS_DST_ALPHA            = 0x0305,
    
    /* BlendingFactorSrc */
    /*      ZERO */
    /*      ONE */
    DST_COLOR                      = 0x0306,
    ONE_MINUS_DST_COLOR            = 0x0307,
    SRC_ALPHA_SATURATE             = 0x0308,
    /*      SRC_ALPHA */
    /*      ONE_MINUS_SRC_ALPHA */
    /*      DST_ALPHA */
    /*      ONE_MINUS_DST_ALPHA */
    
    /* BlendEquationSeparate */
    FUNC_ADD                       = 0x8006,
    BLEND_EQUATION                 = 0x8009,
    BLEND_EQUATION_RGB             = 0x8009,   /* same as BLEND_EQUATION */
    BLEND_EQUATION_ALPHA           = 0x883D,
    
    /* BlendSubtract */
    FUNC_SUBTRACT                  = 0x800A,
    FUNC_REVERSE_SUBTRACT          = 0x800B,
    
    /* Separate Blend Functions */
    BLEND_DST_RGB                  = 0x80C8,
    BLEND_SRC_RGB                  = 0x80C9,
    BLEND_DST_ALPHA                = 0x80CA,
    BLEND_SRC_ALPHA                = 0x80CB,
    CONSTANT_COLOR                 = 0x8001,
    ONE_MINUS_CONSTANT_COLOR       = 0x8002,
    CONSTANT_ALPHA                 = 0x8003,
    ONE_MINUS_CONSTANT_ALPHA       = 0x8004,
    BLEND_COLOR                    = 0x8005,
    
    /* Buffer Objects */
    ARRAY_BUFFER                   = 0x8892,
    ELEMENT_ARRAY_BUFFER           = 0x8893,
    ARRAY_BUFFER_BINDING           = 0x8894,
    ELEMENT_ARRAY_BUFFER_BINDING   = 0x8895,
    
    STREAM_DRAW                    = 0x88E0,
    STATIC_DRAW                    = 0x88E4,
    DYNAMIC_DRAW                   = 0x88E8,
    
    BUFFER_SIZE                    = 0x8764,
    BUFFER_USAGE                   = 0x8765,
    
    CURRENT_VERTEX_ATTRIB          = 0x8626,
    
    /* CullFaceMode */
    FRONT                          = 0x0404,
    BACK                           = 0x0405,
    FRONT_AND_BACK                 = 0x0408,
    
    /* DepthFunction */
    /*      NEVER */
    /*      LESS */
    /*      EQUAL */
    /*      LEQUAL */
    /*      GREATER */
    /*      NOTEQUAL */
    /*      GEQUAL */
    /*      ALWAYS */
    
    /* EnableCap */
    /* TEXTURE_2D */
    CULL_FACE                      = 0x0B44,
    BLEND                          = 0x0BE2,
    DITHER                         = 0x0BD0,
    STENCIL_TEST                   = 0x0B90,
    DEPTH_TEST                     = 0x0B71,
    SCISSOR_TEST                   = 0x0C11,
    POLYGON_OFFSET_FILL            = 0x8037,
    SAMPLE_ALPHA_TO_COVERAGE       = 0x809E,
    SAMPLE_COVERAGE                = 0x80A0,
    
    /* ErrorCode */
    NO_ERROR                       = 0,
    INVALID_ENUM                   = 0x0500,
    INVALID_VALUE                  = 0x0501,
    INVALID_OPERATION              = 0x0502,
    OUT_OF_MEMORY                  = 0x0505,
    
    /* FrontFaceDirection */
    CW                             = 0x0900,
    CCW                            = 0x0901,
    
    /* GetPName */
    LINE_WIDTH                     = 0x0B21,
    ALIASED_POINT_SIZE_RANGE       = 0x846D,
    ALIASED_LINE_WIDTH_RANGE       = 0x846E,
    CULL_FACE_MODE                 = 0x0B45,
    FRONT_FACE                     = 0x0B46,
    DEPTH_RANGE                    = 0x0B70,
    DEPTH_WRITEMASK                = 0x0B72,
    DEPTH_CLEAR_VALUE              = 0x0B73,
    DEPTH_FUNC                     = 0x0B74,
    STENCIL_CLEAR_VALUE            = 0x0B91,
    STENCIL_FUNC                   = 0x0B92,
    STENCIL_FAIL                   = 0x0B94,
    STENCIL_PASS_DEPTH_FAIL        = 0x0B95,
    STENCIL_PASS_DEPTH_PASS        = 0x0B96,
    STENCIL_REF                    = 0x0B97,
    STENCIL_VALUE_MASK             = 0x0B93,
    STENCIL_WRITEMASK              = 0x0B98,
    STENCIL_BACK_FUNC              = 0x8800,
    STENCIL_BACK_FAIL              = 0x8801,
    STENCIL_BACK_PASS_DEPTH_FAIL   = 0x8802,
    STENCIL_BACK_PASS_DEPTH_PASS   = 0x8803,
    STENCIL_BACK_REF               = 0x8CA3,
    STENCIL_BACK_VALUE_MASK        = 0x8CA4,
    STENCIL_BACK_WRITEMASK         = 0x8CA5,
    VIEWPORT                       = 0x0BA2,
    SCISSOR_BOX                    = 0x0C10,
    /*      SCISSOR_TEST */
    COLOR_CLEAR_VALUE              = 0x0C22,
    COLOR_WRITEMASK                = 0x0C23,
    UNPACK_ALIGNMENT               = 0x0CF5,
    PACK_ALIGNMENT                 = 0x0D05,
    MAX_TEXTURE_SIZE               = 0x0D33,
    MAX_VIEWPORT_DIMS              = 0x0D3A,
    SUBPIXEL_BITS                  = 0x0D50,
    RED_BITS                       = 0x0D52,
    GREEN_BITS                     = 0x0D53,
    BLUE_BITS                      = 0x0D54,
    ALPHA_BITS                     = 0x0D55,
    DEPTH_BITS                     = 0x0D56,
    STENCIL_BITS                   = 0x0D57,
    POLYGON_OFFSET_UNITS           = 0x2A00,
    /*      POLYGON_OFFSET_FILL */
    POLYGON_OFFSET_FACTOR          = 0x8038,
    TEXTURE_BINDING_2D             = 0x8069,
    SAMPLE_BUFFERS                 = 0x80A8,
    SAMPLES                        = 0x80A9,
    SAMPLE_COVERAGE_VALUE          = 0x80AA,
    SAMPLE_COVERAGE_INVERT         = 0x80AB,
    
    /* GetTextureParameter */
    /*      TEXTURE_MAG_FILTER */
    /*      TEXTURE_MIN_FILTER */
    /*      TEXTURE_WRAP_S */
    /*      TEXTURE_WRAP_T */
    
    NUM_COMPRESSED_TEXTURE_FORMATS = 0x86A2,
    COMPRESSED_TEXTURE_FORMATS     = 0x86A3,
    
    /* HintMode */
    DONT_CARE                      = 0x1100,
    FASTEST                        = 0x1101,
    NICEST                         = 0x1102,
    
    /* HintTarget */
    GENERATE_MIPMAP_HINT            = 0x8192,
    
    /* DataType */
    BYTE                           = 0x1400,
    UNSIGNED_BYTE                  = 0x1401,
    SHORT                          = 0x1402,
    UNSIGNED_SHORT                 = 0x1403,
    INT                            = 0x1404,
    UNSIGNED_INT                   = 0x1405,
    FLOAT                          = 0x1406,
    
    /* PixelFormat */
    DEPTH_COMPONENT                = 0x1902,
    ALPHA                          = 0x1906,
    RGB                            = 0x1907,
    RGBA                           = 0x1908,
    LUMINANCE                      = 0x1909,
    LUMINANCE_ALPHA                = 0x190A,
    
    /* PixelType */
    /*      UNSIGNED_BYTE */
    UNSIGNED_SHORT_4_4_4_4         = 0x8033,
    UNSIGNED_SHORT_5_5_5_1         = 0x8034,
    UNSIGNED_SHORT_5_6_5           = 0x8363,
    
    /* Shaders */
    FRAGMENT_SHADER                  = 0x8B30,
    VERTEX_SHADER                    = 0x8B31,
    MAX_VERTEX_ATTRIBS               = 0x8869,
    MAX_VERTEX_UNIFORM_VECTORS       = 0x8DFB,
    MAX_VARYING_VECTORS              = 0x8DFC,
    MAX_COMBINED_TEXTURE_IMAGE_UNITS = 0x8B4D,
    MAX_VERTEX_TEXTURE_IMAGE_UNITS   = 0x8B4C,
    MAX_TEXTURE_IMAGE_UNITS          = 0x8872,
    MAX_FRAGMENT_UNIFORM_VECTORS     = 0x8DFD,
    SHADER_TYPE                      = 0x8B4F,
    DELETE_STATUS                    = 0x8B80,
    LINK_STATUS                      = 0x8B82,
    VALIDATE_STATUS                  = 0x8B83,
    ATTACHED_SHADERS                 = 0x8B85,
    ACTIVE_UNIFORMS                  = 0x8B86,
    ACTIVE_UNIFORM_MAX_LENGTH        = 0x8B87,
    ACTIVE_ATTRIBUTES                = 0x8B89,
    ACTIVE_ATTRIBUTE_MAX_LENGTH      = 0x8B8A,
    SHADING_LANGUAGE_VERSION         = 0x8B8C,
    CURRENT_PROGRAM                  = 0x8B8D,
    
    /* StencilFunction */
    NEVER                          = 0x0200,
    LESS                           = 0x0201,
    EQUAL                          = 0x0202,
    LEQUAL                         = 0x0203,
    GREATER                        = 0x0204,
    NOTEQUAL                       = 0x0205,
    GEQUAL                         = 0x0206,
    ALWAYS                         = 0x0207,
    
    /* StencilOp */
    /*      ZERO */
    KEEP                           = 0x1E00,
    REPLACE                        = 0x1E01,
    INCR                           = 0x1E02,
    DECR                           = 0x1E03,
    INVERT                         = 0x150A,
    INCR_WRAP                      = 0x8507,
    DECR_WRAP                      = 0x8508,
    
    /* StringName */
    VENDOR                         = 0x1F00,
    RENDERER                       = 0x1F01,
    VERSION                        = 0x1F02,
    
    /* TextureMagFilter */
    NEAREST                        = 0x2600,
    LINEAR                         = 0x2601,
    
    /* TextureMinFilter */
    /*      NEAREST */
    /*      LINEAR */
    NEAREST_MIPMAP_NEAREST         = 0x2700,
    LINEAR_MIPMAP_NEAREST          = 0x2701,
    NEAREST_MIPMAP_LINEAR          = 0x2702,
    LINEAR_MIPMAP_LINEAR           = 0x2703,
    
    /* TextureParameterName */
    TEXTURE_MAG_FILTER             = 0x2800,
    TEXTURE_MIN_FILTER             = 0x2801,
    TEXTURE_WRAP_S                 = 0x2802,
    TEXTURE_WRAP_T                 = 0x2803,
    
    /* TextureTarget */
    TEXTURE_2D                     = 0x0DE1,
    TEXTURE                        = 0x1702,
    
    TEXTURE_CUBE_MAP               = 0x8513,
    TEXTURE_BINDING_CUBE_MAP       = 0x8514,
    TEXTURE_CUBE_MAP_POSITIVE_X    = 0x8515,
    TEXTURE_CUBE_MAP_NEGATIVE_X    = 0x8516,
    TEXTURE_CUBE_MAP_POSITIVE_Y    = 0x8517,
    TEXTURE_CUBE_MAP_NEGATIVE_Y    = 0x8518,
    TEXTURE_CUBE_MAP_POSITIVE_Z    = 0x8519,
    TEXTURE_CUBE_MAP_NEGATIVE_Z    = 0x851A,
    MAX_CUBE_MAP_TEXTURE_SIZE      = 0x851C,
    
    /* TextureUnit */
    TEXTURE0                       = 0x84C0,
    TEXTURE1                       = 0x84C1,
    TEXTURE2                       = 0x84C2,
    TEXTURE3                       = 0x84C3,
    TEXTURE4                       = 0x84C4,
    TEXTURE5                       = 0x84C5,
    TEXTURE6                       = 0x84C6,
    TEXTURE7                       = 0x84C7,
    TEXTURE8                       = 0x84C8,
    TEXTURE9                       = 0x84C9,
    TEXTURE10                      = 0x84CA,
    TEXTURE11                      = 0x84CB,
    TEXTURE12                      = 0x84CC,
    TEXTURE13                      = 0x84CD,
    TEXTURE14                      = 0x84CE,
    TEXTURE15                      = 0x84CF,
    TEXTURE16                      = 0x84D0,
    TEXTURE17                      = 0x84D1,
    TEXTURE18                      = 0x84D2,
    TEXTURE19                      = 0x84D3,
    TEXTURE20                      = 0x84D4,
    TEXTURE21                      = 0x84D5,
    TEXTURE22                      = 0x84D6,
    TEXTURE23                      = 0x84D7,
    TEXTURE24                      = 0x84D8,
    TEXTURE25                      = 0x84D9,
    TEXTURE26                      = 0x84DA,
    TEXTURE27                      = 0x84DB,
    TEXTURE28                      = 0x84DC,
    TEXTURE29                      = 0x84DD,
    TEXTURE30                      = 0x84DE,
    TEXTURE31                      = 0x84DF,
    ACTIVE_TEXTURE                 = 0x84E0,
    
    /* TextureWrapMode */
    REPEAT                         = 0x2901,
    CLAMP_TO_EDGE                  = 0x812F,
    MIRRORED_REPEAT                = 0x8370,
    
    /* Uniform Types */
    FLOAT_VEC2                     = 0x8B50,
    FLOAT_VEC3                     = 0x8B51,
    FLOAT_VEC4                     = 0x8B52,
    INT_VEC2                       = 0x8B53,
    INT_VEC3                       = 0x8B54,
    INT_VEC4                       = 0x8B55,
    BOOL                           = 0x8B56,
    BOOL_VEC2                      = 0x8B57,
    BOOL_VEC3                      = 0x8B58,
    BOOL_VEC4                      = 0x8B59,
    FLOAT_MAT2                     = 0x8B5A,
    FLOAT_MAT3                     = 0x8B5B,
    FLOAT_MAT4                     = 0x8B5C,
    SAMPLER_2D                     = 0x8B5E,
    SAMPLER_CUBE                   = 0x8B60,
    
    /* Vertex Arrays */
    VERTEX_ATTRIB_ARRAY_ENABLED        = 0x8622,
    VERTEX_ATTRIB_ARRAY_SIZE           = 0x8623,
    VERTEX_ATTRIB_ARRAY_STRIDE         = 0x8624,
    VERTEX_ATTRIB_ARRAY_TYPE           = 0x8625,
    VERTEX_ATTRIB_ARRAY_NORMALIZED     = 0x886A,
    VERTEX_ATTRIB_ARRAY_POINTER        = 0x8645,
    VERTEX_ATTRIB_ARRAY_BUFFER_BINDING = 0x889F,
    
    /* Shader Source */
    COMPILE_STATUS                 = 0x8B81,
    INFO_LOG_LENGTH                = 0x8B84,
    SHADER_SOURCE_LENGTH           = 0x8B88,
    
    /* Shader Precision-Specified Types */
    LOW_FLOAT                      = 0x8DF0,
    MEDIUM_FLOAT                   = 0x8DF1,
    HIGH_FLOAT                     = 0x8DF2,
    LOW_INT                        = 0x8DF3,
    MEDIUM_INT                     = 0x8DF4,
    HIGH_INT                       = 0x8DF5,
    
    /* Framebuffer Object. */
    FRAMEBUFFER                    = 0x8D40,
    RENDERBUFFER                   = 0x8D41,
    
    RGBA4                          = 0x8056,
    RGB5_A1                        = 0x8057,
    RGB565                         = 0x8D62,
    DEPTH_COMPONENT16              = 0x81A5,
    STENCIL_INDEX                  = 0x1901,
    STENCIL_INDEX8                 = 0x8D48,
    DEPTH_STENCIL                  = 0x84F9,
    
    RENDERBUFFER_WIDTH             = 0x8D42,
    RENDERBUFFER_HEIGHT            = 0x8D43,
    RENDERBUFFER_INTERNAL_FORMAT   = 0x8D44,
    RENDERBUFFER_RED_SIZE          = 0x8D50,
    RENDERBUFFER_GREEN_SIZE        = 0x8D51,
    RENDERBUFFER_BLUE_SIZE         = 0x8D52,
    RENDERBUFFER_ALPHA_SIZE        = 0x8D53,
    RENDERBUFFER_DEPTH_SIZE        = 0x8D54,
    RENDERBUFFER_STENCIL_SIZE      = 0x8D55,
    
    FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE           = 0x8CD0,
    FRAMEBUFFER_ATTACHMENT_OBJECT_NAME           = 0x8CD1,
    FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL         = 0x8CD2,
    FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE = 0x8CD3,
    
    COLOR_ATTACHMENT0              = 0x8CE0,
    DEPTH_ATTACHMENT               = 0x8D00,
    STENCIL_ATTACHMENT             = 0x8D20,
    DEPTH_STENCIL_ATTACHMENT       = 0x821A,
    
    NONE                           = 0,
    
    FRAMEBUFFER_COMPLETE                      = 0x8CD5,
    FRAMEBUFFER_INCOMPLETE_ATTACHMENT         = 0x8CD6,
    FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT = 0x8CD7,
    FRAMEBUFFER_INCOMPLETE_DIMENSIONS         = 0x8CD9,
    FRAMEBUFFER_UNSUPPORTED                   = 0x8CDD,
    
    FRAMEBUFFER_BINDING            = 0x8CA6,
    RENDERBUFFER_BINDING           = 0x8CA7,
    MAX_RENDERBUFFER_SIZE          = 0x84E8,
    
    INVALID_FRAMEBUFFER_OPERATION  = 0x0506,
    
    /* WebGL-specific enums */
    UNPACK_FLIP_Y_WEBGL            = 0x9240,
    UNPACK_PREMULTIPLY_ALPHA_WEBGL = 0x9241,
    CONTEXT_LOST_WEBGL             = 0x9242,
    UNPACK_COLORSPACE_CONVERSION_WEBGL = 0x9243,
    BROWSER_DEFAULT_WEBGL          = 0x9244,
  };
  
  
  /*! @name WebGL methods
   * The WebGL methods are mostly 1-on-1 translated to the identical
   * JavaScript call. You can use the WebGL methods in your resizeGL(),
   * paintGL() and updateGL() specializations. Wt takes care that data,
   * arguments, ... are transfered to the client side and that the equivalent
   * JavaScript WebGL funtion is executed.
   * @{
   */
  void debugger();
  /*! \brief GL function to activate an existing texture
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glActiveTexture.xml">
   * glActiveTexture() OpenGL ES manpage</a>
   */
  void activeTexture(GLenum texture);

  /*! \brief GL function to attach a shader to a program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glAttachShader.xml">
   * glAttachShader() OpenGL ES manpage</a>
   */
  void attachShader(Program program, Shader shader);

  /*! \brief GL function to bind an attribute to a given location
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindAttribLocation.xml">
   * glBindAttribLocation() OpenGL ES manpage</a>
   */
  void bindAttribLocation(Program program, unsigned index,
                          const std::string &name);

  /*! \brief GL function to bind a buffer to a target
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindBuffer.xml">
   * glBindBuffer() OpenGL ES manpage</a>
   */
  void bindBuffer(GLenum target, Buffer buffer);

  //void bindFramebuffer(GLenum target, WebGLFramebuffer framebuffer);
  //void bindRenderbuffer(GLenum target, WebGLRenderbuffer renderbuffer);

  /*! \brief GL function to bind a texture to a target
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindTexture.xml">
   * glBindTexture() OpenGL ES manpage</a>
   */
  void bindTexture(GLenum target, Texture texture);

  /*! \brief GL function to set the blending color
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendColor.xml">
   * glBlendColor() OpenGL ES manpage</a>
   */
  void blendColor(double red, double green, double blue, double alpha);

  /*! \brief GL function to set the blending equation
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendEquation.xml">
   * glBlendEquation() OpenGL ES manpage</a>
   */
  void blendEquation(GLenum mode);

  /*! \brief GL function that sets separate blending functions for RGB and alpha
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendEquationSeparate.xml">
   * glBlendEquationSeparate() OpenGL ES manpage</a>
   */
  void blendEquationSeparate(GLenum modeRGB, GLenum modeAlpha);

  /*! \brief GL function to configure the blending function
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendFunc.xml">
   * glBlendFunc() OpenGL ES manpage</a>
   */
  void blendFunc(GLenum sfactor, GLenum dfactor);

  /*! \brief GL function that configures the blending function
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendFuncSeparate.xml">
   * glBlendFuncSeparate() OpenGL ES manpage</a>
   */
  void blendFuncSeparate(GLenum srcRGB, GLenum dstRGB, 
                         GLenum srcAlpha, GLenum dstAlpha);

  /*! \brief GL function that loads float or double data in a VBO
   *
   * Unlike the C version, we can't accept a void * here. We must be able
   * to interpret the buffer's data in order to transmit it to the JS side.
   *
   * Later we may also want versions with strides and offsets to cope with
   * more complex buffer layouts that we typically see on desktop WebGL apps;
   * suggestions to improve this are welcome
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferData.xml">
   * glBufferData() OpenGL ES manpage</a>
   */
  template<typename Iterator>
  void bufferDatafv(GLenum target, const Iterator begin, const Iterator end, GLenum usage) {
    js_ << "ctx.bufferData(" << toString(target) << ",";
    renderfv(js_, begin, end);
    js_ << ","<< toString(usage) << ");";
    GLDEBUG;
  }

  /*! \brief GL function that updates an existing VBO with new integer data
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferData.xml">
   * glBufferData() OpenGL ES manpage</a>
   */
  template<typename Iterator>
  void bufferDataiv(GLenum target, const Iterator begin, const Iterator end,
                    GLenum usage, GLenum type)
  {
    js_ << "ctx.bufferData(" << toString(target) << ",";
    renderiv(js_, begin, end, type);
    js_ << ","<< toString(usage) << ");";
    GLDEBUG;
  }

  /*! \brief GL function that updates an existing VBO with new float or double
   * data
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferSubData.xml">
   * glBufferSubData() OpenGL ES manpage</a>
   */
  template<typename Iterator>
  void bufferSubDatafv(GLenum target, unsigned offset, const Iterator begin, const Iterator end)
  {
    js_ << "ctx.bufferSubData(" << toString(target) << "," << offset << ",";
    renderfv(js_, begin, end);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function that loads integer data in a VBO
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferSubData.xml">
   * glBufferSubData() OpenGL ES manpage</a>
   */
  template<typename Iterator>
  void bufferSubDataiv(GLenum target, unsigned offset, const Iterator begin, Iterator end, GLenum type)
  {
    js_ << "ctx.bufferSubData(" << toString(target) << "," << offset << ",";
    renderiv(js_, begin, end, type);
    js_ << ");";
    GLDEBUG;
  }


  //GLenum checkFramebufferStatus(GLenum target);

  /*! \brief GL function that clears the given buffers
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClear.xml">
   * glClear() OpenGL ES manpage</a>
   */
  void clear(WFlags<GLenum> mask);

  /*! \brief GL function that sets the clear color of the color buffer
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClearColor.xml">
   * glClearColor() OpenGL ES manpage</a>
   */
  void clearColor(double r, double g, double b, double a);

  /*! \brief GL function that configures the depth to be set when the
   * depth buffer is cleared
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClearDepthf.xml">
   * glClearDepthf() OpenGL ES manpage</a>
   */
  void clearDepth(double depth);

  /*! \brief GL function
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClearStencil.xml">
   * glClearStencil() OpenGL ES manpage</a>
   */
  void clearStencil(int s);

  /*! \brief GL function
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glColorMask.xml">
   * glColorMask() OpenGL ES manpage</a>
   */
  void colorMask(bool red, bool green, bool blue, bool alpha);

  /*! \brief GL function to compile a shader
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCompileShader.xml">
   * glCompileShader() OpenGL ES manpage</a>
   */
  void compileShader(Shader shader);

  /*! \brief GL function to copy a texture image
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCopyTexImage2D.xml">
   * glCopyTexImage2D() OpenGL ES manpage</a>
   */
  void copyTexImage2D(GLenum target, int level,
                      GLenum internalformat,
                      int x, int y,
                      unsigned width, unsigned height, 
                      int border);

  /*! \brief GL function that copies a part of a texture image
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCopyTexSubImage2D.xml">
   * glCopyTexSubImage2D() OpenGL ES manpage</a>
   */
  void copyTexSubImage2D(GLenum target, int level,
                         int xoffset, int yoffset,
                         int x, int y,
                         unsigned width, unsigned height);

  /*! \brief GL function that creates an empty VBO
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenBuffers.xml">
   * glGenBuffers() OpenGL ES manpage</a>
   */
  Buffer createBuffer();

  //WebGLFramebuffer createFramebuffer();

  /*! \brief GL function that creates an empty program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCreateProgram.xml">
   * glCreateProgram() OpenGL ES manpage</a>
   */
  Program createProgram();

  //WebGLRenderbuffer createRenderbuffer();

  /*! \brief GL function that creates an empty shader
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCreateShader.xml">
   * glCreateShader() OpenGL ES manpage</a>
   */
  Shader createShader(GLenum shader);

  /*! \brief GL function that creates an empty texture
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenTextures.xml">
   * glGenTextures() OpenGL ES manpage</a>
   */
  Texture createTexture();

  /*! \brief GL function that creates an image texture
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenTextures.xml">
   * glGenTextures() OpenGL ES manpage</a>
   */
  Texture createTextureAndLoad(const std::string &url);

  /*! \brief GL function that configures the backface culling mode
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCullFace.xml">
   * glCullFace() OpenGL ES manpage</a>
   */
  void cullFace(GLenum mode);

  /*! \brief GL function that deletes a VBO
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteBuffers.xml">
   * glDeleteBuffers() OpenGL ES manpage</a>
   */
  void deleteBuffer(Buffer buffer);

  //void deleteFramebuffer(WebGLFramebuffer framebuffer);

  /*! \brief GL function that deletes a program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteProgram.xml">
   * glDeleteProgram() OpenGL ES manpage</a>
   */
  void deleteProgram(Program program);

  //void deleteRenderbuffer(WebGLRenderbuffer renderbuffer);

  /*! \brief GL function that depetes a shader
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteShader.xml">
   * glDeleteShader() OpenGL ES manpage</a>
   */
  void deleteShader(Shader shader);

  /*! \brief GL function that deletes a texture
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteTextures.xml">
   * glDeleteTextures() OpenGL ES manpage</a>
   */
  void deleteTexture(Texture texture);

  /*! \brief GL function to set the depth test function
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDepthFunc.xml">
   * glDepthFunc() OpenGL ES manpage</a>
   */
  void depthFunc(GLenum func);

  /*! \brief GL function that enables or disables writing to the depth buffer
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDepthMask.xml">
   * glDepthMask() OpenGL ES manpage</a>
   */
  void depthMask(bool flag);

  /*! \brief GL function that specifies to what range the normalized [-1,1] z
   * values should match.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDepthRangef.xml">
   * glDepthRangef() OpenGL ES manpage</a>
   */
  void depthRange(double zNear, double zFar);

  /*! \brief GL function that detaches a shader from a program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDetachShader.xml">
   * glDetachShader() OpenGL ES manpage</a>
   */
  void detachShader(Program program, Shader shader);

  /*! \brief GL function to disable features
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDisable.xml">
   * glDisable() OpenGL ES manpage</a>
   */
  void disable(GLenum cap);

  /*! \brief GL function to draw a VBO
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDrawArrays.xml">
   * glDrawArrays() OpenGL ES manpage</a>
   */
  void drawArrays(GLenum mode, int first, unsigned count);

  /*! \brief GL function to draw indexed VBOs
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDrawElements.xml">
   * glDrawElements() OpenGL ES manpage</a>
   */
  void drawElements(GLenum mode, unsigned count, GLenum type, unsigned offset);

  /*! \brief GL function to enable features
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glEnable.xml">
   * glEnable() OpenGL ES manpage</a>
   */
  void enable(GLenum cap);

  /*! \brief GL function to enable the vertex attribute array
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glEnableVertexAttribArray.xml">
   * glEnableVertexAttribArray() OpenGL ES manpage</a>
   */
  void enableVertexAttribArray(AttribLocation index);

  /*! \brief GL function to wait until given commands are executed
   *
   * This call is transfered to JS, but the server will never wait on
   * this call.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFinish.xml">
   * glFinish() OpenGL ES manpage</a>
   */
  void finish();

  /*! \brief GL function to force execution of GL commands in finite time.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFlush.xml">
   * glFlush() OpenGL ES manpage</a>
   */
  void flush();

  //void framebufferRenderbuffer(GLenum target, GLenum attachment, 
  //                             GLenum renderbuffertarget, 
  //                             WebGLRenderbuffer renderbuffer);

  //void framebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, 
  //                          WebGLTexture texture, GLint level);

  /*! \brief GL function that specifies which side of a triangle is the
   * front side
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFrontFace.xml">
   * glFrontFace() OpenGL ES manpage</a>
   */
  void frontFace(GLenum mode);

  /*! \brief GL function that generates a set of mipmaps for a texture
   * object.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenerateMipmap.xml">
   * glGenerateMipmap() OpenGL ES manpage</a>
   */
  void generateMipmap(GLenum target);

  //WebGLActiveInfo getActiveAttrib(WebGLProgram program, GLuint index);
  //WebGLActiveInfo getActiveUniform(WebGLProgram program, GLuint index);
  //WebGLShader[ ] getAttachedShaders(WebGLProgram program);

  /*! \brief GL function to retrieve an attribute's location in a Program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetAttribLocation.xml">
   * glGetAttribLocation() OpenGL ES manpage</a>
   */
  AttribLocation getAttribLocation(Program program, const std::string &attrib);

  //any getParameter(GLenum pname);
  //any getBufferParameter(GLenum target, GLenum pname);

  //GLenum getError();

  //any getFramebufferAttachmentParameter(GLenum target, GLenum attachment, 
  //                                      GLenum pname);
  //any getProgramParameter(WebGLProgram program, GLenum pname);
  //DOMString getProgramInfoLog(WebGLProgram program);
  //any getRenderbufferParameter(GLenum target, GLenum pname);
  //any getShaderParameter(WebGLShader shader, GLenum pname);
  //DOMString getShaderInfoLog(WebGLShader shader);

  //DOMString getShaderSource(WebGLShader shader);

  //any getTexParameter(GLenum target, GLenum pname);

  //any getUniform(WebGLProgram program, WebGLUniformLocation location);

  /*! \brief GL function to retrieve a Uniform's location in a Program.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetUniformLocation.xml">
   * glGetUniformLocation() OpenGL ES manpage</a>
   */
  UniformLocation getUniformLocation(Program program, const std::string location);

  //any getVertexAttrib(GLuint index, GLenum pname);

  //GLsizeiptr getVertexAttribOffset(GLuint index, GLenum pname);

  /*! \brief GL function to give hints to the render pipeline
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glHint.xml">
   * glHint() OpenGL ES manpage</a>
   */
  void hint(GLenum target, GLenum mode);

  //GLboolean isBuffer(WebGLBuffer buffer);
  //GLboolean isEnabled(GLenum cap);
  //GLboolean isFramebuffer(WebGLFramebuffer framebuffer);
  //GLboolean isProgram(WebGLProgram program);
  //GLboolean isRenderbuffer(WebGLRenderbuffer renderbuffer);
  //GLboolean isShader(WebGLShader shader);
  //GLboolean isTexture(WebGLTexture texture);

  /*! \brief GL function to set the line width
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glLineWidth.xml">
   * glLineWidth() OpenGL ES manpage</a>
   */
  void lineWidth(double width);

  /*! \brief GL function to link a program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glLinkProgram.xml">
   * glLinkProgram() OpenGL ES manpage</a>
   */
  void linkProgram(Program program);

  /*! \brief GL function to set the pixel storage mode
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glPixelStorei.xml">
   * glPixelStorei() OpenGL ES manpage</a>
   */
  void pixelStorei(GLenum pname, int param);

  /*! \brief GL function to apply modifications to Z values
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glPolygonOffset.xml">
   * glPolygonOffset() OpenGL ES manpage</a>
   */
  void polygonOffset(double factor, double units);

  //void readPixels(GLint x, GLint y, GLsizei width, GLsizei height, 
  //                GLenum format, GLenum type, ArrayBufferView pixels);

  //void renderbufferStorage(GLenum target, GLenum internalformat, 
  //                         GLsizei width, GLsizei height);

  /*! \brief GL function to set multisample parameters
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glSampleCoverage.xml">
   * glSampleCoverage() OpenGL ES manpage</a>
   */
  void sampleCoverage(double value, bool invert);

  /*! \brief GL function to define the scissor box
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glScissor.xml">
   * glScissor() OpenGL ES manpage</a>
   */
  void scissor(int x, int y, unsigned width, unsigned height);

  /*! \brief GL function to set a shader's source code
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glShaderSource.xml">
   * glShaderSource() OpenGL ES manpage</a>
   */
  void shaderSource(Shader shader, const std::string &src);

  /*! \brief GL function to set stencil test parameters
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilFunc.xml">
   * glStencilFunc() OpenGL ES manpage</a>
   */
  void stencilFunc(GLenum func, int ref, unsigned mask);

  /*! \brief GL function to set stencil test parameters for front and/or
   * back stencils
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilFuncSeparate.xml">
   * glStencilFuncSeparate() OpenGL ES manpage</a>
   */
  void stencilFuncSeparate(GLenum face, GLenum func, int ref, unsigned mask);

  /*! \brief GL function to control which bits are to be written in the stencil
   * buffer
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilMask.xml">
   * glStencilMask() OpenGL ES manpage</a>
   */
  void stencilMask(unsigned mask);

  /*! \brief GL function to control which bits are written to the front and/or
   * back stencil buffers
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilMaskSeparate.xml">
   * glStencilMaskSeparate() OpenGL ES manpage</a>
   */
  void stencilMaskSeparate(GLenum face, unsigned mask);

  /*! \brief GL function to set stencil test actions
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilOp.xml">
   * glStencilOp() OpenGL ES manpage</a>
   */
  void stencilOp(GLenum fail, GLenum zfail, GLenum zpass);

  /*! \brief GL function to set front and/or back stencil test actions
   * separately
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilOpSeparate.xml">
   * glStencilOpSeparate() OpenGL ES manpage</a>
   */
  void stencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass);

  //void texImage2D(TextureTargetEnum target, int level, PixelFormatEnum internalformat, 
  //                GLsizei width, GLsizei height, GLint border, PixelFormatEnum format, 
  //                GLenum type, ArrayBufferView pixels);

  //void texImage2D(TextureTargetEnum target, int level, PixelFormatEnum internalformat,
  //                PixelFormatEnum format, GLenum type, ImageData pixels);

  /*! \brief GL function to load a 2D texture from a WImage
   *
   * Note: WImage must be loaded before this function is executed.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexImage2D.xml">
   * glTexImage2D() OpenGL ES manpage</a>
   */
  void texImage2D(GLenum target, int level, GLenum internalformat,
                  GLenum format, GLenum type, WImage *image);

  //void texImage2D(TextureTargetEnum target, int level, PixelFormatEnum internalformat,
  //                PixelFormatEnum format, GLenum type, HTMLCanvasElement canvas);

  /*! \brief GL function to load a 2D texture from a HTML5Video object
   *
   * Note: the video must be loaded prior to calling this function. The
   * current frame is used as texture image.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexImage2D.xml">
   * glTexImage2D() OpenGL ES manpage</a>
   */
  void texImage2D(GLenum target, int level, GLenum internalformat, GLenum format,
                  GLenum type, WHTML5Video *video);

  /*! \brief GL function to load a 2D texture loaded with createTextureAndLoad()
   *
   * This function must only be used for textures created with
   * createTextureAndLoad()
   *
   * Note: the WGLWidget implementation will delay rendering until
   * all textures created with createTextureAndLoad() are loaded in the
   * browser.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexImage2D.xml">
   * glTexImage2D() OpenGL ES manpage</a>
   */
  void texImage2D(GLenum target, int level, GLenum internalformat,
                  GLenum format, GLenum type, Texture texture);

  //void texParameterf(TextureTargetEnum target,
  //                   TextureParameterNameEnum pname, double param);

  /*! \brief GL function to set texture parameters
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexParameter.xml">
   * glTexParameter() OpenGL ES manpage</a>
   */
  void texParameteri(GLenum target, GLenum pname, GLenum param);

  //void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, 
  //                   GLsizei width, GLsizei height, 
  //                   GLenum format, GLenum type, ArrayBufferView pixels);
  //void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, 
  //                   GLenum format, GLenum type, ImageData pixels);
  //void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, 
  //                   GLenum format, GLenum type, HTMLImageElement image);
  //void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, 
  //                   GLenum format, GLenum type, HTMLCanvasElement canvas);
  //void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, 
  //                   GLenum format, GLenum type, HTMLVideoElement video);


  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform1f(const UniformLocation &location, double x) {
    char buf[30];
    js_ << "ctx.uniform1f(" << location << "," << makeFloat(x, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform1fv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform1fv(" << location << ",";
    renderfv(js_, value, value + 1);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform1i(const UniformLocation &location, int x) {
    char buf[30];
    js_ << "ctx.uniform1i(" << location << ",";
    js_ << makeInt(x, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform1iv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform1iv(" << location << ",";
    renderiv(js_, value, value + 1, INT);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform2f(const UniformLocation &location, double x, double y) {
    char buf[30];
    js_ << "ctx.uniform2f(" << location << ",";
    js_ << makeFloat(x, buf) << ",";
    js_ << makeFloat(y, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform2fv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform2fv(" << location << ",";
    renderfv(js_, value, value + 2);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform2i(const UniformLocation &location, int x, int y) {
    char buf[30];
    js_ << "ctx.uniform2i(" << location << ",";
    js_ << makeInt(x, buf) << ",";
    js_ << makeInt(y, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform2iv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform2iv(" << location << ",";
    renderiv(js_, value, value + 2, INT);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform3f(const UniformLocation &location,
                 double x, double y, double z) {
    char buf[30];
    js_ << "ctx.uniform3f(" << location << ",";
    js_ << makeFloat(x, buf) << ",";
    js_ << makeFloat(y, buf) << ",";
    js_ << makeFloat(z, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform3fv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform3fv(" << location << ",";
    renderfv(js_, value, value + 3);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform3i(const UniformLocation &location, int x, int y, int z) {
    char buf[30];
    js_ << "ctx.uniform3i(" << location << ",";
    js_ << makeInt(x, buf) << ",";
    js_ << makeInt(y, buf) << ",";
    js_ << makeInt(z, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform3iv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform3iv(" << location << ",";
    renderiv(js_, value, value + 3, INT);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform4f(const UniformLocation &location,
                 double x, double y, double z, double w) {
    char buf[30];
    js_ << "ctx.uniform4f(" << location << ",";
    js_ << makeFloat(x, buf) << ",";
    js_ << makeFloat(y, buf) << ",";
    js_ << makeFloat(z, buf) << ",";
    js_ << makeFloat(w, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform4fv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform4fv(" << location << ",";
    renderfv(js_, value, value + 4);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniform4i(const UniformLocation &location, int x, int y, int z, int w) {
    char buf[30];
    js_ << "ctx.uniform4i(" << location << ",";
    js_ << makeInt(x, buf) << ",";
    js_ << makeInt(y, buf) << ",";
    js_ << makeInt(z, buf) << ",";
    js_ << makeInt(w, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform variable of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename Array>
  void uniform4iv(const UniformLocation &location, const Array *value) {
    js_ << "ctx.uniform4iv(" << location << ",";
    renderiv(js_, value, value + 4, INT);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * Attention: The OpenGL ES specification states that transpose MUST be
   * false.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename MatrixType>
  void uniformMatrix2fv(const UniformLocation &location,
                        bool transpose, const MatrixType *value) {
    js_ << "ctx.uniformMatrix2fv(" << location << ","
      << (transpose?"true":"false") << ",";
    renderfv(js_, value, value + 4);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * This function renders the matrix in the proper row/column order.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template< typename T>
  void uniformMatrix2(const UniformLocation &location,
                      const WGenericMatrix<T, 2, 2> &m) {
    js_ << "ctx.uniformMatrix2fv(" << location << ",false,";
    WGenericMatrix<T, 2, 2> t(m.transposed());
    renderfv(js_, t.data().begin(), t.data().end());
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * Attention: The OpenGL ES specification states that transpose MUST be
   * false.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename MatrixType>
  void uniformMatrix3fv(const UniformLocation &location, bool transpose, const MatrixType *value) {
    js_ << "ctx.uniformMatrix3fv(" << location << ","
      << (transpose?"true":"false") << ",";
    renderfv(js_, value,value + 9);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * This function renders the matrix in the proper row/column order.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename T>
  void uniformMatrix3(const UniformLocation &location,
                      const WGenericMatrix<T, 3, 3> &m) {
    js_ << "ctx.uniformMatrix3fv(" << location << ",false,";
    WGenericMatrix<T, 3, 3> t(m.transposed());
    renderfv(js_, t.data().begin(), t.data().end());
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * Attention: The OpenGL ES specification states that transpose MUST be
   * false.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename MatrixType>
  void uniformMatrix4fv(const UniformLocation &location, bool transpose,
                        const MatrixType *value) {
    js_ << "ctx.uniformMatrix4fv(" << location << ","
      << (transpose?"true":"false") << ",";
    renderfv(js_, value, value + 16);
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * This function renders the matrix in the proper row/column order.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  template<typename T>
  void uniformMatrix4(const UniformLocation &location,
                      const WGenericMatrix<T, 4, 4> &m) {
    js_ << "ctx.uniformMatrix4fv(" << location << ",false,";
    WGenericMatrix<T, 4, 4> t(m.transposed());
    renderfv(js_, t.data().begin(), t.data().end());
    js_ << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of a uniform matrix of the current
   * program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">
   * glUniform() OpenGL ES manpage</a>
   */
  void uniformMatrix4(const UniformLocation &location,
                      const JavaScriptMatrix4x4 &m) {
    js_ << "ctx.uniformMatrix4fv(" << location << ",false,";
    js_ << m.jsRef() << ");";
    GLDEBUG;
  }


  /*! \brief GL function to set the current active shader program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUseProgram.xml">
   * glUseProgram() OpenGL ES manpage</a>
   */
  void useProgram(Program program);

  /*! \brief GL function to validate a program
   *
   * implementation note: there is currently not yet a method to read
   * out the validation result.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glValidateProgram.xml">
   * glValidateProgram() OpenGL ES manpage</a>
   */
  void validateProgram(Program program);

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  void vertexAttrib1f(AttribLocation location, double x) {
    char buf[30];
    js_ << "ctx.vertexAttrib1f(" << location << ",";
    js_ << makeFloat(x, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  template<typename Array>
  void vertexAttrib1fv(AttribLocation location, const Array *values) {
    vertexAttrib1f(location, values[0]);
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  void vertexAttrib2f(AttribLocation location, double x, double y) {
    char buf[30];
    js_ << "ctx.vertexAttrib2f(" << location << ",";
    js_ << makeFloat(x, buf) << ",";
    js_ << makeFloat(y, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  template<typename Array>
  void vertexAttrib2fv(AttribLocation location, const Array *values) {
    vertexAttrib2f(location, values[0], values[1]);
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  void vertexAttrib3f(AttribLocation location, double x, double y, double z) {
    char buf[30];
    js_ << "ctx.vertexAttrib3f(" << location << ",";
    js_ << makeFloat(x, buf) << ",";
    js_ << makeFloat(y, buf) << ",";
    js_ << makeFloat(z, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  template<typename Array>
  void vertexAttrib3fv(AttribLocation location, const Array *values) {
    vertexAttrib3f(location, values[0], values[1], values[2]);
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  void vertexAttrib4f(AttribLocation location,
                      double x, double y, double z, double w) {
    char buf[30];
    js_ << "ctx.vertexAttrib4f(" << location << ",";
    js_ << makeFloat(x, buf) << ",";
    js_ << makeFloat(y, buf) << ",";
    js_ << makeFloat(z, buf) << ",";
    js_ << makeFloat(w, buf) << ");";
    GLDEBUG;
  }

  /*! \brief GL function to set the value of an attribute of the current program
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">
   * glVertexAttrib() OpenGL ES manpage</a>
   */
  template<typename Array>
  void vertexAttrib4fv(AttribLocation location, const Array *values) {
    vertexAttrib4f(location, values[0], values[1], values[2], values[3]);
  }

  /*! \brief GL function to bind a VBO to an attribute
   *
   * This function links the given attribute to the VBO currently bound
   * to the ARRAY_BUFFER target.
   *
   * The size parameter specifies the number of components per attribute (1
   * to 4). The type parameter is also used to determine the size of each
   * component.
   *
   * The size of a float is 8 bytes.
   *
   * In WGLWidget, the size of an int is 4 bytes.
   *
   * The stride is in bytes.
   *
   * The maximum stride is 255.
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttribPointer.xml">
   * glVertexAttribPointer() OpenGL ES manpage</a>
   */
  void vertexAttribPointer(AttribLocation location, int size,
    GLenum type, bool normalized, unsigned stride, unsigned offset);

  /*! \brief GL function to set the viewport
   *
   * <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glViewport.xml">
   * glViewport() OpenGL ES manpage</a>
   */
  void viewport(int x, int y, unsigned width, unsigned height);

  /*! @}
   */

  /*! @name Additional WebGL methods
   *
   * These methods are used to render WebGL content, but have no equivalent
   * in WebGL.
   *
   * Like the WebGL methods, you can use the WebGL methods in your resizeGL(),
   * paintGL() and updateGL() specializations. It makes no sense to call these
   * methods outside those functions.
   * @{
   */
  /*! \brief Create a matrix that can be manipulated in client-side
   * JavaScript
   */
  JavaScriptMatrix4x4 createJavaScriptMatrix4();

  /*! \brief Set the value of a client-side JavaScript matrix created by
   * createJavaScriptMatrix4x4()
   */
  template<typename T>
  void setJavaScriptMatrix4(const JavaScriptMatrix4x4 &jsm,
                            const WGenericMatrix<T, 4, 4> &m) {
    js_ << WT_CLASS ".glMatrix.mat4.set(";
    WGenericMatrix<T, 4, 4> t(m.transposed());
    renderfv(js_, t.data().begin(), t.data().end());
    js_ << ", " << jsm.jsRef() << ");";
    GLDEBUG;
  }

  /*! @}
   */

  // Todo:
  // Get the current client-side value of a JavaScriptMatrix
  //WMatrix4x4 getJavaScriptMatrix4();

  /*! \brief Add a mouse handler to the widget that looks at a given point
   *
   * This will allow a user to change client-side matrix m with the
   * mouse. M is a model transformation matrix, representing the viewpoint of
   * the camera.
   *
   * Through mouse operations, the camera can be changed by the user, but
   * (lX, lY, lZ) will always be at the center of the display, (uX, uY, uZ)
   * is considered to be the up direction, and the distance of the camera to
   * (lX, lY, lZ) will never change.
   *
   * Pressing the left mouse button and moving the mouse left/right will
   * rotate the camera around the up (uX, uY, uZ) direction. Moving up/down
   * will tilt the camera (causing it to move up/down to keep the lookpoint
   * centered). The scroll wheel simulates zooming by scaling the scene.
   *
   * pitchRate and yawRate control how much the camera will move per mouse
   * pixel.
   *
   * Usually this method is called after setting a camera transformation
   * with a client-side matrix in initializeGL(). However, this function
   * may also be called from outside the intializeGL()/paintGL()/updateGL()
   * methods (but not before m was initialized).
   */
  void setClientSideLookAtHandler(const JavaScriptMatrix4x4 &m,
                                  double lX, double lY, double lZ,
                                  double uX, double uY, double uZ,
                                  double pitchRate, double yawRate);

  /*! \brief Add a mouse handler to the widget that allows 'walking' in
   * the scene
   *
   * This will allow a user to change client-side matrix m with the
   * mouse. M is a model transformation matrix, representing the viewpoint of
   * the camera.
   *
   * Through mouse operations, the camera can be changed by the user, as if
   * he is walking around on a plane. 
   *
   * Pressing the left mouse button and moving the mouse left/right will
   * rotate the camera around Y axis. Moving the mouse up/down will move
   * the camera in the Z direction (walking forward/backward).
   * centered).
   *
   * frontStep and rotStep control how much the camera will move per mouse
   * pixel.
   *
   * Usually this method is called after setting a camera transformation
   * with a client-side matrix in initializeGL(). However, this function
   * may also be called from outside the intializeGL()/paintGL()/updateGL()
   * methods (but not before m was initialized).
   */
  void setClientSideWalkHandler(const JavaScriptMatrix4x4 &m,
                                double frontStep, double rotStep);

  /*! \brief Sets the content to be displayed when WebGL is not available.
   *
   * If Wt cannot create a working WebGL context, this content will be
   * shown to the user. This may be a text explanation, or a pre-rendered
   * image, or a video, a flash movie, ...
   *
   * The default is a widget that explains to the user that he has no
   * WebGL support.
   */
  void setAlternativeContent(WWidget *alternative);

  /*! \brief A JavaScript slot that repaints the widget when triggered.
   *
   * This is useful for client-side initiated repaints. You may e.g. use this
   * if you write your own client-side mouse handler, or if you updated
   * a texture, or if you're playing a video texture.
   */
  JSlot &repaintSlot() { return repaintSlot_; }

protected:
  DomElementType domElementType() const;
  DomElement *createDomElement(WApplication *app);
  void getDomChanges(std::vector<DomElement *>& result, WApplication *app);
  void updateDom(DomElement &element, bool all);

  void render(WFlags<RenderFlag> flags);
  std::string renderRemoveJs();

private:
  std::string glObjJsRef();
  void layoutSizeChanged(int width, int height);

  int renderWidth_;
  int renderHeight_;
  bool updatePaintGL_;
  bool updateResizeGL_;
  bool updateGL_;
  bool sizeChanged_;

  WWidget *alternative_;

  unsigned shaders_;
  unsigned programs_;
  unsigned attributes_;
  unsigned uniforms_;
  unsigned buffers_;
  unsigned textures_;
  unsigned matrices_;
  std::vector<std::pair<std::string, std::string> > preloadImages_;

  // If client detects that a WebGL context cannot be created, it fires this
  // signal, and the handler sets wegGlNotAvailable_ to true. If this happens,
  // the client side will have deleted the canvas widget.
  JSignal<void> webglNotAvailable_;
  void webglNotAvailable();
  bool webGlNotAvailable_;

  JSlot mouseWentDownSlot_;
  JSlot mouseWentUpSlot_;
  JSlot mouseDraggedSlot_;
  JSlot mouseWheelSlot_;
  JSlot repaintSlot_;

  std::stringstream delayedJavaScript_;
  std::stringstream js_;

#ifndef WT_TARGET_JAVA
  template<typename Iterator>
  static void renderfv(std::ostream &os, Iterator begin, Iterator end)
  {
    char buf[30];
    os << "new Float32Array([";
    for (Iterator i = begin; i != end; ++i)
      os << (i == begin ? "" : ",") << makeFloat(*i, buf);
    os << "])";
  }
#endif

  template<typename Iterator>
  static void renderiv(std::ostream &os, Iterator begin, Iterator end, GLenum type)
  {
    switch (type) {
    case BYTE:
      os << "new Int8Array([";
      break;
    case UNSIGNED_BYTE:
      os << "new Uint8Array([";
      break;
    case SHORT:
      os << "new Int16Array([";
      break;
    case UNSIGNED_SHORT:
      os << "new Uint16Array([";
      break;
    case INT:
      os << "new Int32Array([";
      break;
    default:
      // Should we warn?
    case UNSIGNED_INT:
      os << "new Uint32Array([";
      break;
    }
    char buf[30];
    for (Iterator i = begin; i != end; ++i)
      os << (i == begin ? "" : ",") << makeInt(*i, buf);
    os << "])";
  }

  static char *makeFloat(double d, char *buf);
  static char *makeInt(int i, char *buf);

  static const char *toString(GLenum e);

  void defineJavaScript();
  void connectJavaScript(EventSignalBase &s,
                         const std::string &methodName);

};

W_DECLARE_OPERATORS_FOR_FLAGS(WGLWidget::GLenum)
W_DECLARE_OPERATORS_FOR_FLAGS(WGLWidget::ClientSideRenderer)
}

#endif