summaryrefslogtreecommitdiff
path: root/src/i_video.c
blob: 76ad23af03e57a1e53ffe76cc03c04699ed7cdec (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
//
// Copyright(C) 1993-1996 Id Software, Inc.
// Copyright(C) 2005-2014 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// DESCRIPTION:
//	DOOM graphics stuff for SDL.
//


#include "SDL.h"
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#include <string.h>

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif

#include "icon.c"

#include "config.h"
#include "deh_str.h"
#include "doomtype.h"
#include "doomkeys.h"
#include "i_joystick.h"
#include "i_system.h"
#include "i_swap.h"
#include "i_timer.h"
#include "i_video.h"
#include "i_scale.h"
#include "m_argv.h"
#include "m_config.h"
#include "m_misc.h"
#include "tables.h"
#include "v_video.h"
#include "w_wad.h"
#include "z_zone.h"

// Lookup table for mapping ASCII characters to their equivalent when
// shift is pressed on an American layout keyboard:

static const char shiftxform[] =
{
    0, 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, ' ', '!', '"', '#', '$', '%', '&',
    '"', // shift-'
    '(', ')', '*', '+',
    '<', // shift-,
    '_', // shift--
    '>', // shift-.
    '?', // shift-/
    ')', // shift-0
    '!', // shift-1
    '@', // shift-2
    '#', // shift-3
    '$', // shift-4
    '%', // shift-5
    '^', // shift-6
    '&', // shift-7
    '*', // shift-8
    '(', // shift-9
    ':',
    ':', // shift-;
    '<',
    '+', // shift-=
    '>', '?', '@',
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
    'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    '[', // shift-[
    '!', // shift-backslash - OH MY GOD DOES WATCOM SUCK
    ']', // shift-]
    '"', '_',
    '\'', // shift-`
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
    'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
    '{', '|', '}', '~', 127
};


#define LOADING_DISK_W 16
#define LOADING_DISK_H 16

// Non aspect ratio-corrected modes (direct multiples of 320x200)

static screen_mode_t *screen_modes[] = {
    &mode_scale_1x,
    &mode_scale_2x,
    &mode_scale_3x,
    &mode_scale_4x,
    &mode_scale_5x,
};

// Aspect ratio corrected modes (4:3 ratio)

static screen_mode_t *screen_modes_corrected[] = {

    // Vertically stretched modes (320x200 -> 320x240 and multiples)

    &mode_stretch_1x,
    &mode_stretch_2x,
    &mode_stretch_3x,
    &mode_stretch_4x,
    &mode_stretch_5x,

    // Horizontally squashed modes (320x200 -> 256x200 and multiples)

    &mode_squash_1x,
    &mode_squash_2x,
    &mode_squash_3x,
    &mode_squash_4x,
};

// SDL video driver name

char *video_driver = "";

// Window position:

static char *window_position = "";

// SDL surface for the screen.

static SDL_Surface *screen;

// Window title

static char *window_title = "";

// Intermediate 8-bit buffer that we draw to instead of 'screen'.
// This is used when we are rendering in 32-bit screen mode.
// When in a real 8-bit screen mode, screenbuffer == screen.

static SDL_Surface *screenbuffer = NULL;

// palette

static SDL_Color palette[256];
static boolean palette_to_set;

// display has been set up?

static boolean initialized = false;

// disable mouse?

static boolean nomouse = false;
int usemouse = 1;

// Bit mask of mouse button state.

static unsigned int mouse_button_state = 0;

// Disallow mouse and joystick movement to cause forward/backward
// motion.  Specified with the '-novert' command line parameter.
// This is an int to allow saving to config file

int novert = 0;

// Save screenshots in PNG format.

int png_screenshots = 0;

// if true, I_VideoBuffer is screen->pixels

static boolean native_surface;

// Screen width and height, from configuration file.

int screen_width = SCREENWIDTH;
int screen_height = SCREENHEIGHT;

// Color depth.

int screen_bpp = 0;

// Automatically adjust video settings if the selected mode is 
// not a valid video mode.

static int autoadjust_video_settings = 1;

// Run in full screen mode?  (int type for config code)

int fullscreen = true;

// Aspect ratio correction mode

int aspect_ratio_correct = true;

// Time to wait for the screen to settle on startup before starting the
// game (ms)

static int startup_delay = 1000;

// Grab the mouse? (int type for config code)

static int grabmouse = true;

// The screen buffer; this is modified to draw things to the screen

byte *I_VideoBuffer = NULL;

// If true, game is running as a screensaver

boolean screensaver_mode = false;

// Flag indicating whether the screen is currently visible:
// when the screen isnt visible, don't render the screen

boolean screenvisible;

// If true, we display dots at the bottom of the screen to 
// indicate FPS.

static boolean display_fps_dots;

// If this is true, the screen is rendered but not blitted to the
// video buffer.

static boolean noblit;

// Callback function to invoke to determine whether to grab the 
// mouse pointer.

static grabmouse_callback_t grabmouse_callback = NULL;

// disk image data and background overwritten by the disk to be
// restored by EndRead

static byte *disk_image = NULL;
static byte *saved_background;
static boolean window_focused;

// Empty mouse cursor

static SDL_Cursor *cursors[2];

// The screen mode and scale functions being used

static screen_mode_t *screen_mode;

// Window resize state.

static boolean need_resize = false;
static unsigned int resize_w, resize_h;
static unsigned int last_resize_time;

// If true, keyboard mapping is ignored, like in Vanilla Doom.
// The sensible thing to do is to disable this if you have a non-US
// keyboard.

int vanilla_keyboard_mapping = true;

// Is the shift key currently down?

static int shiftdown = 0;

// Mouse acceleration
//
// This emulates some of the behavior of DOS mouse drivers by increasing
// the speed when the mouse is moved fast.
//
// The mouse input values are input directly to the game, but when
// the values exceed the value of mouse_threshold, they are multiplied
// by mouse_acceleration to increase the speed.

float mouse_acceleration = 2.0;
int mouse_threshold = 10;

// Gamma correction level to use

int usegamma = 0;

static void ApplyWindowResize(unsigned int w, unsigned int h);

static boolean MouseShouldBeGrabbed()
{
    // never grab the mouse when in screensaver mode
   
    if (screensaver_mode)
        return false;

    // if the window doesn't have focus, never grab it

    if (!window_focused)
        return false;

    // always grab the mouse when full screen (dont want to 
    // see the mouse pointer)

    if (fullscreen)
        return true;

    // Don't grab the mouse if mouse input is disabled

    if (!usemouse || nomouse)
        return false;

    // if we specify not to grab the mouse, never grab

    if (!grabmouse)
        return false;

    // Invoke the grabmouse callback function to determine whether
    // the mouse should be grabbed

    if (grabmouse_callback != NULL)
    {
        return grabmouse_callback();
    }
    else
    {
        return true;
    }
}

void I_SetGrabMouseCallback(grabmouse_callback_t func)
{
    grabmouse_callback = func;
}

// Set the variable controlling FPS dots.

void I_DisplayFPSDots(boolean dots_on)
{
    display_fps_dots = dots_on;
}

// Update the value of window_focused when we get a focus event
//
// We try to make ourselves be well-behaved: the grab on the mouse
// is removed if we lose focus (such as a popup window appearing),
// and we dont move the mouse around if we aren't focused either.

static void UpdateFocus(void)
{
    Uint8 state;

    state = SDL_GetAppState();

    // We should have input (keyboard) focus and be visible 
    // (not minimized)

    window_focused = (state & SDL_APPINPUTFOCUS) && (state & SDL_APPACTIVE);

    // Should the screen be grabbed?

    screenvisible = (state & SDL_APPACTIVE) != 0;
}

// Show or hide the mouse cursor. We have to use different techniques
// depending on the OS.

static void SetShowCursor(boolean show)
{
    // On Windows, using SDL_ShowCursor() adds lag to the mouse input,
    // so work around this by setting an invisible cursor instead. On
    // other systems, it isn't possible to change the cursor, so this
    // hack has to be Windows-only. (Thanks to entryway for this)

#ifdef _WIN32
    if (show)
    {
        SDL_SetCursor(cursors[1]);
    }
    else
    {
        SDL_SetCursor(cursors[0]);
    }
#else
    SDL_ShowCursor(show);
#endif

    // When the cursor is hidden, grab the input.

    if (!screensaver_mode)
    {
        SDL_WM_GrabInput(!show);
    }
}

void I_EnableLoadingDisk(void)
{
    patch_t *disk;
    byte *tmpbuf;
    char *disk_name;
    int y;
    char buf[20];

    SDL_VideoDriverName(buf, 15);

    if (!strcmp(buf, "Quartz"))
    {
        // MacOS Quartz gives us pageflipped graphics that screw up the 
        // display when we use the loading disk.  Disable it.
        // This is a gross hack.

        return;
    }

    if (M_CheckParm("-cdrom") > 0)
        disk_name = DEH_String("STCDROM");
    else
        disk_name = DEH_String("STDISK");

    disk = W_CacheLumpName(disk_name, PU_STATIC);

    // Draw the patch into a temporary buffer

    tmpbuf = Z_Malloc(SCREENWIDTH * (disk->height + 1), PU_STATIC, NULL);
    V_UseBuffer(tmpbuf);

    // Draw the disk to the screen:

    V_DrawPatch(0, 0, disk);

    disk_image = Z_Malloc(LOADING_DISK_W * LOADING_DISK_H, PU_STATIC, NULL);
    saved_background = Z_Malloc(LOADING_DISK_W * LOADING_DISK_H, PU_STATIC, NULL);

    for (y=0; y<LOADING_DISK_H; ++y) 
    {
        memcpy(disk_image + LOADING_DISK_W * y,
               tmpbuf + SCREENWIDTH * y,
               LOADING_DISK_W);
    }

    // All done - free the screen buffer and restore the normal 
    // video buffer.

    W_ReleaseLumpName(disk_name);
    V_RestoreBuffer();
    Z_Free(tmpbuf);
}

//
// Translates the SDL key
//

static int TranslateKey(SDL_keysym *sym)
{
    switch(sym->sym)
    {
      case SDLK_LEFT:	return KEY_LEFTARROW;
      case SDLK_RIGHT:	return KEY_RIGHTARROW;
      case SDLK_DOWN:	return KEY_DOWNARROW;
      case SDLK_UP:	return KEY_UPARROW;
      case SDLK_ESCAPE:	return KEY_ESCAPE;
      case SDLK_RETURN:	return KEY_ENTER;
      case SDLK_TAB:	return KEY_TAB;
      case SDLK_F1:	return KEY_F1;
      case SDLK_F2:	return KEY_F2;
      case SDLK_F3:	return KEY_F3;
      case SDLK_F4:	return KEY_F4;
      case SDLK_F5:	return KEY_F5;
      case SDLK_F6:	return KEY_F6;
      case SDLK_F7:	return KEY_F7;
      case SDLK_F8:	return KEY_F8;
      case SDLK_F9:	return KEY_F9;
      case SDLK_F10:	return KEY_F10;
      case SDLK_F11:	return KEY_F11;
      case SDLK_F12:	return KEY_F12;
      case SDLK_PRINT:  return KEY_PRTSCR;

      case SDLK_BACKSPACE: return KEY_BACKSPACE;
      case SDLK_DELETE:	return KEY_DEL;

      case SDLK_PAUSE:	return KEY_PAUSE;

#if !SDL_VERSION_ATLEAST(1, 3, 0)
      case SDLK_EQUALS: return KEY_EQUALS;
#endif

      case SDLK_MINUS:          return KEY_MINUS;

      case SDLK_LSHIFT:
      case SDLK_RSHIFT:
	return KEY_RSHIFT;
	
      case SDLK_LCTRL:
      case SDLK_RCTRL:
	return KEY_RCTRL;
	
      case SDLK_LALT:
      case SDLK_RALT:
#if !SDL_VERSION_ATLEAST(1, 3, 0)
      case SDLK_LMETA:
      case SDLK_RMETA:
#endif
        return KEY_RALT;

      case SDLK_CAPSLOCK: return KEY_CAPSLOCK;
      case SDLK_SCROLLOCK: return KEY_SCRLCK;
      case SDLK_NUMLOCK: return KEY_NUMLOCK;

      case SDLK_KP0: return KEYP_0;
      case SDLK_KP1: return KEYP_1;
      case SDLK_KP2: return KEYP_2;
      case SDLK_KP3: return KEYP_3;
      case SDLK_KP4: return KEYP_4;
      case SDLK_KP5: return KEYP_5;
      case SDLK_KP6: return KEYP_6;
      case SDLK_KP7: return KEYP_7;
      case SDLK_KP8: return KEYP_8;
      case SDLK_KP9: return KEYP_9;

      case SDLK_KP_PERIOD:   return KEYP_PERIOD;
      case SDLK_KP_MULTIPLY: return KEYP_MULTIPLY;
      case SDLK_KP_PLUS:     return KEYP_PLUS;
      case SDLK_KP_MINUS:    return KEYP_MINUS;
      case SDLK_KP_DIVIDE:   return KEYP_DIVIDE;
      case SDLK_KP_EQUALS:   return KEYP_EQUALS;
      case SDLK_KP_ENTER:    return KEYP_ENTER;

      case SDLK_HOME: return KEY_HOME;
      case SDLK_INSERT: return KEY_INS;
      case SDLK_END: return KEY_END;
      case SDLK_PAGEUP: return KEY_PGUP;
      case SDLK_PAGEDOWN: return KEY_PGDN;

#ifdef SDL_HAVE_APP_KEYS
        case SDLK_APP1:        return KEY_F1;
        case SDLK_APP2:        return KEY_F2;
        case SDLK_APP3:        return KEY_F3;
        case SDLK_APP4:        return KEY_F4;
        case SDLK_APP5:        return KEY_F5;
        case SDLK_APP6:        return KEY_F6;
#endif

      default:
        return tolower(sym->sym);
    }
}

void I_ShutdownGraphics(void)
{
    if (initialized)
    {
        SetShowCursor(true);

        SDL_QuitSubSystem(SDL_INIT_VIDEO);

        initialized = false;
    }
}



//
// I_StartFrame
//
void I_StartFrame (void)
{
    // er?

}

static void UpdateMouseButtonState(unsigned int button, boolean on)
{
    event_t event;

    if (button < SDL_BUTTON_LEFT || button > MAX_MOUSE_BUTTONS)
    {
        return;
    }

    // Note: button "0" is left, button "1" is right,
    // button "2" is middle for Doom.  This is different
    // to how SDL sees things.

    switch (button)
    {
        case SDL_BUTTON_LEFT:
            button = 0;
            break;

        case SDL_BUTTON_RIGHT:
            button = 1;
            break;

        case SDL_BUTTON_MIDDLE:
            button = 2;
            break;

        default:
            // SDL buttons are indexed from 1.
            --button;
            break;
    }

    // Turn bit representing this button on or off.

    if (on)
    {
        mouse_button_state |= (1 << button);
    }
    else
    {
        mouse_button_state &= ~(1 << button);
    }

    // Post an event with the new button state.

    event.type = ev_mouse;
    event.data1 = mouse_button_state;
    event.data2 = event.data3 = 0;
    D_PostEvent(&event);
}

static int AccelerateMouse(int val)
{
    if (val < 0)
        return -AccelerateMouse(-val);

    if (val > mouse_threshold)
    {
        return (int)((val - mouse_threshold) * mouse_acceleration + mouse_threshold);
    }
    else
    {
        return val;
    }
}

// Get the equivalent ASCII (Unicode?) character for a keypress.

static int GetTypedChar(SDL_Event *event)
{
    int key;

    // If Vanilla keyboard mapping enabled, the keyboard
    // scan code is used to give the character typed.
    // This does not change depending on keyboard layout.
    // If you have a German keyboard, pressing 'z' will
    // give 'y', for example.  It is desirable to be able
    // to fix this so that people with non-standard 
    // keyboard mappings can type properly.  If vanilla
    // mode is disabled, use the properly translated 
    // version.

    if (vanilla_keyboard_mapping)
    {
        key = TranslateKey(&event->key.keysym);

        // Is shift held down?  If so, perform a translation.

        if (shiftdown > 0)
        {
            if (key >= 0 && key < arrlen(shiftxform))
            {
                key = shiftxform[key];
            }
            else
            {
                key = 0;
            }
        }

        return key;
    }
    else
    {
        // Unicode value, from key layout.

        return tolower(event->key.keysym.unicode);
    }
}

static void UpdateShiftStatus(SDL_Event *event)
{
    int change;

    if (event->type == SDL_KEYDOWN)
    {
        change = 1;
    }
    else if (event->type == SDL_KEYUP)
    {
        change = -1;
    }
    else
    {
        return;
    }

    if (event->key.keysym.sym == SDLK_LSHIFT 
     || event->key.keysym.sym == SDLK_RSHIFT)
    {
        shiftdown += change;
    }
}

void I_GetEvent(void)
{
    SDL_Event sdlevent;
    event_t event;

    // possibly not needed
    
    SDL_PumpEvents();

    // put event-grabbing stuff in here
    
    while (SDL_PollEvent(&sdlevent))
    {
        // ignore mouse events when the window is not focused

        if (!window_focused 
         && (sdlevent.type == SDL_MOUSEMOTION
          || sdlevent.type == SDL_MOUSEBUTTONDOWN
          || sdlevent.type == SDL_MOUSEBUTTONUP))
        {
            continue;
        }

        if (screensaver_mode && sdlevent.type == SDL_QUIT)
        {
            I_Quit();
        }

        UpdateShiftStatus(&sdlevent);

        // process event
        
        switch (sdlevent.type)
        {
            case SDL_KEYDOWN:
                // data1 has the key pressed, data2 has the character
                // (shift-translated, etc)
                event.type = ev_keydown;
                event.data1 = TranslateKey(&sdlevent.key.keysym);
                event.data2 = GetTypedChar(&sdlevent);

                if (event.data1 != 0)
                {
                    D_PostEvent(&event);
                }
                break;

            case SDL_KEYUP:
                event.type = ev_keyup;
                event.data1 = TranslateKey(&sdlevent.key.keysym);

                // data2 is just initialized to zero for ev_keyup.
                // For ev_keydown it's the shifted Unicode character
                // that was typed, but if something wants to detect
                // key releases it should do so based on data1
                // (key ID), not the printable char.

                event.data2 = 0;

                if (event.data1 != 0)
                {
                    D_PostEvent(&event);
                }
                break;

                /*
            case SDL_MOUSEMOTION:
                event.type = ev_mouse;
                event.data1 = mouse_button_state;
                event.data2 = AccelerateMouse(sdlevent.motion.xrel);
                event.data3 = -AccelerateMouse(sdlevent.motion.yrel);
                D_PostEvent(&event);
                break;
                */

            case SDL_MOUSEBUTTONDOWN:
		if (usemouse && !nomouse)
		{
                    UpdateMouseButtonState(sdlevent.button.button, true);
		}
                break;

            case SDL_MOUSEBUTTONUP:
		if (usemouse && !nomouse)
		{
                    UpdateMouseButtonState(sdlevent.button.button, false);
		}
                break;

            case SDL_QUIT:
                event.type = ev_quit;
                D_PostEvent(&event);
                break;

            case SDL_ACTIVEEVENT:
                // need to update our focus state
                UpdateFocus();
                break;

            case SDL_VIDEOEXPOSE:
                palette_to_set = true;
                break;

            case SDL_RESIZABLE:
                need_resize = true;
                resize_w = sdlevent.resize.w;
                resize_h = sdlevent.resize.h;
                last_resize_time = SDL_GetTicks();
                break;

            default:
                break;
        }
    }
}

// Warp the mouse back to the middle of the screen

static void CenterMouse(void)
{
    // Warp the the screen center

    SDL_WarpMouse(screen->w / 2, screen->h / 2);

    // Clear any relative movement caused by warping

    SDL_PumpEvents();
#if SDL_VERSION_ATLEAST(1, 3, 0)
    SDL_GetRelativeMouseState(0, NULL, NULL);
#else
    SDL_GetRelativeMouseState(NULL, NULL);
#endif
}

//
// Read the change in mouse state to generate mouse motion events
//
// This is to combine all mouse movement for a tic into one mouse
// motion event.

static void I_ReadMouse(void)
{
    int x, y;
    event_t ev;

#if SDL_VERSION_ATLEAST(1, 3, 0)
    SDL_GetRelativeMouseState(0, &x, &y);
#else
    SDL_GetRelativeMouseState(&x, &y);
#endif

    if (x != 0 || y != 0) 
    {
        ev.type = ev_mouse;
        ev.data1 = mouse_button_state;
        ev.data2 = AccelerateMouse(x);

        if (!novert)
        {
            ev.data3 = -AccelerateMouse(y);
        }
        else
        {
            ev.data3 = 0;
        }
        
        D_PostEvent(&ev);
    }

    if (MouseShouldBeGrabbed())
    {
        CenterMouse();
    }
}

//
// I_StartTic
//
void I_StartTic (void)
{
    if (!initialized)
    {
        return;
    }

    I_GetEvent();

    if (usemouse && !nomouse)
    {
        I_ReadMouse();
    }

    I_UpdateJoystick();
}


//
// I_UpdateNoBlit
//
void I_UpdateNoBlit (void)
{
    // what is this?
}

static void UpdateGrab(void)
{
    static boolean currently_grabbed = false;
    boolean grab;

    grab = MouseShouldBeGrabbed();

    if (screensaver_mode)
    {
        // Hide the cursor in screensaver mode

        SetShowCursor(false);
    }
    else if (grab && !currently_grabbed)
    {
        SetShowCursor(false);
        CenterMouse();
    }
    else if (!grab && currently_grabbed)
    {
        SetShowCursor(true);

        // When releasing the mouse from grab, warp the mouse cursor to
        // the bottom-right of the screen. This is a minimally distracting
        // place for it to appear - we may only have released the grab
        // because we're at an end of level intermission screen, for
        // example.

        SDL_WarpMouse(screen->w - 16, screen->h - 16);
        SDL_GetRelativeMouseState(NULL, NULL);
    }

    currently_grabbed = grab;

}

// Update a small portion of the screen
//
// Does stretching and buffer blitting if neccessary
//
// Return true if blit was successful.

static boolean BlitArea(int x1, int y1, int x2, int y2)
{
    int x_offset, y_offset;
    boolean result;

    // No blit needed on native surface

    if (native_surface)
    {
	return true;
    }

    x_offset = (screenbuffer->w - screen_mode->width) / 2;
    y_offset = (screenbuffer->h - screen_mode->height) / 2;

    if (SDL_LockSurface(screenbuffer) >= 0)
    {
        I_InitScale(I_VideoBuffer,
                    (byte *) screenbuffer->pixels
                                + (y_offset * screenbuffer->pitch)
                                + x_offset,
                    screenbuffer->pitch);
        result = screen_mode->DrawScreen(x1, y1, x2, y2);
      	SDL_UnlockSurface(screenbuffer);
    }
    else
    {
        result = false;
    }

    return result;
}

static void UpdateRect(int x1, int y1, int x2, int y2)
{
    int x1_scaled, x2_scaled, y1_scaled, y2_scaled;

    // Do stretching and blitting

    if (BlitArea(x1, y1, x2, y2))
    {
        // Update the area

        x1_scaled = (x1 * screen_mode->width) / SCREENWIDTH;
        y1_scaled = (y1 * screen_mode->height) / SCREENHEIGHT;
        x2_scaled = (x2 * screen_mode->width) / SCREENWIDTH;
        y2_scaled = (y2 * screen_mode->height) / SCREENHEIGHT;

        SDL_UpdateRect(screen,
                       x1_scaled, y1_scaled,
                       x2_scaled - x1_scaled,
                       y2_scaled - y1_scaled);
    }
}

void I_BeginRead(void)
{
    byte *screenloc = I_VideoBuffer
                    + (SCREENHEIGHT - LOADING_DISK_H) * SCREENWIDTH
                    + (SCREENWIDTH - LOADING_DISK_W);
    int y;

    if (!initialized || disk_image == NULL)
        return;

    // save background and copy the disk image in

    for (y=0; y<LOADING_DISK_H; ++y)
    {
        memcpy(saved_background + y * LOADING_DISK_W,
               screenloc,
               LOADING_DISK_W);
        memcpy(screenloc,
               disk_image + y * LOADING_DISK_W,
               LOADING_DISK_W);

        screenloc += SCREENWIDTH;
    }

    UpdateRect(SCREENWIDTH - LOADING_DISK_W, SCREENHEIGHT - LOADING_DISK_H,
               SCREENWIDTH, SCREENHEIGHT);
}

void I_EndRead(void)
{
    byte *screenloc = I_VideoBuffer
                    + (SCREENHEIGHT - LOADING_DISK_H) * SCREENWIDTH
                    + (SCREENWIDTH - LOADING_DISK_W);
    int y;

    if (!initialized || disk_image == NULL)
        return;

    // save background and copy the disk image in

    for (y=0; y<LOADING_DISK_H; ++y)
    {
        memcpy(screenloc,
               saved_background + y * LOADING_DISK_W,
               LOADING_DISK_W);

        screenloc += SCREENWIDTH;
    }

    UpdateRect(SCREENWIDTH - LOADING_DISK_W, SCREENHEIGHT - LOADING_DISK_H,
               SCREENWIDTH, SCREENHEIGHT);
}

//
// I_FinishUpdate
//
void I_FinishUpdate (void)
{
    static int	lasttic;
    int		tics;
    int		i;

    if (!initialized)
        return;

    if (noblit)
        return;

    if (need_resize && SDL_GetTicks() > last_resize_time + 500)
    {
        ApplyWindowResize(resize_w, resize_h);
        need_resize = false;
        palette_to_set = true;
    }

    UpdateGrab();

    // Don't update the screen if the window isn't visible.
    // Not doing this breaks under Windows when we alt-tab away 
    // while fullscreen.

    if (!(SDL_GetAppState() & SDL_APPACTIVE))
        return;

    // draws little dots on the bottom of the screen

    if (display_fps_dots)
    {
	i = I_GetTime();
	tics = i - lasttic;
	lasttic = i;
	if (tics > 20) tics = 20;

	for (i=0 ; i<tics*4 ; i+=4)
	    I_VideoBuffer[ (SCREENHEIGHT-1)*SCREENWIDTH + i] = 0xff;
	for ( ; i<20*4 ; i+=4)
	    I_VideoBuffer[ (SCREENHEIGHT-1)*SCREENWIDTH + i] = 0x0;
    }

    // draw to screen

    BlitArea(0, 0, SCREENWIDTH, SCREENHEIGHT);

    if (palette_to_set)
    {
        SDL_SetColors(screenbuffer, palette, 0, 256);
        palette_to_set = false;

        // In native 8-bit mode, if we have a palette to set, the act
        // of setting the palette updates the screen

        if (screenbuffer == screen)
        {
            return;
        }
    }

    // In 8in32 mode, we must blit from the fake 8-bit screen buffer
    // to the real screen before doing a screen flip.

    if (screenbuffer != screen)
    {
        SDL_Rect dst_rect;

        // Center the buffer within the full screen space.

        dst_rect.x = (screen->w - screenbuffer->w) / 2;
        dst_rect.y = (screen->h - screenbuffer->h) / 2;

        SDL_BlitSurface(screenbuffer, NULL, screen, &dst_rect);
    }

    SDL_Flip(screen);
}


//
// I_ReadScreen
//
void I_ReadScreen (byte* scr)
{
    memcpy(scr, I_VideoBuffer, SCREENWIDTH*SCREENHEIGHT);
}


//
// I_SetPalette
//
void I_SetPalette (byte *doompalette)
{
    int i;

    for (i=0; i<256; ++i)
    {
        // Zero out the bottom two bits of each channel - the PC VGA
        // controller only supports 6 bits of accuracy.

        palette[i].r = gammatable[usegamma][*doompalette++] & ~3;
        palette[i].g = gammatable[usegamma][*doompalette++] & ~3;
        palette[i].b = gammatable[usegamma][*doompalette++] & ~3;
    }

    palette_to_set = true;
}

// Given an RGB value, find the closest matching palette index.

int I_GetPaletteIndex(int r, int g, int b)
{
    int best, best_diff, diff;
    int i;

    best = 0; best_diff = INT_MAX;

    for (i = 0; i < 256; ++i)
    {
        diff = (r - palette[i].r) * (r - palette[i].r)
             + (g - palette[i].g) * (g - palette[i].g)
             + (b - palette[i].b) * (b - palette[i].b);

        if (diff < best_diff)
        {
            best = i;
            best_diff = diff;
        }

        if (diff == 0)
        {
            break;
        }
    }

    return best;
}

// 
// Set the window title
//

void I_SetWindowTitle(char *title)
{
    window_title = title;
}

//
// Call the SDL function to set the window title, based on 
// the title set with I_SetWindowTitle.
//

void I_InitWindowTitle(void)
{
    char *buf;

    buf = M_StringJoin(window_title, " - ", PACKAGE_STRING, NULL);
    SDL_WM_SetCaption(buf, NULL);
    free(buf);
}

// Set the application icon

void I_InitWindowIcon(void)
{
    SDL_Surface *surface;
    Uint8 *mask;
    int i;

    // Generate the mask

    mask = malloc(icon_w * icon_h / 8);
    memset(mask, 0, icon_w * icon_h / 8);

    for (i=0; i<icon_w * icon_h; ++i)
    {
        if (icon_data[i * 3] != 0x00
         || icon_data[i * 3 + 1] != 0x00
         || icon_data[i * 3 + 2] != 0x00)
        {
            mask[i / 8] |= 1 << (7 - i % 8);
        }
    }

    surface = SDL_CreateRGBSurfaceFrom(icon_data,
                                       icon_w,
                                       icon_h,
                                       24,
                                       icon_w * 3,
                                       0xff << 0,
                                       0xff << 8,
                                       0xff << 16,
                                       0);

    SDL_WM_SetIcon(surface, mask);
    SDL_FreeSurface(surface);
    free(mask);
}

// Pick the modes list to use:

static void GetScreenModes(screen_mode_t ***modes_list, int *num_modes)
{
    if (aspect_ratio_correct)
    {
        *modes_list = screen_modes_corrected;
        *num_modes = arrlen(screen_modes_corrected);
    }
    else
    {
        *modes_list = screen_modes;
        *num_modes = arrlen(screen_modes);
    }
}

// Find which screen_mode_t to use for the given width and height.

static screen_mode_t *I_FindScreenMode(int w, int h)
{
    screen_mode_t **modes_list;
    screen_mode_t *best_mode;
    int modes_list_length;
    int num_pixels;
    int best_num_pixels;
    int i;

    // Special case: 320x200 and 640x400 are available even if aspect 
    // ratio correction is turned on.  These modes have non-square
    // pixels.

    if (fullscreen)
    {
        if (w == SCREENWIDTH && h == SCREENHEIGHT)
        {
            return &mode_scale_1x;
        }
        else if (w == SCREENWIDTH*2 && h == SCREENHEIGHT*2)
        {
            return &mode_scale_2x;
        }
    }

    GetScreenModes(&modes_list, &modes_list_length);

    // Find the biggest screen_mode_t in the list that fits within these 
    // dimensions

    best_mode = NULL;
    best_num_pixels = 0;

    for (i=0; i<modes_list_length; ++i) 
    {
        // Will this fit within the dimensions? If not, ignore.

        if (modes_list[i]->width > w || modes_list[i]->height > h)
        {
            continue;
        }

        num_pixels = modes_list[i]->width * modes_list[i]->height;

        if (num_pixels > best_num_pixels)
        {
            // This is a better mode than the current one

            best_mode = modes_list[i];
            best_num_pixels = num_pixels;
        }
    }

    return best_mode;
}

// Adjust to an appropriate fullscreen mode.
// Returns true if successful.

static boolean AutoAdjustFullscreen(void)
{
    SDL_Rect **modes;
    SDL_Rect *best_mode;
    screen_mode_t *screen_mode;
    int diff, best_diff;
    int i;

    modes = SDL_ListModes(NULL, SDL_FULLSCREEN);

    // No fullscreen modes available at all?

    if (modes == NULL || modes == (SDL_Rect **) -1 || *modes == NULL)
    {
        return false;
    }

    // Find the best mode that matches the mode specified in the
    // configuration file

    best_mode = NULL;
    best_diff = INT_MAX;

    for (i=0; modes[i] != NULL; ++i)
    {
        //printf("%ix%i?\n", modes[i]->w, modes[i]->h);

        // What screen_mode_t would be used for this video mode?

        screen_mode = I_FindScreenMode(modes[i]->w, modes[i]->h);

        // Never choose a screen mode that we cannot run in, or
        // is poor quality for fullscreen

        if (screen_mode == NULL || screen_mode->poor_quality)
        {
        //    printf("\tUnsupported / poor quality\n");
            continue;
        }

        // Do we have the exact mode?
        // If so, no autoadjust needed

        if (screen_width == modes[i]->w && screen_height == modes[i]->h)
        {
        //    printf("\tExact mode!\n");
            return true;
        }

        // Is this mode better than the current mode?

        diff = (screen_width - modes[i]->w) * (screen_width - modes[i]->w)
             + (screen_height - modes[i]->h) * (screen_height - modes[i]->h);

        if (diff < best_diff)
        {
        //    printf("\tA valid mode\n");
            best_mode = modes[i];
            best_diff = diff;
        }
    }

    if (best_mode == NULL)
    {
        // Unable to find a valid mode!

        return false;
    }

    printf("I_InitGraphics: %ix%i mode not supported on this machine.\n",
           screen_width, screen_height);

    screen_width = best_mode->w;
    screen_height = best_mode->h;

    return true;
}

// Auto-adjust to a valid windowed mode.

static void AutoAdjustWindowed(void)
{
    screen_mode_t *best_mode;

    // Find a screen_mode_t to fit within the current settings

    best_mode = I_FindScreenMode(screen_width, screen_height);

    if (best_mode == NULL)
    {
        // Nothing fits within the current settings.
        // Pick the closest to 320x200 possible.

        best_mode = I_FindScreenMode(SCREENWIDTH, SCREENHEIGHT_4_3);
    }

    // Switch to the best mode if necessary.

    if (best_mode->width != screen_width || best_mode->height != screen_height)
    {
        printf("I_InitGraphics: Cannot run at specified mode: %ix%i\n",
               screen_width, screen_height);

        screen_width = best_mode->width;
        screen_height = best_mode->height;
    }
}

// Auto-adjust to a valid color depth.

static void AutoAdjustColorDepth(void)
{
    SDL_Rect **modes;
    SDL_PixelFormat format;
    const SDL_VideoInfo *info;
    int flags;

    // If screen_bpp=0, we should use the current (default) pixel depth.
    // Fetch it from SDL.

    if (screen_bpp == 0)
    {
        info = SDL_GetVideoInfo();

        if (info != NULL && info->vfmt != NULL)
        {
            screen_bpp = info->vfmt->BitsPerPixel;
        }
    }

    if (fullscreen)
    {
        flags = SDL_FULLSCREEN;
    }
    else
    {
        flags = 0;
    }

    format.BitsPerPixel = screen_bpp;
    format.BytesPerPixel = (screen_bpp + 7) / 8;

    // Are any screen modes supported at the configured color depth?

    modes = SDL_ListModes(&format, flags);

    // If not, we must autoadjust to something sensible.

    if (modes == NULL)
    {
        printf("I_InitGraphics: %ibpp color depth not supported.\n",
               screen_bpp);

        info = SDL_GetVideoInfo();

        if (info != NULL && info->vfmt != NULL)
        {
            screen_bpp = info->vfmt->BitsPerPixel;
        }
    }
}

// If the video mode set in the configuration file is not available,
// try to choose a different mode.

static void I_AutoAdjustSettings(void)
{
    int old_screen_w, old_screen_h, old_screen_bpp;

    old_screen_w = screen_width;
    old_screen_h = screen_height;
    old_screen_bpp = screen_bpp;

    // Possibly adjust color depth.

    AutoAdjustColorDepth();

    // If we are running fullscreen, try to autoadjust to a valid fullscreen
    // mode.  If this is impossible, switch to windowed.

    if (fullscreen && !AutoAdjustFullscreen())
    {
        fullscreen = 0;
    }

    // If we are running windowed, pick a valid window size.

    if (!fullscreen)
    {
        AutoAdjustWindowed();
    }

    // Have the settings changed?  Show a message.

    if (screen_width != old_screen_w || screen_height != old_screen_h
     || screen_bpp != old_screen_bpp)
    {
        printf("I_InitGraphics: Auto-adjusted to %ix%ix%ibpp.\n",
               screen_width, screen_height, screen_bpp);

        printf("NOTE: Your video settings have been adjusted.  "
               "To disable this behavior,\n"
               "set autoadjust_video_settings to 0 in your "
               "configuration file.\n");
    }
}

// Set video size to a particular scale factor (1x, 2x, 3x, etc.)

static void SetScaleFactor(int factor)
{
    int w, h;

    // Pick 320x200 or 320x240, depending on aspect ratio correct

    if (aspect_ratio_correct)
    {
        w = SCREENWIDTH;
        h = SCREENHEIGHT_4_3;
    }
    else
    {
        w = SCREENWIDTH;
        h = SCREENHEIGHT;
    }

    screen_width = w * factor;
    screen_height = h * factor;
}

void I_GraphicsCheckCommandLine(void)
{
    int i;

    //!
    // @vanilla
    //
    // Disable blitting the screen.
    //

    noblit = M_CheckParm ("-noblit"); 

    //!
    // @category video 
    //
    // Grab the mouse when running in windowed mode.
    //

    if (M_CheckParm("-grabmouse"))
    {
        grabmouse = true;
    }

    //!
    // @category video 
    //
    // Don't grab the mouse when running in windowed mode.
    //

    if (M_CheckParm("-nograbmouse"))
    {
        grabmouse = false;
    }

    // default to fullscreen mode, allow override with command line
    // nofullscreen because we love prboom

    //!
    // @category video 
    //
    // Run in a window.
    //

    if (M_CheckParm("-window") || M_CheckParm("-nofullscreen"))
    {
        fullscreen = false;
    }

    //!
    // @category video 
    //
    // Run in fullscreen mode.
    //

    if (M_CheckParm("-fullscreen"))
    {
        fullscreen = true;
    }

    //!
    // @category video 
    //
    // Disable the mouse.
    //

    nomouse = M_CheckParm("-nomouse") > 0;

    //!
    // @category video
    // @arg <x>
    //
    // Specify the screen width, in pixels.
    //

    i = M_CheckParmWithArgs("-width", 1);

    if (i > 0)
    {
        screen_width = atoi(myargv[i + 1]);
    }

    //!
    // @category video
    // @arg <y>
    //
    // Specify the screen height, in pixels.
    //

    i = M_CheckParmWithArgs("-height", 1);

    if (i > 0)
    {
        screen_height = atoi(myargv[i + 1]);
    }

    //!
    // @category video
    // @arg <bpp>
    //
    // Specify the color depth of the screen, in bits per pixel.
    //

    i = M_CheckParmWithArgs("-bpp", 1);

    if (i > 0)
    {
        screen_bpp = atoi(myargv[i + 1]);
    }

    // Because we love Eternity:

    //!
    // @category video
    //
    // Set the color depth of the screen to 32 bits per pixel.
    //

    if (M_CheckParm("-8in32"))
    {
        screen_bpp = 32;
    }

    //!
    // @category video
    // @arg <WxY>[wf]
    //
    // Specify the dimensions of the window or fullscreen mode.  An
    // optional letter of w or f appended to the dimensions selects
    // windowed or fullscreen mode.

    i = M_CheckParmWithArgs("-geometry", 1);

    if (i > 0)
    {
        int w, h, s;
        char f;

        s = sscanf(myargv[i + 1], "%ix%i%1c", &w, &h, &f);
        if (s == 2 || s == 3)
        {
            screen_width = w;
            screen_height = h;

            if (s == 3 && f == 'f')
            {
                fullscreen = true;
            }
            else if (s == 3 && f == 'w')
            {
                fullscreen = false;
            }
        }
    }

    //!
    // @category video
    //
    // Don't scale up the screen.
    //

    if (M_CheckParm("-1")) 
    {
        SetScaleFactor(1);
    }

    //!
    // @category video
    //
    // Double up the screen to 2x its normal size.
    //

    if (M_CheckParm("-2")) 
    {
        SetScaleFactor(2);
    }

    //!
    // @category video
    //
    // Double up the screen to 3x its normal size.
    //

    if (M_CheckParm("-3")) 
    {
        SetScaleFactor(3);
    }

    //!
    // @category video
    //
    // Disable vertical mouse movement.
    //

    if (M_CheckParm("-novert"))
    {
        novert = true;
    }

    //!
    // @category video
    //
    // Enable vertical mouse movement.
    //

    if (M_CheckParm("-nonovert"))
    {
        novert = false;
    }
}

// Check if we have been invoked as a screensaver by xscreensaver.

void I_CheckIsScreensaver(void)
{
    char *env;

    env = getenv("XSCREENSAVER_WINDOW");

    if (env != NULL)
    {
        screensaver_mode = true;
    }
}

static void CreateCursors(void)
{
    static Uint8 empty_cursor_data = 0;

    // Save the default cursor so it can be recalled later

    cursors[1] = SDL_GetCursor();

    // Create an empty cursor

    cursors[0] = SDL_CreateCursor(&empty_cursor_data,
                                  &empty_cursor_data,
                                  1, 1, 0, 0);
}

static void SetSDLVideoDriver(void)
{
    // Allow a default value for the SDL video driver to be specified
    // in the configuration file.

    if (strcmp(video_driver, "") != 0)
    {
        char *env_string;

        env_string = M_StringJoin("SDL_VIDEODRIVER=", video_driver, NULL);
        putenv(env_string);
        free(env_string);
    }
}

static void SetWindowPositionVars(void)
{
    char buf[64];
    int x, y;

    if (window_position == NULL || !strcmp(window_position, ""))
    {
        return;
    }

    if (!strcmp(window_position, "center"))
    {
        putenv("SDL_VIDEO_CENTERED=1");
    }
    else if (sscanf(window_position, "%i,%i", &x, &y) == 2)
    {
        M_snprintf(buf, sizeof(buf), "SDL_VIDEO_WINDOW_POS=%i,%i", x, y);
        putenv(buf);
    }
}

static char *WindowBoxType(screen_mode_t *mode, int w, int h)
{
    if (mode->width != w && mode->height != h) 
    {
        return "Windowboxed";
    }
    else if (mode->width == w) 
    {
        return "Letterboxed";
    }
    else if (mode->height == h)
    {
        return "Pillarboxed";
    }
    else
    {
        return "...";
    }
}

static void SetVideoMode(screen_mode_t *mode, int w, int h)
{
    byte *doompal;
    int flags = 0;

    doompal = W_CacheLumpName(DEH_String("PLAYPAL"), PU_CACHE);

    // If we are already running and in a true color mode, we need
    // to free the screenbuffer surface before setting the new mode.

    if (screenbuffer != NULL && screen != screenbuffer)
    {
        SDL_FreeSurface(screenbuffer);
    }

    // Generate lookup tables before setting the video mode.

    if (mode != NULL && mode->InitMode != NULL)
    {
        mode->InitMode(doompal);
    }

    // Set the video mode.

    flags |= SDL_SWSURFACE | SDL_DOUBLEBUF;

    if (screen_bpp == 8)
    {
        flags |= SDL_HWPALETTE;
    }

    if (fullscreen)
    {
        flags |= SDL_FULLSCREEN;
    }
    else
    {
        // In windowed mode, the window can be resized while the game is
        // running.  This feature is disabled on OS X, as it adds an ugly
        // scroll handle to the corner of the screen.

#ifndef __MACOSX__
        flags |= SDL_RESIZABLE;
#endif
    }

    screen = SDL_SetVideoMode(w, h, screen_bpp, flags);

    if (screen == NULL)
    {
        I_Error("Error setting video mode %ix%ix%ibpp: %s\n",
                w, h, screen_bpp, SDL_GetError());
    }

    // Blank out the full screen area in case there is any junk in
    // the borders that won't otherwise be overwritten.

    SDL_FillRect(screen, NULL, 0);

    // If mode was not set, it must be set now that we know the
    // screen size.

    if (mode == NULL)
    {
        mode = I_FindScreenMode(screen->w, screen->h);

        if (mode == NULL)
        {
            I_Error("I_InitGraphics: Unable to find a screen mode small "
                    "enough for %ix%i", screen->w, screen->h);
        }

        // Generate lookup tables before setting the video mode.

        if (mode->InitMode != NULL)
        {
            mode->InitMode(doompal);
        }
    }

    // Create the screenbuffer surface; if we have a real 8-bit palettized
    // screen, then we can use the screen as the screenbuffer.

    if (screen->format->BitsPerPixel == 8)
    {
        screenbuffer = screen;
    }
    else
    {
        screenbuffer = SDL_CreateRGBSurface(SDL_SWSURFACE,
                                            mode->width, mode->height, 8,
                                            0, 0, 0, 0);

        SDL_FillRect(screenbuffer, NULL, 0);
    }

    // Save screen mode.

    screen_mode = mode;
}

static void ApplyWindowResize(unsigned int w, unsigned int h)
{
    screen_mode_t *mode;

    // Find the biggest screen mode that will fall within these
    // dimensions, falling back to the smallest mode possible if
    // none is found.

    mode = I_FindScreenMode(w, h);

    if (mode == NULL)
    {
        mode = I_FindScreenMode(SCREENWIDTH, SCREENHEIGHT);
    }

    // Reset mode to resize window.

    printf("Resize to %ix%i\n", mode->width, mode->height);
    SetVideoMode(mode, mode->width, mode->height);

    // Save settings.

    screen_width = mode->width;
    screen_height = mode->height;
}

void I_InitGraphics(void)
{
    SDL_Event dummy;
    byte *doompal;
    char *env;

    // Pass through the XSCREENSAVER_WINDOW environment variable to 
    // SDL_WINDOWID, to embed the SDL window into the Xscreensaver
    // window.

    env = getenv("XSCREENSAVER_WINDOW");

    if (env != NULL)
    {
        char winenv[30];
        int winid;

        sscanf(env, "0x%x", &winid);
        M_snprintf(winenv, sizeof(winenv), "SDL_WINDOWID=%i", winid);

        putenv(winenv);
    }

    SetSDLVideoDriver();
    SetWindowPositionVars();

    if (SDL_Init(SDL_INIT_VIDEO) < 0) 
    {
        I_Error("Failed to initialize video: %s", SDL_GetError());
    }

    // Set up title and icon.  Windows cares about the ordering; this
    // has to be done before the call to SDL_SetVideoMode.

    I_InitWindowTitle();
#if !SDL_VERSION_ATLEAST(1, 3, 0)
    I_InitWindowIcon();
#endif

    // Warning to OS X users... though they might never see it :(
#ifdef __MACOSX__
    if (fullscreen)
    {
        printf("Some old versions of OS X might crash in fullscreen mode.\n"
               "If this happens to you, switch back to windowed mode.\n");
    }
#endif

    //
    // Enter into graphics mode.
    //
    // When in screensaver mode, run full screen and auto detect
    // screen dimensions (don't change video mode)
    //

    if (screensaver_mode)
    {
        SetVideoMode(NULL, 0, 0);
    }
    else
    {
        int w, h;

        if (autoadjust_video_settings)
        {
            I_AutoAdjustSettings();
        }

        w = screen_width;
        h = screen_height;

        screen_mode = I_FindScreenMode(w, h);

        if (screen_mode == NULL)
        {
            I_Error("I_InitGraphics: Unable to find a screen mode small "
                    "enough for %ix%i", w, h);
        }

        if (w != screen_mode->width || h != screen_mode->height)
        {
            printf("I_InitGraphics: %s (%ix%i within %ix%i)\n",
                   WindowBoxType(screen_mode, w, h),
                   screen_mode->width, screen_mode->height, w, h);
        }

        SetVideoMode(screen_mode, w, h);
    }

    // Start with a clear black screen
    // (screen will be flipped after we set the palette)

    SDL_FillRect(screenbuffer, NULL, 0);

    // Set the palette

    doompal = W_CacheLumpName(DEH_String("PLAYPAL"), PU_CACHE);
    I_SetPalette(doompal);
    SDL_SetColors(screenbuffer, palette, 0, 256);

    CreateCursors();

    UpdateFocus();
    UpdateGrab();

    // On some systems, it takes a second or so for the screen to settle
    // after changing modes.  We include the option to add a delay when
    // setting the screen mode, so that the game doesn't start immediately
    // with the player unable to see anything.

    if (fullscreen && !screensaver_mode)
    {
        SDL_Delay(startup_delay);
    }

    // Check if we have a native surface we can use
    // If we have to lock the screen, draw to a buffer and copy
    // Likewise if the screen pitch is not the same as the width
    // If we have to multiply, drawing is done to a separate 320x200 buf

    native_surface = screen == screenbuffer
                  && !SDL_MUSTLOCK(screen)
                  && screen_mode == &mode_scale_1x
                  && screen->pitch == SCREENWIDTH
                  && aspect_ratio_correct;

    // If not, allocate a buffer and copy from that buffer to the
    // screen when we do an update

    if (native_surface)
    {
	I_VideoBuffer = (unsigned char *) screen->pixels;

        I_VideoBuffer += (screen->h - SCREENHEIGHT) / 2;
    }
    else
    {
	I_VideoBuffer = (unsigned char *) Z_Malloc (SCREENWIDTH * SCREENHEIGHT, 
                                                    PU_STATIC, NULL);
    }

    V_RestoreBuffer();

    // Clear the screen to black.

    memset(I_VideoBuffer, 0, SCREENWIDTH * SCREENHEIGHT);

    // We need SDL to give us translated versions of keys as well

    SDL_EnableUNICODE(1);

    // Repeat key presses - this is what Vanilla Doom does
    // Not sure about repeat rate - probably dependent on which DOS
    // driver is used.  This is good enough though.

    SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY, SDL_DEFAULT_REPEAT_INTERVAL);

    // clear out any events waiting at the start and center the mouse
  
    while (SDL_PollEvent(&dummy));

    initialized = true;

    // Call I_ShutdownGraphics on quit

    I_AtExit(I_ShutdownGraphics, true);
}

// Bind all variables controlling video options into the configuration
// file system.

void I_BindVideoVariables(void)
{
    M_BindVariable("use_mouse",                 &usemouse);
    M_BindVariable("autoadjust_video_settings", &autoadjust_video_settings);
    M_BindVariable("fullscreen",                &fullscreen);
    M_BindVariable("aspect_ratio_correct",      &aspect_ratio_correct);
    M_BindVariable("startup_delay",             &startup_delay);
    M_BindVariable("screen_width",              &screen_width);
    M_BindVariable("screen_height",             &screen_height);
    M_BindVariable("screen_bpp",                &screen_bpp);
    M_BindVariable("grabmouse",                 &grabmouse);
    M_BindVariable("mouse_acceleration",        &mouse_acceleration);
    M_BindVariable("mouse_threshold",           &mouse_threshold);
    M_BindVariable("video_driver",              &video_driver);
    M_BindVariable("window_position",           &window_position);
    M_BindVariable("usegamma",                  &usegamma);
    M_BindVariable("vanilla_keyboard_mapping",  &vanilla_keyboard_mapping);
    M_BindVariable("novert",                    &novert);
    M_BindVariable("png_screenshots",           &png_screenshots);

    // Windows Vista or later?  Set screen color depth to
    // 32 bits per pixel, as 8-bit palettized screen modes
    // don't work properly in recent versions.

#if defined(_WIN32) && !defined(_WIN32_WCE)
    {
        OSVERSIONINFOEX version_info;

        ZeroMemory(&version_info, sizeof(OSVERSIONINFOEX));
        version_info.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

        GetVersionEx((OSVERSIONINFO *) &version_info);

        if (version_info.dwPlatformId == VER_PLATFORM_WIN32_NT
         && version_info.dwMajorVersion >= 6)
        {
            screen_bpp = 32;
        }
    }
#endif

    // Disable fullscreen by default on OS X, as there is an SDL bug
    // where some old versions of OS X (<= Snow Leopard) crash.

#ifdef __MACOSX__
    fullscreen = 0;
    screen_width = 800;
    screen_height = 600;
#endif
}