1==============================================================================
2Using the Simple DirectMedia Layer with OpenBSD/wscons
3==============================================================================
4
5The wscons SDL driver can be used to run SDL programs on OpenBSD
6without running X.  So far, the driver only runs on the Sharp Zaurus,
7but the driver is written to be easily extended for other machines.
8The main missing pieces are blitting routines for anything but 16 bit
9displays, and keycode maps for other keyboards.  Also, there is no
10support for hardware palettes.
11
12There is currently no mouse support.
13
14To compile SDL with support for wscons, use the
15"--enable-video-wscons" option when running configure.  I used the
16following command line:
17
18./configure --disable-oss --disable-ltdl --enable-pthread-sem \
19	    --disable-esd --disable-arts --disable-video-aalib  \
20	    --enable-openbsdaudio --enable-video-wscons \
21	    --prefix=/usr/local --sysconfdir=/etc
22
23
24Setting the console device to use
25=================================
26
27When starting an SDL program on a wscons console, the driver uses the
28current virtual terminal (usually /dev/ttyC0).  To force the driver to
29use a specific terminal device, set the environment variable
30SDL_WSCONSDEV:
31
32bash$ SDL_WSCONSDEV=/dev/ttyC1 ./some-sdl-program
33
34This is especially useful when starting an SDL program from a remote
35login prompt (which is great for development).  If you do this, and
36want to use keyboard input, you should avoid having some other program
37reading from the used virtual console (i.e., do not have a getty
38running).
39
40
41Rotating the display
42====================
43
44The display can be rotated by the wscons SDL driver.  This is useful
45for the Sharp Zaurus, since the display hardware is wired so that it
46is correctly rotated only when the display is folded into "PDA mode."
47When using the Zaurus in "normal," or "keyboard" mode, the hardware
48screen is rotated 90 degrees anti-clockwise.
49
50To let the wscons SDL driver rotate the screen, set the environment
51variable SDL_VIDEO_WSCONS_ROTATION to "CW", "CCW", or "UD", for
52clockwise, counter clockwise, and upside-down rotation respectively.
53"CW" makes the screen appear correct on a Sharp Zaurus SL-C3100.
54
55When using rotation in the driver, a "shadow" frame buffer is used to
56hold the intermediary display, before blitting it to the actual
57hardware frame buffer.  This slows down performance a bit.
58
59For completeness, the rotation "NONE" can be specified to use a shadow
60frame buffer without actually rotating.  Unsetting
61SDL_VIDEO_WSCONS_ROTATION, or setting it to '' turns off the shadow
62frame buffer for maximum performance.
63
64
65Running MAME
66============
67
68Since my main motivation for writing the driver was playing MAME on
69the Zaurus, I'll give a few hints:
70
71XMame compiles just fine under OpenBSD.
72
73I'm not sure this is strictly necessary, but set
74
75MY_CPU = arm
76
77in makefile.unix, and
78
79CFLAGS.arm = -DLSB_FIRST -DALIGN_INTS -DALIGN_SHORTS
80
81in src/unix/unix.max
82
83to be sure.
84
85The latest XMame (0.101 at this writing) is a very large program.
86Either tinker with the make files to compile a version without support
87for all drivers, or, get an older version of XMame.  My recommendation
88would be 0.37b16.
89
90When running MAME, DO NOT SET SDL_VIDEO_WSCONS_ROTATION!  Performace
91is MUCH better without this, and it is COMPLETELY UNNECESSARY, since
92MAME can rotate the picture itself while drawing, and does so MUCH
93FASTER.
94
95Use the Xmame command line option "-ror" to rotate the picture to the
96right.
97
98
99Acknowledgments
100===============
101
102I studied the wsfb driver for XFree86/Xorg quite a bit before writing
103this, so there ought to be some similarities.
104
105
106--
107Staffan Ulfberg <staffan@ulfberg.se>
108