README.wscons
author Ryan C. Gordon <icculus@icculus.org>
Fri, 13 Jan 2006 02:32:07 +0000
changeset 1246 ca51a76a7328
parent 1187 19d8949b4584
permissions -rw-r--r--
Make error message meaningful if dlopen() fails on libX11.
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==============================================================================
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Using the Simple DirectMedia Layer with OpenBSD/wscons
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==============================================================================
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The wscons SDL driver can be used to run SDL programs on OpenBSD
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without running X.  So far, the driver only runs on the Sharp Zaurus,
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but the driver is written to be easily extended for other machines.
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The main missing pieces are blitting routines for anything but 16 bit
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displays, and keycode maps for other keyboards.  Also, there is no
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support for hardware palettes.
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There is currently no mouse support.
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To compile SDL with support for wscons, use the
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"--enable-video-wscons" option when running configure.  I used the
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following command line:
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./configure --disable-oss --disable-ltdl --enable-pthread-sem \
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	    --disable-esd --disable-arts --disable-video-aalib  \
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	    --enable-openbsdaudio --enable-video-wscons \
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	    --prefix=/usr/local --sysconfdir=/etc
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Setting the console device to use
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=================================
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When starting an SDL program on a wscons console, the driver uses the
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current virtual terminal (usually /dev/ttyC0).  To force the driver to
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use a specific terminal device, set the environment variable
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SDL_WSCONSDEV:
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bash$ SDL_WSCONSDEV=/dev/ttyC1 ./some-sdl-program
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This is especially useful when starting an SDL program from a remote
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login prompt (which is great for development).  If you do this, and
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want to use keyboard input, you should avoid having some other program
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reading from the used virtual console (i.e., do not have a getty
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running).
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Rotating the display
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====================
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The display can be rotated by the wscons SDL driver.  This is useful
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for the Sharp Zaurus, since the display hardware is wired so that it
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is correctly rotated only when the display is folded into "PDA mode."
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When using the Zaurus in "normal," or "keyboard" mode, the hardware
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screen is rotated 90 degrees anti-clockwise.
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To let the wscons SDL driver rotate the screen, set the environment
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variable SDL_VIDEO_WSCONS_ROTATION to "CW", "CCW", or "UD", for
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clockwise, counter clockwise, and upside-down rotation respectively.
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"CW" makes the screen appear correct on a Sharp Zaurus SL-C3100.
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When using rotation in the driver, a "shadow" frame buffer is used to
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hold the intermediary display, before blitting it to the actual
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hardware frame buffer.  This slows down performance a bit.
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For completeness, the rotation "NONE" can be specified to use a shadow
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frame buffer without actually rotating.  Unsetting
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SDL_VIDEO_WSCONS_ROTATION, or setting it to '' turns off the shadow
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frame buffer for maximum performance.
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Running MAME
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============
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Since my main motivation for writing the driver was playing MAME on
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the Zaurus, I'll give a few hints:
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XMame compiles just fine under OpenBSD.
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I'm not sure this is strictly necessary, but set
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MY_CPU = arm
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in makefile.unix, and
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CFLAGS.arm = -DLSB_FIRST -DALIGN_INTS -DALIGN_SHORTS
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in src/unix/unix.max
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to be sure.
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The latest XMame (0.101 at this writing) is a very large program.
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Either tinker with the make files to compile a version without support
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for all drivers, or, get an older version of XMame.  My recommendation
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would be 0.37b16.
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When running MAME, DO NOT SET SDL_VIDEO_WSCONS_ROTATION!  Performace
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is MUCH better without this, and it is COMPLETELY UNNECESSARY, since
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MAME can rotate the picture itself while drawing, and does so MUCH
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FASTER.
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Use the Xmame command line option "-ror" to rotate the picture to the
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right.
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Acknowledgments
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===============
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I studied the wsfb driver for XFree86/Xorg quite a bit before writing
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this, so there ought to be some similarities.
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--
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Staffan Ulfberg <staffan@ulfberg.se>