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[PATCH] SDL_GetVideoMode() does not find best mode, part 2
Following commit 1.51, I come accross a problem when SDL must choose between
several video modes that could suit the one asked.
If I ask 320x240 with this list:
768x480 768x240 640x400 640x200 384x480 384x240 320x400 320x200
The smallest selectables modes are 384x240 and 320x400. And SDL choose the later
in this list, but 384x240 is more suitable. So I added a check to compare
the pixel count (surface) of modes, and select the one which has the smallest
pixel count.
In my example, 384x240 has 92160 pixels, and 320x400 has 128000 pixels. So now
SDL will choose 384x240 for the asked 320x240 mode.
author | Patrice Mandin <patmandin@gmail.com> |
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date | Thu, 19 Jan 2006 21:28:52 +0000 |
parents | 19d8949b4584 |
children |
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============================================================================== Using the Simple DirectMedia Layer with OpenBSD/wscons ============================================================================== The wscons SDL driver can be used to run SDL programs on OpenBSD without running X. So far, the driver only runs on the Sharp Zaurus, but the driver is written to be easily extended for other machines. The main missing pieces are blitting routines for anything but 16 bit displays, and keycode maps for other keyboards. Also, there is no support for hardware palettes. There is currently no mouse support. To compile SDL with support for wscons, use the "--enable-video-wscons" option when running configure. I used the following command line: ./configure --disable-oss --disable-ltdl --enable-pthread-sem \ --disable-esd --disable-arts --disable-video-aalib \ --enable-openbsdaudio --enable-video-wscons \ --prefix=/usr/local --sysconfdir=/etc Setting the console device to use ================================= When starting an SDL program on a wscons console, the driver uses the current virtual terminal (usually /dev/ttyC0). To force the driver to use a specific terminal device, set the environment variable SDL_WSCONSDEV: bash$ SDL_WSCONSDEV=/dev/ttyC1 ./some-sdl-program This is especially useful when starting an SDL program from a remote login prompt (which is great for development). If you do this, and want to use keyboard input, you should avoid having some other program reading from the used virtual console (i.e., do not have a getty running). Rotating the display ==================== The display can be rotated by the wscons SDL driver. This is useful for the Sharp Zaurus, since the display hardware is wired so that it is correctly rotated only when the display is folded into "PDA mode." When using the Zaurus in "normal," or "keyboard" mode, the hardware screen is rotated 90 degrees anti-clockwise. To let the wscons SDL driver rotate the screen, set the environment variable SDL_VIDEO_WSCONS_ROTATION to "CW", "CCW", or "UD", for clockwise, counter clockwise, and upside-down rotation respectively. "CW" makes the screen appear correct on a Sharp Zaurus SL-C3100. When using rotation in the driver, a "shadow" frame buffer is used to hold the intermediary display, before blitting it to the actual hardware frame buffer. This slows down performance a bit. For completeness, the rotation "NONE" can be specified to use a shadow frame buffer without actually rotating. Unsetting SDL_VIDEO_WSCONS_ROTATION, or setting it to '' turns off the shadow frame buffer for maximum performance. Running MAME ============ Since my main motivation for writing the driver was playing MAME on the Zaurus, I'll give a few hints: XMame compiles just fine under OpenBSD. I'm not sure this is strictly necessary, but set MY_CPU = arm in makefile.unix, and CFLAGS.arm = -DLSB_FIRST -DALIGN_INTS -DALIGN_SHORTS in src/unix/unix.max to be sure. The latest XMame (0.101 at this writing) is a very large program. Either tinker with the make files to compile a version without support for all drivers, or, get an older version of XMame. My recommendation would be 0.37b16. When running MAME, DO NOT SET SDL_VIDEO_WSCONS_ROTATION! Performace is MUCH better without this, and it is COMPLETELY UNNECESSARY, since MAME can rotate the picture itself while drawing, and does so MUCH FASTER. Use the Xmame command line option "-ror" to rotate the picture to the right. Acknowledgments =============== I studied the wsfb driver for XFree86/Xorg quite a bit before writing this, so there ought to be some similarities. -- Staffan Ulfberg <staffan@ulfberg.se>