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1187
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1 ==============================================================================
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2 Using the Simple DirectMedia Layer with OpenBSD/wscons
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3 ==============================================================================
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4
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5 The wscons SDL driver can be used to run SDL programs on OpenBSD
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6 without running X. So far, the driver only runs on the Sharp Zaurus,
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7 but the driver is written to be easily extended for other machines.
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8 The main missing pieces are blitting routines for anything but 16 bit
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9 displays, and keycode maps for other keyboards. Also, there is no
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10 support for hardware palettes.
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11
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12 There is currently no mouse support.
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13
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14 To compile SDL with support for wscons, use the
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15 "--enable-video-wscons" option when running configure. I used the
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16 following command line:
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17
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18 ./configure --disable-oss --disable-ltdl --enable-pthread-sem \
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19 --disable-esd --disable-arts --disable-video-aalib \
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20 --enable-openbsdaudio --enable-video-wscons \
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21 --prefix=/usr/local --sysconfdir=/etc
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22
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23
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24 Setting the console device to use
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25 =================================
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26
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27 When starting an SDL program on a wscons console, the driver uses the
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28 current virtual terminal (usually /dev/ttyC0). To force the driver to
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29 use a specific terminal device, set the environment variable
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30 SDL_WSCONSDEV:
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31
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32 bash$ SDL_WSCONSDEV=/dev/ttyC1 ./some-sdl-program
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33
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34 This is especially useful when starting an SDL program from a remote
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35 login prompt (which is great for development). If you do this, and
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36 want to use keyboard input, you should avoid having some other program
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37 reading from the used virtual console (i.e., do not have a getty
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38 running).
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39
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40
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41 Rotating the display
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42 ====================
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43
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44 The display can be rotated by the wscons SDL driver. This is useful
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45 for the Sharp Zaurus, since the display hardware is wired so that it
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46 is correctly rotated only when the display is folded into "PDA mode."
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47 When using the Zaurus in "normal," or "keyboard" mode, the hardware
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48 screen is rotated 90 degrees anti-clockwise.
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49
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50 To let the wscons SDL driver rotate the screen, set the environment
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51 variable SDL_VIDEO_WSCONS_ROTATION to "CW", "CCW", or "UD", for
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52 clockwise, counter clockwise, and upside-down rotation respectively.
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53 "CW" makes the screen appear correct on a Sharp Zaurus SL-C3100.
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54
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55 When using rotation in the driver, a "shadow" frame buffer is used to
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56 hold the intermediary display, before blitting it to the actual
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57 hardware frame buffer. This slows down performance a bit.
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58
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59 For completeness, the rotation "NONE" can be specified to use a shadow
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60 frame buffer without actually rotating. Unsetting
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61 SDL_VIDEO_WSCONS_ROTATION, or setting it to '' turns off the shadow
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62 frame buffer for maximum performance.
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63
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64
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65 Running MAME
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66 ============
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67
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68 Since my main motivation for writing the driver was playing MAME on
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69 the Zaurus, I'll give a few hints:
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70
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71 XMame compiles just fine under OpenBSD.
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72
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73 I'm not sure this is strictly necessary, but set
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74
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75 MY_CPU = arm
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76
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77 in makefile.unix, and
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78
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79 CFLAGS.arm = -DLSB_FIRST -DALIGN_INTS -DALIGN_SHORTS
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80
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81 in src/unix/unix.max
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82
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83 to be sure.
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84
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85 The latest XMame (0.101 at this writing) is a very large program.
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86 Either tinker with the make files to compile a version without support
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87 for all drivers, or, get an older version of XMame. My recommendation
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88 would be 0.37b16.
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89
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90 When running MAME, DO NOT SET SDL_VIDEO_WSCONS_ROTATION! Performace
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91 is MUCH better without this, and it is COMPLETELY UNNECESSARY, since
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92 MAME can rotate the picture itself while drawing, and does so MUCH
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93 FASTER.
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94
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95 Use the Xmame command line option "-ror" to rotate the picture to the
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96 right.
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97
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98
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99 Acknowledgments
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100 ===============
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101
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102 I studied the wsfb driver for XFree86/Xorg quite a bit before writing
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103 this, so there ought to be some similarities.
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104
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105
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106 --
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107 Staffan Ulfberg <staffan@ulfberg.se>
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