config

gameboy 模拟器的源代码

filtering to smooth out the blocky pixels, but it's not available on
all systems. The other way is for gnuboy to scale the screen itself.

Normally gnuboy will choose hardware scaling automatically if it's
available, but if you want to force it on or off, you can set the
option "yuv" (for hardware YUV-colorspace scaling) to 1 or 0. Yes,
this option is poorly named, and is likely to change in future
versions of gnuboy.

On one display platform, Linux fbcon, it's possible to disable the
interpolation filter in the hardware scaling. To do this, set the
variable "yuvinterp" to 0. Some users who like a crisper display may
prefer this setting, especially on video cards that make the picture
look "muddy" when they scale it. Unfortunately SDL does not seem to
provide such an option, so interpolation is always enabled on the SDL
based ports.

When hardware scaling is disabled or not available, gnuboy will do its
own scaling. However, the scale factor is limited to 1, 2, 3, or 4.
Also, when performing its own scaling, gnuboy defaults to leaving some
scanlines blank. This saves a lot of CPU time and allows gnuboy to run
full speed on slower systems. You can configure what portion gets
filled in with the "density" variable. For example.

  set scale 4
  set density 4

will give you 4x scaling with no blank scanlines. Keep in mind that a
fairly fast computer (at least 400 MHz or so on x86, or something
comparable on other types of CPUs) is required to run fullspeed with
this setting. In general, "density" is the number of lines that get
filled in, so set it the same as "scale" if you want everything filled
in, or lower if you need more speed.


  VIDEO MODE

The variable for setting the desired video mode is called "vmode", and
it's made up of three parts: width, height, and bits-per-pixel. For
example, to set 640x480x16bpp mode, use

  set vmode 640 480 16

By default gnuboy will enable hardware scaling and try to scale to the
entire screen size if a video mode at least 320x288 is specified. If
you don't want this behavior, set the "yuv" option (see above) to 0.
Also, if you're setting the "scale" variable to do scaling, you
probably don't need to use the "vmode" option, since gnuboy will
try to automatically pick a mode that fits the scale. It's there in
case you need it, though.

Note that the DOS port is not yet capable of auto-choosing a video
mode, so if you want anything but the default 320x200x8bpp you'll have
to set "vmode" yourself. Also, not all ports are capable of all modes.
Experiment to find what works for you. Video mode selection is a
little bit messy and confusing at this time, and we hope to improve it
a good deal in the future.


  FULLSCREEN VIDEO

Some versions of gnuboy provide both fullscreen and windowed
operation. The variable "fullscreen" can be set to 1 or 0 to enable or
disable fullscreen mode. Also, the variable "altenter" can be set to
enable or disable switching between fullscreen and windowed mode at
runtime with the Alt+Enter key combination. Unfortunately, this does
not yet work on Windows; we hope to fix this limitation in the
future.


  DMG PALETTE SELECTION

gnuboy allows you to set the palette used for grayscale when running
DMG (original mono Gameboy) roms. There are four variables for this
purpose, allowing the background, window, and both sprite palettes to
be colored differently. Each one is made up of four numbers, the color
to use for each shade of gray, from lightest to darkest. Colors are
represented as 24bit numbers, with red in the low (rightmost) places
and blue in the upper (leftmost) places. Although you could specify
colors in decimal (base 10) if you really wanted, they'd be very
difficult to read, so it's preferable to use hex (base 16).

For example, to set the background to shades of white, the window to
shades of red, and the sprite palettes to shades of green and blue,
you could use:

  set dmg_bgp  0xffffff 0xaaaaaa 0x555555 0x000000
  set dmg_wndp 0x0000ff 0x0000aa 0x000055 0x000000
  set dmg_obp0 0x00ff00 0x00aa00 0x005500 0x000000
  set dmg_obp1 0xff0000 0xaa0000 0x550000 0x000000

This will of course look rather ugly, but it does the job illustrating
how you set various colors.

For more extensive examples, see the sample file palette.rc included
with gnuboy, which provides a number of sample palettes to try.


  RGB MODE WITH ONLY 256 COLORS

Normally when run in 256-color (8bpp) modes, gnuboy will dynamically
allocate colors in the palette as they're needed. However, on the
Gameboy Color, it's possible to have well over 1000 colors on the
screen at a time, and in games that make use of these "hicolor"
tricks, gnuboy will run out of colors and things will look bad.

If you prefer, you can set the "rgb332" variable:

  set rgb332 1

This tells gnuboy that instead of using 256-color mode as a
palette-based mode, you want it to setup a static palette and pretend
8bpp is just a really low quality "truecolor" mode, with only 3 bits
of precision in red and green, and only 2 bits of precision in blue.
In general this will make most games look worse, since colors have to
be approximated fairly poorly and since smooth color gradients are not
possible, but it will make "hicolor" Gameboy Color games look a good
deal better. Also, rgb332 mode should run slightly faster since it
avoids the overhead in dynamic palette allocation.

If you have to run at 8bpp mode, try it with and without this option
and see which way you like better. Of course, the better solution, if
at all possible, is to use 16bpp or higher mode, but that may run too
slowly on older computers.


  COLOR FILTERING

Optionally, gnuboy can filter screen colors to make them look more
washed out or faded like on a real GBC. To enable this feature,

  set colorfilter 1

By default, gnuboy will not apply the filter when running DMG (mono)
games, since many of the sample palettes are already designed to
immitate a Gameboy LCD. If you would like to have the filter also take
effect when running in DMG mode,

  set filterdmg 1

You can also customize the filter parameters to get different color
effects from the default ones. See the sample file filters.rc for
examples.


  SPRITE SORTING

Normally sprites are sorted and prioritized according to their x
coordinate when in DMG mode. However, this takes a little bit of extra
cpu time, and it's not needed by most DMG games, so it can be disabled
as follows:

  set sprsort 0

Note that although sprite sorting was disabled in previous releases
because it was not working properly, it now works great, so unless you
really need to maximize performance, you should probably leave it
enabled.


  SOUND OPTIONS

Fortunately sound is a lot simpler than video. At this time, there are
no fancy interpolation or filtering options, only your basic audio
parameters.

To enable or disable sound, set the "sound" variable to 1 or 0. By
default, it's enabled.

To enable or disable stereo sound, set the "stereo" variable to 1 or
0.  It defaults to 1 on most ports, but since stereo sometimes fails
to work properly on DOS, it's disabled by default on the DOS port.
Disabling stereo in no way improves performance, so it should only be
done if stereo mode causes a problem on your computer.

To set the audio sampling rate, use the "samplerate" variable. The
default is 44100 Hz. Setting this lower can improve performance. For
example, if you have a really slow computer, you might use:

  set samplerate 8000

Keep in mind that this will sound really really bad.


  FILESYSTEM OPTIONS

There are a good deal of options that affect where and how files are
saved and loaded by gnuboy. First, there's "rcpath", which specifies
where gnuboy searches for rc files. The default depends on your
operating system; see the beginning of this file for details.

The search path for rc files can contain multiple directories.
Normally, the list is separated by colons (:), but on DOS and Windows
the colon is used for drive letters, so semicolon (;) must be used
instead. Here are some examples, first for *nix:

  set rcpath "/home/laguna/.gnuboy:/usr/local/etc/gnuboy"
  set rcpath "."

and for DOS/Windows:

  set rcpath "c:/gnuboy;."
  set rcpath "c:/Program Files/Gnuboy"

If you really insist on using backslashes on DOS or Windows, you'll
have to double them up, since the backslash normally means "treat the
next character literally." For example,

  set rcpath "c:\\gnuboy"

This is untested, and your milage may vary. I recommend just using
forward slashes and keeping things simple.


  SAVE RELATED OPTIONS

These are all fairly simple, so I'll just list them quickly, then give
a couple examples.

  savedir     - directory to store saved games (SRAM and savestates) in
  savename    - base filename to use for saves
  saveslot    - which savestate slot to use
  forcebatt   - always save SRAM even on carts that don't have battery
  nobatt      - never save SRAM
  syncrtc     - resync the realtime clock for elapsed time when loading

The "savename" variable is particularly useful if you wish to have
more than one save associated with a particular rom. Just do something
like:

  gnuboy --savename=mygame2 mygame.gb

and the save files will be called mygame2.sav, mygame2.000, etc rather
than just mygame.sav, etc.

The "saveslot" variable is normally just changed by keybindings, so
you can pick a savestate slot while you're playing a game. However, if
you for example prefer that the default slot at startup be 1 rather
than 0, you can use:

  set saveslot 1

The "forcebatt" and "nobatt" options are fairly self-explanatory and
not very useful, except perhaps for debugging or use with corrupted
roms.

The "syncrtc" option needs a bit of explanation. Some roms, notably
Pokemon ones and Harvest Moon, use a realtime clock to keep track of
the time of day even when they're not running. Since gnuboy is just an
emulator, it can't work like a real cartridge and make things like
this keep happening while the emulator is not running. However, it can
resync the Gameboy realtime clock based on your computer's clock when
it starts. This is what the "syncrtc" option does. By default it's
enabled. If you disable it, then no time will seem to have elapsed
between when you exit the emulator once and when you start it again
the next time.


  JOYSTICK OPTIONS

So far there is just one joystick option, "joy", used to enable or
disable joystick support.


  DEBUGGING OPTIONS

These probably won't be useful to most people, but if you're trying to
debug a homebrew game you're writing or fix a bug in gnuboy they might
be of help:

The "trace" variable, if enabled, dumps a full execution trace to
stdout. Be prepared for at least 20 megs of logs to look through at
minimum, and more like 150 megs if you want enough to find anything
useful. Redirecting stdout to a file is a must!

The "sprdebug" variable is used to see how many sprites are visible
per line. Try it and see!


  PLATFORM-SPECIFIC OPTIONS

On certain *nix systems, you may need to specify device nodes to use
if the defaults don't work:

  oss_device  - Open Sound System "DSP" device
  fb_device   - Video framebuffer device
  joy_device  - Joystick device
  
The Linux fbcon version of gnuboy does not support the "vmode" option
yet, but it can set the mode for you by running the "fbset" program,
if you have it. Just set the "fb_mode" variable to the exact name of
the mode you want in /etc/fb.modes. For example,

  set fb_mode 640x480-90

You can also override the default color depth with the "fb_depth"
variable.

The DOS port of gnuboy has support for real console system gamepads
via the "Directpad Pro" (DPP) connector. To enable this feature, set
"dpp" to 1, set "dpp_port" to the IO port number the pad is connected
to (e.g. 0x378 -- be sure to prefix it with 0x for hex!!), and set
"dpp_pad" to the number of the pad you want to use. This code has not
been heavily tested, so it may or may not work for you. Be sure to get
the port number right or bad things may happen!


  CONCLUSION

Well, that's about it for configuration. Hopefully this document
clears up a lot of the confusion about what you can and can't
configure in gnuboy yet, and how you go about doing it. Again, check
the sample.rc, palette.rc, and classic.rc files for lots of examples
of how rc files work.

As always, more info will come as time passes on. Keep on the lookout
for new releases and more features. Thank you for flying gnuboy and
have a nice day.



                                                 - Laguna