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# Game Boy (Color) Documentation

Last updated March 19, 2024
Valid as of 1.32.1

Table of Contents:

- Introduction
- Custom Palettes
- Default Key Assignments
- Settings Reference

## Introduction

Mednafen's GameBoy (Color) emulation is based off of VisualBoy Advance.

Super Game Boy is presently not supported. If it ever is supported in the future, it will likely be via the SNES module instead of the GB module.

## Custom Palettes

Global Filename: | Description:
--- | ---
gb.pal | GameBoy(mono) 4 or 8 or 12 RGB triplets
gbc.pal | GameBoy Color 15-bit BGR 32768 RGB triplets

## Default Key Assignments

Key(s): | Action: | Configuration String:
--- | --- | ---
ALT + SHIFT + 1 | Activate in-game input configuration process for GameBoy pad. | input_config1

Key: | Action/Button:
--- | ---
Keypad 2 | B
Keypad 3 | A
Enter/Return | Start
Tab | Select
W | Up
S | Down
A | Left
D | Right

## Settings Reference

Caution: Any settings that change emulation behavior as seen from the emulated game are shown with the setting name bolded in the table. One should be conscious of these settings if one has changed them from the default values when using network play or movies, as they can cause desychronizations if not set the same among hosts(or between the recording emulator and the playing emulator).

Setting: | Value Type: | Possible Values: | Default Value: | Description:
--- | --- | --- | --- | ---

gb.system_type

enum

auto
dmg
cgb
agb

auto

Emulated GB type.

- auto - Auto
  Automatic detection based on headers.
- dmg - DMG
  Original GameBoy Monochrome.
- cgb - CGB
  GameBoy Color.
  This option is not fully implemented in regards to handling of DMG games.
- agb - AGB
  GameBoy Advance.
  This option is not fully implemented in regards to handling of DMG games.

Setting: | Value Type: | Possible Values: | Default Value: | Description:
--- | --- | --- | --- | ---
gb.enable | boolean | 0 1 | 1 | Enable (automatic) usage of this module.
gb.forcemono | boolean | 0 1 | 0 | Force monophonic sound output.

gb.scanlines

integer

-100 through 100

0

Enable scanlines with specified opacity.

Opacity is specified in %; IE a value of "100" will give entirely black scanlines.
Negative values are the same as positive values for non-interlaced video, but for interlaced video will cause the scanlines to be overlaid over the previous(if the "video.deinterlacer" setting is set to "weave", the default) field's lines.

gb.shader

enum

none
autoip
autoipsharper
scale2x
sabr
ipsharper
ipxnoty
ipynotx
ipxnotysharper
ipynotxsharper
goat

none

Enable specified OpenGL shader.

Obviously, this will only work with the OpenGL "video.driver" setting, and only on cards and OpenGL implementations that support shaders, otherwise you will get a black screen, or Mednafen may display an error message when starting up. When a shader is enabled, the "gb.videoip" setting is ignored.

- none - None/Disabled
- autoip - Auto Interpolation
  Will automatically interpolate on each axis if the corresponding effective scaling factor is not an integer.
- autoipsharper - Sharper Auto Interpolation
  Same as "autoip", but when interpolation is done, it is done in a manner that will reduce blurriness if possible.
- scale2x - Scale2x
- sabr - SABR v3.0
  GPU-intensive.
- ipsharper - Sharper bilinear interpolation.
- ipxnoty - Linear interpolation on X axis only.
- ipynotx - Linear interpolation on Y axis only.
- ipxnotysharper - Sharper version of "ipxnoty".
- ipynotxsharper - Sharper version of "ipynotx".
- goat - Simple approximation of a color TV CRT look.
  Intended for fullscreen modes with a vertical resolution of around 1000 to 1500 pixels. Doesn't simulate halation and electron beam energy distribution nuances.

gb.shader.goat.fprog

boolean

0
1

0

Force interlaced video to be treated as progressive.

When disabled, the default, the "video.deinterlacer" setting is effectively ignored with respect to what appears on the screen, unless it's set to "blend" or "blend_rg". When enabled, it may be prudent to disable the scanlines effect controlled by the "gb.shader.goat.slen" setting, or else the scanline effect may look objectionable.

gb.shader.goat.hdiv | real | -2.00 through 2.00 | 0.50 | Constant RGB horizontal divergence.

gb.shader.goat.pat

enum

goatron
borg
slenderman

goatron

Mask pattern.

- goatron - Goatron
  Brightest.
- borg - Borg
  Darkest.
- slenderman - Slenderman
  Spookiest?

gb.shader.goat.slen | boolean | 0 1 | 1 | Enable scanlines effect.
gb.shader.goat.tp | real | 0.00 through 1.00 | 0.50 | Transparency of otherwise-opaque mask areas.
gb.shader.goat.vdiv | real | -2.00 through 2.00 | 0.50 | Constant RGB vertical divergence.

gb.special

enum

none
hq2x
hq3x
hq4x
scale2x
scale3x
scale4x
2xsai
super2xsai
supereagle
nn2x
nn3x
nn4x
nny2x
nny3x
nny4x

none

Enable specified special video scaler.

The destination rectangle is NOT altered by this setting, so if you have xscale and yscale set to "2", and try to use a 3x scaling filter like hq3x, the image is not going to look that great. The nearest-neighbor scalers are intended for use with bilinear interpolation enabled, for a sharper image, though the "autoipsharper" shader may provide better results.

- none - None/Disabled
- hq2x - hq2x
- hq3x - hq3x
- hq4x - hq4x
- scale2x - scale2x
- scale3x - scale3x
- scale4x - scale4x
- 2xsai - 2xSaI
- super2xsai - Super 2xSaI
- supereagle - Super Eagle
- nn2x - Nearest-neighbor 2x
- nn3x - Nearest-neighbor 3x
- nn4x - Nearest-neighbor 4x
- nny2x - Nearest-neighbor 2x, y axis only
- nny3x - Nearest-neighbor 3x, y axis only
- nny4x - Nearest-neighbor 4x, y axis only

gb.stretch

enum

0
full
aspect
aspect_int
aspect_mult2

aspect_mult2

Stretch to fill screen.

- 0 - Disabled
- full - Full
  Full-screen stretch, disregarding aspect ratio.
- aspect - Aspect Preserve
  Full-screen stretch as far as the aspect ratio(in this sense, the equivalent xscalefs == yscalefs) can be maintained.
- aspect_int - Aspect Preserve + Integer Scale
  Full-screen stretch, same as "aspect" except that the equivalent xscalefs and yscalefs are rounded down to the nearest integer.
- aspect_mult2 - Aspect Preserve + Integer Multiple-of-2 Scale
  Full-screen stretch, same as "aspect_int", but rounds down to the nearest multiple of 2.

gb.tblur | boolean | 0 1 | 0 | Enable video temporal blur(50/50 previous/current frame by default).
gb.tblur.accum | boolean | 0 1 | 0 | Accumulate color data rather than discarding it.
gb.tblur.accum.amount | real | 0 through 100 | 50 | Blur amount in accumulation mode, specified in percentage of accumulation buffer to mix with the current frame.

gb.videoip

enum

0
1
x
y

0

Enable (bi)linear interpolation.

- 0 - Disabled
- 1 - Bilinear
- x - Linear (X)
  Interpolation only on the X axis.
- y - Linear (Y)
  Interpolation only on the Y axis.

gb.xres | integer | 0 through 65536 | 0 | Full-screen horizontal resolution. A value of "0" will cause the current desktop horizontal resolution to be used.
gb.xscale | real | 0.01 through 256 | 6.000000 | Scaling factor for the X axis in windowed mode.
gb.xscalefs | real | 0.01 through 256 | 1.000000 | Scaling factor for the X axis in fullscreen mode. For this setting to have any effect, the "gb.stretch" setting must be set to "0".
gb.yres | integer | 0 through 65536 | 0 | Full-screen vertical resolution. A value of "0" will cause the current desktop vertical resolution to be used.
gb.yscale | real | 0.01 through 256 | 6.000000 | Scaling factor for the Y axis in windowed mode.
gb.yscalefs | real | 0.01 through 256 | 1.000000 | Scaling factor for the Y axis in fullscreen mode. For this setting to have any effect, the "gb.stretch" setting must be set to "0".