Gamepad to Keyboard/mouse/xbox360(gamepad) emulator

Based on code by: Kris Henriksen and fake Xbox code from:
Modified to use SDL2 by: Nikolai Wuttke & Shanti Gilbert for Interactive text entry added by Robin Duxfield

List of keycode values start here:


mkdir build
cd build
cmake ..
cmake --build .
strip gptokeyb


gptokeyb provides a kill switch for an application and mapping of gamepad buttons to keys and/or mouse. It also provides an xbox360-compatible controller mode.

Environment Variable

SDL_GAMECONTROLLERCONFIG_FILE must be set so the gamepad buttons are properly assigned within gptokeyb, e.g. SDL_GAMECONTROLLERCONFIG_FILE="./gamecontrollerdb.txt" SDL_GAMECONTROLLERCONFIG_FILE is automatically set in Emuelec

export HOTKEY sets the button used as hotkey. BACK button is automatically selected as hotkey, unless overridden by HOTKEY environment variable

export TEXTINPUT="my name" assigns text as preset for input so that my name is automatically entered, once triggered

export PCKILLMODE="Y" indicates that ALT+F4 should be sent to close the app before kill mode is processed, which can be used on Linux pcs

Command Line Options

xbox360 selects xbox360 joystick mode

textinput select interactive text input mode (see below)

-c <config_file_path_and_name.gptk> specifies button mapping for keyboard and mouse functions, e.g. -c "./app.gptk"

-c as the last of the command line options specifies that the default button mapping file should be used, which is /emuelec/configs/gptokeyb/default.gptk

-1 <application name> or

-k <application name> provides the name of the application that will be closed by pressing start and select together

-sudokill indicates that sudo kill -9 <application name> will be used to close the application instead of killall <application name>

Keyboard Mapping Options

The config file that specifies button mapping for keyboard and mouse functions takes the form of %s = %s which is gamepad button = keyboard key . Any comment lines beginning with # are ignored. Deadzone values are used for analog sticks and triggers, and may be device specific. mouse_scale affects the speed of mouse movement, with a larger value causing slower movement. mouse_scale = 8192 generally works well for RK3326 devices. gamepad button = \" can be used to unassign a button.

The keyboard key values must be in lowercase and simple text strings are translated into key codes, for example enter means KEY_ENTER

Default mappings are:

start = enter
guide = enter

a = x
b = z
x = c
y = a

l1 = rightshift
l2 = home
l3 = mouse_right

r1 = leftshift
r2 = end
r3 = mouse_left

up = up
down = down
left = left
right = right

left_analog_up = w
left_analog_down = s
left_analog_left = a
left_analog_right = d

right_analog_up = end
right_analog_down = home
right_analog_left = left
right_analog_right = right

# Old deadzone code
deadzone_y = 2100
deadzone_x = 1900
mouse_scale = 512
mouse_delay = 16

# New deadzone code, this will overwrite the above deadzone code behaviour
# Choices of: axial, radial, scaled_radial, sloped_axial, sloped_scaled_axial, hybrid
deadzone_mode = scaled_radial
deadzone = 2000
deadzone_scale = 8
deadzone_delay = 16 ## An alias for mouse delay

Mouse slow

You can additionally slow the cursors speed temporarily by defining a button as mouse_slow . The rate at which is slows is controlled by mouse_slow_scale .

l1 = mouse_slow

mouse_slow_scale = 50 # 50%

The scale is proportional, so 75 will run the mouse at 75% of the mouse movement. So for example 7 becomes 5 with mouse_slow_scale = 75 .

Mouse control via Analog stick

The mouse can be controlled via the analog sticks, either the left or the right if the device has one.

left_analog_up = mouse_movement_up
# the rest of these do nothing:
left_analog_down = mouse_movement_down
left_analog_left = mouse_movement_left
left_analog_right = mouse_movement_right

You can only have the left or right analog stick set as mouse movement at one time. If both are set, it will default to the left stick.

You can control the behaviour of the analog stick and the deadzones, we have several different deadzone scaling modes which we used the implementation of from here:

The variable deadzone is the minimum amount the stick needs to move before it registers, deadzone_scale is the amount the mouse will move at the sticks maximum. deadzone_delay / mouse_delay is the delay between moving the mouse measured in milliseconds.

# Choices of: axial, radial, scaled_radial, sloped_axial, sloped_scaled_axial, hybrid
deadzone_mode = scaled_radial
deadzone = 2000
deadzone_scale = 8
deadzone_delay = 16 ## An alias for mouse delay

Dpad as mouse control

You can control the mouse with the dpad, keeping with the normal configuration code, and the mouse movement rate is adjusted by setting dpad_mouse_step . The above mouse_slow keybinding works in conjunction with the mouse control as dpad, and you can still control the mouse via an analog stick.

up = mouse_movement_up

dpad_mouse_step = 7

Note: Enabling mouse control via dpad will disable all keybindings on the dpad.

Hotkey + Button for additional Key Assignments

An additional 8 keys can be assigned through Hotkey combinations for a , b , x , y , l1 , l2 , r1 , r2 buttons. Hotkey+button assignments are specified by adding _hk for the appropriate button (see default mappings below). The keys can use the same Alt , Ctrl or Shift modifiers by including a separate line that indicates add_alt , add_ctrl or add_shift respectively.

The following example assigns ALT+F4 to the combination of hotkey plus A button.

a_hk = f4
a_hk = add_alt

Default mappings are:

a_hk = enter
b_hk = esc
x_hk = c
y_hk = a
l1_hk = esc
l2_hk = home
r1_hk = enter
r2_hk = end

Key Modifiers

Sometimes key presses require a combination of Alt , Ctrl or Shift plus the key. These combinations can be specified by adding a separate line that indicates add_alt , add_ctrl or add_shift respectively. Modified keys can '''not''' be repeated at present.

The following example assigns CTRL+X to the A button.

a = x
a = add_ctrl

Key Repeat

A simple keyboard key repeat function has been added that emulates automatic repeat of a keyboard key, once it has been held for at least an initial delay , at a regular interval . Key repeat works for one key at a time only (the first key that is pressed and held is repeated, and holding another key will not cause that to repeat, unless the first key is released). Key repeat has not been set up to work for analog triggers (L2/R2) at the moment.

The default delay and interval are based on SDL1.2 standard and can be adjusted with repeat_delay = and repeat_interval =


Key repeat is configured by adding gamepad_button = repeat as a separate line, in addition to the line gamepad_button = keyboard key . The following assigns arrow keys with key repeat to the gamepad d-pad and left analog stick.

up = up
up = repeat
down = down
down = repeat
left = left
left = repeat
right = right
right = repeat
left_analog_up = up
left_analog_up = repeat
left_analog_down = down
left_analog_down = repeat
left_analog_left = left
left_analog_left = repeat
left_analog_right = right
left_analog_right = repeat

Text Entry Options

Text entry is possible, either by sending a preset (e.g. to enter your name to begin a game) or via an interactive input mode that's similar to entry of initials for a high score table

Text entry options are enabled by environment variable settings

export TEXTINPUTPRESET="My Name"         # defines preset text to insert
export TEXTINPUTINTERACTIVE="Y"        # enables interactive text input mode
export TEXTINPUTNOAUTOCAPITALS="Y"     # disables automatic capitalisation of first letter of words in interactive text input mode
export TEXTINPUTADDEXTRASYMBOLS="Y"    # enables additional symbols for interactive text input

Interactive input mode is also enabled by command line option "textinput"

Preset Text Input

Text Entry preset mode is enabled by TEXTINPUTPRESET environment variable whereby a name preset can be easily entered whenever a game displays a text prompt. When Text Entry is triggered with START+D-PAD LEFT , the preset text is entered as a series of key strokes.

Text Entry preset mode also assigns START+A to send ENTER .


Interactive Text Input

Interactive Text Entry mode is enabled by launching GPtoKEYB with command line option "textinput" or by environment variable TEXTINPUTINTERACTIVE="Y" , and is triggered with START+D-PAD DOWN . Once activated, Interactive Text Entry mode works similarly to entering initials for game highscores, with D-PAD UP/DOWN switching between letters for the currently selected character, D-PAD RIGHT moving to next character, D-PAD LEFT deleting and moving back one character, SELECT/HOTKEY cancelling interactive text entry, and START to confirm and exit interactive text entry. A sends ENTER KEY in interactive text entry mode and exits interactive text entry.

Interactive Input Mode Controls
START+D-PAD DOWN to activate
once activated
D-PAD UP = previous letter
D-PAD DOWN = next letter
D-PAD RIGHT = next character
D-PAD LEFT = delete and move back one character
L1 = jump back 13 letters for current character
R1 = jump forward 13 letters for current character
A = send ENTER key and exit mode
SELECT/HOTKEY = cancel and exit mode (deletes all characters)
START = confirm and exit mode (also sends ENTER key)

By default Interactive Text Entry mode will start with A as the first letter and immediately after a space, and a otherwise, unless environment variable TEXTINPUTNOAUTOCAPITALS="Y" is set, whereby all letters will start as a .


By default Interactive Text Entry mode includes only a limited number of symbols "[space] . , - _ ( )", and a full set of symbols is included with environment variable TEXTINPUTADDEXTRASYMBOLS="Y" .

Exiting mode

Interactive Text Entry relies on the game providing a text prompt and sends key strokes to add and change characters, so it is only useful in these situations. Interactive Text Entry is automatically exited when either SELECT , HOTKEY , START or A are pressed, to minimise issues by accidentally triggering this mode.