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GMC Configuration File

The gmc.cfg configuration file in your Godot project root contains options for customizing GMC behavior. It uses INI formatting and its supported features are documented here.

Local Overrides

Any configuration options in gmc.cfg can be overridden with a local file gmc.local.cfg in the Godot User Data folder. This allows you to commit the primary configuration to version control while still having platform-specific configurations (e.g. MPF executable path and logging levels) on each machine.

[filter]

The filter section configures a shader for the GMC window, applying effects universally to all displays.

Full documentation can be found on the Window Effects Filters guide.

    [filter]
    filter="virtual_dmd"
    columns=120
    rows=45
    hardness=5
    spacing=2

[gmc]

The GMC section contains settings related to the GMC itself, including logging.

content_root

Single value, type String. Default None

In addition to mode subfolders, GMC will look for slides, widgets, and sounds in those respective folders in the Godot project root (e.g. /sounds, /slides).

You may wish to consolidate your content in a common subfolder rather than the project root. You can define a content root folder here, which will be prepended to the individual content folders (e.g. /content/sounds, /content/slides).

exit_on_esc

If true, the GMC process will exit if the Escape key is pressed during runtime.

Logging

Logging can be specified in the \[gmc\] section with the following components:

  • logging_global for all components not otherwise specified
  • logging_game for the MPF.game script, holding all game-related data
  • logging_server for the BCP Server, with all comms between GMC and MPF
  • logging_process for the MPF.process manager, running the MPF subprocess
  • logging_media for the media controller (slides, widgets, and sound)
  • logging_sound_player for the sound player specifically
    [gmc]
    logging_global=20
    logging_sound_player=10

Each core component's log level can be adjusted here, and any unspecified components will use the global log level. The log levels are stored as integers with the following values:

  • USE_GLOBAL_LEVEL: 0
  • VERBOSE: 1
  • DEBUG: 10
  • INFO: 20
  • LOG: 25
  • WARNING: 30
  • ERROR: 40

By default, debug/editor builds will run at INFO while production builds run at LOG.

Script Overrides (Advanced)

The gmc section can override the core GMC scripts for advanced customization of the GMC itself. Only for advanced users.

Full documentation can be found on the Advanced Custom Code guide.

    [gmc]
    GMCServer="custom_code/my_custom_bcp.gd"

[keyboard]

The keyboard section maps key inputs to switches and events for simulating MPF behavior during development.

Full documentation can be found on the Keyboard Setup guide.

    [keyboard]
    1=["switch", "s_switch_1"]
    enter=["switch", "s_start_button"]
    6=["switch", "s_drop_1", "active"]
    shift+6=["switch", "s_drop_1", "inactive"]
    x=["switch", "s_trough_6", "toggle"]
    m=["event", "start_mode_multiball"]

[mpf]

The MPF section defines parameters for the GMC-spawned MPF process. The full command for the process will be assembled thus:

    <executable_path> <executable_args> <machine_path> <machine_args>

executable_args

Single value, type String. Default None

Additional arguments to pass to the executable. For example, if the executable is a Python interpreter then the executable args may be -m mpf to load the MPF module.

Note that MPF-specific command line args should not go here, even if the executable is an MPF binary.

executable_path

Single value, type String. Default None.

The path to the executable entry point for the MPF process. It can be a Python interpreter, a symlink to a virtual environment mpf executable, or a precompiled MPF binary.

machine_path

Single value, type String. Defaults to the GMC project folder.

The path of the MPF machine folder, i.e. the root folder containing the /config and /modes folders for your project. If not specified, the GMC project folder will be used.

mpf_args

Single value, type String. Default None

Additional arguments to pass to MPF after the machine path. Common values may include -x for virtual mode, -vV for verbose logging, or -P for production mode. Note that values defined specifically for virtal or verbose (see below) will supersede.

spawn_mpf

Single value, type bool. Default false.

If true, GMC will spawn a subprocess to run MPF when the main project is run.

virtual

Single value, type bool. Default false.

If true, the MPF process will spawn in virtual mode (i.e. -x will be appended to the mpf_args).

verbose

Single value, type bool. Default false.

If true, the MPF process will have verbose logging (i.e. -vV will be appended to the mpf_args).

[sound_system]

The sound system section defines playback properties of the Audio Buses defined in your Godot project.

    [sound_system]
    music={"type": "solo"}
    effects={"type": "simultaneous", "simultaneous_sounds": 3, "default": true}
    voice={"type": "sequential"}

default

Single value, type bool. Default false

One audio bus is allowed to be set as default, and any sound playback trigger that does not include a value for bus: will play on this bus.

simultaneous_sounds

Single value, type int. Default None

The maximum number of sounds that can be played concurrently in a simultaneous-type bus. If this limit is reached, subsequent sound calls will be dropped (i.e. they are not queued).

type

Single value, type String. One of "solo", "sequential", "simultaneous"

The type of playback sequencing to use. Solo only allows one track at a time and will replace a current track with a new one. Sequential allows one track at a time and queues subsequent tracks to play sequentially as the previous one finishes. Simultaneous allows multiple tracks to be played concurrently.

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