emulator: Ikemen GO
type: standalone
core_classification: game_engine
source: "https://github.com/ikemen-engine/Ikemen-GO"
upstream: "https://github.com/ikemen-engine/Ikemen-GO"
profiled_date: "2026-10-04"
source_commit: "e8b065f410fa9507dbddc1d6b1abc231de99f8c6"
core_version: ~
display_name: "Ikemen GO"
cores: [ikemen]
systems: []
verification: existence

notes: |
  M.U.G.E.N.-compatible 2D fighting game engine written in Go. It reads the
  .def, .air, .cmd, .cns, .sff and .snd files of M.U.G.E.N. content, plus its
  own .zss state files.

  Every path below is relative to the working directory. The file names come
  from the embedded default configuration, src/resources/defaultConfig.ini,
  which save/config.ini overrides (src/main.go:189-195).

  The repository ships:
    data/: common animations, commands, constants and state files
    external/script/: the Lua scripts that drive menus and game modes
    external/icons/: window icons
    external/shaders/: optional post-processing shaders
    font/: debug.def with Open Sans, and the default-3x5 bitmap fonts

  The default configuration also names files the repository does not hold:
  the motif data/ikemen1/system.def, the effects pack data/gofx/gofx.def and
  the stage stages/stage0-720.def. Release packages copy chars, data, font,
  sound, stages and video from the Ikemen-GO-Screenpack repository next to
  the engine (.github/workflows/releases.yml:585-593).

  Characters and stages are found under chars/ and stages/
  (src/system.go:5364, src/system.go:5590).

files:
  - name: "script"
    path: "external/script"
    category: game_data
    description: "Lua scripts: main.lua and the modules it requires"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:143, src/main.go:213-232"
    note: >
      main.go opens Config.System and panics when it is missing. main.lua
      requires debug, start, options and menu from the same directory.

  - name: "IkemenCylia_256.png"
    path: "external/icons/IkemenCylia_256.png"
    category: game_data
    description: "Window icon, 256 px"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:141, src/system.go:527-538"

  - name: "IkemenCylia_96.png"
    path: "external/icons/IkemenCylia_96.png"
    category: game_data
    description: "Window icon, 96 px"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:141, src/system.go:527-538"

  - name: "IkemenCylia_48.png"
    path: "external/icons/IkemenCylia_48.png"
    category: game_data
    description: "Window icon, 48 px"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:141, src/system.go:527-538"

  - name: "shaders"
    path: "external/shaders"
    category: game_data
    description: "Post-processing shaders offered in the options menu"
    required: false
    bundled: true
    source_ref: "external/script/options.lua:1646, src/system.go:457-470"

  - name: "common.air"
    path: "data/common.air"
    category: game_data
    description: "Common animations merged into every character"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:12, src/char.go:4676-4689"

  - name: "common.cmd"
    path: "data/common.cmd"
    category: game_data
    description: "Common commands appended to every character's command file"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:14, src/compiler.go:8367-8380"

  - name: "common.const"
    path: "data/common.const"
    category: game_data
    description: "Common constants"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:16, src/char.go:4338-4355"

  - name: "functions.zss"
    path: "data/functions.zss"
    category: game_data
    description: "Common states: shared ZSS functions"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "action.zss"
    path: "data/action.zss"
    category: game_data
    description: "Common states: actions"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "demo.zss"
    path: "data/demo.zss"
    category: game_data
    description: "Common states: demo mode"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "dizzy.zss"
    path: "data/dizzy.zss"
    category: game_data
    description: "Common states: dizzy"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "guardbreak.zss"
    path: "data/guardbreak.zss"
    category: game_data
    description: "Common states: guard break"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "score.zss"
    path: "data/score.zss"
    category: game_data
    description: "Common states: score"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "system.zss"
    path: "data/system.zss"
    category: game_data
    description: "Common states: system"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "tag.zss"
    path: "data/tag.zss"
    category: game_data
    description: "Common states: tag team"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "training.zss"
    path: "data/training.zss"
    category: game_data
    description: "Common states: training mode"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:18, src/compiler.go:8545-8552"

  - name: "common1.cns.zss"
    path: "data/common1.cns.zss"
    category: game_data
    description: "ZSS replacement for the common1.cns state file"
    required: true
    bundled: true
    source_ref: "src/compiler.go:6929-6943, src/compiler.go:8538-8543"
    note: >
      A character names its common state file in stcommon. When that file is
      not found, stateCompile retries with the .zss suffix, so a character
      asking for common1.cns gets data/common1.cns.zss.

  - name: "debug.def"
    path: "font/debug.def"
    category: game_data
    description: "Debug overlay font definition"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:174, external/script/main.lua:648, src/script.go:4108-4111"
    note: "loadDebugFont raises a Lua error when the font cannot be loaded."

  - name: "OpenSans-Bold.ttf"
    path: "font/Open_Sans/OpenSans-Bold.ttf"
    category: game_data
    description: "TrueType face named by debug.def"
    required: true
    bundled: true
    source_ref: "font/debug.def:19, src/util_desktop.go:29-40"
    note: >
      When the file is not found, the same name is searched in the system
      font directories; the engine panics when that fails too.

  - name: "default-3x5.def"
    path: "font/default-3x5.def"
    category: game_data
    description: "Default motif font (font1)"
    required: false
    bundled: true
    source_ref: "src/resources/defaultMotif.ini:75, src/motif.go:2593-2609"
    note: "A motif font that fails to load is logged and replaced by an empty font."

  - name: "default-3x5.sff"
    path: "font/default-3x5.sff"
    category: game_data
    description: "Glyph sprites named by default-3x5.def"
    required: false
    bundled: true
    source_ref: "font/default-3x5.def:21, src/font.go:412-418"
    note: "LoadFntSff panics when default-3x5.def is loaded and this file is missing."

  - name: "system.def"
    path: "data/ikemen1/system.def"
    category: game_data
    description: "Default motif definition"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:96, src/motif.go:2627-2659, src/script.go:4249-4252"
    note: >
      Held by the Ikemen-GO-Screenpack repository and copied into release
      packages. main.lua calls loadMotif at startup, which raises a Lua error
      when the definition cannot be read. -r selects another motif.

  - name: "gofx.def"
    path: "data/gofx/gofx.def"
    category: game_data
    description: "Common effects pack"
    required: true
    bundled: true
    source_ref: "src/resources/defaultConfig.ini:21, src/fightscreen.go:85-102, src/system.go:6551-6555"
    note: >
      Held by the Ikemen-GO-Screenpack repository and copied into release
      packages. A load failure puts the match loader in its error state.

  - name: "chars"
    path: "chars"
    category: game_data
    description: "Character directory"
    required: false
    source_ref: "src/system.go:5364, src/script.go:3190-3191"
    note: >
      User supplied. A character path that does not resolve as given is
      searched under chars/.

  - name: "stages"
    path: "stages"
    category: game_data
    description: "Stage directory"
    required: false
    source_ref: "src/system.go:5590, src/resources/defaultConfig.ini:178, external/script/main.lua:1770-1774"
    note: >
      User supplied. Debug.StartStage defaults to stages/stage0-720.def, the
      stage added when select.def lists none.