emulator: OpenJKDF2
type: standalone
core_classification: game_engine
source: "https://github.com/shinyquagsire23/OpenJKDF2"
upstream: "https://github.com/shinyquagsire23/OpenJKDF2"
profiled_date: "2026-10-04"
source_commit: "02297602cb289b113df27be33b5a7dddbe3d91c1"
core_version: "0.9.9.0"
display_name: "OpenJKDF2"
cores: []
systems:
  - dark-forces-ii
  - mysteries-of-the-sith
  - droidworks

notes: |
  Reimplementation of LucasArts' Sith engine. Runs Star Wars Jedi Knight:
  Dark Forces II (1997), its Mysteries of the Sith expansion (1998) with
  the `-motsCompat` switch, and Star Wars DroidWorks (1998) via the
  DroidWorks branch of the build.

  Resource mounting (src/Main/jkRes.c):
    aGobDirectories[3]   "resource" root, auto-mounted at startup
                         (src/Main/jkRes.c:37 jkRes_LoadNew)
    aGobDirectories[1]   "episode\<name>.gob" / ".goo" for the active
                         episode, mounted by jkRes_LoadGob
                         (src/Main/jkRes.c:103-106)
    aGobDirectories[4]   gamedata\resource (CD overlay), mounted by
                         jkRes_LoadCd (src/Main/jkRes.c:130-131)

  The asset root is the working directory when it holds resource/jk_.cd,
  else the per-user data directory, whose last component is openjkdf2,
  openjkmots or opendroidworks (src/Main/InstallHelper.c:97,
  src/Main/InstallHelper.c:239-270). Paths below are written under that
  component.

  jkRes_LoadNew mounts every .gob (.goo in Mysteries of the Sith mode) of
  resource/ (src/Main/jkRes.c:287-300) and jkEpisode lists every one of
  episode/ (src/Main/jkEpisode.c:106).

  Required-asset lists are declared in src/Main/InstallHelper.c and
  checked by InstallHelper_CheckInstalled / AttemptInstallFromExisting;
  a missing entry aborts installation (src/Main/InstallHelper.c:748-756,
  1091-1097, 1229-1256).

  JK.EXE / JKM.EXE are only consumed by the 32-bit static-recomp build
  (src/main.c:696-718, gated by `!ARCH_64BIT && !ARCH_WASM &&
  !TARGET_ANDROID`), which mmaps the retail binary at 0x400000 and
  patches it via do_hooks(). The 64-bit, WASM and Android builds skip
  that path and do not read JK.EXE at all.

files:
  # ================================================================
  # Jedi Knight: Dark Forces II (base game)
  # ================================================================

  - name: "JK1.gob"
    path: "openjkdf2/episode/JK1.gob"
    system: dark-forces-ii
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:34 (aRequiredAssets)"
    note: "Single-player episode data."

  - name: "JK1CTF.gob"
    path: "openjkdf2/episode/JK1CTF.gob"
    system: dark-forces-ii
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:35 (aRequiredAssets)"
    note: "Multiplayer CTF episode."

  - name: "JK1MP.gob"
    path: "openjkdf2/episode/JK1MP.gob"
    system: dark-forces-ii
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:36 (aRequiredAssets)"
    note: "Multiplayer deathmatch episode. Default -episode value in Main.c:120."

  - name: "Res1hi.gob"
    path: "openjkdf2/resource/Res1hi.gob"
    system: dark-forces-ii
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:37 (aRequiredAssets)"
    note: "High-resolution textures and sprites."

  - name: "Res2.gob"
    path: "openjkdf2/resource/Res2.gob"
    system: dark-forces-ii
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:38 (aRequiredAssets)"
    note: "Shared engine resources: sounds, 3DOs, materials."

  - name: "jk_.cd"
    path: "openjkdf2/resource/jk_.cd"
    system: dark-forces-ii
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:39 (aRequiredAssets), src/Main/InstallHelper.c:764-769, src/Main/InstallHelper.c:1334-1336, src/engine_config.h:263"
    note: |
      4-byte marker. The install helper writes JKRES_MAGIC_1 into it once the
      assets are copied, 0x699232C4 for this game. At startup a missing
      marker sends the engine to the required-asset check.

  - name: "jk1demo.gob"
    path: "openjkdf2/episode/jk1demo.gob"
    system: dark-forces-ii
    category: game_data
    required: false
    source_ref: "src/Main/InstallHelper.c:654, src/Main/InstallHelper.c:841"
    note: "Single-player episode of the demo, copied by the install helper when present."

  - name: "jk1mpdem.gob"
    path: "openjkdf2/episode/jk1mpdem.gob"
    aliases: ["jk1mpdemo.gob"]
    system: dark-forces-ii
    category: game_data
    required: false
    source_ref: "src/Main/InstallHelper.c:655-656, src/Main/InstallHelper.c:842-843"
    note: "Multiplayer episode of the demo. The install helper copies it under either name."

  - name: "res1demo.gob"
    path: "openjkdf2/resource/res1demo.gob"
    system: dark-forces-ii
    category: game_data
    required: false
    source_ref: "src/Main/InstallHelper.c:657, src/Main/InstallHelper.c:844"
    note: "Resources of the demo, copied by the install helper when present."

  - name: "Res1low.gob"
    path: "openjkdf2/resource/Res1low.gob"
    system: dark-forces-ii
    category: game_data
    required: false
    source_ref: "src/Main/InstallHelper.c:71 (aDiskAssetMap)"
    note: "Low-resolution textures shipped on the CD under MININSTALL/."

  - name: "JK.EXE"
    system: dark-forces-ii
    category: game_data
    required: false
    source_ref: "src/main.c:696-718, src/Main/InstallHelper.c:494 (aInstallOptionalAssets)"
    note: |
      Retail executable mmap'd at 0x400000 and patched by do_hooks() in the
      32-bit static-recomp build. Not read by the 64-bit, WASM or Android
      builds.

  # ================================================================
  # Mysteries of the Sith (expansion, -motsCompat)
  # ================================================================

  - name: "JKM.goo"
    path: "openjkmots/episode/JKM.goo"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:48 (aRequiredAssetsMots)"
    note: "Main MoTS single-player episode."

  - name: "JKM_KFY.goo"
    path: "openjkmots/episode/JKM_KFY.goo"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:45 (aRequiredAssetsMots)"

  - name: "JKM_MP.goo"
    path: "openjkmots/episode/JKM_MP.goo"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:46 (aRequiredAssetsMots)"

  - name: "JKM_SABER.goo"
    path: "openjkmots/episode/JKM_SABER.goo"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:47 (aRequiredAssetsMots)"

  - name: "Jkmres.goo"
    path: "openjkmots/resource/Jkmres.goo"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:49 (aRequiredAssetsMots)"
    note: "Shared MoTS engine resources."

  - name: "JKMsndLO.goo"
    path: "openjkmots/resource/JKMsndLO.goo"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:50 (aRequiredAssetsMots)"
    note: "Low-quality sound bank (MININSTALL/JKMSNDLO.GOO on the CD)."

  - name: "jk_.cd"
    path: "openjkmots/resource/jk_.cd"
    system: mysteries-of-the-sith
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:51 (aRequiredAssetsMots), src/Main/InstallHelper.c:1318-1320, src/Main/jkRes.c:232-235, src/engine_config.h:267-270"
    note: |
      4-byte marker holding 0x3B426929. InstallHelper_SetCwd reads it at
      startup and enables Mysteries of the Sith mode when it finds that
      value.

  - name: "JKM.EXE"
    system: mysteries-of-the-sith
    category: game_data
    required: false
    source_ref: "src/main.c:696-718, src/Main/InstallHelper.c:495 (aInstallOptionalAssets)"
    note: "MoTS retail executable, used only by the 32-bit static-recomp build."

  # ================================================================
  # Star Wars DroidWorks (Main_bDroidWorks branch)
  # ================================================================

  - name: "dwCD.GOB"
    system: droidworks
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:58 (aRequiredAssetsDroidworks), src/Dw/dwInits.cpp:67-93"
    note: "CD-image data archive, mounted by dwGob."

  - name: "dwHD.GOB"
    system: droidworks
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:59 (aRequiredAssetsDroidworks), src/Dw/dwInits.cpp:67-93"
    note: "Hard-drive install archive."

  - name: "dwMin.GOB"
    system: droidworks
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:60 (aRequiredAssetsDroidworks), src/Dw/dwInits.cpp:67-93"
    note: "Minimum-install archive."

  - name: "dwStream.GOB"
    system: droidworks
    category: game_data
    required: true
    source_ref: "src/Main/InstallHelper.c:61 (aRequiredAssetsDroidworks), src/Dw/dwInits.cpp:93"
    note: "Streamed WAV audio, listed only in the WAV ext search path."