OpenJKDF2 is a function-by-function reimplementation of DF2 in C, with 64-bit ports to MacOS and Linux. Files are organized as closely to the original game as possible, based on symbols from the Grim Fandango Remaster Android/Linux/macOS port, as well as scattered assertions from various other games. It also contains the original versions of byacc and flex used for COG script parsing.
OpenJKDF2 does not include any original game assets; a valid copy of JKDF2 is required and can be purchased from GOG or Steam. The GOG version is recommended, since it is DRM-free and also includes the soundtrack in Ogg Vorbis format. If you'd like to try before you buy, a WebAssembly demo of OpenJKDF2 can be found at https://maxthomas.dev/openjkdf2/.
Support for playing the original soundtrack from Ogg Vorbis files is primarily supported for the GOG and Steam versions of the game assets. Original disk soundtracks can also be loaded from MUSIC/1/Track<1..11>.ogg and MUSIC/2/Track<1..11>.ogg for each disk's soundtrack. If files are missing, it will instead attempt to use a GOG track number from MUSIC/Track<12..32>.ogg. Dumping the soundtrack from disks at install time is planned for a future release of OpenJKDF2, but is not currently implemented.
OpenJKDF2 supports the following configurations:
| Configuration | Renderer | Description |
|---|---|---|
| 64-bit Windows/SDL2 | OpenGL 3.3 | 64-bit Windows compilation with SDL2 and OpenAL. DirectX dependencies are replaced with SDL2 and OpenAL. |
| MacOS x86_64/AArch64 | OpenGL 3.3 | 64-bit MacOS compilation with SDL2 and OpenAL. All release packages include both Intel and ARM64. |
| 64-bit Linux/SDL2 | OpenGL 3.3 | 64-bit Linux compilation with SDL2 and OpenAL. |
| Emscripten/WebAssembly | WebGL 2/OpenGL ES 3 | WebAssembly with SDL2 and OpenAL. Runs in a web browser. Since WASM only supports 32-bit pointers, this will likely be less buggy than 64-bit, but less performant. |
| x86 Linux/SDL2, mmap blobs | OpenGL 3.3 | 32-bit Linux compilation with SDL2 and OpenAL. JK.EXE is memory mapped into the process and used as a "binary blob"; Unimplemented functions will fall back to JK.EXE implementations. |
| 32-bit Linux/SDL2, blobless | OpenGL 3.3 | 32-bit Linux compilation with SDL2 and OpenAL. The output executable is a swap-in replacement for JK.EXE, but will be missing functions and will crash on reaching unimplemented code. |
| x86 Win32/MinGW DLL | Software/DirectX | Win32 hooked build, JK.EXE is patched to load df2_reimpl.dll execute hook_init_win before JK.EXE's main function. Unimplemented functions will fall back to JK.EXE implementations. df2_reimpl_kvm.dll is used for the KVM target |
The following implementations are in-progress or planned:
| Configuration | Renderer | Description |
|---|---|---|
| Android | OpenGL ES 3 | Not a huge priority, but would be nice to have. |
| iOS | Metal? | Not a huge priority, but would be nice to have. |
| Switch libnx | OpenGL ES 3 | Not a huge priority, but would be nice to have. |
| 32-bit Windows/SDL2 | OpenGL 3.3 | Windows compilation with SDL2 and OpenAL. DirectX dependencies are replaced with SDL2 and OpenAL. Unimplemented functions use JK.EXE as a binary blob? |
Linux building works on AArch64/RPi4 with llvmpipe, but V3D GLES has trouble with palettes.
OpenJKDF2 requires game data from a licensed copy of Jedi Knight: Dark Forces II in order to run; No game assets are provided by OpenJKDF2. On Linux, paths and filenames may be case-sensitive. Your directory structure should look something like this:
.
├── JK.EXE
├── MUSIC
│ ├── Track12.ogg
│ ├── Track13.ogg
│ ├── Track14.ogg
│ ├── Track15.ogg
│ ├── Track16.ogg
│ ├── Track17.ogg
│ ├── Track18.ogg
│ ├── Track22.ogg
│ ├── Track23.ogg
│ ├── Track24.ogg
│ ├── Track25.ogg
│ ├── Track26.ogg
│ ├── Track27.ogg
│ ├── Track28.ogg
│ ├── Track29.ogg
│ ├── Track30.ogg
│ ├── Track31.ogg
│ └── Track32.ogg
├── episode
│ ├── JK1.gob
│ ├── JK1CTF.gob
│ └── JK1MP.gob
├── openjkdf2-64
├── player
└── resource
├── Res1hi.gob
├── Res2.gob
├── jk_.cd
└── video
├── 01-02A.SMK
├── 03-04A.SMK
├── 06A.SMK
├── 08-10A.SMK
├── 12A.SMK
├── 16A.SMK
├── 18-19A.SMK
├── 21A.SMK
├── 23A.SMK
├── 25A.SMK
├── 27A.SMK
├── 33-34A.SMK
├── 36A.SMK
├── 38A.SMK
├── 39A.SMK
├── 41-42A.SMK
├── 41DA.SMK
├── 41DSA.SMK
├── 44A.SMK
├── 46A.SMK
├── 48A.SMK
├── 50A.SMK
├── 52-53A.SMK
├── 54A.SMK
└── 57A.SMK
When running on SDL2-based builds (Linux/MacOS/Win64), be sure to have copied the GLSL shaders from resource/shaders/* to <JK.EXE base folder>/resource/shaders/*, as shown above.
See here for instructions.
- Joystick menu in Setup > Controls (input bindings are still loaded and written to config, though)
- Load Configuration and Save Configuration in Setup > Controls > Options
- Multiplayer menu and all submenus
- Multiplayer tally screen
- Multiplayer character builder
- Using plus or minus to resize the screen (with SDL2, resolution auto-resizes to window size)
- In-game screenshots
See here for instructions.
The bulk of research and documentation occurs in IDA. Every function has been identified to a file prefix (ie stdHashTable_) with a corresponding .c/.h file. RenderDroid (rd*) and LEC stdlib (std*) functions are 90% canonically named, based on symbols from Grim Fandango Remastered.
Reverse engineering is a parallel effort between structure documentation and function identification. Once structures are sufficiently documented, Hex-Rays can be used for decompilation. While most Hex-Rays output works outright, many loops and structures require manual intervention. Output is generally cleaned and tidied to remove redunant stack variables or too-deep nesting. sizeof and obvious inlining and macros should also be adjusted as appropriate.
Engine variables and yet-to-be-decompiled functions are referenced using define macros and static function pointers, respectively. Once a file is decompiled enough that an engine variable is no longer referenced by non-decompiled code, the variables can be declared in their respective C files. For decompiled functions which are only referenced by non-decompiled functions, a hook_function call is added in main.c to redirect code execution to df2_reimpl.dll from JK.EXE.
Progress is tracked using analyze.py, output.map and ida_copypaste_funclist_nostdlib.txt: After compiling df2_reimpl.dll, symbols can be compared against the .idb to determine how much of the original .text is actually in use, and how much has been hooked and replaced.
If you'd like a copy of my IDB to examine functions which haven't been decompiled yet (or for any other use), let me know.
Generated using analyze.py. Some filenames may be inaccurate or incomplete (see ida_copypaste_funclist_nostdlib.txt for a full function name listing).
[file] [size] [% of text] [% complete] [decomp / total]
DirectX 0x1e 0.003% 100.000% 5 / 5
sithCorpse 0x27 0.004% 100.000% 1 / 1
jkGob 0x29 0.004% 100.000% 2 / 2
jkGuiDecision 0x45 0.006% 100.000% 3 / 3
sithStrTable 0x5b 0.008% 100.000% 4 / 4
sithCopyright 0x67 0.010% 100.000% 1 / 1
jkStrings 0x89 0.013% 100.000% 5 / 5
jkGuiGeneral 0xc5 0.018% 100.000% 3 / 3
jkSmack 0xee 0.022% 100.000% 4 / 4
rdFace 0xf6 0.023% 100.000% 4 / 4
jkGuiControlOptions 0x105 0.024% 100.000% 3 / 3
stdHashKey 0x107 0.024% 100.000% 10 / 10
rdCanvas 0x113 0.025% 100.000% 4 / 4
jkGuiEsc 0x18f 0.037% 100.000% 3 / 3
rdroid 0x1f6 0.047% 100.000% 27 / 27
sithHeader 0x1f9 0.047% 100.000% 1 / 1
sithTime 0x213 0.049% 100.000% 6 / 6
jkGuiSingleTally 0x21b 0.050% 100.000% 4 / 4
jkGuiSetup 0x240 0.053% 100.000% 4 / 4
jkGuiSound 0x274 0.058% 100.000% 3 / 3
sithItem 0x275 0.058% 100.000% 5 / 5
jkGuiGameplay 0x2b2 0.064% 100.000% 3 / 3
stdMemory 0x2ba 0.065% 100.000% 7 / 7
sithEvent 0x2e3 0.069% 100.000% 9 / 9
stdMci 0x2ef 0.070% 100.000% 7 / 7
jkGuiObjectives 0x308 0.072% 100.000% 4 / 4
jkControl 0x331 0.076% 100.000% 4 / 4
Windows 0x39a 0.085% 100.000% 11 / 11
stdString 0x3b3 0.088% 100.000% 11 / 11
sithRenderSky 0x3c2 0.089% 100.000% 5 / 5
jkGuiDialog 0x3e0 0.092% 100.000% 6 / 6
sithModel 0x3f1 0.094% 100.000% 8 / 8
rdThing 0x42f 0.099% 100.000% 12 / 12
stdGdi 0x430 0.099% 100.000% 10 / 10
jkCutscene 0x443 0.101% 100.000% 7 / 7
sithKeyFrame 0x44e 0.102% 100.000% 5 / 5
stdPcx 0x45e 0.104% 100.000% 2 / 2
sithDSSCog 0x460 0.104% 100.000% 4 / 4
smack 0x466 0.104% 100.000% 6 / 6
rdMath 0x47d 0.107% 100.000% 6 / 6
rdLight 0x49f 0.110% 100.000% 8 / 8
jkGuiMain 0x4b1 0.111% 100.000% 6 / 6
stdFnames 0x4ee 0.117% 100.000% 14 / 14
sithSprite 0x4f1 0.117% 100.000% 6 / 6
jkGui 0x4fb 0.118% 100.000% 10 / 10
jkGuiTitle 0x4fb 0.118% 100.000% 10 / 10
sithMaterial 0x4fd 0.118% 100.000% 9 / 9
sithActor 0x559 0.127% 100.000% 5 / 5
wuRegistry 0x5b2 0.135% 100.000% 12 / 12
stdHashTable 0x5d6 0.138% 100.000% 10 / 10
DebugConsole 0x5de 0.139% 100.000% 13 / 13
sithUnk4 0x5e9 0.140% 100.000% 6 / 6
sithExplosion 0x61d 0.145% 100.000% 4 / 4
sithAIClass 0x689 0.155% 100.000% 7 / 7
rdPrimit2 0x69a 0.157% 100.000% 5 / 5
Window 0x6db 0.163% 100.000% 13 / 13
stdGob 0x6dd 0.163% 100.000% 14 / 14
jkAI 0x6e7 0.164% 100.000% 5 / 5
sith 0x72b 0.170% 100.000% 16 / 16
jkGuiPlayer 0x73a 0.171% 100.000% 5 / 5
jkGuiMultiplayer 0x749 0.173% 100.000% 3 / 3
rdSprite 0x76d 0.176% 100.000% 5 / 5
stdConffile 0x78d 0.179% 100.000% 13 / 13
jkGuiMap 0x793 0.180% 100.000% 8 / 8
sithTemplate 0x79d 0.181% 100.000% 10 / 10
sithParticle 0x7f5 0.189% 100.000% 10 / 10
sithMap 0x814 0.192% 100.000% 6 / 6
jkGuiSingleplayer 0x8d8 0.210% 100.000% 7 / 7
sithCogFunctionSector 0x93a 0.219% 100.000% 22 / 22
sithCogFunctionAI 0x943 0.220% 100.000% 20 / 20
stdSound 0x9bf 0.231% 100.000% 27 / 27
sithGamesave 0x9bf 0.231% 100.000% 7 / 7
jkGuiForce 0x9dd 0.234% 100.000% 11 / 11
sithSound 0xa00 0.237% 100.000% 13 / 13
rdParticle 0xa0d 0.239% 100.000% 10 / 10
rdMaterial 0xa2d 0.241% 100.000% 9 / 9
sithSoundClass 0xa46 0.244% 100.000% 16 / 16
sithCogFunctionSound 0xa97 0.251% 100.000% 14 / 14
rdKeyframe 0xa99 0.251% 100.000% 8 / 8
rdCamera 0xaa8 0.253% 100.000% 26 / 26
jkGuiSaveLoad 0xb21 0.264% 100.000% 9 / 9
rdPolyLine 0xb42 0.267% 100.000% 6 / 6
jkGuiKeyboard 0xb57 0.269% 100.000% 14 / 14
sithOverlayMap 0xbf8 0.284% 100.000% 9 / 9
rdVector 0xd29 0.312% 100.000% 55 / 55
jkGuiMouse 0xdb5 0.325% 100.000% 14 / 14
DirectDraw 0xdd4 0.328% 100.000% 16 / 16
sithCogFunctionPlayer 0xdf0 0.331% 100.000% 42 / 42
jkHudInv 0xe43 0.338% 100.000% 9 / 9
sithCogFunctionSurface 0xe92 0.346% 100.000% 38 / 38
stdConsole 0xfff 0.380% 100.000% 20 / 20
jkCog 0x11b8 0.420% 100.000% 40 / 40
stdControl 0x11ec 0.425% 100.000% 22 / 22
sithCogYACC 0x152b 0.502% 100.000% 10 / 10
jkRes 0x15b6 0.515% 100.000% 23 / 23
sithWorld 0x1718 0.548% 100.000% 22 / 22
sithDSS 0x175d 0.554% 100.000% 22 / 22
stdMath 0x182a 0.573% 100.000% 23 / 23
rdActive 0x1a55 0.625% 100.000% 8 / 8
sithCogParse 0x1b2a 0.645% 100.000% 26 / 26
sithInventory 0x2150 0.791% 100.000% 62 / 62
sithCogVm 0x22f7 0.830% 100.000% 42 / 42
sithRender 0x23de 0.851% 100.000% 22 / 22
sithSoundSys 0x2626 0.905% 100.000% 37 / 37
sithCogFunction 0x26c2 0.920% 100.000% 119 / 119
sithAI 0x2771 0.936% 100.000% 35 / 35
rdModel3 0x2a7e 1.008% 100.000% 23 / 23
std3D 0x2c4a 1.051% 100.000% 39 / 39
rdMatrix 0x2c85 1.056% 100.000% 56 / 56
sithAICmd 0x2cc0 1.062% 100.000% 22 / 22
jkGuiRend 0x2cd7 1.064% 100.000% 68 / 68
jkPlayer 0x2da2 1.083% 100.000% 45 / 45
sithPhysics 0x310b 1.164% 100.000% 13 / 13
sithWeapon 0x32a8 1.202% 100.000% 33 / 33
rdCache 0x331c 1.213% 100.000% 16 / 16
sithCogFunctionThing 0x3a4c 1.383% 100.000% 142 / 142
rdClip 0x81f2 3.084% 100.000% 17 / 17
sithAIAwareness 0x31f 0.074% 90.488% 5 / 6
sithDplay 0x53c 0.124% 2.090% 1 / 17
Video 0x5dc 0.139% 19.800% 3 / 5
stdFileUtil 0x687 0.155% 54.159% 6 / 11
stdBmp 0x6b8 0.159% 0.000% 0 / 3
sithCogScript 0x6ca 0.161% 89.241% 8 / 9
sithAnimClass 0x6cc 0.161% 94.080% 4 / 5
jkGuiControlSaveLoad 0x732 0.171% 0.000% 0 / 6
stdStrTable 0x7b6 0.183% 82.877% 4 / 6
sithSector 0x806 0.190% 90.458% 11 / 13
Main 0x87b 0.201% 96.868% 3 / 4
jkGuiMultiTally 0x8aa 0.206% 0.000% 0 / 7
jkCredits 0x8e4 0.211% 54.350% 5 / 6
jkGuiNet 0x94e 0.221% 0.000% 0 / 10
stdColor 0x97e 0.225% 24.198% 3 / 11
jkGame 0x98f 0.227% 42.705% 8 / 13
stdPalEffects 0xa66 0.247% 85.875% 16 / 21
jkGuiNetHost 0xbc6 0.279% 0.000% 0 / 6
stdLbm 0xc24 0.288% 0.000% 0 / 3
rdColormap 0xcf4 0.307% 47.738% 7 / 12
jkEpisode 0xdd9 0.329% 94.104% 7 / 10
stdPlatform 0xdde 0.329% 27.718% 19 / 43
sithPlayer 0xe72 0.343% 73.905% 18 / 27
stdBitmap 0xeb6 0.349% 47.398% 6 / 14
sithTrackThing 0xf9f 0.371% 90.098% 12 / 15
rdPuppet 0x101f 0.383% 97.407% 15 / 19
DirectPlay 0x10cc 0.399% 0.000% 0 / 31
VBuffer 0x10dc 0.400% 0.000% 0 / 4
stdGif 0x1162 0.412% 0.000% 0 / 4
sithDebugConsole 0x11b2 0.420% 36.269% 6 / 20
sithPuppet 0x1222 0.430% 86.579% 13 / 17
sithCamera 0x124b 0.434% 98.612% 19 / 23
sithIntersect 0x12a8 0.443% 92.588% 9 / 12
jkGuiDisplay 0x12ff 0.451% 0.000% 0 / 11
jkGuiJoystick 0x13f0 0.473% 0.000% 0 / 19
jkMain 0x16cd 0.541% 86.294% 40 / 53
rdPrimit3 0x16e0 0.543% 91.684% 7 / 9
stdFont 0x181a 0.572% 75.284% 12 / 20
sithSurface 0x1c6a 0.674% 95.298% 31 / 35
jkHud 0x1c9b 0.679% 97.952% 16 / 17
sithCog 0x1ed3 0.731% 90.686% 21 / 28
jkSaber 0x1f4a 0.742% 75.980% 23 / 40
jkDev 0x1fd6 0.755% 94.687% 39 / 41
sithDSSThing 0x22aa 0.823% 50.980% 10 / 37
sithMulti 0x252a 0.882% 0.105% 1 / 35
jkGuiBuildMulti 0x258b 0.891% 0.000% 0 / 24
stdDisplay 0x267b 0.913% 61.537% 22 / 37
sithCollision 0x2827 0.953% 91.760% 18 / 22
sithControl 0x285a 0.958% 92.943% 29 / 33
sithThing 0x3c2e 1.428% 87.446% 45 / 53
rdRaster 0xf04d 5.702% 0.195% 1 / 89
rdZRaster 0x15fb4 8.346% 0.000% 0 / 73
rdAFRaster 0x1620d 8.402% 0.000% 0 / 122
rdNRaster 0x304d4 18.339% 0.000% 0 / 87
---------------------------------------------------------------------------------
Total completion:
-----------------
50.391% by weight
85.104% by weight excluding rasterizer
2394 / 3169 functions
2394 / 2798 functions excluding rasterizer
Subsystem Breakdown (Not Decomp'd)
----------------------------------
[subsys] [% of text] [TODO / total]
sith 2.373% 146 / 1323
stdPlatform 0.238% 24 / 43
std 1.844% 61 / 359
jkGui 2.691% 83 / 284
rd 0.216% 11 / 345
jk 0.552% 42 / 324
Raster 40.778% 370 / 371
other 0.916% 38 / 120
-----------------------------------------
total 49.609% 775 / 3169
Subsystem Breakdown (Not Decomp'd, Excl Raster)
-----------------------------------------------
[subsys] [% of text] [TODO / total]
sith 4.008% 146 / 1323
stdPlatform 0.402% 24 / 43
std 3.115% 61 / 359
jkGui 4.545% 83 / 284
rd 0.364% 11 / 345
jk 0.933% 42 / 324
other 1.548% 38 / 120
-----------------------------------------
total 14.915% 405 / 2798