This project is to port Jak 1 (NTSC, "black label" version) to PC. Over 99% of this game is written in GOAL, a custom Lisp language developed by Naughty Dog. Our strategy is:
- decompile the original game code into human-readable GOAL code
- develop our own compiler for GOAL and recompile game code for x86-64
- create a tool to extract game assets into formats that can be easily viewed or modified
- create tools to repack game assets into a format that our port uses.
- make the port a "native application" on x86-64, with high performance. It shouldn't emulated, interpreted, or transpiled.
- Our GOAL compiler's performance should be around the same as unoptimized C.
- try to match things from the original game and development as possible. For example, the original GOAL compiler supported live modification of code while the game is running, so we do the same, even though it's not required for just porting the game.
- support modifications. It should be possible to make edits to the code without everything else breaking.
Install Visual Studio 2019 and get the C++ and CMake tools via the Visual Studio Installer
On Windows, it's recommended to get Scoop to use as a package manager, making the follow steps _much_ easier. Follow the steps on the bottom of the homepage here https://scoop.sh/
Once Scoop is installed, run the following command:
In the toolbar, you should be able to select an individual component to compile, or combine within the root CMakeLists.txt. In the future we will pre-define configurations to make this easier.
![](./doc/imgs/cmake-build-vs.png)
You may also wish to view the files that pertain to each CMake target, rather than the project as it is normally:
The first is `goalc`, which is a GOAL compiler for x86-64. Our implementation of GOAL is called OpenGOAL. All of the compiler source code is in `goalc`. To run the compiler on Linux, there is a script `gc.sh`. The compiler is controlled through a prompt which can be used to enter commands to compile, connect to a running GOAL program for interaction, run the OpenGOAL debugger, or, if you are connected to a running GOAL program, can be used as a REPL to run code interactively. In addition to compiling code files, the compiler has features to pack and build data files.
The second component to the project is the decompiler. You must have a copy of the PS2 game and place all files from the DVD into the `iso_data` folder. Then run `decomp.sh` to run the decompiler. The decompile will extract assets to the `assets` folder. These assets will be used by the compiler when building the port. The decompiler will output code and other data intended to be inspected by humans in the `decompiler_out` folder. Stuff in this folder will not be used by the compiler.
The third is the game source code, written in OpenGOAL. This is located in `goal_src`. All GOAL and GOOS code should be in this folder. Right now most of this is placeholders, but you can take a look at `kernel/gcommon.gc` or `goal-lib.gc` to see some in-progress source code.
The final component is the "runtime", located in `game`. This is the part of the game that's written in C++. In the port, that includes:
- The "C Kernel", which contains the GOAL linker and some low-level GOAL language features. GOAL has a completely custom dynamically linked object file format so in order to load the first GOAL code, you need a linker written in C++. Some low-level functions for memory allocation, communicating with the I/O Processor, symbol table, strings, and the type system are also implemented in C, as these are required for the linker. It also listens for incoming messages from the compiler and passes them to the running game. This also initializes the game, by initializing the PS2 hardware, allocating the GOAL heaps, loading the GOAL kernel off of the DVD, and executing the kernel dispatcher function. This is in the `game/kernel` folder. This should be as close as possible to the game, and all differences should be noted with a comment.
- Implementation of Sony's standard library. GOAL code can call C library functions, and Naughty Dog used some Sony library functions to access files, memory cards, controllers, and communicate with the separate I/O Processor. The library functions are in `game/sce`. Implementations of library features specific to the PC port are located in `game/system`.
- The I/O Processor driver, Overlord. The PS2 had a separate CPU called the I/O Processor (IOP) that was directly connected to the DVD drive hardware and the sound hardware. Naughty Dog created a custom driver for the IOP that handled streaming data off of the DVD. It is much more complicated than I first expected. It's located in `game/overlord`. Like the C kernel, we try to keep this as close as possible to the actual game.
- Sound Code. Naughty Dog used a third party library for sound. We have not started on this yet.
- PC specific graphics stuff. We have not started on this yet.
## Directory Layout
-`.github`: GitHub actions CI setup
-`.vs`: Visual Studio project configurations
-`assets`: extracted assets (textures, translated game text) generated by the decompiler. Not included in the repository. To be used when building the PC port.
-`build`: C++ CMake build folder
-`common`: common C++ code shared between the compiler, decompiler, and game.
-`cross_os_debug`: platform-independent library for implementing the OpenGOAL debugger. Linux-only currently
-`decompiler_out`: output of the decompiler that's not automatically used by the compiler. This is for humans to read and use. Not included in the repository.
Until 16.9 Preview 4, when attaching a debugger to the ASan build, you must disable breaking on Win32 Access Violation exceptions. See the relevant section `Debugging - Exceptions` here https://devblogs.microsoft.com/cppblog/asan-for-windows-x64-and-debug-build-support/#known-issues