gabonator
commented
3 years ago Well, the video precisely covered all important steps to convert a game. When I was recording it for the first time, it took 40 minutes and it would be too boring to watch it, so I decided to speed up some parts and and skip some boring stuff. And if I am too fast, just pause the video and follow me frame by frame :) You will need two things:
- IDA disassembler - I do not know what version it was, any version should work - we are working with games made in early 90's... I was using it through virtualbox because I couldn't find any decent disassembler for mac.
- Then you need some programming IDE - it could be Xcode or Visual studio or Visual studio code, or even pure text editor should be sufficient. You will need to build the cicoparser code - in the video I am using a script which just calls
g++ -std=c++17 ../CicParser2021/main.cpp -o cicoparser -stdlib=libc++, this should work on osx/linux, on windows you need to create new command line tool project in Visual studio and place there the source code. Cicoparser does not have any dependencies - it contains even json parser (buggy, but at least it doesn't require any external library)
And if you have IDA running and cicoparser binary, with the help of a script cico.py (in scripts folder) you can generate assembly code which in turn you use to feed cicoparser. Currently it works with games written in pure assembly, I did not have time to add support for Turbo-C or Pascal, but it is on my very long to-do list. Currently I do not plan further development in near future, hoping that the community will start contributing to this project by following the video tutorial.
After the conversion you will get one CPP source file. Just check whether there any unresolved functions at the end of this file, put there some dummy implementation (e.g. assert(0)) and place forward declarations at the top. There may be some lines which cicoparser fails to automatically convert into C, so they need to be fixed by hand. Generated code cannot be built alone, it has following dependencies (after including cpu.h):
https://github.com/gabonator/Projects/blob/master/XenonResurrection/WasmCdman/source/machine.h
That interface is very simple and clean, it is the "gateway" for the generated code to touch the real computer. You need to implement memory access methods, then emulate interrupts and port reads/writes. After load application binary into memory (this is a bit strange - but sometimes it is not possible to separate data segment from code segment, so we are loading whole blob of binary data which contains X86 instructions which we do not call) and you are ready to run the game.
After emulation of the video/filesystem/dos stuff (machine.cpp), this is the final interface which you can use to obtain the frame buffer (pixels) and to emulate keyboard input:
https://github.com/gabonator/Projects/blob/master/XenonResurrection/WasmCdman/source/interface.cpp
And then it depends on what OS you are using or what API you use for displaying the screen - in my case I have used SDL2.
I recommend using this project for reference, the code is not very clean, but the interfaces are nicely decoupled: https://github.com/gabonator/Projects/tree/master/XenonResurrection/WasmCdman/source
In this code there is one special feature done which I did not cover in the video - to run a game as WASM (webassembly) or for swift (apple ios), it must not be blocking - so you need to break the main game loop and any loops throughout the gameplay. In CDMAN it was a bit painful, because there are many loops (even for death animation). (search for 'breakup' keyword in https://github.com/gabonator/Projects/blob/master/XenonResurrection/WasmCdman/source/app/cdman.cpp) For conversion of the game into javascript I use nasty trick called "javascript generators" - this allows me to to break the infinite loops without modifying the game. If you are building the game as desktop application, you do not need to care about that.
If you have any more questions, feel free to ask...
jan-kleks
xor2003
Hello, I think that this program have a LOT of potential and I could give you an hand, I watched the video but it's too fast for me (I'm an old man of 48) . Can you give us a Step By Step written tutorial that can help us to setup all the toolchain ? (Ex [1] install IDA Pro version x.y.z [2] compile the tools etc etc, how to install the tools for noobs that don't know IDA etc) Thank you Edoz