Add a tutorial on how to setup the client decomp repo

Author: arves100

source/images/decomp-setup/apkunpack.png

@@ -0,0 +1,94 @@
+Setting up an environment for the client decompilation
+========================================================
+
+.. important::
+
+    Building under Windows is not possible (as viking doesn't work on Windows), if you are under Windows,
+    please use a Windows Subsystem for Linux (WSL) Ubuntu instance.
+
+.. important::
+    All commands here are executed trough a Bash shell.
+
+Requirements
+--------------
+
+* Python 3.6 or newer with pip (or a virtual env with pipx)
+* Ninja
+* CMake 3.30+
+* A C++ toolchain (for compiling the Rust tools)
+* `A Rust toolchain <https://www.rust-lang.org/tools/install>`_
+* wget and p7zip
+* The following Python modules (you can install them with pip install ..):
+
+    capstone colorama cxxfilt pyelftools ansiwrap watchdog python-Levenshtein toml
+
+* A Java runtime (like OpenJDK 21)
+* `APKTool <https://apktool.org/docs/install>`_
+
+.. note::
+
+    On Ubuntu, you can install everything except the Rust toolchain and apktool by running the following commands::
+
+        sudo apt install python3 ninja-build cmake clang libssl-dev pkg-config build-essential openjdk-21-jre wget p7zip
+        pip install capstone colorama cxxfilt pyelftools ansiwrap watchdog python-Levenshtein toml
+
+Clong the repository
+---------------------
+
+Using git, clone the `client <https://github.com/decompfrontier/client>`_ repository with the following command::
+
+    git clone --recurse-submodules https://github.com/decompfrontier/client
+
+
+Dumping the executable and data files
+----------------------------------------
+
+You will first need to get an original copy of Brave Frontier for Android (sg.gumi.bravefrontier) for ARM version 2.19.6.0. If you have
+Brave Frontier installed on your phone, you can use apps like APK Manager to get the APK file.
+
+The SHA256 of the file should match: `BFE8D2141280AC51DEBDD819EC0BEBBC6844BF8249474D9FBDF361F8192B8241`.
+
+Run the following command to extract the APK file::
+
+    java -jar apktool.jar d -o apkunpack -s -r "brave frontier apk.apk"
+
+You should see a directory called "apkunpack" in the same directory where you have run apktool, your apkunpack directory should look something like this:
+
+.. image::
+    ../../images/decomp-setup/apkunpack.png
+
+From this directory, only two directories are important for this tutorial, "assets" and "lib".
+
+Copy the whole content of the "assets" directory inside the "data" directory of the decompfrontier client.
+
+Your data directory should look like so:
+
+.. image::
+    ../../images/decomp-setup/datadir.png
+
+Next, copy the "libgame.so" file from the apkunpack/lib/arm64-v8a directory to the replika/romset/android/global/arm64-v8a directory.
+
+The SHA256 of libgame.so **MUST BE** `076C8ED12E84D122938255C1530A4D4B1853D876B5928DD0C2389538FC4CAD95`.
+
+Setting up the repository
+----------------------------
+
+Go to the client directory that we cloned previously and type:
+
+    ./setup.sh
+
+The following command will download the Android NDK r21e required for building brave frontier, if everything has gone successfully
+you should see an `OK`. (Altrought sometimes you might see `Error: found at least one error` which is ok as well).
+
+If you never installed any Android SDK (the script will check for the existance of the environment variable
+`ANDROID_SDK`), if will default the installation to `~/android-sdk`
+
+Make sure to update your `~/.bashrc` to add the following line if you have never setted up an android SDK:
+
+    export ANDROID_SDK=~/android-sdk
+
+Next steps
+---------------
+
+You are now ready to start decompiling, you can modify the files in the src directory and type `./make.sh` to compile the client
+and `./diff.sh (your function)` to check if a function matches or not.

source/images/decomp-setup/datadir.png

@@ -23,3 +23,4 @@ as well as the infrastructure for the client decompilation.
 
     dev-server
     dev-client-winrt
+    decomp-setup