Adding building instructions.

README.md

@@ -4,6 +4,85 @@
 ## Description
 A multi-platform 2D_Engine made in C.
 
+## Summary
+
+ 1. [Licenses](#licences)
+ 2. [Building](#building)
+
 ## Licences
 - This program is open-source : you can redistribute and/or modify it under the term of the **GNU GPLv3**.
   Copyright (C) 2025 - 2026 Ulysse Cura. See [LICENSE](LICENSE.txt) or [gnu.org/licenses/gpl-3.0.html](https://www.gnu.org/licenses/gpl-3.0.html).
+
+## Building
+
+### Setup
+
+### Linux
+
+The only tools needed are :
+ - gcc
+ - make
+ - pkg-config
+
+With the librairies (tested with version) :
+ - sdl3     version >= 3.2.1O
+ - libpng   version >= 1.6.48
+ - json-c   version >= 0.18
+
+On Debian, the command to install dependencies is :
+```
+sudo apt install gcc make pkg-config libsdl3-dev libpng-dev libjson-c-dev
+```
+
+On Nix, the shell.nix file manage the dependencies for you, but it might not be up to date, as support for Nix is not a priority.
+
+### Windows
+
+To build on windows you will need MSYS2 or Cygwin.
+For the moment only MSYS2 is officialy supported.
+
+The only tools needed are :
+ - x86_64-w64-mingw32-gcc
+ - make
+ - x86_64-w64-mingw32-pkg-config
+
+With the librairies (tested with version) :
+ - sdl3     version >= 3.4.10
+ - libpng   version >= 1.6.58
+ - json-c   version >= 0.18
+
+On MSYS2, the command to install dependencies is :
+```
+pacman -S mingw-w64-ucrt-x86_64-gcc make mingw-w64-ucrt-x86_64-pkg-config mingw-w64-ucrt-x86_64-sdl3 mingw-w64-ucrt-x86_64-libpng mingw-w64-ucrt-x86_64-json-c
+```
+
+### Cross compiling
+
+For the moment cross compiling from linux to windows is the only supported cross compiling option.
+To do that you will need the following tools :
+ - x86_64-w64-mingw32-gcc
+ - make
+ - x86_64-w64-mingw32-pkg-config
+
+With the librairies (tested with version) :
+ - sdl3     version >= 3.4.10 (mingw devel)
+ - libpng   version >= 1.6.58
+ - json-c   version >= 0.18
+
+On Debian the command to install dependencies is :
+```
+sudo apt install mingw-w64 mingw-w64-tools mingw-w64-ucrt64-dev make libpng-dev libjson-c-dev
+```
+
+For the sdl3 mingw devel package you will need to install it manually.
+See [README-windows](https://wiki.libsdl.org/SDL3/README-windows).
+Or [releases](https://github.com/libsdl-org/SDL/releases).
+
+### Commands
+
+The [configure](configure) script automaticaly test compilers and libs versions for your target host.
+
+See `./configure --help` for usage.
+
+The aim is to support linux, windows and the fxcg50 calculator.
+However the option `--target-host` only officialy supports `linux` and `windows` but `fxcg50` is also an accepted option.

shell.nix

@@ -12,8 +12,6 @@ pkgs.mkShell {
     libpng
     json_c
     sdl3
-    lua
-    ncurses
   ];
 
   shellHook = ''