Merge pull request #127 from bbarker/nix_flake

add flake.nix

Author: NiklasEi

README.md

@@ -76,6 +76,20 @@ There is a [post about how to set up the iOS release workflow][workflow_bevy_ios
 If you don't want to target Android or iOS, you can just delete the `/mobile`, `/build/android`, and `/build/ios` directories.
 Then delete the `[workspace]` section from `Cargo.toml`.
 
+# Development environments
+
+## Nix Support
+
+nixgl is only used on non-NixOS Linux systems;
+when running there we need to use the `--impure` flag:
+
+```
+nix develop --impure
+```
+
+If using nixgl, then .e.g. `gl cargo run`, other use
+`cargo` as usual.
+
 # Getting started with Bevy
 
 You should check out the Bevy website for [links to resources][bevy-learn] and the [Bevy Cheat Book] for a bunch of helpful documentation and examples. I can also recommend the [official Bevy Discord server][bevy-discord] for keeping up to date with the development and getting help from other Bevy users.

flake.lock

@@ -0,0 +1,139 @@
+{
+  description = "Bevy Game development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
+    # nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    nixgl = {
+      url = "github:guibou/nixGL";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, flake-utils, nixgl }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgsOrig = import nixpkgs {inherit system; };
+        forced = builtins.trace "Current system is: ${system}" null;
+        isLinux = (builtins.match ".*linux.*" system) != null;
+        isDarwin = (builtins.match ".*darwin.*" system) != null;
+        isImpure = builtins.hasAttr "currentTime" builtins;
+
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = if (isLinux && isImpure) 
+            then [ nixgl.overlays.default ]
+            else [ ];
+        };
+        
+        linuxPackages = with pkgs; [
+          alsa-lib
+          alsa-plugins
+          udev
+        ];
+        linuxImpurePackages = with pkgs; [
+          pkgs.nixgl.auto.nixGLDefault
+        ];
+
+        sdkVersion = "15";
+        appleSDK = pkgs."apple-sdk_${sdkVersion}";
+        appleLibs = if isDarwin then ([
+          appleSDK
+        ]) else [];
+
+        # Platform-specific packages
+        platformPackages = 
+          (if (isLinux && !isImpure) then
+            linuxPackages
+          else if isLinux then
+            linuxPackages ++ linuxImpurePackages 
+          else if isDarwin then
+            appleLibs
+          else
+            [ ]);
+        
+        # Common bindgen configuration
+        commonBindgenIncludes = with pkgs; [
+          ''-I"${llvmPackages_latest.libclang.lib}/lib/clang/${llvmPackages_latest.libclang.version}/include"''
+        ];
+
+        # Platform-specific bindgen configuration
+        platformBindgenInputs = if isLinux then
+          with pkgs; [
+            glibc.dev
+          ]
+        else [];
+        
+        platformBindgenIncludes = if isLinux then
+          with pkgs; [
+            ''-I"${glib.dev}/include/glib-2.0"''
+            ''-I${glib.out}/lib/glib-2.0/include/''
+          ]
+        else [];
+
+        # It's standard in nix to pin the versions for reproducibility; here's where we
+        # pin the Rust toolchain.
+        overrides = (builtins.fromTOML (builtins.readFile (self + "/nix/rust-toolchain.toml")));
+        
+        # Platform-specific shell hook
+        platformShellHook = if isLinux then ''
+          alias gl='nixGL'
+          export ALSA_PLUGIN_DIR=${pkgs.alsa-plugins}/lib/alsa-lib
+          ''
+        else
+          "";
+          
+        libPath = with pkgs; lib.makeLibraryPath [
+          # load external libraries that you need in your rust project here
+        ];
+      in
+      {
+        devShells.default = pkgs.mkShell rec {
+          nativeBuildInputs = [ pkgs.pkg-config ];
+          buildInputs = with pkgs; [
+            clang
+            llvmPackages.bintools
+            # shouldn't need this, but rustup (andt thus cargo), is too old for 2024 edition requirements:
+            # https://github.com/NixOS/nixpkgs/pull/397177
+            cargo
+            rustup
+
+            vulkan-loader
+            xorg.libX11
+            xorg.libXcursor
+            xorg.libXi
+            xorg.libXrandr
+            libxkbcommon
+          ] ++ platformPackages;
+
+          RUSTC_VERSION = overrides.toolchain.channel;
+          RUSTC_COMPONENTS = nixpkgs.lib.escapeShellArgs (nixpkgs.lib.concatMap (c: ["-c" c]) overrides.toolchain.components);
+          LIBCLANG_PATH = pkgs.lib.makeLibraryPath [ pkgs.llvmPackages_latest.libclang.lib ];
+          FORCED = forced;
+          shellHook = ''
+            rustup toolchain install $RUSTC_VERSION $RUSTC_COMPONENTS
+            export PATH=$PATH:''${CARGO_HOME:-~/.cargo}/bin
+            export PATH=''${RUSTUP_HOME:-~/.rustup}/toolchains/$RUSTC_VERSION-x86_64-unknown-linux-gnu/bin/:$PATH
+            ${platformShellHook}
+          '';
+
+          # Add precompiled library to rustc search path
+          RUSTFLAGS = (builtins.map (a: ''-L ${a}/lib'') [
+            # add libraries here (e.g. pkgs.libvmi)
+          ]);
+          
+          LD_LIBRARY_PATH = 
+            (pkgs.lib.makeLibraryPath (buildInputs ++ nativeBuildInputs)) + 
+            # packages with non-standard lib paths:
+            (if isLinux then ":${pkgs.alsa-plugins}/lib/alsa-lib" else "");
+
+          # Add clang and other headers to bindgen search path
+          BINDGEN_EXTRA_CLANG_ARGS =
+            (builtins.map (a: ''-I"${a}/include"'') platformBindgenInputs)
+            ++ commonBindgenIncludes
+            ++ platformBindgenIncludes;
+        };
+      }
+    );
+}

flake.nix

@@ -0,0 +1,3 @@
+[toolchain]
+channel = "1.87.0"
+components = ["rustfmt", "clippy", "rust-analyzer"]