chore: Introduce Nix

.envrc

@@ -0,0 +1 @@
+use flake path:.

README.md

@@ -39,7 +39,7 @@
 
 ### Note / Tips
 
-- For example on x86_64 Linux, run:
+- For example on typical x86_64 Linux, run:
   ```sh
   wget https://github.com/google-deepmind/mujoco/releases/download/3.10.0/mujoco-3.10.0-linux-x86_64.tar.gz
   tar -xzf mujoco-3.10.0-linux-x86_64.tar.gz
@@ -61,11 +61,13 @@
   export LD_LIBRARY_PATH="$MUJOCO_LIB:$LD_LIBRARY_PATH"
   ```
 
-- Or, you can get MuJoCo library through Python toolchain like `uv` or `pip`.
-    
+- Or, you can get MuJoCo library through Nix, or Python toolchain like `uv` or `pip`.
+
 - Depending on your setting, be sure to specify `$MUJOCO_LIB` as shared library path
   when executing your app (for example `LD_LIBRARY_PATH=$MUJOCO_LIB cargo run` on Linux)
 
+- For Nix user: Refer to [rusty_mujoco repo's flake.nix](https://github.com/rust-control/rusty_mujoco/blob/main/flake.nix) as an example for the Nix-way to setup specific version of MuJoCo, `MUJOCO_LIB`, or `glfw` or other depending packages for executable app.
+
 ## Example
 
 ```toml

examples/README.md

@@ -8,14 +8,15 @@ This example leaves a single object in the scene and visualizes it.
 
 - Of course [`rusty_mujoco` Requirements](https://github.com/rust-control/rusty_mujoco?tab=readme-ov-file#requirements)
 - Additionally [`glfw` Prerequisites](https://github.com/PistonDevelopers/glfw-rs?tab=readme-ov-file#prerequisites)
+  - (NOTE: This is already configured if you setup with `flake.nix`)
 
 ### Usage
 
 Pass the path to a MuJoCo model XML file as an argument. For example,
-you can use the `humanoid.xml` model provided by MuJoCo:
+you may use the `humanoid.xml` model provided by MuJoCo:
 
 ```sh
-cargo run --example visualize_left_object -- $MUJOCO_LIB/../model/humanoid/humanoid.xml
+cargo run --example visualize_left_object -- $MUJOCO_LIB/../share/mujoco/model/humanoid/humanoid.xml
 ```
 
 *(replace the path to humanoid.xml with yours)*
@@ -35,5 +36,5 @@ Depending on your setting, you may need to specify:
 like:
 
 ```sh
-LD_LIBRARY_PATH="$MUJOCO_LIB" cargo run --example visualize_left_object -- $MUJOCO_LIB/../model/humanoid.xml
+LD_LIBRARY_PATH="$MUJOCO_LIB" cargo run --example visualize_left_object -- $MUJOCO_LIB/../share/mujoco/model/humanoid/humanoid.xml
 ```

flake.nix

@@ -0,0 +1,57 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    nixpkgs-pin-mujoco-3_10_0.url = "github:nixos/nixpkgs/775bdd0467f3de2fb5017830d00fa1f573b2ecda";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    systems.url = "github:nix-systems/default";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = inputs@{
+    flake-parts,
+    systems,
+    ...
+  }: flake-parts.lib.mkFlake { inherit inputs; } {
+    systems = import systems;
+    perSystem = {
+      system,
+      pkgs,
+      pkgs-pin-mujoco-3_10_0,
+      ...
+    }: {
+      _module.args = {
+        pkgs = import inputs.nixpkgs {
+          inherit system;
+          overlays = [ (inputs.rust-overlay.overlays.default) ];
+        };
+        pkgs-pin-mujoco-3_10_0 = import inputs.nixpkgs-pin-mujoco-3_10_0 {
+          inherit system;
+        };
+      };
+      devShells.default =
+        let
+          rustToolchain = pkgs.rust-bin.stable.latest.default.override {
+            extensions = [ "rust-src" ];
+          };
+          mujoco-3_10_0 = pkgs-pin-mujoco-3_10_0.mujoco;
+        in
+        pkgs.mkShell {
+          RUST_SRC_PATH = "${rustToolchain}/lib/rustlib/src/rust/library";
+          RUSTFLAGS = pkgs.lib.optionalString pkgs.stdenv.isLinux "-C link-arg=-fuse-ld=bfd";
+          MUJOCO_LIB = "${mujoco-3_10_0}/lib";
+          packages = [
+            rustToolchain
+          ] ++ (with pkgs-pin-mujoco-3_10_0; [
+            pkg-config
+            glfw3
+          ]) ++ pkgs.lib.optionals pkgs.stdenv.isLinux (with pkgs-pin-mujoco-3_10_0; [
+            libx11
+            wayland
+          ]);
+        };
+    };
+  };
+}