82: Add a pure client build that leverages Nix (#83)

* 82: attempt to make a pure client build + update instructions

.github/workflows/client_build.yml

@@ -42,8 +42,9 @@ jobs:
 
       - name: "[Client] Build"
         run: |
-          nix develop .#ci --impure -c just client-build-ci
+          nix build .#client
 
       - name: "[Client] Tests"
         run: |
+          nix develop .#ci --impure -c just client-build-ci
           nix develop .#ci --impure -c just client-test-ci

README.org

@@ -20,22 +20,14 @@ There are several ways to run this project, but they all leverage [[https://nixo
 single [[https://devenv.sh/][devenv]] configured, that has all the tooling required to run this project,
 it also includes postgres.
 
-** Testing the Game (DEMO)
-
-1. ~nix develop --impure~
-2. ~devenv up~ to launch a local ~postgres~
-3. ~just db-reset~ or ~db-reset~, to initialize ~postgres~ for local development
-5. ~server~ (or ~./result/bin/server foreground~ if you want to run the pure nix build)
-6. followed by ~client-release~
-7. Once you get the client to launch, connect to ~localhost~ and you can try
-   playing with any of the local credentials [[https://github.com/Dr-Nekoma/lyceum/blob/master/server/database/main.input.sql#L3][here]].
-
 ** Development Shell
 
+To enter a development shell we assume you have at least [[https://nixos.org/][Nix]] installed:
+
 #+BEGIN_SRC shell
   # To enter the developmet shell
   nix develop --impure
-  # To spawn postgres
+  # To spawn postgres (for instance)
   devenv up -d
 #+END_SRC
 
@@ -53,16 +45,59 @@ to migrate the local dababase, you can use ~just db-up~ or ~db-up~.
 You can also build the server and related OCI images with Nix.
 
 #+BEGIN_SRC shell
-    nix build .#server
+  nix build .#server
 #+END_SRC
+
 if you prefer running a container for the server:
+
 #+BEGIN_SRC shell
-    nix build .#buildImage
-    docker load < ./result
-    docker container run --network=host lyceum:latest
+  nix build .#buildImage
+  docker load < ./result
+  docker container run --network=host lyceum:latest
 #+END_SRC
 
+or if you want to build the ~zig~ client, run ~nix build .#client~.
+
+** Testing the Game
+
+To run our DEMO you need to follow the steps in this particular order:
+
+1. ~nix develop --impure~ (to enter a development shell)
+2. ~devenv up~ to launch a local ~postgres~
+3. ~just db-reset~ or ~db-reset~, to initialize ~postgres~ for local development
+4. Run the ~erlang~ backend in a separate shell with either:
+
+    #+begin_src shell
+      server
+      # or
+      just server
+      # or if you want a pure build
+      nix build .#server
+      ./result/bin/server foreground
+    #+end_src
+
+5. Followed by running the ~zig~ client in a third shell with either:
+
+    #+begin_src shell
+      client-release
+      # or
+      just client-release
+      # or if you prefer a pure build
+      nix build .#client
+      ./result/bin/lyceum-client
+    #+end_src
+
+    *Addendum*: We got [[https://github.com/Dr-Nekoma/lyceum/pull/83#issuecomment-2550476288][reports]] that (sometimes) non-NixOS users will have to rely on[[https://github.com/nix-community/nixGL][ nixGL]].
+
+    #+begin_src shell
+      nix run --impure github:nix-community/nixGL -- ./result/bin/lyceum-client
+    #+end_src
+
+6. Once you get the client to launch, connect to ~localhost~ and you can try
+   playing with any of the local credentials [[https://github.com/Dr-Nekoma/lyceum/blob/master/server/database/main.input.sql#L3][here]].
+
 ** Deployment
+
 This game is deployed in our [[https://github.com/Dr-Nekoma/trashcan][NixOS server]].
 
 * Assets

client/build.zig

@@ -44,6 +44,20 @@ pub fn build(b: *std.Build) !void {
         exe.root_module.addImport("zerl", zerl.module("zerl"));
     }
 
+    const assets = b.addInstallDirectory(.{
+        .source_dir = b.path("assets"),
+        .install_dir = .prefix,
+        .install_subdir = "assets",
+    });
+
+    exe.step.dependOn(&assets.step);
+
+    // https://ziglang.org/learn/build-system/#conditional-compilation
+    const assets_opt = b.option([]const u8, "assets", "custom path for the assets directory") orelse "./assets";
+    const options = b.addOptions();
+    options.addOption([]const u8, "assets", assets_opt);
+    exe.root_module.addOptions("build_options", options);
+
     if (b.lazyImport(@This(), "zerl")) |zerl_build| {
         if (std.posix.getenv("LIBRARY_PATH")) |lib_path| {
             try zerl_build.add_erlang_paths(b, lib_path);

client/src/assets.zig

@@ -5,8 +5,9 @@ const rl = @import("raylib");
 const rm = rl.math;
 const std = @import("std");
 const GameState = @import("game/state.zig");
+const build_options = @import("build_options");
 
-const base_filepath = "./assets/";
+const base_filepath = build_options.assets;
 
 fn load(
     comptime T: type,

flake.nix

@@ -229,6 +229,7 @@
             zigBuildFlags = [
               "-fsys=raylib"
               "--release=fast"
+              "-Dassets=${builtins.toString ./client}/assets"
             ];
 
             nativeBuildInputs = [
@@ -237,14 +238,9 @@
             ];
 
             buildInputs =
-              with pkgs;
-              [
-                raylib
-                zigLatest
-                erlangLatest
-              ]
-              ++ lib.optionals stdenv.isLinux (linuxPkgs)
-              ++ lib.optionals stdenv.isDarwin darwinPkgs;
+              with pkgs; [ raylib zigLatest erlangLatest ]
+                ++ lib.optionals stdenv.isLinux (linuxPkgs)
+                ++ lib.optionals stdenv.isDarwin darwinPkgs;
 
             postPatch = ''
               ln -s ${pkgs.callPackage ./client/zon-deps.nix { }} $ZIG_GLOBAL_CACHE_DIR/p
@@ -287,14 +283,6 @@
             ];
           };
 
-          # `nix develop .#server`
-          server = pkgs.mkShell {
-            buildInputs = with pkgs; [
-              erlangLatest
-              rebar3
-            ];
-          };
-
           # `nix develop`
           default = devenv.lib.mkShell {
             inherit inputs pkgs;