core: move resources dir to main global state

src/main.zig

@@ -175,6 +175,10 @@ pub const GlobalState = struct {
     action: ?cli.Action,
     logging: Logging,
 
+    /// The app resources directory, equivalent to zig-out/share when we build
+    /// from source. This is null if we can't detect it.
+    resources_dir: ?[]const u8,
+
     /// Where logging should go
     pub const Logging = union(enum) {
         disabled: void,
@@ -192,6 +196,7 @@ pub const GlobalState = struct {
             .tracy = undefined,
             .action = null,
             .logging = .{ .stderr = {} },
+            .resources_dir = null,
         };
         errdefer self.deinit();
 
@@ -271,11 +276,18 @@ pub const GlobalState = struct {
 
         // Initialize glslang for shader compilation
         try glslang.init();
+
+        // Find our resources directory once for the app so every launch
+        // hereafter can use this cached value.
+        self.resources_dir = try internal_os.resourcesDir(self.alloc);
+        errdefer if (self.resources_dir) |dir| self.alloc.free(dir);
     }
 
     /// Cleans up the global state. This doesn't _need_ to be called but
     /// doing so in dev modes will check for memory leaks.
     pub fn deinit(self: *GlobalState) void {
+        if (self.resources_dir) |dir| self.alloc.free(dir);
+
         if (self.gpa) |*value| {
             // We want to ensure that we deinit the GPA because this is
             // the point at which it will output if there were safety violations.