Add load all materials function

src/assets/Materials.zig

@@ -110,6 +110,31 @@ pub fn getOrLoadFilename(self: *Materials, engine: *Engine, textures: *Textures,
     }
 }
 
+pub fn loadAll(self: *Materials, engine: *Engine, textures: *Textures, temp_allocator: std.mem.Allocator) void {
+    const cwd = std.fs.cwd();
+
+    var dir = cwd.openDir("assets/materials", .{ .iterate = true }) catch |err| {
+        std.log.err("Error while opening metarials directory: {s}", .{@errorName(err)});
+        return;
+    };
+    defer dir.close();
+
+    var it = dir.iterate();
+    while (it.next() catch |err| {
+        std.log.err("Error while iterating over materials directory: {s}", .{@errorName(err)});
+        return;
+    }) |entry| {
+        if (entry.kind != .file) {
+            std.log.warn("Skipping material entry {s}, which is not a file", .{entry.name});
+            continue;
+        }
+
+        _ = self.loadMaterial(engine, textures, entry.name, temp_allocator) catch |err| {
+            std.log.err("Error while loading material entry {s}: {s}", .{ entry.name, @errorName(err) });
+        };
+    }
+}
+
 fn loadMaterial(self: *Materials, engine: *Engine, textures: *Textures, filename: []const u8, temp_allocator: std.mem.Allocator) !Id {
     const MaterialJson = struct {
         baseColor: [3]f32 = .{ 1, 1, 1 },