Add HUD

src/engine/datatypes.ts

@@ -80,6 +80,10 @@ export class Size {
     this.w = w;
     this.h = h;
   }
+
+  add(other: Size) {
+    return new Size(this.w + other.w, this.h + other.h);
+  }
 }
 
 export class Rect {