feat(#8): improve debug

modules/game-objects/fps-counter.js

@@ -0,0 +1,21 @@
+import { GameObject } from "./game-object.js";
+
+export class FpsCounter extends GameObject {
+  constructor({ debug = false }) {
+    super({ debug });
+    this.fps = 0;
+  }
+
+  update(delta) {
+    this.fps = Math.floor(1 / delta);
+  }
+
+  render(ctx) {
+    if (!this.debug) {
+      return;
+    }
+    ctx.fillStyle = "Red";
+    ctx.font = "normal 12pt Arial";
+    ctx.fillText(this.fps + " fps", 5, 15);
+  }
+}