Setting the dirty state automatically when there is an animation frame

front/src/Phaser/Game/DirtyScene.ts

@@ -0,0 +1,52 @@
+import {ResizableScene} from "../Login/ResizableScene";
+import GameObject = Phaser.GameObjects.GameObject;
+import Events = Phaser.Scenes.Events;
+import AnimationEvents = Phaser.Animations.Events;
+
+/**
+ * A scene that can track its dirty/pristine state.
+ */
+export abstract class DirtyScene extends ResizableScene {
+    private isAlreadyTracking: boolean = false;
+    protected dirty:boolean = true;
+    private objectListChanged:boolean = true;
+
+    /**
+     * Track all objects added to the scene and adds a callback each time an animation is added.
+     * Whenever an object is added, removed, or when an animation is played, the dirty state is set to true.
+     *
+     * Note: this does not work with animations from sprites inside containers.
+     */
+    protected trackDirtyAnims(): void {
+        if (this.isAlreadyTracking) {
+            return;
+        }
+        this.isAlreadyTracking = true;
+        const trackAnimationFunction = this.trackAnimation.bind(this);
+        this.events.on(Events.ADDED_TO_SCENE, (gameObject: GameObject) => {
+            this.objectListChanged = true;
+            gameObject.on(AnimationEvents.ANIMATION_UPDATE, trackAnimationFunction);
+        });
+
+        this.events.on(Events.REMOVED_FROM_SCENE, (gameObject: GameObject) => {
+            this.objectListChanged = true;
+            gameObject.removeListener(AnimationEvents.ANIMATION_UPDATE, trackAnimationFunction);
+        });
+
+        this.events.on(Events.RENDER, () => {
+            this.objectListChanged = false;
+        });
+    }
+
+    private trackAnimation(): void {
+        this.objectListChanged = true;
+    }
+
+    public isDirty(): boolean {
+        return this.dirty || this.objectListChanged;
+    }
+
+    public onResize(): void {
+        this.objectListChanged = true;
+    }
+}