fix(animation): harden animator state instance data

packages/core/src/animation/AnimationClip.ts

@@ -205,12 +205,11 @@ export class AnimationClip extends EngineObject {
   }
 
   /**
-   * @internal
    * Samples an animation at a given time.
    * @param entity - The animated entity
    * @param time - The time to sample an animation
    */
-  _sampleAnimation(entity: Entity, time: number): void {
+  sampleAnimation(entity: Entity, time: number): void {
     const { _curveBindings: curveBindings } = this;
     const components = AnimationCurveOwner._components;
     for (let i = curveBindings.length - 1; i >= 0; i--) {

packages/core/src/animation/AnimationClipCurveBinding.ts

@@ -33,7 +33,7 @@ export class AnimationClipCurveBinding {
   /** The animation curve. */
   curve: AnimationCurve<KeyframeValueType>;
 
-  private _tempCurveOwner: Record<number, AnimationCurveOwner<KeyframeValueType>> = {};
+  private _tempCurveOwner = new WeakMap<Entity, AnimationCurveOwner<KeyframeValueType>>();
 
   /**
    * @internal
@@ -63,10 +63,11 @@ export class AnimationClipCurveBinding {
    * @internal
    */
   _getTempCurveOwner(entity: Entity, component: Component): AnimationCurveOwner<KeyframeValueType> {
-    const { instanceId } = entity;
-    if (!this._tempCurveOwner[instanceId]) {
-      this._tempCurveOwner[instanceId] = this._createCurveOwner(entity, component);
+    let owner = this._tempCurveOwner.get(entity);
+    if (!owner) {
+      owner = this._createCurveOwner(entity, component);
+      this._tempCurveOwner.set(entity, owner);
     }
-    return this._tempCurveOwner[instanceId];
+    return owner;
   }
 }