Cameras.Scene2D.Events.FOLLOW_UPDATE is a new Event that is dispatched by a Camera when it is following a Game Object. It is dispatched every frame, right after the final Camera position and internal matrices have been updated. Use it if you need to react to a camera, using its most current position and the camera is following something. Fix phaserjs#5253

Author: photonstorm

src/cameras/2d/Camera.js

@@ -11,6 +11,7 @@ var Clamp = require('../../math/Clamp');
 var Class = require('../../utils/Class');
 var Components = require('../../gameobjects/components');
 var Effects = require('./effects');
+var Events = require('./events');
 var Linear = require('../../math/Linear');
 var Rectangle = require('../../geom/rectangle/Rectangle');
 var Vector2 = require('../../math/Vector2');
@@ -774,6 +775,8 @@ var Camera = new Class({
             CenterOn(deadzone, this.midPoint.x, this.midPoint.y);
         }
 
+        var emitFollowEvent = false;
+
         if (follow && !this.panEffect.isRunning)
         {
             var fx = (follow.x - this.followOffset.x);
@@ -804,6 +807,8 @@ var Camera = new Class({
                 sx = Linear(sx, fx - originX, this.lerp.x);
                 sy = Linear(sy, fy - originY, this.lerp.y);
             }
+
+            emitFollowEvent = true;
         }
 
         if (this.useBounds)
@@ -850,6 +855,11 @@ var Camera = new Class({
         matrix.translate(-originX, -originY);
 
         this.shakeEffect.preRender();
+
+        if (emitFollowEvent)
+        {
+            this.emit(Events.FOLLOW_UPDATE, this, follow);
+        }
     },
 
     /**

src/cameras/2d/events/FOLLOW_UPDATE_EVENT.js

@@ -0,0 +1,22 @@
+/**
+ * @author       Richard Davey <rich@photonstorm.com>
+ * @copyright    2020 Photon Storm Ltd.
+ * @license      {@link https://opensource.org/licenses/MIT|MIT License}
+ */
+
+/**
+ * The Camera Follower Update Event.
+ *
+ * This event is dispatched by a Camera instance when it is following a
+ * Game Object and the Camera position has been updated as a result of
+ * that following.
+ *
+ * Listen to it from a Camera instance using: `camera.on('followupdate', listener)`.
+ *
+ * @event Phaser.Cameras.Scene2D.Events#FOLLOW_UPDATE
+ * @since 3.50.0
+ *
+ * @param {Phaser.Cameras.Scene2D.BaseCamera} camera - The camera that emitted the event.
+ * @param {Phaser.GameObjects.GameObject} gameObject - The Game Object the camera is following.
+ */
+module.exports = 'followupdate';

src/cameras/2d/events/index.js

@@ -17,6 +17,7 @@ module.exports = {
     FADE_OUT_START: require('./FADE_OUT_START_EVENT'),
     FLASH_COMPLETE: require('./FLASH_COMPLETE_EVENT'),
     FLASH_START: require('./FLASH_START_EVENT'),
+    FOLLOW_UPDATE: require('./FOLLOW_UPDATE_EVENT'),
     PAN_COMPLETE: require('./PAN_COMPLETE_EVENT'),
     PAN_START: require('./PAN_START_EVENT'),
     POST_RENDER: require('./POST_RENDER_EVENT'),