PostFXPipeline.bootFX is a new method, which is the previous boot method but renamed. This is no longer called from the constructor, but instead when the Post FX Pipeline is activated by the Pipeline Manager. This means that the resources the Post FX requires, such as creating Render Targets and shaders, is delayed until the FX is actually used, saving on memory.

src/renderer/webgl/pipelines/PostFXPipeline.js

@@ -227,12 +227,21 @@ var PostFXPipeline = new Class({
         if (this.renderer.isBooted)
         {
             this.manager = this.renderer.pipelines;
-
-            this.boot();
         }
     },
 
-    boot: function ()
+    /**
+     * This method is called once, when this Post FX Pipeline needs to be used.
+     *
+     * Normally, pipelines will boot automatically, ready for instant-use, but Post FX
+     * Pipelines create quite a lot of internal resources, such as Render Targets, so
+     * they don't boot until they are told to do so by the Pipeline Manager, when an
+     * actual Game Object needs to use them.
+     *
+     * @method Phaser.Renderer.WebGL.Pipelines.PostFXPipeline#bootFX
+     * @since 3.61.0
+     */
+    bootFX: function ()
     {
         WebGLPipeline.prototype.boot.call(this);
 
@@ -257,6 +266,37 @@ var PostFXPipeline = new Class({
         }
     },
 
+    /**
+     * This method is called as a result of the `WebGLPipeline.batchQuad` method, right after a quad
+     * belonging to a Game Object has been added to the batch. When this is called, the
+     * renderer has just performed a flush.
+     *
+     * It calls the `onDraw` hook followed by the `onPostBatch` hook, which can be used to perform
+     * additional Post FX Pipeline processing.
+     *
+     * It is also called as part of the `PipelineManager.postBatch` method when processing Post FX Pipelines.
+     *
+     * @method Phaser.Renderer.WebGL.Pipelines.PostFXPipeline#postBatch
+     * @since 3.61.0
+     *
+     * @param {(Phaser.GameObjects.GameObject|Phaser.Cameras.Scene2D.Camera)} [gameObject] - The Game Object or Camera that invoked this pipeline, if any.
+     *
+     * @return {this} This WebGLPipeline instance.
+     */
+    postBatch: function (gameObject)
+    {
+        if (!this.hasBooted)
+        {
+            this.bootFX();
+        }
+
+        this.onDraw(this.currentRenderTarget);
+
+        this.onPostBatch(gameObject);
+
+        return this;
+    },
+
     onDraw: function (renderTarget)
     {
         this.bindAndDraw(renderTarget);