Fixing disposePostProcesses of default rendering pipeline

src/PostProcess/RenderPipeline/Pipelines/babylon.defaultRenderingPipeline.ts

@@ -250,44 +250,45 @@
 
                 if (this.pass) {
                     this.pass.dispose(camera);
-                    this.pass = null;
                 }
 
                 if (this.highlights) {
                     this.highlights.dispose(camera);
-                    this.highlights = null;
                 }        
 
                 if (this.blurX) {
                     this.blurX.dispose(camera);
-                    this.blurX = null;
                 }      
 
                 if (this.blurY) {
                     this.blurY.dispose(camera);
-                    this.blurY = null;
                 }         
 
                 if (this.copyBack) {
                     this.copyBack.dispose(camera);
-                    this.copyBack = null;
                 }   
 
                 if (this.imageProcessing) {
                     this.imageProcessing.dispose(camera);
-                    this.imageProcessing = null;
                 }                                                                
 
                 if (this.fxaa) {
                     this.fxaa.dispose(camera);
-                    this.fxaa = null;
                 }
 
                 if (this.finalMerge) {
                     this.finalMerge.dispose(camera);
-                    this.finalMerge = null;
                 }                
             }
+
+            this.pass = null;
+            this.highlights = null;
+            this.blurX = null;
+            this.blurY = null;
+            this.copyBack = null;
+            this.imageProcessing = null;
+            this.fxaa = null;
+            this.finalMerge = null;
         }
 
         // Dispose