Added the ability for a pipeline to be locked or unlocked

src/renderer/webgl/PipelineManager.js

@@ -124,6 +124,29 @@ var PipelineManager = new Class({
          * @since 3.50.0
          */
         this.BITMAPMASK_PIPELINE = null;
+
+        /**
+         * A stack of pipeline instances that is used to manage when the pipelines
+         * are locked and unlocked.
+         *
+         * Treat this array as read-only.
+         *
+         * @name Phaser.Renderer.WebGL.PipelineManager#stack
+         * @type {array}
+         * @since 3.50.0
+         */
+        this.stack = [];
+
+        /**
+         * Is the Pipeline Manager currently locked from setting a new pipeline?
+         *
+         * Treat this property as read-only.
+         *
+         * @name Phaser.Renderer.WebGL.PipelineManager#locked
+         * @type {boolean}
+         * @since 3.50.0
+         */
+        this.locked = false;
     },
 
     /**
@@ -378,8 +401,7 @@ var PipelineManager = new Class({
      *
      * This method accepts a pipeline instance as its parameter, not the name.
      *
-     * If the pipeline isn't already the current one, it will also call `resetTextures` on
-     * the `WebGLRenderer`. After this, `WebGLPipeline.bind` and then `onBind` are called.
+     * If the pipeline isn't already the current one it will call `WebGLPipeline.bind` and then `onBind`.
      *
      * @method Phaser.Renderer.WebGL.PipelineManager#set
      * @since 3.50.0
@@ -395,23 +417,96 @@ var PipelineManager = new Class({
         var current = this.current;
 
         if (
-            current !== pipeline ||
+            !this.locked &&
+            (current !== pipeline ||
             current.vertexBuffer !== renderer.currentVertexBuffer ||
-            current.currentShader.program !== renderer.currentProgram
+            current.currentShader.program !== renderer.currentProgram)
         )
         {
-            renderer.resetTextures();
-
             this.current = pipeline;
 
             pipeline.bind();
         }
 
+        if (!this.locked)
+        {
             pipeline.onBind(gameObject);
+        }
 
         return pipeline;
     },
 
+    /**
+     * Sets the current pipeline to be used by the `WebGLRenderer` and then locks it.
+     *
+     * Once a pipeline is locked, further calls to `PipelineManager.set` are ignored.
+     *
+     * However, another pipeline may also be locked. If this happens, the previous pipeline
+     * is flushed and the new one is locked in place.
+     *
+     * Make sure to call `PipelineManager.unlock` when you're done.
+     *
+     * This method accepts a pipeline instance as its parameter, not the name.
+     *
+     * If the pipeline isn't already the current one it will call `WebGLPipeline.bind` and then `onBind`.
+     *
+     * @method Phaser.Renderer.WebGL.PipelineManager#lock
+     * @since 3.50.0
+     *
+     * @param {Phaser.Renderer.WebGL.WebGLPipeline} pipeline - The pipeline instance to be set as current.
+     * @param {Phaser.GameObjects.GameObject} [gameObject] - The Game Object that invoked this pipeline, if any.
+     *
+     * @return {this} This Pipeline Manager.
+     */
+    lock: function (pipeline, gameObject)
+    {
+        this.flush();
+
+        this.stack.push({ pipeline: pipeline, gameObject: gameObject });
+
+        this.locked = false;
+
+        this.set(pipeline, gameObject);
+
+        this.locked = true;
+
+        return this;
+    },
+
+    /**
+     * Flushes the current pipeline, pops the previous one from the locked stack (if any)
+     * and then sets that, locking it in turn. If there aren't any other pipelines on
+     * the stack, the Pipeline Manager is fully unlocked.
+     *
+     * @method Phaser.Renderer.WebGL.PipelineManager#unlock
+     * @since 3.50.0
+     *
+     * @return {this} This Pipeline Manager.
+     */
+    unlock: function ()
+    {
+        this.flush();
+
+        this.stack.pop();
+
+        if (this.stack.length > 0)
+        {
+            var previous = this.stack[this.stack.length - 1];
+
+            this.locked = false;
+
+            this.set(previous.pipeline, previous.gameObject);
+
+            this.locked = true;
+        }
+        else
+        {
+            this.locked = false;
+        }
+
+        return this;
+    },
+
     /**
      * Sets the Multi Pipeline to be the currently bound pipeline.
      *
@@ -535,6 +630,7 @@ var PipelineManager = new Class({
         this.renderer = null;
         this.game = null;
         this.pipelines = null;
+        this.stack = null;
         this.current = null;
         this.previous = null;
     }