text: //
  // Copyright 2016 Pixar
  //
  // Licensed under the Apache License, Version 2.0 (the "Apache License")
  // with the following modification; you may not use this file except in
  // compliance with the Apache License and the following modification to it:
  // Section 6. Trademarks. is deleted and replaced with:
  //
  // 6. Trademarks. This License does not grant permission to use the trade
  //    names, trademarks, service marks, or product names of the Licensor
  //    and its affiliates, except as required to comply with Section 4(c) of
  //    the License and to reproduce the content of the NOTICE file.
  //
  // You may obtain a copy of the Apache License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the Apache License with the above modification is
  // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied. See the Apache License for the specific
  // language governing permissions and limitations under the Apache License.
  //
  #ifndef HDX_RENDER_TASK_H
  #define HDX_RENDER_TASK_H
  
  #include "pxr/pxr.h"
  #include "pxr/imaging/hdx/api.h"
  #include "pxr/imaging/hdx/version.h"
  #include "pxr/imaging/hd/task.h"
  #include "pxr/imaging/hdx/renderSetupTask.h"  // for short-term compatibility.
  #include "pxr/imaging/hdSt/renderPassState.h"
  
  #include <boost/shared_ptr.hpp>
  
  PXR_NAMESPACE_OPEN_SCOPE
  
  
  class HdSceneDelegate;
  
  typedef boost::shared_ptr<class HdRenderPassState> HdRenderPassStateSharedPtr;
  typedef boost::shared_ptr<class HdRenderPass> HdRenderPassSharedPtr;
  typedef boost::shared_ptr<class HdxRenderSetupTask> HdxRenderSetupTaskSharedPtr;
  typedef std::vector<HdRenderPassSharedPtr> HdRenderPassSharedPtrVector;
  
  /// \class HdxRenderTask
  ///
  /// A task for rendering geometry to pixels.
  ///
  /// Rendering state management can be handled two ways:
  /// 1.) An application can create an HdxRenderTask and pass it the
  ///     HdxRenderTaskParams struct as "params".
  /// 2.) An application can create an HdxRenderSetupTask and an
  ///     HdxRenderTask, and pass params to the setup task. In this case
  ///     the setup task must run first.
  ///
  /// Parameter unpacking is handled by HdxRenderSetupTask; in case #1,
  /// HdxRenderTask creates a dummy setup task internally to manage the sync
  /// process.
  ///
  /// Case #2 introduces complexity; the benefit is that by changing which
  /// setup task you run before the render task, you can change the render
  /// parameters without incurring a hydra sync or rebuilding any resources.
  ///
  class HdxRenderTask : public HdSceneTask 
  {
  public:
      HDX_API
      HdxRenderTask(HdSceneDelegate* delegate, SdfPath const& id);
  
      /// Hooks for progressive rendering (delegated to renderpasses).
      bool IsConverged() const;
  
  protected:
      /// Execute render pass task
      HDX_API
      virtual void _Execute(HdTaskContext* ctx);
  
      /// Sync the render pass resources
      HDX_API
      virtual void _Sync(HdTaskContext* ctx);
  
  private:
      HdRenderPassSharedPtrVector _passes;
  
      // Optional internal render setup task, for params unpacking.
      HdxRenderSetupTaskSharedPtr _setupTask;
  
      // Setup additional state that HdStRenderPassState requires.
      // XXX: This should be moved to hdSt!
      void _SetHdStRenderPassState(HdTaskContext *ctx,
                                   HdStRenderPassState *renderPassState);
  };
  
  
  PXR_NAMESPACE_CLOSE_SCOPE
  
  #endif //HDX_RENDER_TASK_H
  