/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkSSAAPass.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkSSAAPass - Implement Screen Space Anti Aliasing pass.
// .SECTION Description
// Render to a larger image and then sample down
//
// This pass expects an initialized depth buffer and color buffer.
// Initialized buffers means they have been cleared with farest z-value and
// background color/gradient/transparent color.
//
// The delegate is used once.
//
// Its delegate is usually set to a vtkCameraPass or to a post-processing pass.
//
// .SECTION Implementation
// As the filter is separable, it first blurs the image horizontally and then
// vertically. This reduces the number of texture samples taken.

// .SECTION See Also
// vtkRenderPass

#ifndef vtkSSAAPass_h
#define vtkSSAAPass_h

#include "vtkRenderingOpenGL2Module.h" // For export macro
#include "vtkRenderPass.h"

class vtkFrameBufferObject;
class vtkOpenGLHelper;
class vtkTextureObject;

class VTKRENDERINGOPENGL2_EXPORT vtkSSAAPass : public vtkRenderPass
{
public:
  static vtkSSAAPass *New();
  vtkTypeMacro(vtkSSAAPass,vtkRenderPass);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Perform rendering according to a render state \p s.
  // \pre s_exists: s!=0
  virtual void Render(const vtkRenderState *s);

  // Description:
  // Release graphics resources and ask components to release their own
  // resources.
  // \pre w_exists: w!=0
  void ReleaseGraphicsResources(vtkWindow *w);

  // Description:
  // Delegate for rendering the image to be processed.
  // If it is NULL, nothing will be rendered and a warning will be emitted.
  // It is usually set to a vtkCameraPass or to a post-processing pass.
  // Initial value is a NULL pointer.
  vtkGetObjectMacro(DelegatePass,vtkRenderPass);
  virtual void SetDelegatePass(vtkRenderPass *delegatePass);

 protected:
  // Description:
  // Default constructor. DelegatePass is set to NULL.
  vtkSSAAPass();

  // Description:
  // Destructor.
  virtual ~vtkSSAAPass();

  // Description:
  // Graphics resources.
  vtkFrameBufferObject *FrameBufferObject;
  vtkTextureObject *Pass1; // render target for the scene
  vtkTextureObject *Pass2; // render target for the horizontal pass

  // Structures for the various cell types we render.
  vtkOpenGLHelper *SSAAProgram;

  bool Supported;
  bool SupportProbed;

  vtkRenderPass *DelegatePass;

 private:
  vtkSSAAPass(const vtkSSAAPass&) VTK_DELETE_FUNCTION;
  void operator=(const vtkSSAAPass&) VTK_DELETE_FUNCTION;
};

#endif
