vtkDualDepthPeelingPass.h

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

  Program:   Visualization Toolkit
  Module:    vtkDualDepthPeelingPass.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.

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

#ifndef vtkDualDepthPeelingPass_h
#define vtkDualDepthPeelingPass_h

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

class vtkFrameBufferObject2;
class vtkOpenGLBufferObject;
class vtkOpenGLVertexArrayObject;
class vtkShaderProgram;
class vtkTextureObject;

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

  virtual void Render(const vtkRenderState *s);
  virtual void ReleaseGraphicsResources(vtkWindow *w);

  // vtkOpenGLRenderPass virtuals:
  virtual bool ReplaceShaderValues(std::string &vertexShader,
                                   std::string &geometryShader,
                                   std::string &fragmentShader,
                                   vtkAbstractMapper *mapper,
                                   vtkProp *prop);
  virtual bool SetShaderParameters(vtkShaderProgram *program,
                                   vtkAbstractMapper *mapper, vtkProp *prop);
  virtual vtkMTimeType GetShaderStageMTime();

protected:

  // Name the textures used by this render pass. These are indexes into
  // this->Textures
  enum TextureName
  {
    BackTemp = 0, // RGBA8 back-to-front peeling buffer
    Back, // RGBA8 back-to-front accumulation buffer
    FrontA, // RGBA8 front-to-back accumulation buffer
    FrontB, // RGBA8 front-to-back accumulation buffer
    DepthA, // RG32F min-max depth buffer
    DepthB, // RG32F min-max depth buffer
    OpaqueDepth, // Stores the depth map from the opaque passes

    NumberOfTextures
  };

  // The stages of this multipass render pass:
  enum ShaderStage
  {
    InitializingDepth,
    Peeling,
    AlphaBlending,

    NumberOfPasses,
    Inactive = -1,
  };

  vtkDualDepthPeelingPass();
  ~vtkDualDepthPeelingPass();

  void SetCurrentStage(ShaderStage stage);

  void FreeGLObjects();

  void RenderTranslucentPass();

  void Initialize(const vtkRenderState *s);


  void InitColorTexture(vtkTextureObject *tex, const vtkRenderState *s);
  void InitDepthTexture(vtkTextureObject *tex, const vtkRenderState *s);
  void InitOpaqueDepthTexture(vtkTextureObject *tex, const vtkRenderState *s);
  void InitFramebuffer(const vtkRenderState *s);


  void Prepare();
  void InitializeOcclusionQuery();
  void CopyOpaqueDepthBuffer();
  void InitializeDepth();

  bool PeelingDone();

  void Peel();

  void InitializeTargets();

  void PeelRender();

  void BlendBackBuffer();
  void StartOcclusionQuery();
  void EndOcclusionQuery();

  void SwapTargets();

  void Finalize();

  void AlphaBlendRender();

  void BlendFinalImage();
  void DeleteOcclusionQueryId();

  const vtkRenderState *RenderState;

  vtkShaderProgram *CopyDepthProgram;
  vtkOpenGLVertexArrayObject *CopyDepthVAO;
  vtkOpenGLBufferObject *CopyDepthVBO;

  vtkShaderProgram *BackBlendProgram;
  vtkOpenGLVertexArrayObject *BackBlendVAO;
  vtkOpenGLBufferObject *BackBlendVBO;

  vtkShaderProgram *BlendProgram;
  vtkOpenGLVertexArrayObject *BlendVAO;
  vtkOpenGLBufferObject *BlendVBO;

  vtkFrameBufferObject2 *Framebuffer;
  vtkTextureObject *Textures[NumberOfTextures];

  TextureName FrontSource; // The current front source buffer
  TextureName FrontDestination; // The current front destination buffer
  TextureName DepthSource; // The current depth source buffer
  TextureName DepthDestination; // The current depth destination buffer

  ShaderStage CurrentStage;
  vtkTimeStamp CurrentStageTimeStamp;

  int CurrentPeel;
  unsigned int OcclusionQueryId;
  unsigned int WrittenPixels;
  unsigned int OcclusionThreshold;

  int RenderCount; // Debug info, counts number of geometry passes.

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

#endif // vtkDualDepthPeelingPass_h