vtkDepthPeelingPass.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#ifndef vtkDepthPeelingPass_h
#define vtkDepthPeelingPass_h

#include "vtkOpenGLRenderPass.h"
#include "vtkRenderingOpenGL2Module.h" // For export macro
#include "vtkWrappingHints.h"          // For VTK_MARSHALAUTO
#include <vector>                      // STL Header

VTK_ABI_NAMESPACE_BEGIN
class vtkOpenGLFramebufferObject;
class vtkTextureObject;
class vtkOpenGLRenderWindow;
class vtkOpenGLState;
class vtkOpenGLQuadHelper;

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

  void Render(const vtkRenderState* s) override;

  void ReleaseGraphicsResources(vtkWindow* w) override;


  vtkGetObjectMacro(TranslucentPass, vtkRenderPass);
  virtual void SetTranslucentPass(vtkRenderPass* translucentPass);


  vtkSetClampMacro(OcclusionRatio, double, 0.0, 0.5);
  vtkGetMacro(OcclusionRatio, double);


  vtkSetMacro(MaximumNumberOfPeels, int);
  vtkGetMacro(MaximumNumberOfPeels, int);

  // vtkOpenGLRenderPass virtuals:
  bool PostReplaceShaderValues(std::string& vertexShader, std::string& geometryShader,
    std::string& fragmentShader, vtkAbstractMapper* mapper, vtkProp* prop) override;
  bool SetShaderParameters(vtkShaderProgram* program, vtkAbstractMapper* mapper, vtkProp* prop,
    vtkOpenGLVertexArrayObject* VAO = nullptr) override;

  // Set Opaque Z texture, this must be set from the outer FO
  void SetOpaqueZTexture(vtkTextureObject*);

  // Set Opaque RGBA texture, this must be set from the outer FO
  void SetOpaqueRGBATexture(vtkTextureObject*);

  vtkSetMacro(DepthFormat, int);

protected:
  vtkDepthPeelingPass();

  ~vtkDepthPeelingPass() override;

  vtkRenderPass* TranslucentPass;
  vtkTimeStamp CheckTime;


  int ViewportX;
  int ViewportY;
  int ViewportWidth;
  int ViewportHeight;

  double OcclusionRatio;

  int MaximumNumberOfPeels;

  vtkOpenGLFramebufferObject* Framebuffer;

  vtkOpenGLQuadHelper* FinalBlend;
  vtkOpenGLQuadHelper* IntermediateBlend;

  // obtained from the outer FO, we read from them
  vtkTextureObject* OpaqueZTexture;
  vtkTextureObject* OpaqueRGBATexture;
  bool OwnOpaqueZTexture;
  bool OwnOpaqueRGBATexture;

  // each peel merges two color buffers into one result
  vtkTextureObject* TranslucentRGBATexture[3];
  int ColorDrawCount;
  int PeelCount;

  // each peel compares a prior Z and writes to next
  vtkTextureObject* TranslucentZTexture[2];
  int DepthFormat;

  void BlendIntermediatePeels(vtkOpenGLRenderWindow* renWin, bool);
  void BlendFinalPeel(vtkOpenGLRenderWindow* renWin);

  // useful to store
  vtkOpenGLState* State;

private:
  vtkDepthPeelingPass(const vtkDepthPeelingPass&) = delete;
  void operator=(const vtkDepthPeelingPass&) = delete;
};

VTK_ABI_NAMESPACE_END
#endif