vtkTransformFeedback.h

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/*=========================================================================
 
  Program:   Visualization Toolkit
  Module:    vtkTransformFeedback.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 vtkTransformFeedback_h
#define vtkTransformFeedback_h
 
#include "vtkObject.h"
#include "vtkRenderingOpenGL2Module.h" // For export macro
 
#include <string> // For string
#include <vector> // For vector
 
class vtkShaderProgram;
class vtkWindow;
class vtkOpenGLBufferObject;
 
class VTKRENDERINGOPENGL2_EXPORT vtkTransformFeedback : public vtkObject
{
public:
  static vtkTransformFeedback* New();
  vtkTypeMacro(vtkTransformFeedback, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;
 
  enum VaryingRole
  {
    Vertex_ClipCoordinate_F, // Projected XYZW
    Color_RGBA_F,
    Normal_F,
    Next_Buffer // Switch to next vertex stream (varying name must be "gl_NextBuffer")
  };
 
  struct VaryingMetaData
  {
    VaryingMetaData(VaryingRole role, const std::string& id)
      : Role(role)
      , Identifier(id)
    {
    }
    VaryingRole Role;
    std::string Identifier;
  };
 
  void ClearVaryings();
 
  void AddVarying(VaryingRole role, const std::string& var);
 
  const std::vector<VaryingMetaData>& GetVaryings() const { return this->Varyings; }
 
  static size_t GetBytesPerVertex(VaryingRole role);
 
  size_t GetBytesPerVertex() const;
 
 
  vtkSetMacro(NumberOfVertices, size_t);
  void SetNumberOfVertices(int drawMode, size_t inputVerts);
  vtkGetMacro(NumberOfVertices, size_t);
 
  size_t GetBufferSize() const;
 
  void BindVaryings(vtkShaderProgram* prog);
 
  vtkOpenGLBufferObject* GetBuffer(int index);
 
  int GetBufferHandle(int index = 0);
 
 
  vtkSetMacro(PrimitiveMode, int);
  vtkGetMacro(PrimitiveMode, int);
 
  void Allocate(int nbBuffers, size_t size, unsigned int hint);
 
  void BindBuffer(bool allocateOneBuffer = true);
 
  void ReadBuffer(int index = 0);
 
 
  vtkGetMacro(BufferData, void*);
 
  void ReleaseGraphicsResources();
 
  void ReleaseBufferData(bool freeBuffer = true);
 
protected:
  vtkTransformFeedback();
  ~vtkTransformFeedback() override;
 
private:
  vtkTransformFeedback(const vtkTransformFeedback&) = delete;
  void operator=(const vtkTransformFeedback&) = delete;
 
  bool VaryingsBound;
 
  std::vector<VaryingMetaData> Varyings;
  size_t NumberOfVertices;
  int BufferMode;
 
  std::vector<vtkOpenGLBufferObject*> Buffers;
  int PrimitiveMode;
 
  unsigned char* BufferData;
};
 
//------------------------------------------------------------------------------
inline size_t vtkTransformFeedback::GetBytesPerVertex(vtkTransformFeedback::VaryingRole role)
{
  switch (role)
  {
    case Vertex_ClipCoordinate_F:
      return 4 * sizeof(float);
    case Color_RGBA_F:
      return 4 * sizeof(float);
    case Normal_F:
      return 3 * sizeof(float);
    case Next_Buffer:
      return 0;
  }
 
  vtkGenericWarningMacro("Unknown role enum value: " << role);
  return 0;
}
 
#endif // vtkTransformFeedback_h