/usr/include/vtk-6.3/vtkUnstructuredGridPartialPreIntegration.h is in libvtk6-dev 6.3.0+dfsg1-11build1.
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Program: Visualization Toolkit
Module: vtkUnstructuredGridPartialPreIntegration.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.
=========================================================================*/
/*
* Copyright 2004 Sandia Corporation.
* Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
* license for use of this work by or on behalf of the
* U.S. Government. Redistribution and use in source and binary forms, with
* or without modification, are permitted provided that this Notice and any
* statement of authorship are reproduced on all copies.
*/
// .NAME vtkUnstructuredGridPartialPreIntegration - performs piecewise linear ray integration.
//
// .SECTION Description
//
// vtkUnstructuredGridPartialPreIntegration performs piecewise linear ray
// integration. This will give the same results as
// vtkUnstructuredGridLinearRayIntegration (with potentially a error due to
// table lookup quantization), but should be notably faster. The algorithm
// used is given by Moreland and Angel, "A Fast High Accuracy Volume
// Renderer for Unstructured Data."
//
// This class is thread safe only after the first instance is created.
//
#ifndef vtkUnstructuredGridPartialPreIntegration_h
#define vtkUnstructuredGridPartialPreIntegration_h
#include "vtkRenderingVolumeModule.h" // For export macro
#include "vtkUnstructuredGridVolumeRayIntegrator.h"
#include "vtkMath.h" // For all the inline methods
class vtkPartialPreIntegrationTransferFunction;
class vtkVolumeProperty;
class VTKRENDERINGVOLUME_EXPORT vtkUnstructuredGridPartialPreIntegration : public vtkUnstructuredGridVolumeRayIntegrator
{
public:
vtkTypeMacro(vtkUnstructuredGridPartialPreIntegration,
vtkUnstructuredGridVolumeRayIntegrator);
static vtkUnstructuredGridPartialPreIntegration *New();
virtual void PrintSelf(ostream &os, vtkIndent indent);
virtual void Initialize(vtkVolume *volume, vtkDataArray *scalars);
virtual void Integrate(vtkDoubleArray *intersectionLengths,
vtkDataArray *nearIntersections,
vtkDataArray *farIntersections,
float color[4]);
// Description:
// Integrates a single ray segment. \c color is blended with the result
// (with \c color in front). The result is written back into \c color.
static void IntegrateRay(double length,
double intensity_front, double attenuation_front,
double intensity_back, double attenuation_back,
float color[4]);
static void IntegrateRay(double length,
const double color_front[3],
double attenuation_front,
const double color_back[3],
double attenuation_back,
float color[4]);
// Description:
// Looks up Psi (as defined by Moreland and Angel, "A Fast High Accuracy
// Volume Renderer for Unstructured Data") in a table. The table must be
// created first, which happens on the first instantiation of this class
// or when BuildPsiTable is first called.
static float Psi(float taufD, float taubD);
static float *GetPsiTable(int &size);
static void BuildPsiTable();
protected:
vtkUnstructuredGridPartialPreIntegration();
~vtkUnstructuredGridPartialPreIntegration();
vtkVolumeProperty *Property;
vtkPartialPreIntegrationTransferFunction *TransferFunctions;
vtkTimeStamp TransferFunctionsModified;
int NumIndependentComponents;
//BTX
enum {PSI_TABLE_SIZE = 512};
//ETX
static float PsiTable[PSI_TABLE_SIZE*PSI_TABLE_SIZE];
static int PsiTableBuilt;
private:
vtkUnstructuredGridPartialPreIntegration(const vtkUnstructuredGridPartialPreIntegration&); // Not implemented.
void operator=(const vtkUnstructuredGridPartialPreIntegration&); // Not implemented.
};
inline float vtkUnstructuredGridPartialPreIntegration::Psi(float taufD,
float taubD)
{
float gammaf = taufD/(taufD+1);
float gammab = taubD/(taubD+1);
int gammafi = vtkMath::Floor(gammaf*PSI_TABLE_SIZE);
int gammabi = vtkMath::Floor(gammab*PSI_TABLE_SIZE);
return PsiTable[gammafi*PSI_TABLE_SIZE + gammabi];
}
inline float *vtkUnstructuredGridPartialPreIntegration::GetPsiTable(int &size)
{
size = PSI_TABLE_SIZE;
return PsiTable;
}
inline void vtkUnstructuredGridPartialPreIntegration::IntegrateRay(
double length,
double intensity_front,
double attenuation_front,
double intensity_back,
double attenuation_back,
float color[4])
{
float taufD = length*attenuation_front;
float taubD = length*attenuation_back;
float Psi = vtkUnstructuredGridPartialPreIntegration::Psi(taufD, taubD);
float zeta = static_cast<float>(exp(-0.5*(taufD+taubD)));
float alpha = 1-zeta;
float newintensity = (1-color[3])*( intensity_front*(1-Psi)
+ intensity_back*(Psi-zeta) );
// Is setting the RGB values the same the right thing to do?
color[0] += newintensity;
color[1] += newintensity;
color[2] += newintensity;
color[3] += (1-color[3])*alpha;
}
inline void vtkUnstructuredGridPartialPreIntegration::IntegrateRay(
double length,
const double color_front[3],
double attenuation_front,
const double color_back[3],
double attenuation_back,
float color[4])
{
float taufD = length*attenuation_front;
float taubD = length*attenuation_back;
float Psi = vtkUnstructuredGridPartialPreIntegration::Psi(taufD, taubD);
float zeta = static_cast<float>(exp(-0.5*(taufD+taubD)));
float alpha = 1-zeta;
color[0] += (1-color[3])*(color_front[0]*(1-Psi) + color_back[0]*(Psi-zeta));
color[1] += (1-color[3])*(color_front[1]*(1-Psi) + color_back[1]*(Psi-zeta));
color[2] += (1-color[3])*(color_front[2]*(1-Psi) + color_back[2]*(Psi-zeta));
color[3] += (1-color[3])*alpha;
}
#endif //vtkUnstructuredGridPartialPreIntegration_h
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