VTK
vtkUnstructuredGridPartialPreIntegration.h
Go to the documentation of this file.
1 /*=========================================================================
2 
3  Program: Visualization Toolkit
4  Module: vtkUnstructuredGridPartialPreIntegration.h
5 
6  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
7  All rights reserved.
8  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
9 
10  This software is distributed WITHOUT ANY WARRANTY; without even
11  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
12  PURPOSE. See the above copyright notice for more information.
13 
14 =========================================================================*/
15 
16 /*
17  * Copyright 2004 Sandia Corporation.
18  * Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
19  * license for use of this work by or on behalf of the
20  * U.S. Government. Redistribution and use in source and binary forms, with
21  * or without modification, are permitted provided that this Notice and any
22  * statement of authorship are reproduced on all copies.
23  */
24 
42 #ifndef vtkUnstructuredGridPartialPreIntegration_h
43 #define vtkUnstructuredGridPartialPreIntegration_h
44 
45 #include "vtkRenderingVolumeModule.h" // For export macro
47 #include "vtkMath.h" // For all the inline methods
48 
49 class vtkPartialPreIntegrationTransferFunction;
50 class vtkVolumeProperty;
51 
53 {
54 public:
58  void PrintSelf(ostream &os, vtkIndent indent) override;
59 
60  void Initialize(vtkVolume *volume, vtkDataArray *scalars) override;
61 
62  void Integrate(vtkDoubleArray *intersectionLengths,
63  vtkDataArray *nearIntersections,
64  vtkDataArray *farIntersections,
65  float color[4]) override;
66 
68 
72  static void IntegrateRay(double length,
73  double intensity_front, double attenuation_front,
74  double intensity_back, double attenuation_back,
75  float color[4]);
76  static void IntegrateRay(double length,
77  const double color_front[3],
78  double attenuation_front,
79  const double color_back[3],
80  double attenuation_back,
81  float color[4]);
83 
85 
91  static float Psi(float taufD, float taubD);
92  static float *GetPsiTable(int &size);
93  static void BuildPsiTable();
95 
96 protected:
99 
101 
102  vtkPartialPreIntegrationTransferFunction *TransferFunctions;
105 
106  enum {PSI_TABLE_SIZE = 512};
107 
108  static float PsiTable[PSI_TABLE_SIZE*PSI_TABLE_SIZE];
109  static int PsiTableBuilt;
110 
111 private:
113  void operator=(const vtkUnstructuredGridPartialPreIntegration&) = delete;
114 };
115 
117  float taubD)
118 {
119  float gammaf = taufD/(taufD+1);
120  float gammab = taubD/(taubD+1);
121  int gammafi = vtkMath::Floor(gammaf*PSI_TABLE_SIZE);
122  int gammabi = vtkMath::Floor(gammab*PSI_TABLE_SIZE);
123  return PsiTable[gammafi*PSI_TABLE_SIZE + gammabi];
124 }
125 
127 {
129  return PsiTable;
130 }
131 
133  double length,
134  double intensity_front,
135  double attenuation_front,
136  double intensity_back,
137  double attenuation_back,
138  float color[4])
139 {
140  float taufD = length*attenuation_front;
141  float taubD = length*attenuation_back;
143  float zeta = static_cast<float>(exp(-0.5*(taufD+taubD)));
144  float alpha = 1-zeta;
145 
146  float newintensity = (1-color[3])*( intensity_front*(1-Psi)
147  + intensity_back*(Psi-zeta) );
148  // Is setting the RGB values the same the right thing to do?
149  color[0] += newintensity;
150  color[1] += newintensity;
151  color[2] += newintensity;
152  color[3] += (1-color[3])*alpha;
153 }
154 
156  double length,
157  const double color_front[3],
158  double attenuation_front,
159  const double color_back[3],
160  double attenuation_back,
161  float color[4])
162 {
163  float taufD = length*attenuation_front;
164  float taubD = length*attenuation_back;
166  float zeta = static_cast<float>(exp(-0.5*(taufD+taubD)));
167  float alpha = 1-zeta;
168 
169  color[0] += (1-color[3])*(color_front[0]*(1-Psi) + color_back[0]*(Psi-zeta));
170  color[1] += (1-color[3])*(color_front[1]*(1-Psi) + color_back[1]*(Psi-zeta));
171  color[2] += (1-color[3])*(color_front[2]*(1-Psi) + color_back[2]*(Psi-zeta));
172  color[3] += (1-color[3])*alpha;
173 }
174 
175 #endif //vtkUnstructuredGridPartialPreIntegration_h
vtkUnstructuredGridVolumeRayIntegrator
a superclass for volume ray integration functions
Definition: vtkUnstructuredGridVolumeRayIntegrator.h:41
vtkMath::Floor
static int Floor(double x)
Rounds a double to the nearest integer not greater than itself.
Definition: vtkMath.h:1344
vtkUnstructuredGridVolumeRayIntegrator::Integrate
virtual void Integrate(vtkDoubleArray *intersectionLengths, vtkDataArray *nearIntersections, vtkDataArray *farIntersections, float color[4])=0
Given a set of intersections (defined by the three arrays), compute the piecewise integration of the ...
vtkX3D::alpha
Definition: vtkX3D.h:250
vtkVolume
represents a volume (data & properties) in a rendered scene
Definition: vtkVolume.h:50
vtkMath.h
vtkObject::New
static vtkObject * New()
Create an object with Debug turned off, modified time initialized to zero, and reference counting on.
vtkTimeStamp
record modification and/or execution time
Definition: vtkTimeStamp.h:35
vtkUnstructuredGridPartialPreIntegration::PsiTableBuilt
static int PsiTableBuilt
Definition: vtkUnstructuredGridPartialPreIntegration.h:109
vtkX3D::length
Definition: vtkX3D.h:393
vtkUnstructuredGridPartialPreIntegration::TransferFunctions
vtkPartialPreIntegrationTransferFunction * TransferFunctions
Definition: vtkUnstructuredGridPartialPreIntegration.h:102
vtkDataArray
abstract superclass for arrays of numeric data
Definition: vtkDataArray.h:54
vtkUnstructuredGridPartialPreIntegration::Property
vtkVolumeProperty * Property
Definition: vtkUnstructuredGridPartialPreIntegration.h:100
vtkUnstructuredGridPartialPreIntegration::PsiTable
static float PsiTable[PSI_TABLE_SIZE *PSI_TABLE_SIZE]
Definition: vtkUnstructuredGridPartialPreIntegration.h:108
vtkUnstructuredGridPartialPreIntegration::TransferFunctionsModified
vtkTimeStamp TransferFunctionsModified
Definition: vtkUnstructuredGridPartialPreIntegration.h:103
vtkUnstructuredGridPartialPreIntegration::GetPsiTable
static float * GetPsiTable(int &size)
Definition: vtkUnstructuredGridPartialPreIntegration.h:126
vtkX3D::color
Definition: vtkX3D.h:221
vtkUnstructuredGridPartialPreIntegration::PSI_TABLE_SIZE
Definition: vtkUnstructuredGridPartialPreIntegration.h:106
vtkIndent
a simple class to control print indentation
Definition: vtkIndent.h:39
vtkUnstructuredGridPartialPreIntegration::NumIndependentComponents
int NumIndependentComponents
Definition: vtkUnstructuredGridPartialPreIntegration.h:104
vtkUnstructuredGridVolumeRayIntegrator.h
vtkX3D::size
Definition: vtkX3D.h:253
vtkUnstructuredGridPartialPreIntegration
performs piecewise linear ray integration.
Definition: vtkUnstructuredGridPartialPreIntegration.h:52
vtkUnstructuredGridPartialPreIntegration::IntegrateRay
static void IntegrateRay(double length, double intensity_front, double attenuation_front, double intensity_back, double attenuation_back, float color[4])
Integrates a single ray segment.
Definition: vtkUnstructuredGridPartialPreIntegration.h:132
vtkUnstructuredGridVolumeRayIntegrator::Initialize
virtual void Initialize(vtkVolume *volume, vtkDataArray *scalars)=0
Set up the integrator with the given properties and scalars.
vtkDoubleArray
dynamic, self-adjusting array of double
Definition: vtkDoubleArray.h:41
vtkUnstructuredGridPartialPreIntegration::Psi
static float Psi(float taufD, float taubD)
Looks up Psi (as defined by Moreland and Angel, "A Fast High Accuracy Volume Renderer for Unstructure...
Definition: vtkUnstructuredGridPartialPreIntegration.h:116
vtkVolumeProperty
represents the common properties for rendering a volume.
Definition: vtkVolumeProperty.h:68
vtkUnstructuredGridVolumeRayIntegrator::PrintSelf
void PrintSelf(ostream &os, vtkIndent indent) override
Methods invoked by print to print information about the object including superclasses.