vtkUnstructuredGridPreIntegration.h

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/*=========================================================================
 
  Program:   Visualization Toolkit
  Module:    vtkUnstructuredGridPreIntegration.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.
 */
 
#ifndef vtkUnstructuredGridPreIntegration_h
#define vtkUnstructuredGridPreIntegration_h
 
#include "vtkRenderingVolumeModule.h" // For export macro
#include "vtkUnstructuredGridVolumeRayIntegrator.h"
 
class vtkVolumeProperty;
 
class VTKRENDERINGVOLUME_EXPORT vtkUnstructuredGridPreIntegration
  : public vtkUnstructuredGridVolumeRayIntegrator
{
public:
  vtkTypeMacro(vtkUnstructuredGridPreIntegration, vtkUnstructuredGridVolumeRayIntegrator);
  static vtkUnstructuredGridPreIntegration* New();
  void PrintSelf(ostream& os, vtkIndent indent) override;
 
  void Initialize(vtkVolume* volume, vtkDataArray* scalars) override;
 
  void Integrate(vtkDoubleArray* intersectionLengths, vtkDataArray* nearIntersections,
    vtkDataArray* farIntersections, float color[4]) override;
 
 
  vtkGetObjectMacro(Integrator, vtkUnstructuredGridVolumeRayIntegrator);
  virtual void SetIntegrator(vtkUnstructuredGridVolumeRayIntegrator*);
 
 
  vtkSetMacro(IntegrationTableScalarResolution, int);
  vtkGetMacro(IntegrationTableScalarResolution, int);
  vtkSetMacro(IntegrationTableLengthResolution, int);
  vtkGetMacro(IntegrationTableLengthResolution, int);
 
 
  virtual double GetIntegrationTableScalarShift(int component = 0);
  virtual double GetIntegrationTableScalarScale(int component = 0);
  virtual double GetIntegrationTableLengthScale();
 
 
  vtkGetMacro(IncrementalPreIntegration, vtkTypeBool);
  vtkSetMacro(IncrementalPreIntegration, vtkTypeBool);
  vtkBooleanMacro(IncrementalPreIntegration, vtkTypeBool);
 
  virtual float* GetPreIntegrationTable(int component = 0);
 
  float* GetTableEntry(double scalar_front, double scalar_back, double length, int component = 0);
 
  float* GetIndexedTableEntry(
    int scalar_front_index, int scalar_back_index, int length_index, int component = 0);
 
protected:
  vtkUnstructuredGridPreIntegration();
  ~vtkUnstructuredGridPreIntegration() override;
 
  vtkUnstructuredGridVolumeRayIntegrator* Integrator;
 
  vtkVolume* Volume;
  vtkVolumeProperty* Property;
  double MaxLength;
 
  int NumComponents;
  float** IntegrationTable;
  double* IntegrationTableScalarShift;
  double* IntegrationTableScalarScale;
  double IntegrationTableLengthScale;
  vtkTimeStamp IntegrationTableBuilt;
 
  int IntegrationTableScalarResolution;
  int IntegrationTableLengthResolution;
 
  vtkTypeBool IncrementalPreIntegration;
 
  virtual void BuildPreIntegrationTables(vtkDataArray* scalars);
 
private:
  vtkUnstructuredGridPreIntegration(const vtkUnstructuredGridPreIntegration&) = delete;
  void operator=(const vtkUnstructuredGridPreIntegration&) = delete;
};
 
inline float* vtkUnstructuredGridPreIntegration::GetIndexedTableEntry(
  int scalar_front_index, int scalar_back_index, int length_index, int component)
{
  // Snap entries to bounds.  I don't really want to spend cycles doing
  // this, but I've had the ray caster give me values that are noticeably
  // out of bounds.
  if (scalar_front_index < 0)
    scalar_front_index = 0;
  if (scalar_front_index >= this->IntegrationTableScalarResolution)
    scalar_front_index = this->IntegrationTableScalarResolution - 1;
  if (scalar_back_index < 0)
    scalar_back_index = 0;
  if (scalar_back_index >= this->IntegrationTableScalarResolution)
    scalar_back_index = this->IntegrationTableScalarResolution - 1;
  if (length_index < 0)
    length_index = 0;
  if (length_index >= this->IntegrationTableLengthResolution)
    length_index = this->IntegrationTableLengthResolution - 1;
 
  return (this->IntegrationTable[component] +
    4 *
      (((length_index * this->IntegrationTableScalarResolution + scalar_back_index) *
         this->IntegrationTableScalarResolution) +
        scalar_front_index));
}
 
inline float* vtkUnstructuredGridPreIntegration::GetTableEntry(
  double scalar_front, double scalar_back, double length, int component)
{
  int sfi = static_cast<int>(scalar_front * this->IntegrationTableScalarScale[component] +
    this->IntegrationTableScalarShift[component] + 0.5);
  int sbi = static_cast<int>(scalar_back * this->IntegrationTableScalarScale[component] +
    this->IntegrationTableScalarShift[component] + 0.5);
  int li = static_cast<int>(length * this->IntegrationTableLengthScale + 0.5);
  return this->GetIndexedTableEntry(sfi, sbi, li, component);
}
 
#endif // vtkUnstructuredGridPreIntegration_h