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C++

/*=========================================================================
Program: Visualization Toolkit
Module: vtkEncodedGradientShader.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.
=========================================================================*/
/**
* @class vtkEncodedGradientShader
* @brief Compute shading tables for encoded normals.
*
*
* vtkEncodedGradientShader computes shading tables for encoded normals
* that indicates the amount of diffuse and specular illumination that is
* received from all light sources at a surface location with that normal.
* For diffuse illumination this is accurate, but for specular illumination
* it is approximate for perspective projections since the center view
* direction is always used as the view direction. Since the shading table is
* dependent on the volume (for the transformation that must be applied to
* the normals to put them into world coordinates) there is a shading table
* per volume. This is necessary because multiple volumes can share a
* volume mapper.
*/
#ifndef vtkEncodedGradientShader_h
#define vtkEncodedGradientShader_h
#include "vtkObject.h"
#include "vtkRenderingVolumeModule.h" // For export macro
class vtkVolume;
class vtkRenderer;
class vtkEncodedGradientEstimator;
#define VTK_MAX_SHADING_TABLES 100
class VTKRENDERINGVOLUME_EXPORT vtkEncodedGradientShader : public vtkObject
{
public:
static vtkEncodedGradientShader* New();
vtkTypeMacro(vtkEncodedGradientShader, vtkObject);
/**
* Print the vtkEncodedGradientShader
*/
void PrintSelf(ostream& os, vtkIndent indent) override;
//@{
/**
* Set / Get the intensity diffuse / specular light used for the
* zero normals.
*/
vtkSetClampMacro(ZeroNormalDiffuseIntensity, float, 0.0f, 1.0f);
vtkGetMacro(ZeroNormalDiffuseIntensity, float);
vtkSetClampMacro(ZeroNormalSpecularIntensity, float, 0.0f, 1.0f);
vtkGetMacro(ZeroNormalSpecularIntensity, float);
//@}
/**
* Cause the shading table to be updated
*/
void UpdateShadingTable(vtkRenderer* ren, vtkVolume* vol, vtkEncodedGradientEstimator* gradest);
//@{
/**
* Get the red/green/blue shading table.
*/
float* GetRedDiffuseShadingTable(vtkVolume* vol);
float* GetGreenDiffuseShadingTable(vtkVolume* vol);
float* GetBlueDiffuseShadingTable(vtkVolume* vol);
float* GetRedSpecularShadingTable(vtkVolume* vol);
float* GetGreenSpecularShadingTable(vtkVolume* vol);
float* GetBlueSpecularShadingTable(vtkVolume* vol);
//@}
//@{
/**
* Set the active component for shading. This component's
* ambient / diffuse / specular / specular power values will
* be used to create the shading table. The default is 1.0
*/
vtkSetClampMacro(ActiveComponent, int, 0, 3);
vtkGetMacro(ActiveComponent, int);
//@}
protected:
vtkEncodedGradientShader();
~vtkEncodedGradientShader() override;
/**
* Build a shading table for a light with the specified direction,
* and color for an object of the specified material properties.
* material[0] = ambient, material[1] = diffuse, material[2] = specular
* and material[3] = specular exponent. If the ambient flag is 1,
* then ambient illumination is added. If not, then this means we
* are calculating the "other side" of two sided lighting, so no
* ambient intensity is added in. If the update flag is 0,
* the shading table is overwritten with these new shading values.
* If the updateFlag is 1, then the computed light contribution is
* added to the current shading table values. There is one shading
* table per volume, and the index value indicated which index table
* should be used. It is computed in the UpdateShadingTable method.
*/
void BuildShadingTable(int index, double lightDirection[3], double lightAmbientColor[3],
double lightDiffuseColor[3], double lightSpecularColor[3], double lightIntensity,
double viewDirection[3], double material[4], int twoSided, vtkEncodedGradientEstimator* gradest,
int updateFlag);
// The six shading tables (r diffuse ,g diffuse ,b diffuse,
// r specular, g specular, b specular ) - with an entry for each
// encoded normal plus one entry at the end for the zero normal
// There is one shading table per volume listed in the ShadingTableVolume
// array. A null entry indicates an available slot.
float* ShadingTable[VTK_MAX_SHADING_TABLES][6];
vtkVolume* ShadingTableVolume[VTK_MAX_SHADING_TABLES];
int ShadingTableSize[VTK_MAX_SHADING_TABLES];
int ActiveComponent;
// The intensity of light used for the zero normals, since it
// can not be computed from the normal angles. Defaults to 0.0.
float ZeroNormalDiffuseIntensity;
float ZeroNormalSpecularIntensity;
private:
vtkEncodedGradientShader(const vtkEncodedGradientShader&) = delete;
void operator=(const vtkEncodedGradientShader&) = delete;
};
#endif