/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkVolumeProperty.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
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=========================================================================*/

// .NAME vtkVolumeProperty - represents the common properties for rendering a volume.
//
// .SECTION Description
// vtkVolumeProperty is used to represent common properties associated 
// with volume rendering. This includes properties for determining the type
// of interpolation to use when sampling a volume, the color of a volume, 
// the scalar opacity of a volume, the gradient opacity of a volume, and the 
// shading parameters of a volume.
//
// When the scalar opacity or the gradient opacity of a volume is not set,
// then the function is defined to be a constant value of 1.0. When both a
// scalar and gradient opacity are both set simultaneously, then the opacity
// is defined to be the product of the scalar opacity and gradient opacity 
// transfer functions.

// .SECTION see also
// vtkPiecewiseFunction vtkColorTransferFunction


#ifndef __vtkVolumeProperty_h
#define __vtkVolumeProperty_h

#include "vtkObject.h"
#include "vtkPiecewiseFunction.h"
#include "vtkColorTransferFunction.h"
#include "vtkTimeStamp.h"

// Constants for InterpolationType
#define	VTK_NEAREST_INTERPOLATION	0
#define	VTK_LINEAR_INTERPOLATION	1


class VTK_EXPORT vtkVolumeProperty : public vtkObject
{
public:
  static vtkVolumeProperty *New();
  vtkTypeMacro(vtkVolumeProperty,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Get the modified time for this object (or the properties registered
  // with this object).
  unsigned long GetMTime();
  

  // Description:
  // Set the interpolation type for sampling a volume.
  vtkSetClampMacro( InterpolationType, int,
	VTK_NEAREST_INTERPOLATION, VTK_LINEAR_INTERPOLATION);
  vtkGetMacro(InterpolationType,int);
  void SetInterpolationTypeToNearest() 
	{this->SetInterpolationType(VTK_NEAREST_INTERPOLATION);};
  void SetInterpolationTypeToLinear() 
	{this->SetInterpolationType(VTK_LINEAR_INTERPOLATION);};
  char *GetInterpolationTypeAsString(void);

  // Description:
  // Set the color of a volume to a gray level transfer function. This 
  // will also set the ColorChannels to 1.
  void SetColor( vtkPiecewiseFunction *function );

  // Description:
  // Set the color of a volume to an RGB transfer function. This 
  // will also set the ColorChannels to 3.
  void SetColor( vtkColorTransferFunction *function );

  // Description:
  // Get the number of color channels in the transfer function
  vtkGetMacro(ColorChannels,int);

  // Description:
  // Get the gray transfer function.
  vtkPiecewiseFunction *GetGrayTransferFunction();

  // Description:
  // Get the RGB transfer function.
  vtkColorTransferFunction *GetRGBTransferFunction();

  // Description:
  // Set the opacity of a volume to an opacity transfer function based
  // on scalar value. 
  void SetScalarOpacity( vtkPiecewiseFunction *function );

  // Description:
  // Get the scalar opacity transfer function.
  vtkPiecewiseFunction *GetScalarOpacity();

  // Description:
  // Set the opacity of a volume to an opacity transfer function based
  // on gradient magnitude. 
  void SetGradientOpacity( vtkPiecewiseFunction *function );

  // Description:
  // Get the gradient magnitude opacity transfer function.
  vtkPiecewiseFunction *GetGradientOpacity();

  // Description:
  // Set/Get the shading of a volume. If shading is turned off, then
  // the mapper for the volume will not perform shading calculations.
  // If shading is turned on, the mapper may perform shading 
  // calculations - in some cases shading does not apply (for example,
  // in a maximum intensity projection) and therefore shading will
  // not be performed even if this flag is on. For a compositing type
  // of mapper, turning shading off is generally the same as setting
  // ambient=1, diffuse=0, specular=0.
  vtkSetMacro(Shade,int);
  vtkGetMacro(Shade,int);
  vtkBooleanMacro(Shade,int);

  // Description:
  // Set/Get the ambient lighting coefficient.
  vtkSetClampMacro(Ambient,float,0.0,1.0);
  vtkGetMacro(Ambient,float);

  // Description:
  // Set/Get the diffuse lighting coefficient.
  vtkSetClampMacro(Diffuse,float,0.0,1.0);
  vtkGetMacro(Diffuse,float);

  // Description:
  // Set/Get the specular lighting coefficient.
  vtkSetClampMacro(Specular,float,0.0,1.0);
  vtkGetMacro(Specular,float);

  // Description:
  // Set/Get the specular power.
  vtkSetClampMacro(SpecularPower,float,0.0,100.0);
  vtkGetMacro(SpecularPower,float);

  // Description:
  // Set/Get the texture coefficient. This controls how much of the
  // color comes from the color transfer function and how much comes
  // from the RGB texture, with RGBTextureCoefficient used for the texture
  // and (1 - RGBTextureCoefficient) used for the transfer function.
  vtkSetClampMacro(RGBTextureCoefficient,float,0.0,1.0);
  vtkGetMacro(RGBTextureCoefficient,float);

//BTX
  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // UpdateMTimes performes a Modified() on all TimeStamps.
  // This is used by vtkVolume when the property is set, so
  // that any other object that might have been caching
  // information for the property will rebuild.
  void UpdateMTimes(); 

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // Get the time that the gradient opacity transfer function was set
  vtkGetMacro(GradientOpacityMTime, vtkTimeStamp);

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // Get the time that the scalar opacity transfer function was set.
  vtkGetMacro(ScalarOpacityMTime, vtkTimeStamp);

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // Get the time that the RGBTransferFunction was set
  vtkGetMacro(RGBTransferFunctionMTime, vtkTimeStamp);

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // Get the time that the GrayTransferFunction was set
  vtkGetMacro(GrayTransferFunctionMTime, vtkTimeStamp);
//ETX


protected:
  vtkVolumeProperty();
  ~vtkVolumeProperty();
  vtkVolumeProperty(const vtkVolumeProperty&) {};
  void operator=(const vtkVolumeProperty&) {};

  int				InterpolationType;

  int				ColorChannels;

  vtkPiecewiseFunction		*GrayTransferFunction;
  vtkTimeStamp			GrayTransferFunctionMTime;

  vtkColorTransferFunction	*RGBTransferFunction;
  vtkTimeStamp			RGBTransferFunctionMTime;

  vtkPiecewiseFunction		*ScalarOpacity;
  vtkTimeStamp			ScalarOpacityMTime;

  vtkPiecewiseFunction		*GradientOpacity;
  vtkTimeStamp			GradientOpacityMTime;

  int				Shade;
  float				Ambient;
  float 			Diffuse;
  float				Specular;
  float				SpecularPower;
  float                         RGBTextureCoefficient;
};

// Description:
// Return the interpolation type as a descriptive character string.
inline char *vtkVolumeProperty::GetInterpolationTypeAsString(void)
{
  if( this->InterpolationType == VTK_NEAREST_INTERPOLATION )
    {
    return "Nearest Neighbor";
    }
  else if( this->InterpolationType == VTK_LINEAR_INTERPOLATION )
    {
    return "Linear";
    }
  else
    {
    return "Unknown";
    }
}

#endif
