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

  Program:   Visualization Toolkit
  Module:    vtkVolumeTextureMapper.cxx
  Language:  C++
  Date:      $Date$
  Version:   $Revision$

  Copyright (c) 1993-2002 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.

=========================================================================*/
#include "vtkVolumeTextureMapper.h"

#include "vtkEncodedGradientShader.h"
#include "vtkFiniteDifferenceGradientEstimator.h"
#include "vtkImageData.h"
#include "vtkRenderer.h"
#include "vtkVolume.h"
#include "vtkVolumeProperty.h"

vtkCxxRevisionMacro(vtkVolumeTextureMapper, "1.25");

vtkVolumeTextureMapper::vtkVolumeTextureMapper()
{
  this->GradientOpacityArray    = NULL;
  this->RGBAArray               = NULL;
  this->ArraySize               = -1;
  this->SampleDistance          = 1.0;
  this->GradientEstimator       = vtkFiniteDifferenceGradientEstimator::New();
  this->GradientShader          = vtkEncodedGradientShader::New();
}

vtkVolumeTextureMapper::~vtkVolumeTextureMapper()
{
  this->SetGradientEstimator( NULL );
  this->GradientShader->Delete();
  
  if ( this->RGBAArray )
    {
    delete [] this->RGBAArray;
    }
}

void vtkVolumeTextureMapper::SetGradientEstimator( 
                                      vtkEncodedGradientEstimator *gradest )
{

  // If we are setting it to its current value, don't do anything
  if ( this->GradientEstimator == gradest )
    {
    return;
    }

  // If we already have a gradient estimator, unregister it.
  if ( this->GradientEstimator )
    {
    this->GradientEstimator->UnRegister(this);
    this->GradientEstimator = NULL;
    }

  // If we are passing in a non-NULL estimator, register it
  if ( gradest )
    {
    gradest->Register( this );
    }

  // Actually set the estimator, and consider the object Modified
  this->GradientEstimator = gradest;
  this->Modified();
}

void vtkVolumeTextureMapper::Update()
{
  if ( this->GetInput() )
    {
    this->GetInput()->UpdateInformation();
    this->GetInput()->SetUpdateExtentToWholeExtent();
    this->GetInput()->Update();
    }
}

void vtkVolumeTextureMapper::InitializeRender( vtkRenderer *ren,
                                               vtkVolume *vol )
{
  int   size, i, j, k;
  float *AArray;
  float *RGBArray;
  float *GArray;
  int   colorChannels;
  float gradientOpacityConstant;
  
  // Hang on to the render window - we'll need it to test for abort
  this->RenderWindow = ren->GetRenderWindow();

  vol->UpdateTransferFunctions( ren );

  vol->UpdateScalarOpacityforSampleSize( ren, this->SampleDistance );

  colorChannels = vol->GetProperty()->GetColorChannels();

  size = (int) vol->GetArraySize();

  if ( this->ArraySize != size )
    {
    if ( this->RGBAArray )
      {
      delete [] this->RGBAArray;
      }

    this->RGBAArray             = new unsigned char[4*size];    
    this->ArraySize = size;
    }

  this->GradientOpacityArray = vol->GetGradientOpacityArray();

  AArray = vol->GetCorrectedScalarOpacityArray();

  // Being less than 0.0 implies a transfer function, so just multiply by
  // 1.0 here since the transfer function will supply the true opacity
  // modulation value
  gradientOpacityConstant = vol->GetGradientOpacityConstant();
  if ( gradientOpacityConstant <= 0.0 )
    {
    gradientOpacityConstant = 1.0;
    }

  if ( colorChannels == 3 )
    {
    RGBArray = vol->GetRGBArray();    
    for ( i=0, j=0, k=0; i < size; i++ )
      {
      this->RGBAArray[j++] = (unsigned char) (0.5 + (RGBArray[k++]*255.0));
      this->RGBAArray[j++] = (unsigned char) (0.5 + (RGBArray[k++]*255.0));
      this->RGBAArray[j++] = (unsigned char) (0.5 + (RGBArray[k++]*255.0));
      this->RGBAArray[j++] = (unsigned char) (0.5 + AArray[i]*255.0*gradientOpacityConstant);
      }
    }
  else if ( colorChannels == 1 )
    {
    GArray = vol->GetGrayArray();
    for ( i=0, j=0; i < size; i++ )
      {
      this->RGBAArray[j++] = (unsigned char) (0.5 + (GArray[i]*255.0));
      this->RGBAArray[j++] = (unsigned char) (0.5 + (GArray[i]*255.0));
      this->RGBAArray[j++] = (unsigned char) (0.5 + (GArray[i]*255.0));
      this->RGBAArray[j++] = (unsigned char) (0.5 + AArray[i]*255.0*gradientOpacityConstant);
      }
    }

  this->Shade =  vol->GetProperty()->GetShade();  

  this->GradientEstimator->SetInput( this->GetInput() );

  if ( this->Shade )
    {
    this->GradientShader->UpdateShadingTable( ren, vol, 
                                              this->GradientEstimator );
    this->EncodedNormals = 
      this->GradientEstimator->GetEncodedNormals();

    this->RedDiffuseShadingTable = 
      this->GradientShader->GetRedDiffuseShadingTable(vol);
    this->GreenDiffuseShadingTable = 
      this->GradientShader->GetGreenDiffuseShadingTable(vol);
    this->BlueDiffuseShadingTable = 
      this->GradientShader->GetBlueDiffuseShadingTable(vol);
    
    this->RedSpecularShadingTable = 
      this->GradientShader->GetRedSpecularShadingTable(vol);
    this->GreenSpecularShadingTable = 
      this->GradientShader->GetGreenSpecularShadingTable(vol);
    this->BlueSpecularShadingTable = 
      this->GradientShader->GetBlueSpecularShadingTable(vol);    
    }
  else
    {
    this->EncodedNormals = NULL;
    this->RedDiffuseShadingTable = NULL;
    this->GreenDiffuseShadingTable = NULL;
    this->BlueDiffuseShadingTable = NULL;
    this->RedSpecularShadingTable = NULL;
    this->GreenSpecularShadingTable = NULL;
    this->BlueSpecularShadingTable = NULL;
    }

  // If we have non-constant opacity on the gradient magnitudes,
  // we need to use the gradient magnitudes to look up the opacity
  if ( vol->GetGradientOpacityConstant() == -1.0 )
    {
    this->GradientMagnitudes = 
      this->GradientEstimator->GetGradientMagnitudes();
    }
  else
    {
    this->GradientMagnitudes = NULL;
    }

  this->GetInput()->GetOrigin( this->DataOrigin );
  this->GetInput()->GetSpacing( this->DataSpacing );
  
  this->ConvertCroppingRegionPlanesToVoxels();
  
}

float vtkVolumeTextureMapper::GetGradientMagnitudeScale()
{
  if ( !this->GradientEstimator ) 
    {
    vtkErrorMacro( "You must have a gradient estimator set to get the scale" );
    return 1.0;
    }
  
  return this->GradientEstimator->GetGradientMagnitudeScale();  
}

float vtkVolumeTextureMapper::GetGradientMagnitudeBias()
{
  if ( !this->GradientEstimator ) 
    {
    vtkErrorMacro( "You must have a gradient estimator set to get the bias" );
    return 1.0;
    }
  
  return this->GradientEstimator->GetGradientMagnitudeBias();  
}

// Print the vtkVolumeTextureMapper
void vtkVolumeTextureMapper::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  if ( this->GradientEstimator )
    {
      os << indent << "Gradient Estimator: " << (this->GradientEstimator) <<
        endl;
    }
  else
    {
      os << indent << "Gradient Estimator: (none)" << endl;
    }

  if ( this->GradientShader )
    {
      os << indent << "Gradient Shader: " << (this->GradientShader) << endl;
    }
  else
    {
      os << indent << "Gradient Shader: (none)" << endl;
    }

  // this->Shade is a temporary variable that should not be printed
  // this->RenderWindow is a temporary variable that should not be printed
  // this->DataSpacing is a temporary variable that should not be printed
  // this->DataOrigin is a temporary variable that should not be printed
}
