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

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


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
#include <math.h>

#include "vtkVolumeRayCastMIPFunction.h"
#include "vtkVolume.h"
#include "vtkObjectFactory.h"



//------------------------------------------------------------------------------
vtkVolumeRayCastMIPFunction* vtkVolumeRayCastMIPFunction::New()
{
  // First try to create the object from the vtkObjectFactory
  vtkObject* ret = vtkObjectFactory::CreateInstance("vtkVolumeRayCastMIPFunction");
  if(ret)
    {
    return (vtkVolumeRayCastMIPFunction*)ret;
    }
  // If the factory was unable to create the object, then create it here.
  return new vtkVolumeRayCastMIPFunction;
}




#define vtkRoundFuncMacro(x)   (int)((x)+0.5)

// Macro for trilinear interpolation - do four linear interpolations on
// edges, two linear interpolations between pairs of edges, then a final
// interpolation between faces
#define vtkTrilinFuncMacro(v,x,y,z,a,b,c,d,e,f,g,h)         \
        t00 =   a + (x)*(b-a);      \
        t01 =   c + (x)*(d-c);      \
        t10 =   e + (x)*(f-e);      \
        t11 =   g + (x)*(h-g);      \
        t0  = t00 + (y)*(t01-t00);  \
        t1  = t10 + (y)*(t11-t10);  \
        v   =  t0 + (z)*(t1-t0);

// This is the templated function that actually casts a ray and computes
// the maximum value.  It is valid for unsigned char and unsigned short,
template <class T>
static void CastMaxScalarValueRay( T *data_ptr,
				   VTKRayCastRayInfo *rayInfo,
				   VTKRayCastVolumeInfo *volumeInfo )
{
  float     triMax, triValue;
  int       max;
  float     max_opacity;
  int       loop;
  int       xinc, yinc, zinc;
  int       voxel[3], prev_voxel[3];
  float     ray_position[3];
  T         A, B, C, D, E, F, G, H;
  float     t00, t01, t10, t11, t0, t1;
  int       Binc, Cinc, Dinc, Einc, Finc, Ginc, Hinc;
  float     xoff, yoff, zoff;
  T         *dptr;
  int       num_steps;
  float     *ray_increment;
  float     *grayArray, *RGBArray;
  float     *scalarArray;
  T         nnValue, nnMax;

  num_steps = rayInfo->NumberOfStepsToTake;
  ray_increment = rayInfo->TransformedIncrement;

  grayArray = volumeInfo->Volume->GetGrayArray();
  RGBArray = volumeInfo->Volume->GetRGBArray();
  scalarArray = volumeInfo->Volume->GetScalarOpacityArray();

  xinc = volumeInfo->DataIncrement[0];
  yinc = volumeInfo->DataIncrement[1];
  zinc = volumeInfo->DataIncrement[2];

  // Initialize the ray position and voxel location
  memcpy( ray_position, rayInfo->TransformedStart, 3*sizeof(float) );

  // If we have nearest neighbor interpolation
  if ( volumeInfo->InterpolationType == VTK_NEAREST_INTERPOLATION )
    {
    voxel[0] = vtkRoundFuncMacro( ray_position[0] );
    voxel[1] = vtkRoundFuncMacro( ray_position[1] );
    voxel[2] = vtkRoundFuncMacro( ray_position[2] );

    // Access the value at this voxel location
    nnMax = *(data_ptr + voxel[2] * zinc +
	      voxel[1] * yinc + voxel[0] );

    // Increment our position and compute our voxel location
    ray_position[0] += ray_increment[0];
    ray_position[1] += ray_increment[1];
    ray_position[2] += ray_increment[2];
    voxel[0] = vtkRoundFuncMacro( ray_position[0] );
    voxel[1] = vtkRoundFuncMacro( ray_position[1] );
    voxel[2] = vtkRoundFuncMacro( ray_position[2] );

    // For each step along the ray
    for ( loop = 1; loop < num_steps; loop++ )
      {	    
      // Access the value at this voxel location
      nnValue = *(data_ptr + voxel[2] * zinc +
		  voxel[1] * yinc + voxel[0] );

      // If this is greater than the max, this is the new max.
      if ( nnValue > nnMax )
	{
	nnMax = nnValue;
	}
      
      // Increment our position and compute our voxel location
      ray_position[0] += ray_increment[0];
      ray_position[1] += ray_increment[1];
      ray_position[2] += ray_increment[2];
      voxel[0] = vtkRoundFuncMacro( ray_position[0] );
      voxel[1] = vtkRoundFuncMacro( ray_position[1] );
      voxel[2] = vtkRoundFuncMacro( ray_position[2] );
      }
    max = (int)nnMax;
    }
  // We are using trilinear interpolation
  else if ( volumeInfo->InterpolationType == VTK_LINEAR_INTERPOLATION )
    {
    voxel[0] = (int)( ray_position[0] );
    voxel[1] = (int)( ray_position[1] );
    voxel[2] = (int)( ray_position[2] );

    // Compute the increments to get to the other 7 voxel vertices from A
    Binc = xinc;
    Cinc = yinc;
    Dinc = xinc + yinc;
    Einc = zinc;
    Finc = zinc + xinc;
    Ginc = zinc + yinc;
    Hinc = zinc + xinc + yinc;
  
    // Set values for the first pass through the loop
    dptr = data_ptr + voxel[2] * zinc + voxel[1] * yinc + voxel[0];
    A = *(dptr);
    B = *(dptr + Binc);
    C = *(dptr + Cinc);
    D = *(dptr + Dinc);
    E = *(dptr + Einc);
    F = *(dptr + Finc);
    G = *(dptr + Ginc);
    H = *(dptr + Hinc);

    // Compute our offset in the voxel, and use that to trilinearly
    // interpolate a value
    xoff = ray_position[0] - (float) voxel[0];
    yoff = ray_position[1] - (float) voxel[1];
    zoff = ray_position[2] - (float) voxel[2];
    vtkTrilinFuncMacro( triMax, xoff, yoff, zoff, A, B, C, D, E, F, G, H );

    // Keep the voxel location so that we know when we've moved into a
    // new voxel
    memcpy( prev_voxel, voxel, 3*sizeof(int) );

    // Increment our position and compute our voxel location
    ray_position[0] += ray_increment[0];
    ray_position[1] += ray_increment[1];
    ray_position[2] += ray_increment[2];      
    voxel[0] = (int)( ray_position[0] );
    voxel[1] = (int)( ray_position[1] );
    voxel[2] = (int)( ray_position[2] );

    // For each step along the ray
    for ( loop = 1; loop < num_steps; loop++ )
      {	    
      // Have we moved into a new voxel? If so we need to recompute A-H
      if ( prev_voxel[0] != voxel[0] ||
	   prev_voxel[1] != voxel[1] ||
	   prev_voxel[2] != voxel[2] )
	{
	dptr = data_ptr + voxel[2] * zinc + voxel[1] * yinc + voxel[0];

	A = *(dptr);
	B = *(dptr + Binc);
	C = *(dptr + Cinc);
	D = *(dptr + Dinc);
	E = *(dptr + Einc);
	F = *(dptr + Finc);
	G = *(dptr + Ginc);
	H = *(dptr + Hinc);

	memcpy( prev_voxel, voxel, 3*sizeof(float) );
	}

      // Compute our offset in the voxel, and use that to trilinearly
      // interpolate a value
      xoff = ray_position[0] - (float) voxel[0];
      yoff = ray_position[1] - (float) voxel[1];
      zoff = ray_position[2] - (float) voxel[2];
      vtkTrilinFuncMacro( triValue, xoff, yoff, zoff, A, B, C, D, E, F, G, H );

      // If this value is greater than max, it is the new max
      if ( triValue > triMax )
	{
	triMax = triValue;
	}

      // Increment our position and compute our voxel location
      ray_position[0] += ray_increment[0];
      ray_position[1] += ray_increment[1];
      ray_position[2] += ray_increment[2];      
      voxel[0] = (int)( ray_position[0] );
      voxel[1] = (int)( ray_position[1] );
      voxel[2] = (int)( ray_position[2] );
      }
    max = (int)triMax;
    }

  if ( max < 0 ) 
    {
    max = 0;
    }
  else if ( max > volumeInfo->Volume->GetArraySize() - 1 )
    {
    max = (int)(volumeInfo->Volume->GetArraySize() - 1);
    }

  max_opacity = scalarArray[max];
  
  // Set the return pixel value.  
  if( volumeInfo->ColorChannels == 1 )
    {
    rayInfo->Color[0] = max_opacity * grayArray[max];
    rayInfo->Color[1] = max_opacity * grayArray[max];
    rayInfo->Color[2] = max_opacity * grayArray[max];
    rayInfo->Color[3] = max_opacity;
    }
  else if ( volumeInfo->ColorChannels == 3 )
    {
    rayInfo->Color[0] = max_opacity * RGBArray[max*3];
    rayInfo->Color[1] = max_opacity * RGBArray[max*3+1];
    rayInfo->Color[2] = max_opacity * RGBArray[max*3+2];
    rayInfo->Color[3] = max_opacity;
    }

  rayInfo->Depth = 
    ( max_opacity > 0 )?(volumeInfo->CenterDistance):(VTK_LARGE_FLOAT);

  rayInfo->NumberOfStepsTaken = num_steps;
}


// This is the templated function that actually casts a ray and computes
// the maximum value.  It is valid for unsigned char and unsigned short,
template <class T>
static void CastMaxOpacityRay( T *data_ptr,
			       VTKRayCastRayInfo *rayInfo,
			       VTKRayCastVolumeInfo *volumeInfo )
{
  float     max;
  float     opacity;
  float     value;
  int       max_value;
  int       loop;
  int       xinc, yinc, zinc;
  int       voxel[3];
  int       prev_voxel[3];
  float     ray_position[3];
  T         A, B, C, D, E, F, G, H;
  float     t00, t01, t10, t11, t0, t1;
  int       Binc, Cinc, Dinc, Einc, Finc, Ginc, Hinc;
  float     xoff, yoff, zoff;
  T         *dptr;
  int       steps_this_ray = 0;
  float     *SOTF;
  int       num_steps;
  float     *ray_start, *ray_increment;
  float     *grayArray, *RGBArray;

  num_steps = rayInfo->NumberOfStepsToTake;
  ray_start = rayInfo->TransformedStart;
  ray_increment = rayInfo->TransformedIncrement;


  SOTF = volumeInfo->Volume->GetScalarOpacityArray();
  grayArray = volumeInfo->Volume->GetGrayArray();
  RGBArray = volumeInfo->Volume->GetRGBArray();

  // Set the max value.  This will not always be correct and should be fixed
  max = -999999.0;

  xinc = volumeInfo->DataIncrement[0];
  yinc = volumeInfo->DataIncrement[1];
  zinc = volumeInfo->DataIncrement[2];

  // Initialize the ray position and voxel location
  ray_position[0] = ray_start[0];
  ray_position[1] = ray_start[1];
  ray_position[2] = ray_start[2];

  // If we have nearest neighbor interpolation
  if ( volumeInfo->InterpolationType == VTK_NEAREST_INTERPOLATION )
    {

    voxel[0] = vtkRoundFuncMacro( ray_position[0] );
    voxel[1] = vtkRoundFuncMacro( ray_position[1] );
    voxel[2] = vtkRoundFuncMacro( ray_position[2] );

    // For each step along the ray
    for ( loop = 0; loop < num_steps; loop++ )
      {	    
      // We've taken another step
      steps_this_ray++;
      
      // Access the value at this voxel location
      value = *(data_ptr + voxel[2] * zinc +
		voxel[1] * yinc + voxel[0] );

      if ( value < 0 ) 
	{
	value = 0;
	}
      else if ( value > volumeInfo->Volume->GetArraySize() - 1 )
	{
	value = volumeInfo->Volume->GetArraySize() - 1;
	}

      opacity = SOTF[(int)value];
 
      // If this is greater than the max, this is the new max.
      if ( opacity > max ) 
	{
	max = opacity;
	max_value = (int) value;
	}

      // Increment our position and compute our voxel location
      ray_position[0] += ray_increment[0];
      ray_position[1] += ray_increment[1];
      ray_position[2] += ray_increment[2];
      voxel[0] = vtkRoundFuncMacro( ray_position[0] );
      voxel[1] = vtkRoundFuncMacro( ray_position[1] );
      voxel[2] = vtkRoundFuncMacro( ray_position[2] );
      }
    }
  // We are using trilinear interpolation
  else if ( volumeInfo->InterpolationType == VTK_LINEAR_INTERPOLATION )
    {
    voxel[0] = (int)( ray_position[0] );
    voxel[1] = (int)( ray_position[1] );
    voxel[2] = (int)( ray_position[2] );

    // Compute the increments to get to the other 7 voxel vertices from A
    Binc = xinc;
    Cinc = yinc;
    Dinc = xinc + yinc;
    Einc = zinc;
    Finc = zinc + xinc;
    Ginc = zinc + yinc;
    Hinc = zinc + xinc + yinc;
  
    // Set values for the first pass through the loop
    dptr = data_ptr + voxel[2] * zinc + voxel[1] * yinc + voxel[0];
    A = *(dptr);
    B = *(dptr + Binc);
    C = *(dptr + Cinc);
    D = *(dptr + Dinc);
    E = *(dptr + Einc);
    F = *(dptr + Finc);
    G = *(dptr + Ginc);
    H = *(dptr + Hinc);

    // Keep the voxel location so that we know when we've moved into a
    // new voxel
    prev_voxel[0] = voxel[0];
    prev_voxel[1] = voxel[1];
    prev_voxel[2] = voxel[2];

    // For each step along the ray
    for ( loop = 0; loop < num_steps; loop++ )
      {	    
      // We've taken another step
      steps_this_ray++;

      // Have we moved into a new voxel? If so we need to recompute A-H
      if ( prev_voxel[0] != voxel[0] ||
	   prev_voxel[1] != voxel[1] ||
	   prev_voxel[2] != voxel[2] )
	{
	dptr = data_ptr + voxel[2] * zinc + voxel[1] * yinc + voxel[0];

	A = *(dptr);
	B = *(dptr + Binc);
	C = *(dptr + Cinc);
	D = *(dptr + Dinc);
	E = *(dptr + Einc);
	F = *(dptr + Finc);
	G = *(dptr + Ginc);
	H = *(dptr + Hinc);

	prev_voxel[0] = voxel[0];
	prev_voxel[1] = voxel[1];
	prev_voxel[2] = voxel[2];
	}

      // Compute our offset in the voxel, and use that to trilinearly
      // interpolate a value
      xoff = ray_position[0] - (float) voxel[0];
      yoff = ray_position[1] - (float) voxel[1];
      zoff = ray_position[2] - (float) voxel[2];
      vtkTrilinFuncMacro( value, xoff, yoff, zoff, A, B, C, D, E, F, G, H );

      if ( value < 0 ) 
	{
	value = 0;
	}
      else if ( value > volumeInfo->Volume->GetArraySize() - 1 )
	{
	value = volumeInfo->Volume->GetArraySize() - 1;
	}

      opacity = SOTF[(int)value];
 
      // If this is greater than the max, this is the new max.
      if ( opacity > max ) 
	{
	max = opacity;
	max_value = (int) value;
	}
      
      // Increment our position and compute our voxel location
      ray_position[0] += ray_increment[0];
      ray_position[1] += ray_increment[1];
      ray_position[2] += ray_increment[2];      
      voxel[0] = (int)( ray_position[0] );
      voxel[1] = (int)( ray_position[1] );
      voxel[2] = (int)( ray_position[2] );
      }
    }

  // Set the return pixel value.  The depth value is currently useless and
  // should be fixed.
  if( volumeInfo->ColorChannels == 1 )
    {
    rayInfo->Color[0] = max * grayArray[max_value];
    rayInfo->Color[1] = max * grayArray[max_value];
    rayInfo->Color[2] = max * grayArray[max_value];
    rayInfo->Color[3] = max;
    }
  else if ( volumeInfo->ColorChannels == 3 )
    {
    rayInfo->Color[0] = max * RGBArray[max_value*3];
    rayInfo->Color[1] = max * RGBArray[max_value*3+1];
    rayInfo->Color[2] = max * RGBArray[max_value*3+2];
    rayInfo->Color[3] = max;
    }

  rayInfo->Depth = 
    ( max > 0 )?(volumeInfo->CenterDistance):(VTK_LARGE_FLOAT);

  rayInfo->NumberOfStepsTaken = steps_this_ray;
}

// Construct a new vtkVolumeRayCastMIPFunction 
vtkVolumeRayCastMIPFunction::vtkVolumeRayCastMIPFunction()
{
  this->MaximizeMethod = VTK_MAXIMIZE_SCALAR_VALUE;
}

// Destruct the vtkVolumeRayCastMIPFunction
vtkVolumeRayCastMIPFunction::~vtkVolumeRayCastMIPFunction()
{
}

// This is called from RenderAnImage (in vtkDepthPARCMapper.cxx)
// It uses the integer data type flag that is passed in to
// determine what type of ray needs to be cast (which is handled
// by a templated function. 
void vtkVolumeRayCastMIPFunction::CastRay( VTKRayCastRayInfo *rayInfo,
					   VTKRayCastVolumeInfo *volumeInfo)
{
  void *data_ptr;
  
  data_ptr = volumeInfo->ScalarDataPointer;

  if ( this->MaximizeMethod == VTK_MAXIMIZE_SCALAR_VALUE )
    {
    switch ( volumeInfo->ScalarDataType )
      {
      case VTK_UNSIGNED_CHAR:
	CastMaxScalarValueRay( (unsigned char *)data_ptr, rayInfo, volumeInfo );
	break;
      case VTK_UNSIGNED_SHORT:
	CastMaxScalarValueRay( (unsigned short *)data_ptr, rayInfo, volumeInfo );
      }  
    }
  else
    {
    switch ( volumeInfo->ScalarDataType )
      {
      case VTK_UNSIGNED_CHAR:
	CastMaxOpacityRay( (unsigned char *)data_ptr, rayInfo, volumeInfo );
	break;
      case VTK_UNSIGNED_SHORT:
	CastMaxOpacityRay( (unsigned short *)data_ptr, rayInfo, volumeInfo );
      }  
    }
}

float vtkVolumeRayCastMIPFunction::GetZeroOpacityThreshold( vtkVolume *vtkNotUsed(vol) )
{
  return ( 1.0 );
}

// This is an update method that is called from Render (in
// vtkDepthPARCMapper.cxx).  It allows the specific mapper type to
// update any local caster variables.  In this case, nothing needs
// to be done here
void vtkVolumeRayCastMIPFunction::SpecificFunctionInitialize( 
                                      vtkRenderer *vtkNotUsed(ren), 
				      vtkVolume *vtkNotUsed(vol),
				      VTKRayCastVolumeInfo *vtkNotUsed(volumeInfo),
				      vtkVolumeRayCastMapper *vtkNotUsed(mapper) )
{
}

// Description:
// Return the maximize method as a descriptive character string.
char *vtkVolumeRayCastMIPFunction::GetMaximizeMethodAsString(void)
{
  if( this->MaximizeMethod == VTK_MAXIMIZE_SCALAR_VALUE )
    {
    return "Maximize Scalar Value";
    }
  if( this->MaximizeMethod == VTK_MAXIMIZE_OPACITY )
    {
    return "Maximize Opacity";
    }
  else
    {
    return "Unknown";
    }
}

// Print method for vtkVolumeRayCastMIPFunction
void vtkVolumeRayCastMIPFunction::PrintSelf(ostream& os, vtkIndent indent)
{
  vtkVolumeRayCastFunction::PrintSelf(os,indent);

  os << indent << "Maximize Method: " << this->GetMaximizeMethodAsString()
     << "\n";
}
