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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkSmoothErrorMetric.cxx,v $

  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.

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

#include "vtkObjectFactory.h"
#include "vtkGenericAttribute.h"
#include "vtkGenericAttributeCollection.h"
#include "vtkGenericAdaptorCell.h"
#include "vtkGenericDataSet.h"
#include "vtkMath.h"
#include <assert.h>

vtkCxxRevisionMacro(vtkSmoothErrorMetric,"$Revision: 1.1 $");
vtkStandardNewMacro(vtkSmoothErrorMetric);

//-----------------------------------------------------------------------------
vtkSmoothErrorMetric::vtkSmoothErrorMetric()
{
  this->AngleTolerance=90.1; // in degrees
  this->CosTolerance=cos(this->AngleTolerance*vtkMath::DoubleDegreesToRadians());
}

//-----------------------------------------------------------------------------
vtkSmoothErrorMetric::~vtkSmoothErrorMetric()
{
}

//-----------------------------------------------------------------------------
double vtkSmoothErrorMetric::GetAngleTolerance()
{
  return this->AngleTolerance;
}

//-----------------------------------------------------------------------------
void vtkSmoothErrorMetric::SetAngleTolerance(double value)
{
//  assert("pre: positive_value" && value>90 && value<180);
  if(this->AngleTolerance!=value)
    {
    // Clamp the value
    if(value<=90)
      {
      vtkWarningMacro(<< "value " << value << " out of range ]90,180[, clamped to 90.1" );
      this->AngleTolerance=90.1;
      }
    else
      {
      if(value>=180)
        {
        vtkWarningMacro(<< "value " << value << " out of range ]90,180[, clamped to 179.9" );
        this->AngleTolerance=179.9;
        }
      else
        {
        this->AngleTolerance=value;
        }
      }
    this->CosTolerance=cos(this->AngleTolerance*vtkMath::DoubleDegreesToRadians());
    this->Modified();
    }
}

//-----------------------------------------------------------------------------
int vtkSmoothErrorMetric::RequiresEdgeSubdivision(double *leftPoint,
                                                  double *midPoint,
                                                  double *rightPoint,
                                                  double vtkNotUsed(alpha)
  )
{
  assert("pre: leftPoint_exists" && leftPoint!=0);
  assert("pre: midPoint_exists" && midPoint!=0);
  assert("pre: rightPoint_exists" && rightPoint!=0);
//  assert("pre: clamped_alpha" && alpha>0 && alpha<1); // or else true
  if( this->GenericCell->IsGeometryLinear() )
    {
    //don't need to do anything:
    return 0;
    }
  
  double a[3];
  double b[3];
  
  a[0]=leftPoint[0]-midPoint[0];
  a[1]=leftPoint[1]-midPoint[1];
  a[2]=leftPoint[2]-midPoint[2];
  b[0]=rightPoint[0]-midPoint[0];
  b[1]=rightPoint[1]-midPoint[1];
  b[2]=rightPoint[2]-midPoint[2];
  
  
  double dota=vtkMath::Dot(a,a);
  double dotb=vtkMath::Dot(b,b);
  double cosa;
  
  if(dota==0 || dotb==0)
    {
    cosa=-1;
    }
  else
    {
    cosa=vtkMath::Dot(a,b)/sqrt(dota*dotb);
    }
  
  int result=(cosa>this->CosTolerance);

  return result;
}

//-----------------------------------------------------------------------------
// Description:
// Return the error at the mid-point. The type of error depends on the state
// of the concrete error metric. For instance, it can return an absolute
// or relative error metric.
// See RequiresEdgeSubdivision() for a description of the arguments.
// \post positive_result: result>=0
double vtkSmoothErrorMetric::GetError(double *leftPoint,
                                      double *midPoint,
                                      double *rightPoint,
                                      double vtkNotUsed(alpha)
  )
{
  assert("pre: leftPoint_exists" && leftPoint!=0);
  assert("pre: midPoint_exists" && midPoint!=0);
  assert("pre: rightPoint_exists" && rightPoint!=0);
//  assert("pre: clamped_alpha" && alpha>0 && alpha<1);
  if( this->GenericCell->IsGeometryLinear() )
    {
    //don't need to do anything:
    return 0;
    }
  
  double a[3];
  double b[3];
  
  a[0]=leftPoint[0]-midPoint[0];
  a[1]=leftPoint[1]-midPoint[1];
  a[2]=leftPoint[2]-midPoint[2];
  b[0]=rightPoint[0]-midPoint[0];
  b[1]=rightPoint[1]-midPoint[1];
  b[2]=rightPoint[2]-midPoint[2];
  
  
  double dota=vtkMath::Dot(a,a);
  double dotb=vtkMath::Dot(b,b);
  double cosa;
  
  if(dota==0 || dotb==0)
    {
    cosa=-1;
    }
  else
    {
    cosa=vtkMath::Dot(a,b)/sqrt(dota*dotb);
    }
  
  if(cosa>1)
    {
    cosa=1;
    }
  else if(cosa<-1)
    {
    cosa=-1;
    }
  double result=180-acos(cosa)*vtkMath::DoubleRadiansToDegrees();
  assert("post: positive_result" && result>=0);
  return result;
}

//-----------------------------------------------------------------------------
void vtkSmoothErrorMetric::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);
  
  os << indent << "AngleTolerance: "  << this->AngleTolerance << endl;
  os << indent << "CosTolerance: "  << this->CosTolerance << endl;
}