vtkGeometricErrorMetric.cxx

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

  Program:   Visualization Toolkit
  Module:    vtkGeometricErrorMetric.cxx

  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 "vtkGeometricErrorMetric.h"

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

vtkStandardNewMacro(vtkGeometricErrorMetric);

//-----------------------------------------------------------------------------
vtkGeometricErrorMetric::vtkGeometricErrorMetric()
{
  this->AbsoluteGeometricTolerance = 1.0; // arbitrary positive value
  this->Relative=0; // GetError() will return the square absolute error.
  this->SmallestSize=1;
}

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

//-----------------------------------------------------------------------------
// Description :
// Set the geometric accuracy with an absolute value.
// Subdivision will be required if the square distance is greater than
// value. For instance 0.01 will give better result than 0.1.
// \pre positive_value: value>0
void vtkGeometricErrorMetric::SetAbsoluteGeometricTolerance(double value)
{
  assert("pre: positive_value" && value>0);
  this->Relative=0;
  if(this->AbsoluteGeometricTolerance!=value)
    {
    this->AbsoluteGeometricTolerance=value;
    this->Modified();
    }
}

//-----------------------------------------------------------------------------
// Description :
// Set the geometric accuracy with a value relative to the bounding box of
// the dataset. Internally compute the absolute tolerance.
// For instance 0.01 will give better result than 0.1.
// \pre valid_range_value: value>0 && value<1
// \pre ds_exists: ds!=0
void vtkGeometricErrorMetric::SetRelativeGeometricTolerance(double value,
                                                            vtkGenericDataSet *ds)
{
  assert("pre: valid_range_value" && value>0 && value<1);
  assert("pre: ds_exists" && ds!=0);

  double bounds[6];
  ds->GetBounds(bounds);
  double smallest;
  double length;
  smallest = bounds[1] - bounds[0];
  length   = bounds[3] - bounds[2];
  if(length < smallest || smallest == 0.0)
    {
    smallest = length;
    }
  length = bounds[5] - bounds[4];
  if(length < smallest || smallest == 0.0)
    {
    smallest = length;
    }
  length = ds->GetLength();
  if(length < smallest || smallest == 0.0)
    {
    smallest = length;
    }
  if(smallest == 0)
    {
    smallest = 1;
    }
  double tmp = value*smallest;
  this->SmallestSize=smallest;
  cout<<"this->SmallestSize="<<this->SmallestSize<<endl;
  this->Relative=1;
  tmp=tmp*tmp;
  
  if(this->AbsoluteGeometricTolerance!=tmp)
    {
    this->AbsoluteGeometricTolerance = tmp;
    this->Modified();
    }
}

#define VTK_DISTANCE_LINE_POINT

//-----------------------------------------------------------------------------
int vtkGeometricErrorMetric::RequiresEdgeSubdivision(double *leftPoint,
                                                     double *midPoint,
                                                     double *rightPoint,
#ifdef VTK_DISTANCE_LINE_POINT
                                                     double vtkNotUsed(alpha)
#else
                                                     double alpha
#endif
  )
{
  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;
    }
  // distance between the line (leftPoint,rightPoint) and the point midPoint.
#ifdef VTK_DISTANCE_LINE_POINT
  return this->Distance2LinePoint(leftPoint,rightPoint,midPoint)>this->AbsoluteGeometricTolerance;
#else
  // Interpolated point
  double interpolatedPoint[3];
  int i=0;
  while(i<3)
    {
    interpolatedPoint[i]=leftPoint[i] + alpha*(rightPoint[i] - leftPoint[i]);
    ++i;
    }
  return vtkMath::Distance2BetweenPoints(midPoint,interpolatedPoint)>this->AbsoluteGeometricTolerance;
#endif
}

//-----------------------------------------------------------------------------
// 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 vtkGeometricErrorMetric::GetError(double *leftPoint,
                                         double *midPoint,
                                         double *rightPoint,
#ifdef VTK_DISTANCE_LINE_POINT
                                         double vtkNotUsed(alpha)
#else
                                         double alpha
#endif
  )
{
  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;
    }
  // distance between the line (leftPoint,rightPoint) and the point midPoint.
#ifdef VTK_DISTANCE_LINE_POINT
  double squareAbsoluteError=this->Distance2LinePoint(leftPoint,rightPoint,midPoint);
#else
   // Interpolated point
  double interpolatedPoint[3];
  int i=0;
  while(i<3)
    {
    interpolatedPoint[i]=leftPoint[i] + alpha*(rightPoint[i] - leftPoint[i]);
    ++i;
    }
  double squareAbsoluteError=vtkMath::Distance2BetweenPoints(midPoint,interpolatedPoint);
#endif
  if(this->Relative)
    {
    return sqrt(squareAbsoluteError)/this->SmallestSize;
    }
  else
    {
    return squareAbsoluteError;
    }
}

//-----------------------------------------------------------------------------
// Description:
// Return the type of output of GetError()
int vtkGeometricErrorMetric::GetRelative()
{
  return this->Relative;
}

//-----------------------------------------------------------------------------
// Description:
// Square distance between a straight line (defined by points x and y)
// and a point z. Property: if x and y are equal, the line is a point and
// the result is the square distance between points x and z.
double vtkGeometricErrorMetric::Distance2LinePoint(double x[3],
                                                   double y[3],
                                                   double z[3])
{
  double u[3];
  double v[3];
  double w[3];

  u[0] = y[0] - x[0];
  u[1] = y[1] - x[1];
  u[2] = y[2] - x[2];
  
  vtkMath::Normalize(u);
  
  v[0] = z[0] - x[0];
  v[1] = z[1] - x[1];
  v[2] = z[2] - x[2];
  
  double dot = vtkMath::Dot(u,v);
  
  w[0] = v[0] - dot*u[0];
  w[1] = v[1] - dot*u[1];
  w[2] = v[2] - dot*u[2];
  
  return vtkMath::Dot(w,w);
}

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