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/*=========================================================================
Program: Visualization Toolkit
Module: vtkViewDependentErrorMetric.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 "vtkViewDependentErrorMetric.h"
#include "vtkObjectFactory.h"
#include "vtkGenericAttribute.h"
#include "vtkGenericAttributeCollection.h"
#include "vtkGenericAdaptorCell.h"
#include "vtkGenericDataSet.h"
#include "vtkMath.h"
#include <assert.h>
#include "vtkCoordinate.h"
#include "vtkViewport.h"
vtkStandardNewMacro(vtkViewDependentErrorMetric);
//-----------------------------------------------------------------------------
vtkViewDependentErrorMetric::vtkViewDependentErrorMetric()
{
this->PixelTolerance = 0.25; // arbitrary positive value
this->Viewport = 0;
this->Coordinate = vtkCoordinate::New();
this->Coordinate->SetCoordinateSystemToWorld();
}
//-----------------------------------------------------------------------------
vtkViewDependentErrorMetric::~vtkViewDependentErrorMetric()
{
this->Coordinate->Delete();
}
//-----------------------------------------------------------------------------
// Description:
// Set the squared screen-based geometric accuracy measured in pixels.
// Subdivision will be required if the square distance between the projection
// of the real point and the straight line passing through the projection
// of the vertices of the edge is greater than `value'.
// For instance, 0.25 will give better result than 1.
// \pre positive_value: value>0
void vtkViewDependentErrorMetric::SetPixelTolerance(double value)
{
assert("pre: positive_value" && value>0);
if(this->PixelTolerance!=value)
{
this->PixelTolerance=value;
this->Modified();
}
}
//-----------------------------------------------------------------------------
// Avoid reference loop
void vtkViewDependentErrorMetric::SetViewport(vtkViewport *viewport)
{
if(this->Viewport!=viewport)
{
this->Viewport = viewport;
this->Modified();
}
}
//-----------------------------------------------------------------------------
int vtkViewDependentErrorMetric::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;
}
#if 0
if( !this->RayFrustumIntersection(leftPoint,rightPoint,frustum) && !this->PointFrustumIntersection(midPoint,frustum))
{
// not in the frustum, don't need subdivision
return 0;
}
#endif
// Get the projection of the left, mid and right points
double leftProjPoint[2];
double midProjPoint[2];
// double rightProjPoint[2];
this->Coordinate->SetValue(leftPoint);
double *pix = this->Coordinate->GetComputedDoubleDisplayValue(this->Viewport);
// pix is a volatile pointer
leftProjPoint[0] = pix[0];
leftProjPoint[1] = pix[1];
this->Coordinate->SetValue(midPoint);
pix = this->Coordinate->GetComputedDoubleDisplayValue(this->Viewport);
// pix is a volatile pointer
midProjPoint[0] = pix[0];
midProjPoint[1] = pix[1];
this->Coordinate->SetValue(rightPoint);
pix = this->Coordinate->GetComputedDoubleDisplayValue(this->Viewport);
// distance between the line (leftProjPoint,rightProjPoint) and the point midProjPoint.
return this->Distance2LinePoint(leftProjPoint,pix,midProjPoint)>this->PixelTolerance;
}
//-----------------------------------------------------------------------------
// 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.
// \pre leftPoint_exists: leftPoint!=0
// \pre midPoint_exists: midPoint!=0
// \pre rightPoint_exists: rightPoint!=0
// \pre clamped_alpha: alpha>0 && alpha<1
// \pre valid_size: sizeof(leftPoint)=sizeof(midPoint)=sizeof(rightPoint)
// =GetAttributeCollection()->GetNumberOfPointCenteredComponents()+6
// \post positive_result: result>=0
double vtkViewDependentErrorMetric::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); // or else true
if( this->GenericCell->IsGeometryLinear() )
{
//don't need to do anything:
return 0;
}
// Get the projection of the left, mid and right points
double leftProjPoint[2];
double midProjPoint[2];
// double rightProjPoint[2];
this->Coordinate->SetValue(leftPoint);
double *pix = this->Coordinate->GetComputedDoubleDisplayValue(this->Viewport);
// pix is a volatile pointer
leftProjPoint[0] = pix[0];
leftProjPoint[1] = pix[1];
this->Coordinate->SetValue(midPoint);
pix = this->Coordinate->GetComputedDoubleDisplayValue(this->Viewport);
// pix is a volatile pointer
midProjPoint[0] = pix[0];
midProjPoint[1] = pix[1];
this->Coordinate->SetValue(rightPoint);
pix = this->Coordinate->GetComputedDoubleDisplayValue(this->Viewport);
// distance between the line (leftProjPoint,rightProjPoint) and the point midProjPoint.
return this->Distance2LinePoint(leftProjPoint,pix,midProjPoint);
}
//-----------------------------------------------------------------------------
// 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 vtkViewDependentErrorMetric::Distance2LinePoint(double x[2],
double y[2],
double z[2])
{
double u[2];
double v[2];
double w[2];
u[0] = y[0] - x[0];
u[1] = y[1] - x[1];
vtkMath::Normalize2D(u);
v[0] = z[0] - x[0];
v[1] = z[1] - x[1];
double dot = vtkMath::Dot2D(u,v);
w[0] = v[0] - dot*u[0];
w[1] = v[1] - dot*u[1];
return vtkMath::Dot2D(w,w);
}
//-----------------------------------------------------------------------------
void vtkViewDependentErrorMetric::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os,indent);
os << indent << "PixelTolerance: " << this->PixelTolerance << endl;
os << indent << "ViewPort: ";
if( this->Viewport )
{
this->Viewport->PrintSelf( os << endl, indent.GetNextIndent());
}
else
{
os << "(none)" << endl;
}
}