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/*=========================================================================
Program: Visualization Toolkit
Module: vtkGenericSubdivisionErrorMetric.h
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.
=========================================================================*/
/**
* @class vtkGenericSubdivisionErrorMetric
* @brief Objects that compute
* error during cell tessellation.
*
*
* Objects of that class answer the following question during the cell
* subdivision: "does the edge need to be subdivided?" through
* RequiresEdgeSubdivision().
* The answer depends on the criterium actually used in the subclass of this
* abstract class: a geometric-based error
* metric (variation of edge from a straight line), an attribute-based error
* metric (variation of the active attribute/component value from a linear
* ramp) , a view-depend error metric, ...
* Cell subdivision is performed in the context of the adaptor
* framework: higher-order, or complex cells, are automatically tessellated
* into simplices so that they can be processed with conventional
* visualization algorithms.
*
* @sa
* vtkGenericCellTessellator
*/
#ifndef vtkGenericSubdivisionErrorMetric_h
#define vtkGenericSubdivisionErrorMetric_h
#include "vtkCommonDataModelModule.h" // For export macro
#include "vtkObject.h"
class vtkGenericAttributeCollection;
class vtkGenericAdaptorCell;
class vtkGenericDataSet;
class VTKCOMMONDATAMODEL_EXPORT vtkGenericSubdivisionErrorMetric : public vtkObject
{
public:
//@{
/**
* Standard VTK type and error macros.
*/
vtkTypeMacro(vtkGenericSubdivisionErrorMetric, vtkObject);
void PrintSelf(ostream& os, vtkIndent indent) override;
//@}
/**
* Does the edge need to be subdivided according to the implemented
* computation?
* The edge is defined by its `leftPoint' and its `rightPoint'.
* `leftPoint', `midPoint' and `rightPoint' have to be initialized before
* calling RequiresEdgeSubdivision().
* Their format is global coordinates, parametric coordinates and
* point centered attributes: xyx rst abc de...
* `alpha' is the normalized abscissa of the midpoint along the edge.
* (close to 0 means close to the left point, close to 1 means close to the
* right point)
* \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
*/
virtual int RequiresEdgeSubdivision(
double* leftPoint, double* midPoint, double* rightPoint, double alpha) = 0;
/**
* 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
*/
virtual double GetError(
double* leftPoint, double* midPoint, double* rightPoint, double alpha) = 0;
//@{
/**
* The cell that the edge belongs to.
*/
void SetGenericCell(vtkGenericAdaptorCell* cell);
vtkGetObjectMacro(GenericCell, vtkGenericAdaptorCell);
//@}
//@{
/**
* Set/Get the dataset to be tessellated.
*/
void SetDataSet(vtkGenericDataSet* ds);
vtkGetObjectMacro(DataSet, vtkGenericDataSet);
//@}
protected:
vtkGenericSubdivisionErrorMetric();
~vtkGenericSubdivisionErrorMetric() override;
vtkGenericAdaptorCell* GenericCell;
vtkGenericDataSet* DataSet;
private:
vtkGenericSubdivisionErrorMetric(const vtkGenericSubdivisionErrorMetric&) = delete;
void operator=(const vtkGenericSubdivisionErrorMetric&) = delete;
};
#endif