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/*=========================================================================
Program: Visualization Toolkit
Module: vtkGeoEdgeStrategy.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.
=========================================================================*/
/*-------------------------------------------------------------------------
Copyright 2008 Sandia Corporation.
Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
the U.S. Government retains certain rights in this software.
-------------------------------------------------------------------------*/
#include "vtkGeoEdgeStrategy.h"
#include "vtkCellArray.h"
#include "vtkCellData.h"
#include "vtkCommand.h"
#include "vtkEdgeListIterator.h"
#include "vtkFloatArray.h"
#include "vtkGeoMath.h"
#include "vtkGraph.h"
#include "vtkMath.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkSmartPointer.h"
#include <vtksys/stl/utility>
#include <vtksys/stl/vector>
#include <vtksys/stl/map>
vtkStandardNewMacro(vtkGeoEdgeStrategy);
vtkGeoEdgeStrategy::vtkGeoEdgeStrategy()
{
this->GlobeRadius = vtkGeoMath::EarthRadiusMeters();
this->ExplodeFactor = 0.2;
this->NumberOfSubdivisions = 20;
}
void vtkGeoEdgeStrategy::Layout()
{
vtksys_stl::map<vtksys_stl::pair<vtkIdType, vtkIdType>, int> edgeCount;
vtksys_stl::map<vtksys_stl::pair<vtkIdType, vtkIdType>, int> edgeNumber;
vtksys_stl::vector<vtkEdgeType> edgeVector(this->Graph->GetNumberOfEdges());
vtkSmartPointer<vtkEdgeListIterator> it =
vtkSmartPointer<vtkEdgeListIterator>::New();
this->Graph->GetEdges(it);
while (it->HasNext())
{
vtkEdgeType e = it->Next();
vtkIdType src, tgt;
if (e.Source < e.Target)
{
src = e.Source;
tgt = e.Target;
}
else
{
src = e.Target;
tgt = e.Source;
}
edgeCount[vtksys_stl::pair<vtkIdType, vtkIdType>(src, tgt)]++;
edgeVector[e.Id] = e;
}
vtkIdType numEdges = this->Graph->GetNumberOfEdges();
double* pts = new double[this->NumberOfSubdivisions*3];
for (vtkIdType eid = 0; eid < numEdges; ++eid)
{
vtkEdgeType e = edgeVector[eid];
vtkIdType src, tgt;
if (e.Source < e.Target)
{
src = e.Source;
tgt = e.Target;
}
else
{
src = e.Target;
tgt = e.Source;
}
// Lookup the total number of edges with this source
// and target, as well as how many times this pair
// has been found so far.
vtksys_stl::pair<vtkIdType,vtkIdType> p(src, tgt);
edgeNumber[p]++;
int cur = edgeNumber[p];
int total = edgeCount[p];
double sourcePt[3];
double targetPt[3];
this->Graph->GetPoint(e.Source, sourcePt);
this->Graph->GetPoint(e.Target, targetPt);
// Find w, a unit vector pointing from the center of the
// earth directly between the two endpoints.
double w[3];
for (int c = 0; c < 3; ++c)
{
w[c] = (sourcePt[c] + targetPt[c])/2.0;
}
vtkMath::Normalize(w);
// The center of the circle used to draw the arc is a
// point along the vector w scaled by the explode factor.
// Use cur and total to separate parallel arcs.
double center[3];
for (int c = 0; c < 3; ++c)
{
center[c] = this->ExplodeFactor * this->GlobeRadius * w[c]
* (cur + 1) / total;
}
// The vectors u and x are unit vectors pointing from the
// center of the circle to the two endpoints of the arc,
// lastPoint and curPoint, respectively.
double u[3], x[3];
for (int c = 0; c < 3; ++c)
{
u[c] = sourcePt[c] - center[c];
x[c] = targetPt[c] - center[c];
}
double radius = vtkMath::Norm(u);
vtkMath::Normalize(u);
vtkMath::Normalize(x);
// Find the angle that the arc spans.
double theta = acos(vtkMath::Dot(u, x));
// If the vectors u, x point toward the center of the earth, take
// the larger angle between the vectors.
// We determine whether u points toward the center of the earth
// by checking whether the dot product of u and w is negative.
if (vtkMath::Dot(w, u) < 0)
{
theta = 2.0*vtkMath::Pi() - theta;
}
// We need two perpendicular vectors on the plane of the circle
// in order to draw the circle. First we calculate n, a vector
// normal to the circle, by crossing u and w. Next, we cross
// n and u in order to get a vector v in the plane of the circle
// that is perpendicular to u.
double n[3];
vtkMath::Cross(u, w, n);
vtkMath::Normalize(n);
double v[3];
vtkMath::Cross(n, u, v);
vtkMath::Normalize(v);
// Use the general equation for a circle in three dimensions
// to draw an arc from the last point to the current point.
for (int s = 0; s < this->NumberOfSubdivisions; ++s)
{
double angle = (this->NumberOfSubdivisions - 1.0 - s)
* theta / (this->NumberOfSubdivisions - 1.0);
for (int c = 0; c < 3; ++c)
{
pts[3*s + c] = center[c]
+ radius*cos(angle)*u[c]
+ radius*sin(angle)*v[c];
}
}
this->Graph->SetEdgePoints(e.Id, this->NumberOfSubdivisions, pts);
if (eid % 1000 == 0)
{
double progress = eid / static_cast<double>(numEdges);
this->InvokeEvent(vtkCommand::ProgressEvent, static_cast<void*>(&progress));
}
}
double progress = 1.0;
this->InvokeEvent(vtkCommand::ProgressEvent, static_cast<void*>(&progress));
delete [] pts;
}
void vtkGeoEdgeStrategy::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os,indent);
os << indent << "GlobeRadius: " << this->GlobeRadius << endl;
os << indent << "ExplodeFactor: " << this->ExplodeFactor << endl;
os << indent << "NumberOfSubdivisions: " << this->NumberOfSubdivisions << endl;
}
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