Permalink
Switch branches/tags
Nothing to show
Find file
Fetching contributors…
Cannot retrieve contributors at this time
354 lines (307 sloc) 9.21 KB
/*=========================================================================
Program: Visualization Toolkit
Module: vtkSimpleScalarTree.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 "vtkSimpleScalarTree.h"
#include "vtkCell.h"
#include "vtkDataSet.h"
#include "vtkDoubleArray.h"
#include "vtkIdList.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
vtkStandardNewMacro(vtkSimpleScalarTree);
class vtkScalarNode {};
template <class TScalar>
class vtkScalarRange : public vtkScalarNode
{
public:
TScalar min;
TScalar max;
};
// Instantiate scalar tree with maximum level of 20 and branching
// factor of 5.
vtkSimpleScalarTree::vtkSimpleScalarTree()
{
this->DataSet = NULL;
this->Level = 0;
this->MaxLevel = 20;
this->BranchingFactor = 3;
this->Tree = NULL;
this->TreeSize = 0;
}
vtkSimpleScalarTree::~vtkSimpleScalarTree()
{
if ( this->Tree )
{
delete [] this->Tree;
}
}
// Initialize locator. Frees memory and resets object as appropriate.
void vtkSimpleScalarTree::Initialize()
{
if ( this->Tree )
{
delete [] this->Tree;
}
this->Tree = NULL;
}
// Construct the scalar tree from the dataset provided. Checks build times
// and modified time from input and reconstructs the tree if necessaery.
void vtkSimpleScalarTree::BuildTree()
{
vtkIdType numCells, cellId, i, j, numScalars;
int level, offset, parentOffset, prod;
vtkIdType numNodes, node, numLeafs, leaf, numParentLeafs;
vtkCell *cell;
vtkIdList *cellPts;
vtkScalarRange<double> *tree, *parent;
double *s;
vtkDoubleArray *cellScalars;
// Check input...see whether we have to rebuild
//
if ( !this->DataSet || (numCells = this->DataSet->GetNumberOfCells()) < 1 )
{
vtkErrorMacro( << "No data to build tree with");
return;
}
if ( this->Tree != NULL && this->BuildTime > this->MTime
&& this->BuildTime > this->DataSet->GetMTime() )
{
return;
}
vtkDebugMacro( << "Building scalar tree..." );
this->Scalars = this->DataSet->GetPointData()->GetScalars();
if ( ! this->Scalars )
{
vtkErrorMacro( << "No scalar data to build trees with");
return;
}
this->Initialize();
cellScalars = vtkDoubleArray::New();
cellScalars->Allocate(100);
// Compute the number of levels in the tree
//
numLeafs = static_cast<int>(
ceil(static_cast<double>(numCells)/this->BranchingFactor));
for (prod=1, numNodes=1, this->Level=0;
prod < numLeafs && this->Level <= this->MaxLevel; this->Level++ )
{
prod *= this->BranchingFactor;
numNodes += prod;
}
this->LeafOffset = offset = numNodes - prod;
vtkScalarRange<double> *TTree;
this->TreeSize = numNodes - (prod - numLeafs);
this->Tree = TTree = new vtkScalarRange<double>[this->TreeSize];
for ( i=0; i < this->TreeSize; i++ )
{
TTree[i].min = VTK_DOUBLE_MAX;
TTree[i].max = -VTK_DOUBLE_MAX;
}
// Loop over all cells getting range of scalar data and place into leafs
//
for ( cellId=0, node=0; node < numLeafs; node++ )
{
tree = TTree + offset + node;
for ( i=0; i < this->BranchingFactor && cellId < numCells; i++, cellId++ )
{
cell = this->DataSet->GetCell(cellId);
cellPts = cell->GetPointIds();
numScalars = cellPts->GetNumberOfIds();
cellScalars->SetNumberOfTuples(numScalars);
this->Scalars->GetTuples(cellPts, cellScalars);
s = cellScalars->GetPointer(0);
for ( j=0; j < numScalars; j++ )
{
if ( s[j] < tree->min )
{
tree->min = s[j];
}
if ( s[j] > tree->max )
{
tree->max = s[j];
}
}
}
}
// Now build top levels of tree in bottom-up fashion
//
for ( level=this->Level; level > 0; level-- )
{
parentOffset = offset - prod/this->BranchingFactor;
prod /= this->BranchingFactor;
numParentLeafs = static_cast<int>(
ceil(static_cast<double>(numLeafs)/this->BranchingFactor));
for ( leaf=0, node=0; node < numParentLeafs; node++ )
{
parent = TTree + parentOffset + node;
for ( i=0; i < this->BranchingFactor && leaf < numLeafs; i++, leaf++ )
{
tree = TTree + offset + leaf;
if ( tree->min < parent->min )
{
parent->min = tree->min;
}
if ( tree->max > parent->max )
{
parent->max = tree->max;
}
}
}
numLeafs = numParentLeafs;
offset = parentOffset;
}
this->BuildTime.Modified();
cellScalars->Delete();
}
// Begin to traverse the cells based on a scalar value. Returned cells
// will have scalar values that span the scalar value specified.
void vtkSimpleScalarTree::InitTraversal(double scalarValue)
{
this->BuildTree();
vtkScalarRange<double> *TTree =
static_cast< vtkScalarRange<double> * > (this->Tree);
this->ScalarValue = scalarValue;
this->TreeIndex = this->TreeSize;
// Check root of tree for overlap with scalar value
//
if ( TTree[0].min > scalarValue || TTree[0].max < scalarValue )
{
return;
}
else //find leaf that does overlap with scalar value
{
this->FindStartLeaf(0,0); //recursive function call
}
}
int vtkSimpleScalarTree::FindStartLeaf(vtkIdType index, int level)
{
if ( level < this->Level )
{
int i;
vtkIdType childIndex=this->BranchingFactor*index+1;
level++;
for ( i=0; i < this->BranchingFactor; i++ )
{
index = childIndex + i;
if ( index >= this->TreeSize )
{
this->TreeIndex = this->TreeSize;
return 0;
}
else if ( this->FindStartLeaf(childIndex+i, level) )
{
return 1;
}
}
return 0;
}
else //recursion terminated
{
vtkScalarRange<double> *tree = static_cast<
vtkScalarRange<double>*>(this->Tree) + index;
if ( tree->min > this->ScalarValue || tree->max < this->ScalarValue )
{
return 0;
}
else
{
this->ChildNumber = 0;
this->TreeIndex = index;
this->CellId = (index - this->LeafOffset) * this->BranchingFactor;
return 1;
}
}
}
int vtkSimpleScalarTree::FindNextLeaf(vtkIdType childIndex, int childLevel)
{
vtkIdType myIndex=(childIndex-1)/this->BranchingFactor;
int myLevel=childLevel-1;
vtkIdType firstChildIndex, childNum, index;
//Find which child invoked this method
firstChildIndex = myIndex*this->BranchingFactor + 1;
childNum = childIndex - firstChildIndex;
for ( childNum++; childNum < this->BranchingFactor; childNum++ )
{
index = firstChildIndex + childNum;
if ( index >= this->TreeSize )
{
this->TreeIndex = this->TreeSize;
return 0;
}
else if ( this->FindStartLeaf(index, childLevel) )
{
return 1;
}
}
//If here, didn't find anything yet
if ( myLevel <= 0 ) //at root, can't go any higher in tree
{
this->TreeIndex = this->TreeSize;
return 0;
}
else
{
return this->FindNextLeaf(myIndex,myLevel);
}
}
// Return the next cell that may contain scalar value specified to
// initialize traversal. The value NULL is returned if the list is
// exhausted. Make sure that InitTraversal() has been invoked first or
// you'll get erratic behavior.
vtkCell *vtkSimpleScalarTree::GetNextCell(vtkIdType& cellId,
vtkIdList* &cellPts,
vtkDataArray *cellScalars)
{
double s, min=VTK_DOUBLE_MAX, max=(-VTK_DOUBLE_MAX);
vtkIdType i, numScalars;
vtkCell *cell;
vtkIdType numCells = this->DataSet->GetNumberOfCells();
while ( this->TreeIndex < this->TreeSize )
{
for ( ; this->ChildNumber<this->BranchingFactor && this->CellId<numCells;
this->ChildNumber++, this->CellId++ )
{
cell = this->DataSet->GetCell(this->CellId);
cellPts = cell->GetPointIds();
numScalars = cellPts->GetNumberOfIds();
cellScalars->SetNumberOfTuples(numScalars);
this->Scalars->GetTuples(cellPts, cellScalars);
for (i=0; i < numScalars; i++)
{
s = cellScalars->GetTuple1(i);
if ( s < min )
{
min = s;
}
if ( s > max )
{
max = s;
}
}
if ( this->ScalarValue >= min && this->ScalarValue <= max )
{
cellId = this->CellId;
this->ChildNumber++; //prepare for next time
this->CellId++;
return cell;
}
} //for each cell in this leaf
// If here, must have not found anything in this leaf
this->FindNextLeaf(this->TreeIndex, this->Level);
} //while not all leafs visited
return NULL;
}
void vtkSimpleScalarTree::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os,indent);
os << indent << "Level: " << this->Level << "\n" ;
os << indent << "Max Level: " << this->MaxLevel << "\n" ;
os << indent << "Branching Factor: " << this->BranchingFactor << "\n" ;
}