vtkOFFReader.cxx

/*=========================================================================
  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkOFFReader.cxx,v $
  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 "vtkOFFReader.h"

#include "vtkCellArray.h"
#include "vtkFloatArray.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPointData.h"
#include "vtkPolyData.h"
#include "vtkTriangle.h"

#include <sstream>
#include <fstream>

vtkStandardNewMacro(vtkOFFReader);

// Description:
// Instantiate object with NULL filename.
vtkOFFReader::vtkOFFReader()
{
    this->FileName = NULL;

    this->SetNumberOfInputPorts(0);
}

vtkOFFReader::~vtkOFFReader()
{
    if (this->FileName)
    {
        delete[] this->FileName;
        this->FileName = NULL;
    }
}

/*--------------------------------------------------------
This is only partial support for the OFF format, which is
quite complicated. To find a full specification,
search the net for "OFF format", eg.:
http://people.sc.fsu.edu/~burkardt/data/off/off.html
We support only vertices and faces composed of 3 vertices.
---------------------------------------------------------*/

// a replacement for isspace()
int is_whitespace(char c)
{
    if (c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\v' || c == '\f')
        return 1;
    else
        return 0;
}

int vtkOFFReader::RequestData(
    vtkInformation *vtkNotUsed(request),
    vtkInformationVector **vtkNotUsed(inputVector),
    vtkInformationVector *outputVector)
{
    // get the info object
    vtkInformation *outInfo = outputVector->GetInformationObject(0);

    // get the ouptut
    vtkPolyData *output = vtkPolyData::SafeDownCast(
        outInfo->Get(vtkDataObject::DATA_OBJECT()));

    if (!this->FileName)
    {
        vtkErrorMacro(<< "A FileName must be specified.");
        return 0;
    }

    std::ifstream in(this->FileName);

    if (!in)
    {
        vtkErrorMacro(<< "File " << this->FileName << " not found");
        return 0;
    }

    vtkDebugMacro(<< "Reading file");

    // intialise some structures to store the file contents in
    vtkPoints *points = vtkPoints::New();
    vtkCellArray *polys = vtkCellArray::New();

    // -- work through the file line by line, assigning into the above structures as appropriate --

    float xyz[3];

    std::string line;

    getline(in, line); // throw the 1st line away, it always says "OFF"

    // Read until we get to the first line that is not a comment or a blank line.
    // This line second states the number of vertices, faces, and edges.
    while (getline(in, line))
    {
        // std::cout << line << std::endl;
        if (line.size() == 0)
            continue;
        if (line[0] == '#')
            continue;

        // if we get to here, this is the info line
        break;
    }
    // std::cout << "Found info line." << std::endl;
    // At this point, the line were are interested in is stored in 'line'
    // We are only interested in vertices and faces.
    std::stringstream ss;
    ss << line;
    unsigned int NumberOfVertices, NumberOfFaces;
    ss >> NumberOfVertices >> NumberOfFaces;
    // std::cout << "Vertices: " << NumberOfVertices << " Faces: " << NumberOfFaces << std::endl;
    // Now we can start to read the vertices
    unsigned int VertexCounter = 0;

    while (getline(in, line) && VertexCounter < NumberOfVertices)
    {
        if (line.size() == 0) // skip blank lines (they should only occur before the vertices start)
            continue;

        std::stringstream ssVertex;
        ssVertex << line;
        float x, y, z;
        ssVertex >> x >> y >> z;
        points->InsertNextPoint(x, y, z);
        // std::cout << "adding vertex: " << x << " " << y << " " << z << std::endl;
        VertexCounter++;
    } // (end of vertex while loop)

    unsigned int FaceCounter = 0;

    // read faces
    do
    {
        std::stringstream ssFace;
        ssFace << line;
        unsigned int NumFaceVerts, Vert0, Vert1, Vert2;
        ssFace >> NumFaceVerts >> Vert0 >> Vert1 >> Vert2;
        if (NumFaceVerts != 3)
        {
            vtkErrorMacro(<< "File " << this->FileName << " contains a face with >3 (" << NumFaceVerts << ") vertices.");
            return 0;
        }

        // std::cout << "adding triangle: " << Vert0 << " " << Vert1 << " " << Vert2 << std::endl;
        vtkTriangle *triangle = vtkTriangle::New();

        triangle->GetPointIds()->SetId(0, Vert0);
        triangle->GetPointIds()->SetId(1, Vert1);
        triangle->GetPointIds()->SetId(2, Vert2);

        polys->InsertNextCell(triangle);

        triangle->Delete();

        FaceCounter++;

    } while (getline(in, line) && FaceCounter < NumberOfFaces);

    // we have finished with the file
    in.close();

    output->SetPoints(points);
    output->SetPolys(polys);

    points->Delete();
    polys->Delete();

    return 1;
}

void vtkOFFReader::PrintSelf(ostream &os, vtkIndent indent)
{
    this->Superclass::PrintSelf(os, indent);

    os << indent << "File Name: "
       << (this->FileName ? this->FileName : "(none)") << "\n";
}