readOBJ.C

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/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
\*---------------------------------------------------------------------------*/
 
#include "triSurface.H"
#include "IFstream.H"
#include "IStringStream.H"
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
bool Foam::triSurface::readOBJ(const fileName& OBJfileName)
{
    IFstream OBJfile(OBJfileName);
 
    if (!OBJfile.good())
    {
        FatalErrorInFunction
            << "Cannot read file " << OBJfileName
            << exit(FatalError);
    }
 
    DynamicList<point> points;
    DynamicList<labelledTri> faces;
    HashTable<label> groupToPatch;
 
    label groupID = 0;
    label maxGroupID = 0;
 
    while (OBJfile.good())
    {
        string line = getLineNoComment(OBJfile);
 
        label sz = line.size();
 
        if (sz)
        {
            if (line[sz-1] == '\\')
            {
                line.substr(0, sz-1);
                line += getLineNoComment(OBJfile);
            }
 
            // Read first word
            IStringStream lineStream(line);
            word cmd;
            lineStream >> cmd;
 
            if (cmd == "v")
            {
                scalar x, y, z;
 
                lineStream >> x >> y >> z;
 
                points.append(point(x, y, z));
            }
            else if (cmd == "g")
            {
                word group;
 
                lineStream >> group;
 
                HashTable<label>::const_iterator findGroup =
                    groupToPatch.find(group);
 
                if (findGroup != groupToPatch.end())
                {
                    groupID = findGroup();
                }
                else
                {
                    groupID = maxGroupID;
 
                    groupToPatch.insert(group, groupID);
 
                    maxGroupID++;
                }
            }
            else if (cmd == "f")
            {
                DynamicList<label> verts;
 
                // Assume 'f' is followed by space.
                string::size_type endNum = 1;
 
                while (true)
                {
                    string::size_type startNum =
                        line.find_first_not_of(" \r", endNum);
 
                    if (startNum == string::npos)
                    {
                        break;
                    }
 
                    endNum = line.find(' ', startNum);
 
                    string vertexSpec;
                    if (endNum != string::npos)
                    {
                        vertexSpec = line.substr(startNum, endNum-startNum);
                    }
                    else
                    {
                        vertexSpec = line.substr
                        (
                            startNum,
                            line.size() - startNum
                        );
                    }
 
                    string::size_type slashPos = vertexSpec.find('/');
 
                    label vertI = 0;
                    if (slashPos != string::npos)
                    {
                        IStringStream intStream(vertexSpec.substr(0, slashPos));
 
                        intStream >> vertI;
                    }
                    else
                    {
                        IStringStream intStream(vertexSpec);
 
                        intStream >> vertI;
                    }
                    verts.append(vertI - 1);
                }
 
                verts.shrink();
 
                // Do simple face triangulation around f[0].
                // Cannot use face::triangulation since no complete points yet.
                for (label fp = 1; fp < verts.size() - 1; fp++)
                {
                    label fp1 = verts.fcIndex(fp);
 
                    labelledTri tri(verts[0], verts[fp], verts[fp1], groupID);
 
                    faces.append(tri);
                }
            }
        }
    }
 
    points.shrink();
    faces.shrink();
 
    // Convert groupToPatch to patchList.
    geometricSurfacePatchList patches(maxGroupID);
 
    if (maxGroupID == 0)
    {
        // Generate default patch
        patches.setSize(1);
        patches[0] = geometricSurfacePatch("empty", "patch0", 0);
    }
    else
    {
        forAllConstIter(HashTable<label>, groupToPatch, iter)
        {
            patches[iter()] = geometricSurfacePatch
            (
                "empty",
                iter.key(),
                iter()
            );
        }
    }
 
 
    // Transfer DynamicLists to straight ones.
    pointField allPoints(points.xfer());
 
    // Create triSurface
    *this = triSurface(faces, patches, allPoints, true);
 
    return true;
}
 
 
// ************************************************************************* //