obj文件转off

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vector<string> split(const string &str,const string &pattern)
{
    //进行字符串的切割
    //const char* convert to char*
    char * strc = new char[strlen(str.c_str())+1];
    strcpy(strc, str.c_str());
    vector<string> resultVec;
    char* tmpStr = strtok(strc, pattern.c_str());
    while (tmpStr != NULL)
    {
        resultVec.push_back(string(tmpStr));
        tmpStr = strtok(NULL, pattern.c_str());
    }

    delete[] strc;

    return resultVec;
}
void OBj2OFF(string fname2, string offpath,vector<vector<double> >& vset,vector<vector<int> >& fset) {
    string line;
    fstream f;
    f.open(fname2, ios::in);
    if (!f.is_open())
        cout << "文件打开出错" << endl;
    int v_counter = 1;
    int f_counter  = 1;
    while (!f.eof()) {
        getline(f, line);//拿到obj文件中一行，作为一个字符串
        vector<string>parameters;
        string tailMark = " ";
        string ans = "";
        line = line.append(tailMark);
        if(line[0]!='v'&&line[0]!='f'){
            continue;
        }
        for (int i = 0; i < line.length(); i++) {
            char ch = line[i];
            if (ch != ' ') {
                ans += ch;
            }
            else {
                if(ans!=""){
                parameters.push_back(ans); //取出字符串中的元素，以空格切分
                    ans = "";}
            }
        }
        if (parameters[0] == "v") {   //如果是顶点的话
                vector<double>Point;
                v_counter++;
                Point.push_back(atof( parameters[1].c_str()));
                Point.push_back(atof( parameters[2].c_str()));
                Point.push_back(atof( parameters[3].c_str()));
                vset.push_back(Point);
        }
        else if (parameters[0] == "f") {   //如果是面的话，存放顶点的索引
                vector<int>vIndexSets;          //临时存放点的集合
                for (int i = 1; i < 4; i++) {
                    string x = parameters[i];
                    string ans = "";
                    for (int j = 0; j < x.length(); j++) {   //跳过‘/’
                        char ch = x[j];
                        if (ch != '/')
                            ans += ch;
                        else
                            break;
                    }
                    vector<string >res = split(ans,"/");
                    int index = atof(res[0].c_str());
                    index--;//因为顶点索引在obj文件中是从1开始的，而我们存放的顶点vector是从0开始的，因此要减1
                    vIndexSets.push_back(index);
                }
                fset.push_back(vIndexSets);
            }

    }
    f.close();
    int vert_number = vset.size();
    int face_number = fset.size();
    ofstream out(offpath);
    out << "OFF"<< endl;
    out << vset.size() <<" "<< fset.size() <<" 0"<< endl;
    for (int j = 0; j <vset.size() ; ++j) {
        out << (vset[j][0]) <<" " << vset[j][1]<< " "<< vset[j][2]<<  endl;
    }
    for (int j = 0; j <fset.size() ; ++j) {
        out <<"3 " << (fset[j][0]) <<" " << fset[j][1] <<" " << fset[j][2]<< endl;
    }
    out.close();
}