visual-studio - OBJ 文件加载器无法正确读取人脸

Question

我创建了一个用于 OpenGL 的小型 OBJ 文件加载器，但根本没有读取人脸。在添加面部阅读器之前，程序读取一切都很好，所以我在这里有点难住。这是我的代码:

void OBJLoader::LoadObjFile(std::string f,std::vector<float>& v,std::vector<float>& n,std::vector<float>& u)
{
std::ifstream file;
file.open(f);

OutputDebugStringA("OPENING FILE-\n");
OutputDebugStringA(f.c_str());
std::string vertex,normal,uv,face;

std::string data;
std::string data2;
std::string data3 = "";

uv = "vt";
normal = "vn";
vertex = "v";
face = "f";

std::size_t var1;
int i = 1;
int j = 1;
int k = 1;
bool loop = true;
int loopcount = 1;

std::vector<float> tV,tU,tN;

if(file.is_open())
{
    while(std::getline(file,data) && file.good())
    {

        var1 = data.find(vertex);
        if(var1 != std::string::npos && var1 < data.size() && data[1] == 0x20)
        {
            data3.append(data,2,std::string::npos);

            double v1,v2,v3;
            std::istringstream ss(data3);
            if(ss >> v1 >> v2 >> v3){ v.push_back((float)v1); v.push_back((float)v2); v.push_back((float)v3); i++;}
            else
            {
                OutputDebugStringA("Error reading vertex data.\n");
                std::stringstream ssc;
                ssc << loopcount;
                std::string str = ssc.str();
                OutputDebugStringA((char*)str.c_str());
                OutputDebugStringA("\n");

            }
            data3 = "";
            data2 = "";
        }

        var1 = data.find(normal);
        if(var1 != std::string::npos && var1 < data.size())
        {
            data3.append(data,3,std::string::npos);

            float v1,v2,v3;
            std::istringstream ss(data3);
            if(ss >> v1 >> v2 >> v3){ n.push_back((float)v1); n.push_back((float)v2); n.push_back((float)v3); j++;}
            else
            {
                OutputDebugStringA("Error reading normal data.\n");
                std::stringstream ssc;
                ssc << loopcount;
                std::string str = ssc.str();
                OutputDebugStringA((char*)str.c_str());
                OutputDebugStringA("\n");
            }
            data3 = "";
            data2 = "";
        }

        var1 = data.find(uv);
        if(var1 != std::string::npos && var1 < data.size())
        {
            data3.append(data,3,std::string::npos);

            float v1,v2,v3;
            std::istringstream ss(data3);
            if(ss >> v1 >> v2){ u.push_back((float)v1); u.push_back((float)v2); u.push_back((float)v3); k++;}
            else
            {
                OutputDebugStringA("Error reading UV data.\n");
                std::stringstream ssc;
                ssc << loopcount;
                std::string str = ssc.str();
                OutputDebugStringA((char*)str.c_str());
                OutputDebugStringA("\n");

            }
            data3 = "";
            data2 = "";

        }

        var1 = data.find(face);
        if(var1 != std::string::npos && var1 < data.size())
        {   
            data3.append(data,2,std::string::npos);
            std::istringstream ss(data3);

                for(int l = 0;l < data3.size();l++)
                {
                    if(data3[l] == '/') data3[l] = ' ';
                }

            std::istringstream ss(data3);
            unsigned int verts[9];
            char slashes[6];

                //if(ss >> verts[0] >> slashes[0] >> verts[1] >> slashes[1] >> verts[2] >> verts[3] >> slashes[2] >> verts[4] >> slashes[3] >> verts[5] >> verts[6] >> slashes[4] >> verts[7] >> slashes[5] >> verts[8])
            if (ss >> verts[0] >> verts[1] >> verts[2] >> verts[3] >> verts[4] >> verts[5] >> verts[6] >> verts[7] >> verts[8])
                else
                {
                    try
                    {
                    tV.push_back(v.at(verts[0]));
                    tV.push_back(v.at(verts[0]+1));
                    tV.push_back(v.at(verts[0]+2));

                    tU.push_back(u.at(verts[1]));
                    tU.push_back(u.at(verts[1]+1));
                    tU.push_back(u.at(verts[1]+2));

                    tN.push_back(n.at(verts[2]));
                    tN.push_back(n.at(verts[2]+1));
                    tN.push_back(n.at(verts[2]+2));
                    //
                    tV.push_back(v.at(verts[3]));
                    tV.push_back(v.at(verts[3]+1));
                    tV.push_back(v.at(verts[3]+2));

                    tU.push_back(u.at(verts[4]));
                    tU.push_back(u.at(verts[4]+1));
                    tU.push_back(u.at(verts[4]+2));

                    tN.push_back(n.at(verts[5]));
                    tN.push_back(n.at(verts[5]+1));
                    tN.push_back(n.at(verts[5]+2));
                    //
                    tV.push_back(v.at(verts[6]));
                    tV.push_back(v.at(verts[6]+1));
                    tV.push_back(v.at(verts[6]+2));

                    tU.push_back(u.at(verts[7]));
                    tU.push_back(u.at(verts[7]+1));
                    tU.push_back(u.at(verts[7]+2));

                    tN.push_back(n.at(verts[8]));
                    tN.push_back(n.at(verts[8]+1));
                    tN.push_back(n.at(verts[8]+2));
                    }
                    catch(std::out_of_range e)
                    {
                        OutputDebugStringA("Out of Range!\n");
                    }
                }
            }
            else
            {
                OutputDebugStringA("Invalid face data! Generic     Error!\n");
                std::stringstream ssc;
                std::stringstream ssc2;

                ssc << loopcount;
                std::string str = ssc.str();
                OutputDebugStringA((char*)str.c_str());
                OutputDebugStringA("\n");
            }

            data3 = "";
            data2 = "";
        }
        loopcount++;

    }

}
else
{

}
}

任何帮助表示赞赏!

这里也是我正在使用的 OBJ 文件:

 v 0.000 0.000 0.000
 v 1.000 0.000 0.000
 v 1.000 1.000 0.000
 v 0.000 0.000 0.000
 v 0.000 1.000 0.000
 v 1.000 1.000 0.000
 vt 0.000 0.000
 vt 1.000 0.000
 vt 1.000 1.000
 vn 0.000 0.000 1.000

 f 1/7/10 2/8/10 3/9/10
 f 4/7/10 5/8/10 6/9/10

好的，我修复了斜线问题，但现在这段代码导致 std::out_of_range 异常:

                tV.push_back(v.at(verts[0]));
                tV.push_back(v.at(verts[0]+1));
                tV.push_back(v.at(verts[0]+2));

                tU.push_back(u.at(verts[1]));
                tU.push_back(u.at(verts[1]+1));
                tU.push_back(u.at(verts[1]+2));

                tN.push_back(n.at(verts[2]));
                tN.push_back(n.at(verts[2]+1));
                tN.push_back(n.at(verts[2]+2));
                //
                tV.push_back(v.at(verts[3]));
                tV.push_back(v.at(verts[3]+1));
                tV.push_back(v.at(verts[3]+2));

                tU.push_back(u.at(verts[4]));
                tU.push_back(u.at(verts[4]+1));
                tU.push_back(u.at(verts[4]+2));

                tN.push_back(n.at(verts[5]));
                tN.push_back(n.at(verts[5]+1));
                tN.push_back(n.at(verts[5]+2));
                //
                tV.push_back(v.at(verts[6]));
                tV.push_back(v.at(verts[6]+1));
                tV.push_back(v.at(verts[6]+2));

                tU.push_back(u.at(verts[7]));
                tU.push_back(u.at(verts[7]+1));
                tU.push_back(u.at(verts[7]+2));

                tN.push_back(n.at(verts[8]));
                tN.push_back(n.at(verts[8]+1));
                tN.push_back(n.at(verts[8]+2));

Answer 1

似乎使用 >> 从 istream 解析不像你期望的那样工作。您是否注意到它在解析顶点、法线和 uvs 时会自动跳过空格？然而，对于面孔，您尝试解析每个角色。您还需要非空白斜杠作为分隔符。

这种方法怎么样https://stackoverflow.com/a/1895584/642532 ?一个答案建议告诉流将逗号(在您的情况下是斜杠)视为空格，这样您就可以像解析顶点一样轻松地解析人脸。另一个答案建议使用像 StrTk http://www.partow.net/programming/strtk/index.html 这样的字符串标记器或提升。