STL 格式解析--文本以及二进制格式

版权声明：----------------------------未经博主允许， 随意转载---------------------------- https://blog.csdn.net/yulinxx/article/details/74457276

主入口
判断文件是否有效
以及文件为文本或二进制

read(const char *chFile)
{
    bool bRet = false;
    FILE* fStl = fopen(chFile, "r");
    if (fStl == nullptr)
    {
        return bRet;
    }
    unsigned long long nNumWhiteSpace = 0;
    unsigned char nWhiteSpace;
    if (fread(&nWhiteSpace, 1, 1, fStl) != 1)
    {
        fclose(fStl);
        return bRet;
    }

    while(isspace(nWhiteSpace))
    {
        nNumWhiteSpace++;
        if (fread(&nWhiteSpace, 1, 1, fStl) != 1)
        {
            fclose(fStl);
            return bRet;
        }
    }
    fseek(fStl, nNumWhiteSpace, SEEK_SET);

    char chBuffer[6];
    if (fread(chBuffer, 5, 1, fStl) != 1)
    {
        fclose(fStl);
        return bRet;
    }
    fclose(fStl);

    chBuffer[5] = '\0';

    std::vector<SC_TRIANGLE> m_vecEmpty;
    m_vecEmpty.resize(0);
    m_vecTriangle.swap(m_vecEmpty);
    m_vecTriangle.clear();

    if (stringcasecompare(chBuffer, "solid") == 0)
    {
        bool bLoadSuccess = readVertexTXT(chFile);
        if (!bLoadSuccess)
            return bRet;

        if (m_vecTriangle.size() < 1)
        {
            bRet = readVertexBinary(chFile);
            return bRet;
        }
        return true;
    }

    bRet = readVertexBinary(chFile);
    return bRet;
}

读取文本格式

    FILE *fStl;
    int nRes = fopen_s(&fStl, chFile, "r");
    if (0 != nRes)
    {
        return false;
    }

    char chGet[1024] = { '\0' };


    while (!feof(fStl))
    {
        fgets(chGet, 1024, fStl);
        if (sscanf_s(chGet, " vertex %f %f %f", &pointGet.x, &pointGet.y, &pointGet.z) == 3)
        {
            n++;
            switch(n)
            {
            case 1:
                pt1 = pointGet;
                break;
            case 2:
                pt2 = pointGet;
                break;
            case 3:
                pt3 = pointGet;
                break;
            }
        }
    }

    fclose(fStl);

读取二进制格式

{
    FILE *fStl = nullptr;
    int nRes = fopen_s(&fStl, chFile, "rb");
    if (0 != nRes)
    {
        return false;
    }

    fseek(fStl, 0L, SEEK_END);
    long long file_size = ftell(fStl);
    rewind(fStl);
    size_t face_count = (file_size - 80 - sizeof(uint32_t)) / 50;

    char buffer[80];
    // Skip the header
    if (fread(buffer, 80, 1, fStl) != 1)
    {
        fclose(fStl);
        return false;
    }

    uint32_t nReportedFaceCount;
    // Read the face count. We'll use it as a sort of redundancy code to check for file corruption.
    if (fread(&nReportedFaceCount, sizeof(uint32_t), 1, fStl) != 1)
    {
        fclose(fStl);
        return false;
    }
    if (nReportedFaceCount != face_count)
    {
        //std::to_string(nReportedFaceCount).c_str(), std::to_string(face_count).c_str());
    }

    //For each face read:
    //float(x,y,z) = normal, float(X,Y,Z)*3 = vertexes, uint16_t = flags
    // Every Face is 50 Bytes: Normal(3*float), Vertices(9*float), 2 Bytes Spacer
    //mesh->faces.reserve(face_count);
    //mesh->vertices.reserve(face_count);

    for (unsigned int i = 0; i < face_count; i++)
    {
        if (fread(buffer, 50, 1, fStl) != 1)
        {
            fclose(fStl);
            return false;
        }

        float *v= ((float*)buffer)+3;
        triangle.pt1.x = v[0];
        triangle.pt1.y = v[1];
        triangle.pt1.z = v[2];

        triangle.pt2.x = v[3];
        triangle.pt2.y = v[4];
        triangle.pt2.z = v[5];

        triangle.pt3.x = v[6];
        triangle.pt3.y = v[7];
        triangle.pt3.z = v[8];

        //Point3 v0 = matrix.apply(FPoint3(v[0], v[1], v[2]));
        //Point3 v1 = matrix.apply(FPoint3(v[3], v[4], v[5]));
        //Point3 v2 = matrix.apply(FPoint3(v[6], v[7], v[8]));
        //mesh->addFace(v0, v1, v2);

        m_vecTriangle.push_back(triangle);
    }
    fclose(fStl);

    return true;
}