// загрузка шейдеров

    std::ifstream   fin;
    std::string     buf;
    std::string     file;

    fin.open("shaders/shader.vert", std::fstream::in);
    if (fin.is_open())
    {
        file.clear();
        std::cout<<"Vertex shader source opened"<<std::endl;
        while (std::getline(fin, buf))
            file += buf + '\n';
    }
    else
        std::cout<<"\n!!! VERTEX SHADER NOT FOUND !!!\n"<<std::endl;
    const GLchar* vertexShaderSource = file.c_str();
    fin.close();

    fin.open("shaders/shader.frag", std::fstream::in);
    if (fin.is_open())
    {
        file.clear();
        std::cout<<"Fragment shader source opened"<<std::endl;
        while (std::getline(fin, buf))
            file += buf + '\n';
    }
    else
        std::cout<<"\n!!! VERTEX SHADER NOT FOUND !!!\n"<<std::endl;
    const GLchar* fragmentShaderSource = file.c_str();
    fin.close();

/*
    const GLchar* vertexShaderSource = "#version 330 core\n"
        "layout (location = 0) in vec3 position;\n"
        "void main()\n"
        "{\n"
        "gl_Position = vec4(position.x, position.y, position.z, 1.0);\n"
        "}\0";
    const GLchar* fragmentShaderSource = "#version 330 core\n"
        "out vec4 color;\n"
        "void main()\n"
        "{\n"
        "color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
        "}\n\0";
*/