OSG修改日志输出到文件

你的名字 2023-10-18 06:25 25阅读 0赞

osg嵌入到MFC后，就没有控制台了，为了方便看OSG的各种信息，所以要把输入日志打印到文本。

**源码路径：**  
头文件:OpenSceneGraph-3.7.0\\include\\osg\\Notify  
源文件：OpenSceneGraph-3.7.0\\src\\osg\\Notify.cpp

**日志通知等级**

enum NotifySeverity {
        ALWAYS=0,
        FATAL=1,
        WARN=2,
        NOTICE=3,
        INFO=4,
        DEBUG_INFO=5,
        DEBUG_FP=6
    };

**先别激动，来看看什什么等级的日志能notify**

#define OSG_NOTIFY(level) if (osg::isNotifyEnabled(level)) osg::notify(level)
    #define OSG_ALWAYS OSG_NOTIFY(osg::ALWAYS)
    #define OSG_FATAL OSG_NOTIFY(osg::FATAL)
    #define OSG_WARN OSG_NOTIFY(osg::WARN)
    #define OSG_NOTICE OSG_NOTIFY(osg::NOTICE)
    #define OSG_INFO OSG_NOTIFY(osg::INFO)
    #define OSG_DEBUG OSG_NOTIFY(osg::DEBUG_INFO)
    #define OSG_DEBUG_FP OSG_NOTIFY(osg::DEBUG_FP)

if (osg::isNotifyEnabled(level)) osg::notify(level)，如果osg::isNotifyEnabled(level))返回真就通知，来看看里面都写了什么逻辑：

#ifndef OSG_NOTIFY_DISABLED
    bool osg::isNotifyEnabled( osg::NotifySeverity severity )
    {
        //入参要小于你设置的等级才会被通知，就是说你设置成ALWAYS，
        //永远不会触发notify（），你想全部消息都通告的话就设置成DEBUG_FP
        return severity<=getNotifySingleton()._notifyLevel;
    }
    #endif

上面说的好好注意下，我被坑过，以为把等级设置成ALWAYS是全部消息都打印，其实上什么消息都不被打印！！！！！

**默认的通知等级跟通知输出设置**

struct NotifySingleton
    {
        NotifySingleton()
        {
            // _notifyLevel
            // =============
    
            _notifyLevel = osg::NOTICE; // Default value
    
            std::string OSGNOTIFYLEVEL;
            if(getEnvVar("OSG_NOTIFY_LEVEL", OSGNOTIFYLEVEL) || getEnvVar("OSGNOTIFYLEVEL", OSGNOTIFYLEVEL))
            {
    
                std::string stringOSGNOTIFYLEVEL(OSGNOTIFYLEVEL);
    
                // Convert to upper case
                for(std::string::iterator i=stringOSGNOTIFYLEVEL.begin();
                    i!=stringOSGNOTIFYLEVEL.end();
                    ++i)
                {
                    *i=toupper(*i);
                }
    
                if(stringOSGNOTIFYLEVEL.find("ALWAYS")!=std::string::npos)          _notifyLevel=osg::ALWAYS;
                else if(stringOSGNOTIFYLEVEL.find("FATAL")!=std::string::npos)      _notifyLevel=osg::FATAL;
                else if(stringOSGNOTIFYLEVEL.find("WARN")!=std::string::npos)       _notifyLevel=osg::WARN;
                else if(stringOSGNOTIFYLEVEL.find("NOTICE")!=std::string::npos)     _notifyLevel=osg::NOTICE;
                else if(stringOSGNOTIFYLEVEL.find("DEBUG_INFO")!=std::string::npos) _notifyLevel=osg::DEBUG_INFO;
                else if(stringOSGNOTIFYLEVEL.find("DEBUG_FP")!=std::string::npos)   _notifyLevel=osg::DEBUG_FP;
                else if(stringOSGNOTIFYLEVEL.find("DEBUG")!=std::string::npos)      _notifyLevel=osg::DEBUG_INFO;
                else if(stringOSGNOTIFYLEVEL.find("INFO")!=std::string::npos)       _notifyLevel=osg::INFO;
                else std::cout << "Warning: invalid OSG_NOTIFY_LEVEL set ("<<stringOSGNOTIFYLEVEL<<")"<<std::endl;
    
            }
    
            // Setup standard notify handler
            osg::NotifyStreamBuffer *buffer = dynamic_cast<osg::NotifyStreamBuffer *>(_notifyStream.rdbuf());
            if (buffer && !buffer->getNotifyHandler())
                buffer->setNotifyHandler(new StandardNotifyHandler);
        }
    
        osg::NotifySeverity _notifyLevel;
        osg::NullStream     _nullStream;
        osg::NotifyStream   _notifyStream;
    };

可以看出来，默认等级是**osg::NOTICE**，然后会到系统的环境变量名为：**OSG\_NOTIFY\_LEVEL**去读用户设置的通告等级，环境变量设置的格式为:  
\[变量名：值\]->\[OSG\_NOTIFY\_LEVEL ：NOTICE \]

**用户能干预的设置**

再看头文件有4个导出的函数为：

extern OSG_EXPORT void setNotifyLevel(NotifySeverity severity);
    
    /** get the notify level. */
    extern OSG_EXPORT NotifySeverity getNotifyLevel();
    
    /** initialize notify level. */
    extern OSG_EXPORT bool initNotifyLevel();
    
    #ifdef OSG_NOTIFY_DISABLED
        inline bool isNotifyEnabled(NotifySeverity) { return false; }
    #else
        /** is notification enabled, given the current setNotifyLevel() setting? */
        extern OSG_EXPORT bool isNotifyEnabled(NotifySeverity severity);
    #endif
    
    extern OSG_EXPORT void setNotifyHandler(NotifyHandler *handler);
    
    /** Get currrent notification handler. */
    extern OSG_EXPORT NotifyHandler *getNotifyHandler();

这些函数就是用户能调用的，看函数名不难理解其用意，其中我们需要关心的就是  
**setNotifyLevel** 和 **setNotifyHandler**，一个是设置通知的等级，一个是设置如何处理通告。通告的等级不难理解，如何处理通知看函数的传入参数为**NotifyHandler \*handler**，所以我们需要继承这个类重写里面的方法来实现。

class OSG_EXPORT NotifyHandler : public osg::Referenced
    {
    public:
        virtual void notify(osg::NotifySeverity severity, const char *message) = 0;
    };

写好后在调用的地方set一下就ok了。

### 实战例子 ###

//重定向osg日志输出
    class RoadbedNotifyHandler :public osg::NotifyHandler
    {
    public:
        virtual void notify(osg::NotifySeverity severity, const char *message)
        {
            if (severity <= osg::WARN)
                app_print_info(message_type::MT_INFO,message);
            else
            {
                std::string logFileName= string_tools::CString_to_string(file_tools::get_app_path_with_xg());
                logFileName += "3D_Error.log";
    
                FILE* fp=nullptr;
                fopen_s(&fp, logFileName.c_str(), "w");
                if (!fp)
                {
                    app_print_info(message_type::MT_ERROR, _T("3D日志创建失败！"));
                    return;
                }
                else
                {
                    fprintf_s(fp, message);
                    fputchar('\n');
                    fclose(fp);
                }
            }
        }
    };
    
    /*调用*/
    //设置成INFO就行了，DEBUG_FP每一帧都有N条消息吃不消
    osg::setNotifyLevel(osg::NotifySeverity::INFO);
    osg::setNotifyHandler(new RoadbedNotifyHandler);