dl_time.h

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#pragma once
 
#include <string>
#include <chrono>
 
#include "dl_type.h"
 
namespace dl
{
class Time
{
    friend class System;
public:
    Time() :
        _delta{ 0 },
        _fps{ 0 },
        _fpsExpect{ 60 },
        _countSec{ 0 },
        _countFrame{ 0 }
    {
        _start = std::chrono::high_resolution_clock::now();
        _last = _start;
        _delta = 0;
        _cacl_expect();
    }

    FloatTime GetDelta()
    {
        return _delta;
    }

    unsigned GetFPS()
    {
        return _fps;
    }

    void SetFPS(unsigned fps)
    {
        _fpsExpect = fps;
        _cacl_expect();
    }

    FloatTime GetCurrent()
    {
        auto current = std::chrono::high_resolution_clock::now();
        return std::chrono::duration<FloatTime, std::chrono::seconds::period>
            (current - _start).count();
    }

    double GetCurrent64()
    {
        auto current = std::chrono::high_resolution_clock::now();
        return std::chrono::duration<double, std::chrono::seconds::period>
            (current - _start).count();
    }
    //--------------------------------当前帧时间--------------------------------
    time_t GetFrameTimeStamp()
    {
        return _frame._timeStamp;
    }

    time_t GetFrameTimeStampMs()
    {
        return _frame._timeStampMs;
    }

    unsigned GetFrameTkc()
    {
        return _frame._tkc;
    }
    //--------------------------------时间戳--------------------------------
    static time_t GetTimeStamp();
    static time_t GetTimeStampMs();
    
    static std::string TimeStampDelta2String(time_t t);
 
    enum Type
    {
        ET_YEAR      = 1 << 1,
        ET_MONTH    = 1 << 2,
        ET_DAY        = 1 << 3,
        ET_HOUR      = 1 << 4,
        ET_MINUTE  = 1 << 5,
        ET_SECOND  = 1 << 6,
        ET_YMD = ET_YEAR | ET_MONTH | ET_DAY,
        ET_HMS = ET_HOUR | ET_MINUTE | ET_SECOND,
        ET_YMD_HMS = ET_YMD | ET_HMS
    };

    static std::string TimeStamp2String(time_t t, Type type = ET_HMS,
        std::string_view year = "-", std::string_view month = "-", std::string_view day = " ",
        std::string_view hour = ":", std::string_view minute = ":", std::string_view second = "");
 
    static std::string ExTimeStamp2StringLog()
    {
        return TimeStamp2String(GetTimeStamp(), ET_YMD_HMS, "", "", "", "-", "", "");
    }

    static void Sleep(unsigned t = 0);
private:
    FloatTime _delta;          //(s)真实间隔时间
    FloatTime _deltaExpect;        //(s)一帧应该运行的时间
    unsigned _fps;              //真实帧数
    unsigned _fpsExpect;        //设置的帧数
    FloatTime _countSec;       //时间计数（用于fps计算）
    unsigned _countFrame;       //帧计数（用于fps计算）
 
    std::chrono::nanoseconds _deltaExpectNS;
 
    std::chrono::high_resolution_clock::time_point _start;//起始时间
    std::chrono::high_resolution_clock::time_point _last;//上帧时间
 
    struct Frame
    {
        time_t _timeStamp;
        time_t _timeStampMs;
        unsigned _tkc;
        Frame() :
            _timeStamp{},
            _timeStampMs{},
            _tkc{}
        {
        }
    };
    Frame _frame;
 
    // 帧末尾，计算这一帧花费时间（但是下一帧才访问到）
    void _update();
    // 帧时间信息
    void _update_pre();
 
    // 根据期望fps计算期望delta
    void _cacl_expect();
    // 控制帧率
    void _sleep();
};
extern Time* g_time;
}