al_Time.hpp

#ifndef INCLUDE_AL_TIME_HPP
#define INCLUDE_AL_TIME_HPP
 
/*  Allocore --
  Multimedia / virtual environment application class library
 
  Copyright (C) 2009. AlloSphere Research Group, Media Arts & Technology, UCSB.
  Copyright (C) 2012. The Regents of the University of California.
  All rights reserved.
 
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
 
    Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.
 
    Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 
    Neither the name of the University of California nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.
 
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
 
 
  File description:
  C++ helper wrappers for al_time
 
  File author(s):
  Graham Wakefield, 2010, grrrwaaa@gmail.com
  Lance Putnam, 2010, putnam.lance@gmail.com
 
  Keehong Youn, 2016, younkeehong@gmail.com
*/
 
#include <climits>
#include <string>
 
#include <cmath>
 
typedef long long int
    al_nsec;           
typedef double al_sec; 
#define al_time_ns2s 1.0e-9
#define al_time_s2ns 1.0e9
 
namespace al {
 
al_sec al_system_time();
al_nsec al_system_time_nsec();
 
void al_start_steady_clock();
void al_reset_steady_clock();
al_sec al_steady_time();
al_nsec al_steady_time_nsec();
 
void al_sleep(al_sec dt);
void al_sleep_nsec(al_nsec dt);
void al_sleep_until(al_sec target);
 
// backward compatibility
inline void wait(al_sec dt) { al_sleep(dt); }
inline al_sec walltime() { return al_system_time(); }
inline al_sec timeNow() { return al_system_time(); }
 
std::string toTimecode(al_nsec t, const std::string& format = "D:H:M:S:m:u");
 
class Timer {
 public:
  Timer(bool setStartTime = true) {
    if (setStartTime) start();
  }
 
  al_nsec elapsed() const { return mStop - mStart; }
 
  al_sec elapsedSec() const { return al_time_ns2s * elapsed(); }
 
  void start() { mStart = getTime(); }
 
  void stop() { mStop = getTime(); }
 
  void print() const;
 
 private:
  al_nsec mStart = 0, mStop = 0;  // start and stop times
  static al_nsec getTime() { return al_steady_time_nsec(); }
};
 
 
class DelayLockedLoop {
 public:
  DelayLockedLoop(al_sec step_period, double bandwidth = 0.5) {
    tperiod = step_period;
    setBandwidth(bandwidth);
    mReset = true;
  }
 
  void setBandwidth(double bandwidth);
 
  void reset() { mReset = true; }
 
 
  void step(al_sec realtime);
  void operator()(al_sec realtime) { step(realtime); }
 
  al_sec period_smoothed() const { return t2; }
 
  al_sec rate_smoothed() const { return 1. / t2; }
 
  al_sec period_ideal() const { return tperiod; }
 
  al_sec rate_ideal() const { return 1. / tperiod; }
 
 
  al_sec realtime_interp(double alpha) const { return t0 + alpha * (t1 - t0); }
 
 protected:
  al_sec tperiod;  // event period in seconds
  al_sec t0;       // 0th-order component: timestamp of the current event
  al_sec t1;  // 1st-order component: ideally the timestamp of the next event
  al_sec t2;  // 2nd-order component (akin to acceleration, or smoothed event
              // period)
  double mB, mC;  // 1st & 2nd order weights
  bool mReset;
};
 
class Clock {
 public:
  Clock(bool useRT = true)
      : mNow(0),
        mReferenceTime(al_system_time()),
        mDT(0.33),
        mFPS(1. / mDT),
        mFrame(0),
        bUseRT(useRT) {}
 
  Clock(al_sec dt)
      : mNow(0),
        mReferenceTime(al_system_time()),
        mDT(dt),
        mFPS(1. / mDT),
        mFrame(0),
        bUseRT(false) {}
 
  al_sec now() const { return mNow; }
  al_sec operator()() const { return mNow; }
 
  al_sec dt() const { return mDT; }
 
  double fps() const { return mFPS; }
 
  unsigned frame() const { return mFrame; }
 
  bool rt() const { return bUseRT; }
 
  al_sec update() {
    if (bUseRT) {
      al_sec t2 = al_system_time() - mReferenceTime;
      mDT = t2 - mNow;
      mNow = t2;
      mFrame++;
      mFPS = mFPS + 0.1 * ((1. / mDT) - mFPS);
    } else {
      mNow += mDT;
      mFrame++;
      mFPS = 1. / mDT;
    }
    return now();
  }
  al_sec update(al_sec dt) {
    mDT = dt;
    return update();
  }
 
  void useRT() {
    if (!bUseRT) {
      // need to reset reference time:
      mReferenceTime = al_system_time() - mNow;
    }
    bUseRT = true;
  }
  void useNRT(al_sec dt) {
    mDT = dt;
    bUseRT = false;
  }
 
 protected:
  al_sec mNow, mReferenceTime, mDT;
  double mFPS;
  unsigned mFrame;
  bool bUseRT;
};
 
}  // namespace al
 
#endif /* INCLUDE_AL_TIME_CPP_H */