source/libmarklin/simplephysics.cpp

   1 /* $Id$
   2
   3 This file is part of the MSP Märklin suite
   4 Copyright © 2010  Mikkosoft Productions, Mikko Rasa
   5 Distributed under the GPL
   6 */
   7
   8 #include <msp/core/except.h>
   9 #include <msp/time/units.h>
  10 #include "simplephysics.h"
  11
  12 using namespace std;
  13 using namespace Msp;
  14
  15 namespace Marklin {
  16
  17 SimplePhysics::SimplePhysics():
  18         target_speed(TrainControl::continuous("speed", -1000, 1000)),
  19         accel(0.07),
  20         speed(0)
  21 {
  22         target_speed.set(0);
  23 }
  24
  25 void SimplePhysics::set_control(const string &name, float v)
  26 {
  27         if(name=="speed")
  28         {
  29                 target_speed.set(v);
  30                 signal_control_changed.emit(name, target_speed.value);
  31         }
  32 }
  33
  34 const TrainControl &SimplePhysics::get_control(const string &name) const
  35 {
  36         if(name=="speed")
  37                 return target_speed;
  38         else
  39                 throw KeyError("Unknown control", name);
  40 }
  41
  42 float SimplePhysics::get_braking_distance() const
  43 {
  44         return speed*speed/(2*accel);
  45 }
  46
  47 void SimplePhysics::tick(const Time::TimeDelta &dt)
  48 {
  49         float secs = dt/Time::sec;
  50         if(speed<target_speed.value)
  51         {
  52                 speed += secs*accel;
  53                 if(speed>target_speed.value)
  54                         speed = target_speed.value;
  55         }
  56         else if(speed>target_speed.value)
  57         {
  58                 speed -= secs*accel;
  59                 if(speed<target_speed.value)
  60                         speed = target_speed.value;
  61         }
  62 }
  63
  64 } // namespace Marklin