Angel 3.2
A 2D Game Prototyping Engine
Interval.h
1 
2 // Copyright (C) 2008-2013, Shane Liesegang
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29 
30 #pragma once
31 
32 #include "../Util/MathUtil.h"
33 
35 
50 template<class T>
51 class Interval
52 {
53 public:
54 
65  Interval(T start, T end, float duration, bool smooth=false) :
66  _start(start),
67  _end(end),
68  _current(start),
69  _duration(duration),
70  _timer(0.0f),
71  _shouldStep(true),
72  _smoothStep(smooth)
73  {
74  }
75 
81  {
82  _shouldStep = false;
83  }
84 
85 
94  T Step(float dt)
95  {
96  if (!_shouldStep)
97  {
98  return _current;
99  }
100 
101  _timer += dt;
102 
103  if (_timer >= _duration)
104  {
105  _current = _end;
106  _shouldStep = false;
107  }
108  else
109  {
110  float stepRatio = _timer / _duration;
111  if (_smoothStep)
112  {
113  //smooth step
114  _current = MathUtil::SmoothStep(_start, _end, stepRatio);
115  }
116  else
117  {
118  //simple lerp
119  _current = MathUtil::Lerp(_start, _end, stepRatio);
120  }
121  }
122 
123  return _current;
124  }
125 
131  float GetCurrent()
132  {
133  return _current;
134  }
135 
142  bool ShouldStep()
143  {
144  return _shouldStep;
145  }
146 
147 private:
148  T _start;
149  T _end;
150  T _current;
151 
152  float _duration;
153  float _timer;
154 
155  bool _shouldStep;
156  bool _smoothStep;
157 };