vmmlib  1.13.0
Templatized C++ vector and matrix math library
lowpassFilter.hpp
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32 
33 /* @author Jafet Villafranca
34  *
35  * Implements low pass filtering on a templated data type, which needs to
36  * implement multiplication by a scalar float for smoothing
37  */
38 
39 #ifndef __VMML__LOWPASS_FILTER__HPP__
40 #define __VMML__LOWPASS_FILTER__HPP__
41 
42 #include <deque>
43 
44 namespace vmml
45 {
46 template <size_t M, typename T>
48 {
49 public:
51  LowpassFilter(const float F)
52  : _smoothFactor(F)
53  {
54  }
55  ~LowpassFilter() {}
57  const T& get() const { return _value; }
59  const T* operator->() const { return &_value; }
61  const T& operator*() const { return _value; }
63  const T& add(const T& value);
64 
65 private:
66  std::deque<T> _data;
67  float _smoothFactor;
68  T _value;
69 };
70 
71 template <size_t M, typename T>
72 const T& LowpassFilter<M, T>::add(const T& value)
73 {
74  _data.push_front(value);
75 
76  while (_data.size() > M)
77  _data.pop_back();
78 
79  // update
80  typename std::deque<T>::const_iterator i = _data.begin();
81  _value = *i;
82  double weight = _smoothFactor;
83 
84  for (++i; i != _data.end(); ++i)
85  {
86  _value = _value * (1 - weight) + (*i) * weight;
87  weight *= _smoothFactor;
88  }
89 
90  return _value;
91 }
92 
93 } // namespace vmml
94 
95 #endif
LowpassFilter(const float F)
Construct a new lowpass filter with the given smoothing.
const T * operator->() const
Access the filtered value.
Definition: aabb.hpp:44
const T & operator*() const
Access the filtered value.
const T & add(const T &value)
Add a value to the data set and return the filtered output.