1 // Copyright 2015 Emilie Gillet.
2 //
3 // Author: Emilie Gillet (emilie.o.gillet@gmail.com)
4 //
5 // Permission is hereby granted, free of charge, to any person obtaining a copy
6 // of this software and associated documentation files (the "Software"), to deal
7 // in the Software without restriction, including without limitation the rights
8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // copies of the Software, and to permit persons to whom the Software is
10 // furnished to do so, subject to the following conditions:
11 //
12 // The above copyright notice and this permission notice shall be included in
13 // all copies or substantial portions of the Software.
14 //
15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // THE SOFTWARE.
22 //
23 // See http://creativecommons.org/licenses/MIT/ for more information.
24 //
25 // -----------------------------------------------------------------------------
26 //
27 // Linear interpolation of parameters in rendering loops.
28 
29 #ifndef STMLIB_DSP_PARAMETER_INTERPOLATOR_H_
30 #define STMLIB_DSP_PARAMETER_INTERPOLATOR_H_
31 
32 #include "stmlib/stmlib.h"
33 
34 namespace stmlib {
35 
36 class ParameterInterpolator {
37  public:
ParameterInterpolator()38   ParameterInterpolator() { }
ParameterInterpolator(float * state,float new_value,size_t size)39   ParameterInterpolator(float* state, float new_value, size_t size) {
40     Init(state, new_value, size);
41   }
42 
ParameterInterpolator(float * state,float new_value,float step)43   ParameterInterpolator(float* state, float new_value, float step) {
44     state_ = state;
45     value_ = *state;
46     increment_ = (new_value - *state) * step;
47   }
48 
~ParameterInterpolator()49   ~ParameterInterpolator() {
50     *state_ = value_;
51   }
52 
Init(float * state,float new_value,size_t size)53   inline void Init(float* state, float new_value, size_t size) {
54     state_ = state;
55     value_ = *state;
56     increment_ = (new_value - *state) / static_cast<float>(size);
57   }
58 
Next()59   inline float Next() {
60     value_ += increment_;
61     return value_;
62   }
63 
subsample(float t)64   inline float subsample(float t) {
65     return value_ + increment_ * t;
66   }
67 
68  private:
69   float* state_;
70   float value_;
71   float increment_;
72 };
73 
74 }  // namespace stmlib
75 
76 #endif  // STMLIB_DSP_PARAMETER_INTERPOLATOR_H_
77