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juce_LogRampedValue.h
1/*
2 ==============================================================================
3
4 This file is part of the JUCE library.
5 Copyright (c) 2017 - ROLI Ltd.
6
7 JUCE is an open source library subject to commercial or open-source
8 licensing.
9
10 By using JUCE, you agree to the terms of both the JUCE 5 End-User License
11 Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
12 27th April 2017).
13
14 End User License Agreement: www.juce.com/juce-5-licence
15 Privacy Policy: www.juce.com/juce-5-privacy-policy
16
17 Or: You may also use this code under the terms of the GPL v3 (see
18 www.gnu.org/licenses).
19
20 JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
21 EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
22 DISCLAIMED.
23
24 ==============================================================================
25*/
26
27 namespace juce
28{
29 namespace dsp
30{
31
32//==============================================================================
47 template <typename FloatType>
48 class LogRampedValue : public SmoothedValueBase <LogRampedValue <FloatType>>
49{
50 public:
51 //==============================================================================
53 LogRampedValue() = default;
54
56 LogRampedValue (FloatType initialValue) noexcept
57 {
58 // Visual Studio can't handle base class initialisation with CRTP
59 this->currentValue = initialValue;
60 this->target = initialValue;
61 }
62
63 //==============================================================================
74 void setLogParameters (FloatType midPointAmplitudedB, bool rateOfChangeShouldIncrease) noexcept
75 {
76 jassert (midPointAmplitudedB < (FloatType) 0.0);
77 B = Decibels::decibelsToGain (midPointAmplitudedB);
78
79 increasingRateOfChange = rateOfChangeShouldIncrease;
80 }
81
82 //==============================================================================
87 void reset (double sampleRate, double rampLengthInSeconds) noexcept
88 {
89 jassert (sampleRate > 0 && rampLengthInSeconds >= 0);
90 reset ((int) std::floor (rampLengthInSeconds * sampleRate));
91 }
92
96 void reset (int numSteps) noexcept
97 {
98 stepsToTarget = numSteps;
99
100 this->setCurrentAndTargetValue (this->target);
101
102 updateRampParameters();
103 }
104
105 //==============================================================================
110 void setTargetValue (FloatType newValue) noexcept
111 {
112 if (newValue == this->target)
113 return;
114
115 if (stepsToTarget <= 0)
116 {
117 this->setCurrentAndTargetValue (newValue);
118 return;
119 }
120
121 this->target = newValue;
122 this->countdown = stepsToTarget;
123 source = this->currentValue;
124
125 updateRampParameters();
126 }
127
128 //==============================================================================
132 FloatType getNextValue() noexcept
133 {
134 if (! this->isSmoothing())
135 return this->target;
136
137 --(this->countdown);
138
139 temp *= r; temp += d;
140 this->currentValue = jmap (temp, source, this->target);
141
142 return this->currentValue;
143 }
144
145 //==============================================================================
151 FloatType skip (int numSamples) noexcept
152 {
153 if (numSamples >= this->countdown)
154 {
155 this->setCurrentAndTargetValue (this->target);
156 return this->target;
157 }
158
159 this->countdown -= numSamples;
160
161 auto rN = (FloatType) std::pow (r, numSamples);
162 temp *= rN;
163 temp += d * (rN - (FloatType) 1) / (r - (FloatType) 1);
164
165 this->currentValue = jmap (temp, source, this->target);
166 return this->currentValue;
167 }
168
169 private:
170 //==============================================================================
171 void updateRampParameters()
172 {
173 auto D = increasingRateOfChange ? B : (FloatType) 1 - B;
174 auto base = ((FloatType) 1 / D) - (FloatType) 1;
175 r = std::pow (base, (FloatType) 2 / (FloatType) stepsToTarget);
176 auto rN = std::pow (r, (FloatType) stepsToTarget);
177 d = (r - (FloatType) 1) / (rN - (FloatType) 1);
178 temp = 0;
179 }
180
181 //==============================================================================
182 bool increasingRateOfChange = true;
183 FloatType B = Decibels::decibelsToGain ((FloatType) -40);
184
185 int stepsToTarget = 0;
186 FloatType temp = 0, source = 0, r = 0, d = 1;
187};
188
189} // namespace dsp
190} // namespace juce
juce::Decibels::decibelsToGain
static Type decibelsToGain(Type decibels, Type minusInfinityDb=Type(defaultMinusInfinitydB))
Definition: juce_Decibels.h:42
juce::SmoothedValueBase
Definition: juce_SmoothedValue.h:37
juce::SmoothedValueBase< LogRampedValue< FloatType > >::isSmoothing
bool isSmoothing() const noexcept
Definition: juce_SmoothedValue.h:65
juce::SmoothedValueBase< LogRampedValue< FloatType > >::setCurrentAndTargetValue
void setCurrentAndTargetValue(FloatType newValue)
Definition: juce_SmoothedValue.h:77
juce::dsp::LogRampedValue
Definition: juce_LogRampedValue.h:49
juce::dsp::LogRampedValue::LogRampedValue
LogRampedValue()=default
juce::dsp::LogRampedValue::getNextValue
FloatType getNextValue() noexcept
Definition: juce_LogRampedValue.h:132
juce::dsp::LogRampedValue::reset
void reset(double sampleRate, double rampLengthInSeconds) noexcept
Definition: juce_LogRampedValue.h:87
juce::dsp::LogRampedValue::setLogParameters
void setLogParameters(FloatType midPointAmplitudedB, bool rateOfChangeShouldIncrease) noexcept
Definition: juce_LogRampedValue.h:74
juce::dsp::LogRampedValue::skip
FloatType skip(int numSamples) noexcept
Definition: juce_LogRampedValue.h:151
juce::dsp::LogRampedValue::LogRampedValue
LogRampedValue(FloatType initialValue) noexcept
Definition: juce_LogRampedValue.h:56
juce::dsp::LogRampedValue::reset
void reset(int numSteps) noexcept
Definition: juce_LogRampedValue.h:96
juce::dsp::LogRampedValue::setTargetValue
void setTargetValue(FloatType newValue) noexcept
Definition: juce_LogRampedValue.h:110