sinusoid.h

/*
    Copyright (c) 2019-2023 Brett g Porter
 
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
 
    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
*/
 
#pragma once
 
#include "animatedValue.h"
 
namespace friz
{
class Sinusoid : public TimedValue
{
public:
    Sinusoid (float startPhase_, float endPhase_, int duration)
    : TimedValue (startPhase_, endPhase_, duration)
    , startPhase { startPhase_ }
    , endPhase { endPhase_ }
    {
        jassert (duration > 0);
 
        // requesting the same start/end phase is a request to
        // generate a single cycle
        if (std::abs (endPhase - startPhase) < 0.01f)
        {
            endPhase = startPhase + juce::MathConstants<float>::twoPi;
        }
 
        // if the end phase is less than start, adjust.
        while (endPhase < startPhase)
        {
            endPhase += juce::MathConstants<float>::twoPi;
        }
 
        // hack to make 1st value correct: all of the other value generators
        // correctly use 'startVal` as the first value to be returned. This
        // value generator does *not* want that; startVal is the phase of the
        // sinusoid, and we need to make sure that we convert phase back into
        // the actual sinusoid value on 1st call (and this went undetected for
        // so long because we were only testing with start phase = 0.)
        startVal = std::sin (startPhase);
        // also update the end val in case the animation is cancelled and we jump
        // to the end.
        endVal = std::sin (endPhase);
    }
 
    Sinusoid (int startQuad, int endQuad, int duration)
    : Sinusoid (startQuad * juce::MathConstants<float>::halfPi,
                endQuad * juce::MathConstants<float>::halfPi, duration)
    {
    }
 
private:
    float generateNextValue (float progress) override
    {
        const auto phase { startPhase + (progress * (endPhase - startPhase)) };
        return std::sin (phase);
    }
 
private:
    float startPhase;
    float endPhase;
};
 
} // namespace friz