ADSR envelope

[zsiciarz]

A useful synthesizer component is Attack-Decay-Sustain-Release (ADSR) envelope.

References:

• http://en.wikipedia.org/wiki/Synthesizer#ADSR_envelope
• JavaScript implementation in dsp.js

[zsiciarz]

Idea: write a subclass of SignalSource and reimplement the sample() method:

SampleType ADSR::sample(std::size_t position) const
{
    // calculate gain based on A/D/S/R state and duration progress
    return gain * m_originalSource.sample(position);
}