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49 lines
1.5 KiB
C++

#pragma once
#include <JuceHeader.h>
namespace serum
{
// ===========================================================================
// ADSR envelope with curve tension. Durations are in seconds; the sustain
// level is 0..1. Retriggering (noteOn while active) starts from the current
// value for click-free legato behaviour.
// ===========================================================================
class Envelope
{
public:
void prepare (double sampleRate) { sr = sampleRate; reset(); }
void reset();
void noteOn();
void noteOff();
void setParams (float attackSec, float decaySec, float sustain, float releaseSec, float curve);
float process() noexcept; // advance one sample and return the value
float getValue() const noexcept { return value; }
bool isActive() const noexcept { return stage != Stage::Idle; }
// Snapshot for GUI rendering.
struct Shape { float attack = 0, decay = 0, sustain = 0, release = 0, curve = 0.5f; };
Shape getShape() const noexcept { return shape; }
private:
enum class Stage { Idle, Attack, Decay, Sustain, Release };
Stage stage = Stage::Idle;
double sr = 44100.0;
float value = 0.0f;
float startValue = 0.0f, endValue = 0.0f;
double elapsed = 0.0, duration = 0.0;
double attackShape = 1.0, decayShape = 1.0;
float sustain = 0.7f;
double attackSamples = 0.0, decaySamples = 0.0, releaseSamples = 0.0;
Shape shape;
};
} // namespace serum