portemento, adsr

Source/adsr.h

@@ -0,0 +1,98 @@
+/*
+  ==============================================================================
+
+    adsr.h
+    Created: 25 Oct 2025 2:09:32pm
+    Author:  mickl
+
+  ==============================================================================
+*/
+
+#pragma once
+#include <stdint.h>
+/** Distinct stages that the phase of the envelope can be located in.
+- IDLE   = located at phase location 0, and not currently running
+- ATTACK  = First segment of envelope where phase moves from 0 to 1
+- DECAY   = Second segment of envelope where phase moves from 1 to SUSTAIN value
+- RELEASE =     Fourth segment of envelop where phase moves from SUSTAIN to 0
+*/
+enum
+{
+    ADSR_SEG_IDLE = 0,
+    ADSR_SEG_ATTACK = 1,
+    ADSR_SEG_DECAY = 2,
+    ADSR_SEG_RELEASE = 4
+};
+
+
+/** adsr envelope module
+
+Original author(s) : Paul Batchelor
+
+Ported from Soundpipe by Ben Sergentanis, May 2020
+
+Remake by Steffan DIedrichsen, May 2021
+*/
+class Adsr
+{
+public:
+    Adsr() {}
+    ~Adsr() {}
+    /** Initializes the Adsr module.
+        \param sample_rate - The sample rate of the audio engine being run.
+    */
+    void Init(float sample_rate, int blockSize = 1);
+    /**
+     \function Retrigger forces the envelope back to attack phase
+     \param hard  resets the history to zero, results in a click.
+     */
+    void Retrigger(bool hard);
+    /** Processes one sample through the filter and returns one sample.
+        \param gate - trigger the envelope, hold it to sustain
+    */
+    float Process(bool gate);
+    /** Sets time
+        Set time per segment in seconds
+    */
+    void SetTime(int seg, float time);
+    void SetAttackTime(float timeInS, float shape = 0.0f);
+    void SetDecayTime(float timeInS);
+    void SetReleaseTime(float timeInS);
+
+private:
+    void SetTimeConstant(float timeInS, float& time, float& coeff);
+
+public:
+    /** Sustain level
+        \param sus_level - sets sustain level, 0...1.0
+    */
+    inline void SetSustainLevel(float sus_level)
+    {
+        sus_level = (sus_level <= 0.f) ? -0.01f // forces envelope into idle
+            : (sus_level > 1.f) ? 1.f : sus_level;
+        sus_level_ = sus_level;
+    }
+    /** get the current envelope segment
+        \return the segment of the envelope that the phase is currently located in.
+    */
+    inline uint8_t GetCurrentSegment() { return mode_; }
+    /** Tells whether envelope is active
+        \return true if the envelope is currently in any stage apart from idle.
+    */
+    inline bool IsRunning() const { return mode_ != ADSR_SEG_IDLE; }
+
+private:
+    float   sus_level_{ 0.f };
+    float   x_{ 0.f };
+    float   attackShape_{ -1.f };
+    float   attackTarget_{ 0.0f };
+    float   attackTime_{ -1.0f };
+    float   decayTime_{ -1.0f };
+    float   releaseTime_{ -1.0f };
+    float   attackD0_{ 0.f };
+    float   decayD0_{ 0.f };
+    float   releaseD0_{ 0.f };
+    int     sample_rate_;
+    uint8_t mode_{ ADSR_SEG_IDLE };
+    bool    gate_{ false };
+};