Added DaisySP

daisysp/Utility/smooth_random.h

@@ -0,0 +1,85 @@
+/*
+Copyright (c) 2020 Electrosmith, Corp, Emilie Gillet
+
+Use of this source code is governed by an MIT-style
+license that can be found in the LICENSE file or at
+https://opensource.org/licenses/MIT.
+*/
+
+#pragma once
+#ifndef DSY_SMOOTHRANDOM_H
+#define DSY_SMOOTHRANDOM_H
+
+#include "dsp.h"
+#include <stdint.h>
+#include <stdlib.h>
+#ifdef __cplusplus
+
+/** @file smooth_random.h */
+
+namespace daisysp
+{
+/**  
+       @brief Smooth random generator for internal modulation. \n
+       @author Ported by Ben Sergentanis 
+       @date Jan 2021 
+       Ported from pichenettes/eurorack/plaits/dsp/noise/smooth_random_generator.h \n
+       to an independent module. \n
+       Original code written by Emilie Gillet in 2016. \n
+*/
+class SmoothRandomGenerator
+{
+  public:
+    SmoothRandomGenerator() {}
+    ~SmoothRandomGenerator() {}
+
+    /** Initialize the module
+        \param sample_rate Audio engine sample rate.
+    */
+    void Init(float sample_rate)
+    {
+        sample_rate_ = sample_rate;
+
+        SetFreq(1.f);
+        phase_    = 0.0f;
+        from_     = 0.0f;
+        interval_ = 0.0f;
+    }
+
+    /** Get the next float. Ranges from -1 to 1. */
+    float Process()
+    {
+        phase_ += frequency_;
+        if(phase_ >= 1.0f)
+        {
+            phase_ -= 1.0f;
+            from_ += interval_;
+            interval_ = rand() * kRandFrac * 2.0f - 1.0f - from_;
+        }
+        float t = phase_ * phase_ * (3.0f - 2.0f * phase_);
+        return from_ + interval_ * t;
+    }
+
+    /** How often to slew to a new random value
+        \param freq Rate in Hz
+    */
+    void SetFreq(float freq)
+    {
+        freq       = freq / sample_rate_;
+        frequency_ = fclamp(freq, 0.f, 1.f);
+    }
+
+  private:
+    float frequency_;
+    float phase_;
+    float from_;
+    float interval_;
+
+    float sample_rate_;
+
+    static constexpr float kRandFrac = 1.f / (float)RAND_MAX;
+};
+
+} // namespace daisysp
+#endif
+#endif