Added DaisySP

daisysp/PhysicalModeling/resonator.h

@@ -0,0 +1,191 @@
+/*
+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_RESONATOR_H
+#define DSY_RESONATOR_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "Utility/dsp.h"
+#ifdef __cplusplus
+
+
+/** @file resonator.h */
+
+namespace daisysp
+{
+// We render 4 modes simultaneously since there are enough registers to hold
+// all state variables.
+/**  
+       @brief SVF for use in the Resonator Class \n 
+       @author Ported by Ben Sergentanis 
+       @date Jan 2021 
+       Ported from pichenettes/eurorack/plaits/dsp/physical_modelling/resonator.h \n
+       to an independent module. \n
+       Original code written by Emilie Gillet in 2016. \n
+*/
+template <int batch_size>
+class ResonatorSvf
+{
+  public:
+    enum FilterMode
+    {
+        LOW_PASS,
+        BAND_PASS,
+        BAND_PASS_NORMALIZED,
+        HIGH_PASS
+    };
+
+    ResonatorSvf() {}
+    ~ResonatorSvf() {}
+
+    void Init()
+    {
+        for(int i = 0; i < batch_size; ++i)
+        {
+            state_1_[i] = state_2_[i] = 0.0f;
+        }
+    }
+
+    template <FilterMode mode, bool add>
+    void Process(const float* f,
+                 const float* q,
+                 const float* gain,
+                 const float  in,
+                 float*       out)
+    {
+        float g[batch_size];
+        float r[batch_size];
+        float r_plus_g[batch_size];
+        float h[batch_size];
+        float state_1[batch_size];
+        float state_2[batch_size];
+        float gains[batch_size];
+        for(int i = 0; i < batch_size; ++i)
+        {
+            g[i]        = fasttan(f[i]);
+            r[i]        = 1.0f / q[i];
+            h[i]        = 1.0f / (1.0f + r[i] * g[i] + g[i] * g[i]);
+            r_plus_g[i] = r[i] + g[i];
+            state_1[i]  = state_1_[i];
+            state_2[i]  = state_2_[i];
+            gains[i]    = gain[i];
+        }
+
+        float s_in  = in;
+        float s_out = 0.0f;
+        for(int i = 0; i < batch_size; ++i)
+        {
+            const float hp
+                = (s_in - r_plus_g[i] * state_1[i] - state_2[i]) * h[i];
+            const float bp = g[i] * hp + state_1[i];
+            state_1[i]     = g[i] * hp + bp;
+            const float lp = g[i] * bp + state_2[i];
+            state_2[i]     = g[i] * bp + lp;
+            s_out += gains[i] * ((mode == LOW_PASS) ? lp : bp);
+        }
+        if(add)
+        {
+            *out++ += s_out;
+        }
+        else
+        {
+            *out++ = s_out;
+        }
+
+        for(int i = 0; i < batch_size; ++i)
+        {
+            state_1_[i] = state_1[i];
+            state_2_[i] = state_2[i];
+        }
+    }
+
+  private:
+    static constexpr float kPiPow3 = PI_F * PI_F * PI_F;
+    static constexpr float kPiPow5 = kPiPow3 * PI_F * PI_F;
+    static inline float    fasttan(float f)
+    {
+        const float a  = 3.260e-01 * kPiPow3;
+        const float b  = 1.823e-01 * kPiPow5;
+        float       f2 = f * f;
+        return f * (PI_F + f2 * (a + b * f2));
+    }
+
+    float state_1_[batch_size];
+    float state_2_[batch_size];
+};
+
+
+/**         
+       @brief Resonant Body Simulation
+       @author Ported by Ben Sergentanis 
+       @date Jan 2021 
+       Ported from pichenettes/eurorack/plaits/dsp/physical_modelling/resonator.h \n
+       to an independent module. \n
+       Original code written by Emilie Gillet in 2016. \n 
+*/
+class Resonator
+{
+  public:
+    Resonator() {}
+    ~Resonator() {}
+
+    /** Initialize the module
+        \param position    Offset the phase of the amplitudes. 0-1
+        \param resolution Quality vs speed scalar
+        \param sample_rate Samplerate of the audio engine being run.
+    */
+    void Init(float position, int resolution, float sample_rate);
+
+    /** Get the next sample_rate
+        \param in The signal to excited the resonant body
+    */
+    float Process(const float in);
+
+    /** Resonator frequency.
+        \param freq Frequency in Hz.
+    */
+    void SetFreq(float freq);
+
+    /** Changes the general charater of the resonator (stiffness, brightness)
+        \param structure Works best from 0-1
+    */
+    void SetStructure(float structure);
+
+    /** Set the brighness of the resonator
+        \param brightness Works best 0-1
+    */
+    void SetBrightness(float brightness);
+
+    /** How long the resonant body takes to decay.
+        \param damping Works best 0-1
+    */
+    void SetDamping(float damping);
+
+  private:
+    int   resolution_;
+    float frequency_, brightness_, structure_, damping_;
+
+    static constexpr int   kMaxNumModes   = 24;
+    static constexpr int   kModeBatchSize = 4;
+    static constexpr float ratiofrac_     = 1.f / 12.f;
+    static constexpr float stiff_frac_    = 1.f / 64.f;
+    static constexpr float stiff_frac_2   = 1.f / .6f;
+
+    float sample_rate_;
+
+    float CalcStiff(float sig);
+
+    float                        mode_amplitude_[kMaxNumModes];
+    ResonatorSvf<kModeBatchSize> mode_filters_[kMaxNumModes / kModeBatchSize];
+};
+
+} // namespace daisysp
+#endif
+#endif