zynaddsubfx

commit 18012fbb5c92c4b2f45a4ec8c6d85bea8341a5c7
parent db2756d00fddced77b20b704ed367081e3d3851b
Author: Friedolino <[email protected]>
Date:   Sat,  5 Jun 2021 17:32:14 +0200

moog filter fixes from review

Diffstat:
M
src/DSP/MoogFilter.cpp
 | 
21
++++++++++-----------
M
src/DSP/MoogFilter.h
 | 
15
+++++++--------
M
src/UI/FilterUI.fl
 | 
10
+++++++++-

3 files changed, 26 insertions(+), 20 deletions(-)
diff --git a/src/DSP/MoogFilter.cpp b/src/DSP/MoogFilter.cpp
@@ -13,10 +13,10 @@ namespace zyn{
 
 MoogFilter::MoogFilter(unsigned char Ftype, float Ffreq, float Fq,
     unsigned int srate, int bufsize)
-    :Filter(srate, bufsize), sr(srate), gain(1.0f), type(Ftype)
+    :Filter(srate, bufsize), sr(srate), gain(1.0f)
 {
     setfreq_and_q(Ffreq/srate, Fq);
-    settype(type); // q must be set before
+    settype(Ftype); // q must be set before
     for (unsigned int i = 0; i<(sizeof(state)/sizeof(*state)); i++)
     {
         state[i] = 0.0f;
@@ -28,14 +28,14 @@ MoogFilter::~MoogFilter(void)
 
 }
 
-inline float MoogFilter::tan_2(const float x)
+inline float MoogFilter::tan_2(const float x) const
 {
     //Pade approximation tan(x) hand tuned to map fCutoff
     float x2 = x*x;
     return ((9.5f*(11.15f*x - x2*x))/(105.0f - 45.0f*x2 + x2*x2));
 }
 
-inline float MoogFilter::tanhX(const float x)
+inline float MoogFilter::tanhX(const float x) const
 {
     // Pade approximation of tanh(x) bound to [-1 .. +1]
     // https://mathr.co.uk/blog/2017-09-06_approximating_hyperbolic_tangent.html
@@ -44,7 +44,7 @@ inline float MoogFilter::tanhX(const float x)
 }
 
 
-inline float MoogFilter::tanhXdivX(float x)
+inline float MoogFilter::tanhXdivX(float x) const
 {
     // Pade approximation for tanh(x)/x used in filter stages
     float x2 = x*x;
@@ -153,17 +153,16 @@ void MoogFilter::setgain(float dBgain)
     gain = dB2rap(dBgain);
 }
 
-void MoogFilter::settype(unsigned char type_)
+void MoogFilter::settype(unsigned char ftype)
 {
-    type = type_;
-    switch (type)
+    switch (ftype)
     {
-        case 1:
-            a0 = 0.0f; a1 = 0.0f; a2 = 4.0f; a3 =-8.0f; a4 = 4.0f;
-            break;
         case 0:
             a0 = 1.0f; a1 =-4.0f; a2 = 6.0f; a3 =-4.0f; a4 = 1.0f;
             break;
+        case 1:
+            a0 = 0.0f; a1 = 0.0f; a2 = 4.0f; a3 =-8.0f; a4 = 4.0f;
+            break;
         case 2:
         default:
             a0 = 0.0f; a1 = 0.0f; a2 = 0.0f; a3 = 0.0f; a4 = passbandCompensation;
diff --git a/src/DSP/MoogFilter.h b/src/DSP/MoogFilter.h
@@ -1,9 +1,9 @@
 /*
   ZynAddSubFX - a software synthesizer
 
-  Moog Filter.h - Several analog filters (lowpass, highpass...)
-  Copyright (C) 2018-2018 Mark McCurry
-  Author: Mark McCurry
+  Moog Filter.h - moog style multimode filter (lowpass, highpass...)
+  Copyright (C) 2020-2020 Michael Kirchner
+  Author: Michael Kirchner
 
   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
@@ -28,18 +28,17 @@ class MoogFilter:public Filter
         void setfreq_and_q(float frequency, float q_) override;
         void setq(float /*q_*/) override;
         void setgain(float dBgain) override;
-        void settype(unsigned char type); //
+        void settype(unsigned char ftype);
 
     private:
         unsigned sr;
         float gain;
-        unsigned char type;
 
         float step(float x);
 
-        float tanhXdivX(const float x);
-        float tanhX(const float x);
-        float tan_2(const float x);
+        float tanhXdivX(const float x) const;
+        float tanhX(const float x) const;
+        float tan_2(const float x) const;
 
         float feedbackGain;
         // aN: multimode coefficients for LP,BP,HP configurations
diff --git a/src/UI/FilterUI.fl b/src/UI/FilterUI.fl
@@ -171,9 +171,17 @@ delete (formantparswindow);} {}
           class Fl_Osc_Choice
         } {
           MenuItem {} {
-            label LPF
+            label LP
             xywh {134 134 100 20} labelfont 1 labelsize 10
           }
+          MenuItem {} {
+            label HP
+            xywh {144 144 100 20} labelfont 1 labelsize 10
+          }
+          MenuItem {} {
+            label BP
+            xywh {154 154 100 20} labelfont 1 labelsize 10
+          }
         }
         Fl_Choice filtertype {
           label Category