[SCM] calf/master: + Flanger: add frequency response graph

[js at users.alioth.debian.org]

The following commit has been merged in the master branch:
commit cf36adc67a7de173fbd48db783e6e8fc417678d5
Author: Krzysztof Foltman <wdev at foltman.com>
Date:   Fri Nov 7 19:42:39 2008 +0000

    + Flanger: add frequency response graph

diff --git a/src/calf/audio_fx.h b/src/calf/audio_fx.h
index 1bcf4ae..def9ea6 100644
--- a/src/calf/audio_fx.h
+++ b/src/calf/audio_fx.h
@@ -21,6 +21,8 @@
 #ifndef __CALF_AUDIOFX_H
 #define __CALF_AUDIOFX_H
 
+#include <complex>
+#include <iostream>
 #include "primitives.h"
 #include "delay.h"
 #include "fixed_point.h"
@@ -367,6 +369,22 @@ public:
         }
         last_delay_pos = delay_pos;
     }
+    float freq_gain(float freq, float sr)
+    {
+        typedef std::complex<double> cfloat;
+        freq *= 2.0 * M_PI / sr;
+        cfloat z = 1.0 / exp(cfloat(0.0, freq)); // z^-1
+        
+        float ldp = last_delay_pos / 65536.0;
+        float fldp = floor(ldp);
+        cfloat zn = std::pow(z, fldp); // z^-N
+        cfloat zn1 = zn * z; // z^-(N+1)
+        // simulate a lerped comb filter - H(z) = 1 / (1 + fb * (lerp(z^-N, z^-(N+1), fracpos))), N = int(pos), fracpos = pos - int(pos)
+        cfloat h = cfloat(1.0) / (cfloat(1.0) + cfloat(fb) * (zn + (zn1 - zn) * cfloat(ldp - fldp)));
+        // mix with dry signal
+        float v = std::abs(cfloat(gs_dry.get_last()) + cfloat(gs_wet.get_last()) * h);
+        return v;
+    }
 };
 
 /**
diff --git a/src/calf/modules.h b/src/calf/modules.h
index 67ff820..4769e1c 100644
--- a/src/calf/modules.h
+++ b/src/calf/modules.h
@@ -59,7 +59,19 @@ public:
 };
 #endif
 
-class flanger_audio_module: public audio_module<flanger_metadata>
+template<class Fx>
+bool get_graph(Fx &fx, int subindex, float *data, int points)
+{
+    for (int i = 0; i < points; i++)
+    {
+        typedef std::complex<double> cfloat;
+        double freq = 20.0 * pow (20000.0 / 20.0, i * 1.0 / points);
+        data[i] = log(fx.freq_gain(subindex, freq, fx.srate)) / log(1024.0) + 0.5;
+    }
+    return true;
+}
+
+class flanger_audio_module: public audio_module<flanger_metadata>, public line_graph_iface
 {
 public:
     dsp::simple_flanger<float, 2048> left, right;
@@ -122,6 +134,16 @@ public:
         right.process(outs[1] + offset, ins[1] + offset, nsamples);
         return outputs_mask; // XXXKF allow some delay after input going blank
     }
+    bool get_graph(int index, int subindex, float *data, int points, cairo_t *context)
+    {
+        if (index == par_delay && subindex < 2) 
+            return calf_plugins::get_graph(*this, subindex, data, points);
+        return false;
+    }
+    float freq_gain(int subindex, float freq, float srate)
+    {
+        return (subindex ? right : left).freq_gain(freq, srate);                
+    }
 };
 
 class phaser_audio_module: public audio_module<phaser_metadata>
@@ -379,20 +401,17 @@ public:
     }
     bool get_graph(int index, int subindex, float *data, int points, cairo_t *context)
     {
-        if (index == par_cutoff && !subindex) {
-            for (int i = 0; i < points; i++)
-            {
-                typedef std::complex<double> cfloat;
-                double freq = 20.0 * pow (20000.0 / 20.0, i * 1.0 / points);
-                float level = 1.0;
-                for (int j = 0; j < order; j++)
-                    level *= left[j].freq_gain(freq, srate);                
-                data[i] = log(level) / log(1024.0) + 0.5;
-            }
-            return true;
-        }
+        if (index == par_cutoff && !subindex) 
+            return calf_plugins::get_graph(*this, subindex, data, points);
         return false;
     }
+    float freq_gain(int subindex, float freq, float srate)
+    {
+        float level = 1.0;
+        for (int j = 0; j < order; j++)
+            level *= left[j].freq_gain(freq, srate);                
+        return level;
+    }
 };
 
 class vintage_delay_audio_module: public audio_module<vintage_delay_metadata>
diff --git a/src/modules.cpp b/src/modules.cpp
index 28c62ee..7d84f50 100644
--- a/src/modules.cpp
+++ b/src/modules.cpp
@@ -37,7 +37,7 @@ const char *calf_plugins::calf_copyright_info = "(C) 2001-2008 Krzysztof Foltman
 CALF_PORT_NAMES(flanger) = {"In L", "In R", "Out L", "Out R"};
 
 CALF_PORT_PROPS(flanger) = {
-    { 0.1,      0.1, 10,    0, PF_FLOAT | PF_SCALE_LOG | PF_CTL_KNOB | PF_UNIT_MSEC, NULL, "min_delay", "Minimum delay" },
+    { 0.1,      0.1, 10,    0, PF_FLOAT | PF_SCALE_LOG | PF_CTL_KNOB | PF_UNIT_MSEC | PF_PROP_GRAPH, NULL, "min_delay", "Minimum delay" },
     { 0.5,      0.1, 10,    0, PF_FLOAT | PF_SCALE_LOG | PF_CTL_KNOB | PF_UNIT_MSEC, NULL, "mod_depth", "Modulation depth" },
     { 0.25,    0.01, 20,    0, PF_FLOAT | PF_SCALE_LOG | PF_CTL_KNOB | PF_UNIT_HZ, NULL, "mod_rate", "Modulation rate" },
     { 0.90,   -0.99, 0.99,  0, PF_FLOAT | PF_SCALE_PERC | PF_CTL_KNOB | PF_UNIT_COEF, NULL, "feedback", "Feedback" },

-- 
calf audio plugins packaging