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

[js at users.alioth.debian.org]

The following commit has been merged in the master branch:
commit 2d013c76c2fa31f986ef72b0f52baf2aa3ce5461
Author: Krzysztof Foltman <wdev at foltman.com>
Date:   Mon Jan 19 21:21:49 2009 +0000

    + Phaser: add live frequency response graph

diff --git a/gui/gui-phaser.xml b/gui/gui-phaser.xml
index 01772f2..019e71c 100644
--- a/gui/gui-phaser.xml
+++ b/gui/gui-phaser.xml
@@ -50,4 +50,11 @@
             </vbox>
         </hbox>
     </frame>
+    <if cond="directlink">
+        <frame label="Freq. response" attach-x="0" attach-y="2" >
+            <vbox expand-x="1" fill-x="1" >
+                <line-graph refresh="1" width="160" height="160" param="base_freq"/>
+            </vbox>
+        </frame>
+    </if>
 </table>
diff --git a/src/calf/audio_fx.h b/src/calf/audio_fx.h
index fd9399c..a76ae0b 100644
--- a/src/calf/audio_fx.h
+++ b/src/calf/audio_fx.h
@@ -194,6 +194,21 @@ public:
             *buf_out++ = sdry + swet;
         }
     }
+    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
+        
+        cfloat p = cfloat(1.0);
+        cfloat stg = stage1.h_z(z);
+        
+        for (int i = 0; i < stages; i++)
+            p = p * stg;
+        
+        p = p / (cfloat(1.0) - cfloat(fb) * p);        
+        return std::abs(cfloat(gs_dry.get_last()) + cfloat(gs_wet.get_last()) * p);
+    }
 };
 
 /**
diff --git a/src/calf/biquad.h b/src/calf/biquad.h
index aa81c8a..2e6b4f2 100644
--- a/src/calf/biquad.h
+++ b/src/calf/biquad.h
@@ -315,8 +315,7 @@ public:
     }
     
     /// Return H(z) the filter's gain at frequency freq
-    /// @param freq   Frequency to look up
-    /// @param sr     Filter sample rate (used to convert frequency to angular frequency)
+    /// @param z   Z variable (e^jw)
     cfloat h_z(const cfloat &z)
     {
         
diff --git a/src/calf/modules.h b/src/calf/modules.h
index d60b40f..fc9369c 100644
--- a/src/calf/modules.h
+++ b/src/calf/modules.h
@@ -123,7 +123,7 @@ public:
     float freq_gain(int subindex, float freq, float srate);
 };
 
-class phaser_audio_module: public audio_module<phaser_metadata>
+class phaser_audio_module: public audio_module<phaser_metadata>, public line_graph_iface
 {
 public:
     float *ins[in_count]; 
@@ -182,6 +182,9 @@ 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_iface *context);
+    bool get_gridline(int index, int subindex, float &pos, bool &vertical, std::string &legend, cairo_iface *context);
+    float freq_gain(int subindex, float freq, float srate);
 };
 
 class reverb_audio_module: public audio_module<reverb_metadata>
diff --git a/src/calf/onepole.h b/src/calf/onepole.h
index 9e9dc1a..c9d2e9f 100644
--- a/src/calf/onepole.h
+++ b/src/calf/onepole.h
@@ -34,6 +34,8 @@ template<class T = float, class Coeff = float>
 class onepole
 {
 public:
+    typedef std::complex<double> cfloat;
+
     T x1, y1;
     Coeff a0, a1, b1;
 
@@ -165,6 +167,24 @@ public:
         a1 = src.a1;
         b1 = src.b1;
     }
+    
+    /// Return the filter's gain at frequency freq
+    /// @param freq   Frequency to look up
+    /// @param sr     Filter sample rate (used to convert frequency to angular frequency)
+    float freq_gain(float freq, float sr)
+    {
+        freq *= 2.0 * M_PI / sr;
+        cfloat z = 1.0 / exp(cfloat(0.0, freq));
+        
+        return std::abs(h_z(z));
+    }
+    
+    /// Return H(z) the filter's gain at frequency freq
+    /// @param z   Z variable (e^jw)
+    cfloat h_z(const cfloat &z)
+    {
+        return (cfloat(a0) + double(a1) * z) / (cfloat(1.0) + double(b1) * z);
+    }
 };
 
 };
diff --git a/src/modules_dsp.cpp b/src/modules_dsp.cpp
index 3242bed..d5a81f0 100644
--- a/src/modules_dsp.cpp
+++ b/src/modules_dsp.cpp
@@ -173,6 +173,28 @@ void phaser_audio_module::deactivate()
     is_active = false;
 }
 
+bool phaser_audio_module::get_graph(int index, int subindex, float *data, int points, cairo_iface *context)
+{
+    if (!is_active)
+        return false;
+    if (subindex < 2) 
+    {
+        set_channel_color(context, subindex);
+        return ::get_graph(*this, subindex, data, points);
+    }
+    return false;
+}
+
+float phaser_audio_module::freq_gain(int subindex, float freq, float srate)
+{
+    return (subindex ? right : left).freq_gain(freq, srate);                
+}
+
+bool phaser_audio_module::get_gridline(int index, int subindex, float &pos, bool &vertical, std::string &legend, cairo_iface *context)
+{
+    return get_freq_gridline(subindex, pos, vertical, legend, context);
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////
 
 void reverb_audio_module::activate()

-- 
calf audio plugins packaging