Adds a multifilter class that is a wrapper around the 4 possible filters that

are included in mozzi. The control changes takes values from 0 to 255
and are internally converted to values the fancier filters (hpf,nf,bpf)
can use.

1 files changed, 97 insertions, 0 deletions

diff --git a/multiFilter.h b/multiFilter.h
new file mode 100644
index 0000000..1b65fe0
--- /dev/null
+++ b/multiFilter.h
@@ -0,0 +1,97 @@
+#ifndef MultiFilter_H
+#    define MultiFilter_H
+#    include <StateVariable.h>
+#    include <LowPassFilter.h>
+
+class Multifilter {
+  private:
+    int filterSelection;
+    int freq;
+    int res;
+    LowPassFilter lpf;
+    StateVariable <NOTCH> nf;
+    StateVariable <HIGHPASS> hpf;
+    StateVariable <BANDPASS> bpf;
+
+  public:
+    
+    Multifilter(int type){
+        filterSelection = type;
+    }
+    
+    /**
+    * 0: Lowpass 1: Highpass, 2 : Bandpass, 3: Notch, 4 : Allpass.
+    */
+    int changeFilter(int selection) {
+        if (filterSelection != selection){
+            filterSelection = selection;
+            setResonance(res);
+            setCutoffFreq(freq);
+        }
+    }
+
+    int setResonance(int resonance) {
+        res = resonance;
+        switch (filterSelection) {
+        case 0:
+            lpf.setResonance(resonance);
+            break;
+        case 1:
+            // Oh non, c'est trop louuurd.
+            //hpf.setResonance(map(resonance, 180, 1, 0, 255));
+            // Approximation d'un mappage de valeurs de 0 à 255 vers 20 à 147.
+            hpf.setResonance(180 - (resonance>>1) -33);
+            break;
+        case 2:
+            bpf.setResonance(180 - (resonance>>1) -33);
+            break;
+        case 3:
+            nf.setResonance(180 - (resonance>>1) -33);
+            break;
+        }
+    }
+
+    int setCutoffFreq(int cutoff) {
+        freq = cutoff;
+        switch (filterSelection) {
+        case 0:
+            lpf.setCutoffFreq(cutoff);
+            break;
+        case 1:
+            // Approximation de mappage de valeurs de 0 à 255 vers 20 à 4100.
+            hpf.setCentreFreq((cutoff<<4)+20);
+            break;
+        case 2:
+            
+            bpf.setCentreFreq((cutoff<<4)+20);
+            break;
+        case 3:
+            
+            nf.setCentreFreq((cutoff<<4)+20);
+            break;
+        }
+    }
+
+    int next(int signal) {
+        switch (filterSelection) {
+        case 0:
+            return lpf.next(signal);
+
+        case 1:
+            return hpf.next(signal);
+
+        case 2:
+            return bpf.next(signal);
+
+        case 3:
+            return nf.next(signal);
+
+        case 4:
+            return signal;
+
+        }
+    }
+
+};
+#endif
+