Factored out scale code

lib/scale/scale.h

@@ -4,13 +4,6 @@
 #include <vector>
 #include <string>
 
-struct Note
-{
-    std::string name;
-    double hz;
-    unsigned int number;
-};
-
 static std::vector<std::string> defaultNoteNames = {
     "A",
     "A#",
@@ -46,17 +39,20 @@ public:
     // Default ctor: 12TET @ 48kHz
     Scale(double hz = 440.0)
     {
-        hz /= 64.0;
+        hz /= 32.0;
 
-        for (int i = 0; i < 12 * 8; ++i)
+        for (int oct = 0; oct < 8; ++oct)
         {
-            frequencies.push_back(hz);
-            periods.push_back(sampleRate / hz);
-            names.push_back(defaultNoteNames[i % 12]);
-            hz *= exp2(1.0 / 12.0);
-        }
-    }
             
+            for (int j = 0; j < 12; ++j)
+            {
+                double note = exp2(j / 12.0) * hz * (1 << oct);
+                frequencies.push_back(note);
+                periods.push_back(sampleRate / note);
+                names.push_back(defaultNoteNames[j]);
+            }
+        }
+    }
 
     double getNearestPeriod(double period)
     {
@@ -70,21 +66,27 @@ public:
         return 0;
     }
 
-    unsigned int getNearestNoteNumber(double hz)
+    double getNearestNoteNumber(double hz)
     {
-        for ( unsigned int i = 0; i < frequencies.size(); ++i )
+        for (unsigned int i = 0; i < frequencies.size(); ++i)
         {
-            if (hz < frequencies[i]) return i;
+            if (hz < frequencies[i])
+            {
+                if (i == 0)
+                    return i;
+                return 1.0 * i + (hz - frequencies[i - 1]) / (frequencies[i] - frequencies[i - 1]);
+            }
         }
 
-        return 0;
+        return 0.0;
     }
 
     double getNearestFrequency(double hz)
     {
         for (auto note : frequencies)
         {
-            if (hz < note) return note;
+            if (hz < note)
+                return note;
         }
 
         return 0;
@@ -93,6 +95,4 @@ public:
     // TODO: parse scala files. new ctor that parses arbitrary scales
 };
 
-
-
 #endif