Common file for handling arbitrary tunings.

lib/scale/scale.h

@@ -0,0 +1,53 @@
+#ifndef YAW_SCALE_INCLUDED
+#define YAW_SCALE_INCLUDED
+
+#include <vector>
+
+class Scale
+{
+    double sampleRate = 48000.0;
+
+    // freqs in hz, periods in samples
+    std::vector<double> frequencies;
+    std::vector<double> periods;
+
+public:
+    void newSampleRate(double rate)
+    {
+        double ratio = rate / sampleRate;
+        sampleRate = rate;
+        for (double &note : periods)
+            note *= ratio;
+    };
+
+    // Default ctor: 12TET @ 48kHz
+    Scale(double hz = 440.0)
+    {
+        hz /= 32.0;
+
+        for (int i = 0; i < 12 * 8; ++i)
+        {
+            frequencies.push_back(hz);
+            periods.push_back(sampleRate / hz);
+            hz *= exp2(1.0 / 12.0);
+        }
+    }
+
+    double getNearestPeriod(double period)
+    {
+        for (auto note : periods)
+        {
+            if (period > note)
+                return note;
+        }
+
+        // This should NOT happen.
+        return 0;
+    }
+
+    // TODO: parse scala files. new ctor that parses arbitrary scales
+};
+
+
+
+#endif