Support interpolation to nearest

src/sfizz/Interpolators.h

@@ -9,6 +9,8 @@
 namespace sfz {
 
 enum InterpolatorModel : int {
+    // a nearest interpolator
+    kInterpolatorNearest,
     // a linear interpolator
     kInterpolatorLinear,
     // a Hermite 3rd order interpolator

src/sfizz/Interpolators.hpp

@@ -19,6 +19,19 @@ inline R interpolate(const R* values, R coeff)
     return Interpolator<M, R>::process(values, coeff);
 }
 
+//------------------------------------------------------------------------------
+// Nearest
+
+template <class R>
+class Interpolator<kInterpolatorNearest, R>
+{
+public:
+    static inline R process(const R* values, R coeff)
+    {
+        return values[coeff > static_cast<R>(0.5)];
+    }
+};
+
 //------------------------------------------------------------------------------
 // Linear
 

src/sfizz/Wavetables.cpp

@@ -144,8 +144,9 @@ void WavetableOscillator::process(float frequency, float detuneRatio, float* out
     int quality = clamp(_quality, 0, 3);
 
     switch (quality) {
-    case 0: // supposed to be nearest according to book
+    case 0:
-        // fall through
+        processSingle<kInterpolatorNearest>(frequency, detuneRatio, output, nframes);
+        break;
     case 1:
         processSingle<kInterpolatorLinear>(frequency, detuneRatio, output, nframes);
         break;
@@ -163,8 +164,9 @@ void WavetableOscillator::processModulated(const float* frequencies, float detun
     int quality = clamp(_quality, 0, 3);
 
     switch (quality) {
-    case 0: // supposed to be nearest according to book
+    case 0:
-        // fall through
+        processModulatedSingle<kInterpolatorNearest>(frequencies, detuneRatio, output, nframes);
+        break;
     case 1:
         processModulatedSingle<kInterpolatorLinear>(frequencies, detuneRatio, output, nframes);
         break;