set up for better async handling

src/synthesizer.rs

@@ -7,7 +7,7 @@ pub struct SimpleWavetableSynthesizer<W: Wavetable> {
     clock_freq_hz: usize,
     output_freq_hz: usize,
     enable: bool,
-    counter: usize,
+    pub counter: usize,
     clock_per_sample: usize,
     current_output: <W as Wavetable>::OutputType,
     output_flag: bool,
@@ -33,7 +33,7 @@ impl<W: Wavetable> SimpleWavetableSynthesizer<W> {
 
     pub fn get_output(&mut self) -> <W as Wavetable>::OutputType {
         self.output_flag = false;
-        self.current_output
+        self.wavetable.get_value()
     }
 
     pub fn set_freq(&mut self, freq_hz: usize) {
@@ -43,11 +43,11 @@ impl<W: Wavetable> SimpleWavetableSynthesizer<W> {
     }
 
     pub fn tick(&mut self) {
-        if self.counter == self.clock_per_sample {
-            self.counter = 0;
-            self.current_output = self.wavetable.next();
+        if self.counter >= self.clock_per_sample {
+            self.wavetable.next();
             self.output_flag = true;
+            self.counter = 0;
         }
-        self.counter += 1;
+        self.counter = self.counter.wrapping_add(1)
     }
 }

src/wavetable.rs

@@ -1,7 +1,8 @@
 pub trait Wavetable {
     type OutputType: Default + Copy;
     /// get next sample
-    fn next(&mut self) -> Self::OutputType;
+    fn next(&mut self);
+    fn get_value(&self) -> Self::OutputType;
     fn size(&self) -> usize;
 }
 
@@ -16,13 +17,15 @@ pub struct SimpleWavetable<'a, T: Copy> {
 
 impl<'a, T: Copy + Default> Wavetable for SimpleWavetable<'a, T> {
     type OutputType = T;
-    fn next(&mut self) -> Self::OutputType {
-        let value = self.table[self.index];
+    fn next(&mut self) {
         self.index += 1;
         if self.index > self.table.len() - 1 {
             self.index = 0;
         }
-        value
+    }
+
+    fn get_value(&self) -> Self::OutputType {
+        self.table[self.index]
     }
 
     fn size(&self) -> usize {