Optimize wavetable sampling

 * Created dedicated oversampled versions of dimension + waveform sampling functions to help avoid overhead of calling them over in a loop
 * Update mixer levels viz UI after adding/removing inputs

engine/wavetable/src/fm/mod.rs

@@ -498,19 +498,17 @@ impl Oscillator for WaveTableHandle {
     ];
 
     // 4x oversampling to avoid aliasing
-    let oversample_factor = 4usize;
-    let mut sample = 0.;
+    const OVERSAMPLE_FACTOR: usize = 4usize;
     let mut phase = self.phase;
-    for _ in 0..oversample_factor {
-      phase = Self::compute_new_phase_oversampled(phase, oversample_factor as f32, frequency);
-      sample += wavetable.get_sample(
-        phase * (wavetable.settings.waveform_length - 1) as f32,
-        &mixes,
-      );
-    }
+    let sample_indices: [f32; OVERSAMPLE_FACTOR] = std::array::from_fn(|_| {
+      phase = Self::compute_new_phase_oversampled(phase, OVERSAMPLE_FACTOR as f32, frequency);
+      phase * (wavetable.settings.waveform_length - 1) as f32
+    });
+
+    let sample = wavetable.get_sample_oversampled::<OVERSAMPLE_FACTOR>(sample_indices, &mixes);
 
     self.phase = phase;
-    sample / oversample_factor as f32
+    sample
   }
 }
 

engine/wavetable/src/lib.rs

@@ -109,6 +109,42 @@ impl WaveTable {
     // )
   }
 
+  fn sample_waveform_oversampled<const OVERSAMPLE_FACTOR: usize>(
+    &self,
+    dimension_ix: usize,
+    waveform_ix: usize,
+    sample_indices: [f32; OVERSAMPLE_FACTOR],
+  ) -> f32 {
+    let waveform_offset_samples = (dimension_ix * self.settings.get_samples_per_dimension())
+      + (waveform_ix * self.settings.waveform_length);
+
+    let mut sample_acc = 0.;
+    for sample_ix in sample_indices {
+      let sample_mix = sample_ix.fract();
+      let (sample_low_ix, sample_hi_ix) = (
+        sample_ix.floor() as usize,
+        (sample_ix.ceil() as usize).min(self.samples.len() - 1),
+      );
+
+      let (low_sample, high_sample) = (
+        unsafe {
+          *self
+            .samples
+            .get_unchecked(waveform_offset_samples + sample_low_ix)
+        },
+        unsafe {
+          *self
+            .samples
+            .get_unchecked(waveform_offset_samples + sample_hi_ix)
+        },
+      );
+
+      sample_acc += mix(sample_mix, low_sample, high_sample);
+    }
+
+    sample_acc / OVERSAMPLE_FACTOR as f32
+  }
+
   fn sample_dimension(&self, dimension_ix: usize, waveform_ix: f32, sample_ix: f32) -> f32 {
     let waveform_mix = waveform_ix.fract();
     if waveform_mix == 0. {
@@ -124,6 +160,28 @@ impl WaveTable {
     mix(waveform_mix, low_sample, high_sample)
   }
 
+  fn sample_dimension_oversampled<const OVERSAMPLE_FACTOR: usize>(
+    &self,
+    dimension_ix: usize,
+    waveform_ix: f32,
+    sample_indices: [f32; OVERSAMPLE_FACTOR],
+  ) -> f32 {
+    let waveform_mix = waveform_ix.fract();
+    if waveform_mix == 0. {
+      return self.sample_waveform_oversampled(dimension_ix, waveform_ix as usize, sample_indices);
+    }
+
+    let (waveform_low_ix, waveform_hi_ix) =
+      (waveform_ix.floor() as usize, waveform_ix.ceil() as usize);
+
+    let low_sample =
+      self.sample_waveform_oversampled(dimension_ix, waveform_low_ix, sample_indices);
+    let high_sample =
+      self.sample_waveform_oversampled(dimension_ix, waveform_hi_ix, sample_indices);
+
+    mix(waveform_mix, low_sample, high_sample)
+  }
+
   pub fn get_sample(&self, sample_ix: f32, mixes: &[f32]) -> f32 {
     if cfg!(debug_assertions) {
       if sample_ix < 0.0 || sample_ix >= (self.settings.waveform_length - 1) as f32 {
@@ -135,12 +193,21 @@ impl WaveTable {
     }
 
     let base_sample = if self.settings.waveforms_per_dimension == 1 {
+      return self.sample_waveform(0, 0, sample_ix);
+    } else if self.settings.waveforms_per_dimension == 1 {
       self.sample_waveform(0, 0, sample_ix)
     } else {
       let waveform_ix = mixes[0] * ((self.settings.waveforms_per_dimension - 1) as f32);
       self.sample_dimension(0, waveform_ix, sample_ix)
     };
 
+    // for legacy reasons, there are always two dimensions that have their data duplicated across
+    // both dims.  The mix is set to 0, so there's no reason to waste compute sampling +
+    // interoplating.
+    if self.settings.dimension_count == 2 && mixes[1 * 2 + 1] == 0. {
+      return base_sample;
+    }
+
     // For each higher dimension, mix the base sample from the lowest dimension with the output
     // of the next dimension until a final sample is produced
     let mut sample = base_sample;
@@ -157,6 +224,30 @@ impl WaveTable {
 
     sample
   }
+
+  pub fn get_sample_oversampled<const OVERSAMPLE_FACTOR: usize>(
+    &self,
+    sample_indices: [f32; OVERSAMPLE_FACTOR],
+    mixes: &[f32],
+  ) -> f32 {
+    let base_sample = if self.settings.waveforms_per_dimension == 1 {
+      return self.sample_waveform_oversampled::<OVERSAMPLE_FACTOR>(0, 0, sample_indices);
+    } else if self.settings.waveforms_per_dimension == 1 {
+      self.sample_waveform_oversampled::<OVERSAMPLE_FACTOR>(0, 0, sample_indices)
+    } else {
+      let waveform_ix = mixes[0] * ((self.settings.waveforms_per_dimension - 1) as f32);
+      self.sample_dimension_oversampled::<OVERSAMPLE_FACTOR>(0, waveform_ix, sample_indices)
+    };
+
+    // for legacy reasons, there are always two dimensions that have their data duplicated across
+    // both dims.  The mix is set to 0, so there's no reason to waste compute sampling +
+    // interoplating.
+    if self.settings.dimension_count == 2 && mixes[1 * 2 + 1] == 0. {
+      return base_sample;
+    }
+
+    unimplemented!()
+  }
 }
 
 /// Represents a single voice playing out of an attached `WaveTable`

src/graphEditor/nodes/CustomAudio/mixer/MixerLevelsViz.ts

@@ -179,7 +179,7 @@ export class MixerLevelsViz {
         backgroundColor: BACKGROUND_COLOR,
       });
     } catch (err) {
-      logError('Failed to initialize PixiJS applicationl; WebGL not supported?');
+      logError('Failed to initialize PixiJS application; WebGL not supported?');
       throw err;
     }
 
@@ -213,6 +213,40 @@ export class MixerLevelsViz {
     this.app.stage.addChild(this.levelMetersContainer);
   };
 
+  private updateVizLayout = () => {
+    const inputCount = this.levelMeters.length;
+    const newHeight =
+      BASE_MARGIN_TOP_PX +
+      (inputCount > 2 ? MORE_THAN_TWO_INPUTS_ADDITIONAL_MARGIN_TOP_PX : 0) +
+      (MIXER_LEVELS_VIZ_HEIGHT_PER_INPUT_PX + LEVEL_METER_VERTICAL_SPACING_PX) * inputCount;
+    this.app.renderer.resize(MIXER_LEVELS_VIZ_WIDTH_PX, newHeight);
+
+    for (let i = 0; i < inputCount; i++) {
+      this.levelMeters[i].displayObject.y =
+        BASE_MARGIN_TOP_PX +
+        (inputCount > 2 ? MORE_THAN_TWO_INPUTS_ADDITIONAL_MARGIN_TOP_PX : 0) +
+        i * (LEVEL_METER_VERTICAL_SPACING_PX + MIXER_LEVELS_VIZ_HEIGHT_PER_INPUT_PX);
+    }
+  };
+
+  public addInput = () => {
+    const newMeter = new LevelMeter(this.app.renderer as PIXI.Renderer);
+    this.levelMeters.push(newMeter);
+    this.levelMetersContainer.addChild(newMeter.displayObject);
+    this.updateVizLayout();
+  };
+
+  public removeInput = () => {
+    if (this.levelMeters.length === 0) {
+      return;
+    }
+
+    const removedMeter = this.levelMeters.pop()!;
+    this.levelMetersContainer.removeChild(removedMeter.displayObject);
+    removedMeter.displayObject.destroy({ children: true });
+    this.updateVizLayout();
+  };
+
   public setAudioThreadBuffer = (audioThreadBuffer: Float32Array) => {
     this.audioThreadBuffer = audioThreadBuffer;
   };

src/graphEditor/nodes/CustomAudio/mixer/MixerSmallView.svelte

@@ -160,6 +160,7 @@
     if (awpHandle) {
       connectTrackToAWP(awpHandle, inputCount - 1, false);
     }
+    vizInst?.addInput();
   };
   const removeInput = () => {
     if (awpHandle) {
@@ -168,6 +169,7 @@
 
     mixer.removeInput();
     inputCount = inputCount - 1;
+    vizInst?.removeInput();
   };
 
   $: settings = buildSettings(mixer, inputCount, addInput, removeInput);