Add: Envelope Iterator implementation and click to trigger note

2 files changed, 39 insertions, 22 deletions

diff --git a/klangfarbrs/src/adsr.rs b/klangfarbrs/src/envelope.rs
index 9d51ba3..3da7977 100644
--- a/klangfarbrs/src/adsr.rs
+++ b/klangfarbrs/src/envelope.rs
@@ -4,6 +4,7 @@ pub struct Envelope {
     pub attack: Vec<Amplitude>,
     pub decay: Vec<Amplitude>,
     pub release: Vec<Amplitude>,
+    pub index: usize,
 }
 
 impl Envelope {
@@ -14,7 +15,7 @@ impl Envelope {
         let decay = interpolate(1.0, sustain, ms_to_samples(decay, sample_rate));
         let release = interpolate(sustain, 0.0, ms_to_samples(release, sample_rate));
 
-        Self{attack, decay, release}
+        Self { attack, decay, release, index: 0 }
     }
 
     pub fn len(&self) -> usize {
@@ -22,6 +23,32 @@ impl Envelope {
     }
 }
 
+impl Iterator for Envelope {
+    type Item = Amplitude;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let idx = self.index;
+        let atk = self.attack.len();
+        let atkdcy = atk + self.decay.len();
+
+        self.index += 1;
+
+        if idx < self.len() {
+            let val = if idx < atk {
+                self.attack[idx]
+            } else if idx >= atk && idx < atkdcy  {
+                self.decay[idx - atk]
+            } else {
+                self.release[idx - atkdcy]
+            };
+
+            Some(val)
+        } else {
+            None
+        }
+    }
+}
+
 fn interpolate(start: Amplitude, end: Amplitude, milliseconds: Millisecond) -> Vec<Amplitude> {
     let step_size = (end - start) / milliseconds as f32;
     let mut amps = vec!();
diff --git a/klangfarbrs/src/lib.rs b/klangfarbrs/src/lib.rs
index 8bd1e50..fc5e6f9 100644
--- a/klangfarbrs/src/lib.rs
+++ b/klangfarbrs/src/lib.rs
@@ -17,8 +17,8 @@ mod phasor;
 mod osc;
 use osc::{Osc, Waveform};
 
-pub mod adsr;
-use adsr::Envelope;
+pub mod envelope;
+use envelope::Envelope;
 
 /// Aliasing some types to distinguish various audio properties.
 type Sample = f32;
@@ -47,7 +47,6 @@ pub struct MonoSynth {
     pub fm_frequency: Hz,
     pub fm_depth: Amplitude,
     fm_osc: Osc,
-    current_envelope_position: usize,
 }
 
 #[methods]
@@ -72,13 +71,12 @@ impl MonoSynth {
             phasor_bend: Vector2::new(0.0, 0.0),
             continuous: true,
             duration: 0,
-            envelope: Envelope::new(500, 1000, 0.5, 4000, sprt),
+            envelope: Envelope::new(30, 500, 0.5, 1000, sprt),
             cutoff: 0.0,
             frequency_modulation: false,
             fm_frequency: 10.0,
             fm_depth: 0.1,
             fm_osc: Osc::new(freq * 2.0, sprt),
-            current_envelope_position: 0,
         }
     }
 
@@ -167,6 +165,11 @@ impl MonoSynth {
     }
 
     #[export]
+    fn trigger(&mut self, _owner: &Node) {
+        self.envelope.index = 0;
+    }
+
+    #[export]
     pub fn frames(&mut self, _owner: &Node, samples: i32) -> TypedArray<Vector2> {
         let mut frames = TypedArray::new();
 
@@ -189,22 +192,9 @@ impl MonoSynth {
             // }
 
             if !self.continuous {
-                let pos = self.current_envelope_position;
-                let atk = self.envelope.attack.len();
-                let atkdcy = atk + self.envelope.decay.len();
-
-                if pos < atk {
-                    sample = sample * self.envelope.attack[pos]
-                } else if pos >= atk && pos < atkdcy  {
-                    sample = sample * self.envelope.decay[pos - atk]
-                } else if pos < self.envelope.len() {
-                    sample = sample * self.envelope.release[pos - atkdcy]
-                }
-
-                self.current_envelope_position += 1;
-
-                if self.current_envelope_position >= self.envelope.len() {
-                    self.current_envelope_position = 0;
+                sample *= match self.envelope.next() {
+                    Some(a) => a,
+                    None => 0.0,
                 }
             }