Add guitar tuner example

Author: gridbugs

caw/Cargo.toml

@@ -63,3 +63,7 @@ required-features = [ "interactive" ]
 [[example]]
 name = "audio_file_playback"
 required-features = [ "interactive", "audio_file" ]
+
+[[example]]
+name = "guitar_strings"
+required-features = [ "interactive" ]

caw/examples/guitar_strings.rs

@@ -0,0 +1,36 @@
+use caw::prelude::*;
+
+fn note_from_key(
+    note_by_key: Vec<(KeyFrameSig, Note)>,
+) -> FrameSig<impl FrameSigT<Item = Option<Note>>> {
+    FrameSig::option_first_some(
+        note_by_key
+            .into_iter()
+            .map(|(key, note)| key.on(move || note)),
+    )
+}
+
+fn main() {
+    let window = Window::builder().build();
+    let input = window.input();
+    let sig = {
+        let keyboard = input.keyboard.clone();
+        let (gate, note) = note_from_key(vec![
+            (keyboard.q, Note::E2),
+            (keyboard.w, Note::A2),
+            (keyboard.e, Note::D3),
+            (keyboard.r, Note::G3),
+            (keyboard.t, Note::B3),
+            (keyboard.y, Note::E4),
+        ])
+        .map(|note_opt| (note_opt.is_some(), note_opt))
+        .unzip();
+        let note = note.option_or_last(note::C4);
+        let env = adsr_linear_01(gate).release_s(1.0).build().exp_01(1.0);
+        oscillator(Saw, note.freq_hz())
+            .build()
+            .filter(low_pass::default(env * 10000.0))
+            .filter(reverb::default())
+    };
+    window.play_mono(sig, Default::default()).unwrap();
+}

core/src/frame_sig.rs

@@ -93,6 +93,23 @@ where
     }
 }
 
+impl<S, T, U> FrameSig<S>
+where
+    T: Clone,
+    U: Clone,
+    S: FrameSigT<Item = (T, U)>,
+{
+    pub fn unzip(
+        self,
+    ) -> (
+        FrameSig<impl FrameSigT<Item = T>>,
+        FrameSig<impl FrameSigT<Item = U>>,
+    ) {
+        let shared = frame_sig_shared(self);
+        (shared.clone().map(|x| x.0), shared.map(|x| x.1))
+    }
+}
+
 impl<S> FrameSig<S>
 where
     S: FrameSigT + 'static,
@@ -327,6 +344,16 @@ where
     ) -> FrameSig<impl FrameSigT<Item = Option<T>>> {
         FrameSig(OptionFirstSome(s.into_iter().collect()))
     }
+
+    pub fn option_or_last(self, init: T) -> FrameSig<impl FrameSigT<Item = T>> {
+        let mut last = init;
+        self.map(move |x| {
+            if let Some(x) = x {
+                last = x;
+            }
+            last.clone()
+        })
+    }
 }
 
 impl<F, T> FrameSig<FrameSigFn<F, T>>

interactive/src/input.rs

@@ -37,7 +37,8 @@ impl<P: Clone, B: Clone> MouseGeneric<P, B> {
     }
 }
 
-pub type Keyboard = KeyboardGeneric<FrameSig<FrameSigVar<bool>>>;
+pub type KeyFrameSig = FrameSig<FrameSigVar<bool>>;
+pub type Keyboard = KeyboardGeneric<KeyFrameSig>;
 pub type Mouse =
     MouseGeneric<FrameSig<FrameSigVar<f32>>, FrameSig<FrameSigVar<bool>>>;
 

interactive/src/lib.rs

@@ -1,5 +1,5 @@
 pub mod input;
 pub mod window;
 pub use caw_player::ConfigSync;
-pub use input::{Input, Key, MouseButton};
+pub use input::{Input, Key, KeyFrameSig, MouseButton};
 pub use window::{Visualization, Window};