feat: implement adaptor to turn DSP instances into fundsp nodes

src/contrib/fundsp.rs

@@ -1,6 +1,9 @@
 use crate::dsp::DSP;
 use fundsp::audionode::{AudioNode, Frame};
 use fundsp::combinator::An;
+use fundsp::Float;
+use numeric_array::ArrayLength;
+use std::marker::PhantomData;
 use typenum::Unsigned;
 
 impl<Node: AudioNode> DSP<{ Node::Inputs::USIZE }, { Node::Outputs::USIZE }> for An<Node>
@@ -19,12 +22,51 @@ where
     }
 }
 
+#[derive(Debug, Clone)]
+pub struct DspNode<In, Out, P>(PhantomData<In>, PhantomData<Out>, P);
+
+pub fn dsp_node<In: Unsigned, Out: Unsigned, P: DSP<{ In::USIZE }, { Out::USIZE }>>(
+    dsp: P,
+) -> DspNode<In, Out, P> {
+    DspNode(PhantomData, PhantomData, dsp)
+}
+
+impl<
+        In: Send + Sync + Unsigned,
+        Out: Send + Sync + Unsigned,
+        P: Send + Sync + DSP<{ In::USIZE }, { Out::USIZE }>,
+    > AudioNode for DspNode<In, Out, P>
+where
+    Self: Clone,
+    P::Sample: Float,
+    In: ArrayLength<P::Sample>,
+    Out: ArrayLength<P::Sample>,
+{
+    const ID: u64 = 0;
+    type Sample = P::Sample;
+    type Inputs = In;
+    type Outputs = Out;
+    type Setting = ();
+
+    fn tick(
+        &mut self,
+        input: &Frame<Self::Sample, Self::Inputs>,
+    ) -> Frame<Self::Sample, Self::Outputs> {
+        let input = std::array::from_fn(|i| input[i]);
+        let output = self.2.process(input.into());
+        Frame::from_iter(output)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::dsp::{utils::slice_to_mono_block_mut, DSPBlock};
 
+    use crate::dsp::blocks::Integrator;
     use fundsp::hacker32::*;
 
+    use super::*;
+
     #[test]
     fn test_wrapper() {
         let mut dsp = sine_hz(440.0) * sine_hz(10.0);
@@ -34,4 +76,15 @@ mod tests {
 
         insta::assert_csv_snapshot!(&output as &[_], { "[]" => insta::rounded_redaction(3) })
     }
+
+    #[test]
+    fn test_dsp_node() {
+        let mut integrator_node = dsp_node::<U1, U1, _>(Integrator::<f32>::default());
+        integrator_node.filter_mono(0.0);
+        integrator_node.filter_mono(1.0);
+        let actual = integrator_node.filter_mono(0.0);
+        let expected = 1.0;
+
+        assert_eq!(expected, actual);
+    }
 }