caw_modules/
low_pass_butterworth.rs

1use crate::low_level::biquad_filter::butterworth;
2use caw_builder_proc_macros::builder;
3use caw_core::{Buf, Filter, SigCtx, SigT};
4use itertools::izip;
5
6builder! {
7    #[constructor = "low_pass_butterworth"]
8    #[constructor_doc = "A basic low pass filter"]
9    #[generic_setter_type_name = "X"]
10    pub struct Props {
11        #[generic_with_constraint = "SigT<Item = f32>"]
12        #[generic_name = "C"]
13        cutoff_hz: _,
14        #[default = 1]
15        filter_order_half: usize,
16    }
17}
18
19impl<C> Filter for Props<C>
20where
21    C: SigT<Item = f32>,
22{
23    type ItemIn = f32;
24
25    type Out<S>
26        = LowPassButterworth<S, C>
27    where
28        S: SigT<Item = Self::ItemIn>;
29
30    fn into_sig<S>(self, sig: S) -> Self::Out<S>
31    where
32        S: SigT<Item = Self::ItemIn>,
33    {
34        LowPassButterworth {
35            state: butterworth::State::new(self.filter_order_half),
36            props: self,
37            sig,
38            buf: Vec::new(),
39        }
40    }
41}
42
43pub struct LowPassButterworth<S, C>
44where
45    S: SigT<Item = f32>,
46    C: SigT<Item = f32>,
47{
48    props: Props<C>,
49    sig: S,
50    state: butterworth::State,
51    buf: Vec<f32>,
52}
53
54impl<S, C> SigT for LowPassButterworth<S, C>
55where
56    S: SigT<Item = f32>,
57    C: SigT<Item = f32>,
58{
59    type Item = f32;
60
61    fn sample(&mut self, ctx: &SigCtx) -> impl Buf<Self::Item> {
62        self.buf.resize(ctx.num_samples, 0.0);
63        let sig = self.sig.sample(ctx);
64        let cutoff_hz = self.props.cutoff_hz.sample(ctx);
65        for (out, sample, cutoff_hz) in izip! {
66            self.buf.iter_mut(),
67            sig.iter(),
68            cutoff_hz.iter(),
69        } {
70            *out = butterworth::low_pass::run(
71                &mut self.state,
72                sample as f64,
73                ctx.sample_rate_hz as f64,
74                cutoff_hz as f64,
75            ) as f32;
76        }
77        &self.buf
78    }
79}
caw_modules/low_pass_butterworth.rs

caw_modules/
low_pass_butterworth.rs
