aether_nodes/
delay.rs

1//! Feedback delay line.
2//!
3//! Uses a pre-allocated circular buffer. No heap activity in the RT path.
4//!
5//! Param layout:
6//!   0 = delay time (seconds, max 2.0)
7//!   1 = feedback   (0..0.99)
8//!   2 = wet mix    (0..1)
9
10use aether_core::{node::DspNode, param::ParamBlock, BUFFER_SIZE, MAX_INPUTS};
11
12/// Maximum delay time in seconds. Determines pre-allocated buffer size.
13const MAX_DELAY_SECS: f32 = 2.0;
14const MAX_DELAY_SAMPLES: usize = (48_000.0 * MAX_DELAY_SECS) as usize;
15
16pub struct DelayLine {
17    buffer: Box<[f32; MAX_DELAY_SAMPLES]>,
18    write_pos: usize,
19}
20
21impl DelayLine {
22    pub fn new() -> Self {
23        Self {
24            buffer: Box::new([0.0f32; MAX_DELAY_SAMPLES]),
25            write_pos: 0,
26        }
27    }
28
29    #[inline(always)]
30    fn process_sample(&mut self, input: f32, delay_samples: usize, feedback: f32, wet: f32) -> f32 {
31        let read_pos = (self.write_pos + MAX_DELAY_SAMPLES - delay_samples) % MAX_DELAY_SAMPLES;
32        let delayed = self.buffer[read_pos];
33        self.buffer[self.write_pos] = input + delayed * feedback;
34        self.write_pos = (self.write_pos + 1) % MAX_DELAY_SAMPLES;
35        input * (1.0 - wet) + delayed * wet
36    }
37}
38
39impl Default for DelayLine {
40    fn default() -> Self {
41        Self::new()
42    }
43}
44
45impl DspNode for DelayLine {
46    fn process(
47        &mut self,
48        inputs: &[Option<&[f32; BUFFER_SIZE]>; MAX_INPUTS],
49        output: &mut [f32; BUFFER_SIZE],
50        params: &mut ParamBlock,
51        sample_rate: f32,
52    ) {
53        let silence = [0.0f32; BUFFER_SIZE];
54        let input = inputs[0].unwrap_or(&silence);
55
56        for (i, out) in output.iter_mut().enumerate() {
57            let delay_secs = params.get(0).current.clamp(0.0, MAX_DELAY_SECS);
58            let feedback = params.get(1).current.clamp(0.0, 0.99);
59            let wet = params.get(2).current.clamp(0.0, 1.0);
60            let delay_samples =
61                ((delay_secs * sample_rate) as usize).clamp(1, MAX_DELAY_SAMPLES - 1);
62
63            *out = self.process_sample(input[i], delay_samples, feedback, wet);
64            params.tick_all();
65        }
66    }
67
68    fn type_name(&self) -> &'static str {
69        "DelayLine"
70    }
71}
aether_nodes/delay.rs

aether_nodes/
delay.rs
