tek/crates/tek_mixer/src/sample.rs

use super::*;

/// A sound sample.
#[derive(Default, Debug)]
pub struct Sample {
    pub name:     String,
    pub start:    usize,
    pub end:      usize,
    pub channels: Vec<Vec<f32>>,
    pub rate:     Option<usize>,
}

impl Sample {
    pub fn from_edn <'e> (dir: &str, args: &[Edn<'e>]) -> Usually<(Option<u7>, Arc<RwLock<Self>>)> {
        let mut name = String::new();
        let mut file = String::new();
        let mut midi = None;
        let mut start = 0usize;
        edn!(edn in args {
            Edn::Map(map) => {
                if let Some(Edn::Str(n)) = map.get(&Edn::Key(":name")) {
                    name = String::from(*n);
                }
                if let Some(Edn::Str(f)) = map.get(&Edn::Key(":file")) {
                    file = String::from(*f);
                }
                if let Some(Edn::Int(i)) = map.get(&Edn::Key(":start")) {
                    start = *i as usize;
                }
                if let Some(Edn::Int(m)) = map.get(&Edn::Key(":midi")) {
                    midi = Some(u7::from(*m as u8));
                }
            },
            _ => panic!("unexpected in sample {name}"),
        });
        let (end, data) = read_sample_data(&format!("{dir}/{file}"))?;
        Ok((midi, Arc::new(RwLock::new(Self::new(&name, start, end, data)))))
    }
    pub fn new (name: &str, start: usize, end: usize, channels: Vec<Vec<f32>>) -> Self {
        Self { name: name.to_string(), start, end, channels, rate: None }
    }
    pub fn play (sample: &Arc<RwLock<Self>>, after: usize, velocity: &u7) -> Voice {
        Voice {
            sample: sample.clone(),
            after,
            position: sample.read().unwrap().start,
            velocity: velocity.as_int() as f32 / 127.0,
        }
    }
}


/// Load sample from WAV and assign to MIDI note.
#[macro_export] macro_rules! sample {
    ($note:expr, $name:expr, $src:expr) => {{
        let (end, data) = read_sample_data($src)?;
        (
            u7::from_int_lossy($note).into(),
            Sample::new($name, 0, end, data).into()
        )
    }};
}

/// Read WAV from file
pub fn read_sample_data (src: &str) -> Usually<(usize, Vec<Vec<f32>>)> {
    let mut channels: Vec<wavers::Samples<f32>> = vec![];
    for channel in wavers::Wav::from_path(src)?.channels() {
        channels.push(channel);
    }
    let mut end = 0;
    let mut data: Vec<Vec<f32>> = vec![];
    for samples in channels.iter() {
        let channel = Vec::from(samples.as_ref());
        end = end.max(channel.len());
        data.push(channel);
    }
    Ok((end, data))
}