tek/src/model/sampler.rs

use crate::core::*;

pub struct Sampler {
    pub name:    String,
    pub cursor:  (usize, usize),
    pub samples: BTreeMap<u7, Arc<Sample>>,
    pub voices:  Vec<Voice>,
    pub ports:   JackPorts,
}

render!(Sampler = crate::view::sampler::render);
handle!(Sampler = crate::control::sampler::handle);
//jack!(Sampler {
    //process = Sampler::process,
    //audio = {
        //ins  = |s|Ok(s.jack.audio_ins.values().collect()),
        //outs = |s|Ok(s.jack.audio_outs.values().collect()),
    //}
    //midi = {
        //ins  = |s|Ok(s.jack.midi_ins.values().collect()),
        //outs = |s|Ok(s.jack.midi_outs.values().collect()),
    //}
//});
process!(Sampler = Sampler::process);
//ports!(Sampler {
    //audio: {
        //ins:  |s|Ok(s.ports.audio_ins.values().collect()),
        //outs: |s|Ok(s.ports.audio_outs.values().collect()),
    //}
    //midi: {
        //ins:  |s|Ok(s.ports.midi_ins.values().collect()),
        //outs: |s|Ok(s.ports.midi_outs.values().collect()),
    //}
//});

impl Sampler {
    pub fn new (
        name: &str, samples: Option<BTreeMap<u7, Arc<Sample>>>,
    ) -> Usually<JackDevice> {
        Jack::new(name)?
            .midi_in("midi")
            .audio_in("recL")
            .audio_in("recR")
            .audio_out("outL")
            .audio_out("outR")
            .run(|ports|Box::new(Self {
                name:    name.into(),
                cursor:  (0, 0),
                samples: samples.unwrap_or(BTreeMap::new()),
                voices:  vec![],
                ports
            }))
    }

    pub fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
        // Output buffer: this will be copied to the audio outs.
        let channel_count = self.ports.audio_outs.len();
        let mut mixed = vec![vec![0.0;scope.n_frames() as usize];channel_count];
        // Process MIDI input to add new voices.
        for RawMidi { time, bytes } in self.ports.midi_ins.get("midi").unwrap().iter(scope) {
            if let LiveEvent::Midi { message, .. } = LiveEvent::parse(bytes).unwrap() {
                if let MidiMessage::NoteOn { ref key, .. } = message {
                    if let Some(sample) = self.samples.get(key) {
                        self.voices.push(sample.play(time as usize));
                    }
                }
            }
        }
        // Emit next chunk of each currently playing voice,
        // dropping voices that have reached their ends.
        let mut voices = vec![];
        std::mem::swap(&mut voices, &mut self.voices);
        loop {
            if voices.len() < 1 {
                break
            }
            let mut voice = voices.swap_remove(0);
            if let Some(chunk) = voice.chunk(scope.n_frames() as usize) {
                for (i, channel) in chunk.iter().enumerate() {
                    let buffer = &mut mixed[i % channel_count];
                    for (i, sample) in channel.iter().enumerate() {
                        buffer[i] += sample;
                    }
                }
                self.voices.push(voice);
            }
        }
        // Write output buffer to output ports.
        for (i, port) in self.ports.audio_outs.values_mut().enumerate() {
            let buffer = &mixed[i];
            for (i, value) in port.as_mut_slice(scope).iter_mut().enumerate() {
                *value = *buffer.get(i).unwrap_or(&0.0);
            }
        }
        Control::Continue
    }

    fn load_sample (&mut self, _path: &str) {}
}

#[macro_export] macro_rules! sample {
    ($note:expr, $name:expr, $src:expr) => {
        {
            let mut channels: Vec<wavers::Samples<f32>> = vec![];
            for channel in wavers::Wav::from_path($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);
            }
            (u7::from_int_lossy($note).into(), Sample::new($name, 0, end, data).into())
        }
    };
}

pub struct Sample {
    pub name:     String,
    pub start:    usize,
    pub end:      usize,
    pub channels: Vec<Vec<f32>>,
}

impl Sample {
    pub fn new (name: &str, start: usize, end: usize, channels: Vec<Vec<f32>>) -> Arc<Self> {
        Arc::new(Self { name: name.to_string(), start, end, channels })
    }
    pub fn play (self: &Arc<Self>, after: usize) -> Voice {
        Voice { sample: self.clone(), after, position: self.start }
    }
}

pub struct Voice {
    pub sample:   Arc<Sample>,
    pub after:    usize,
    pub position: usize,
}

impl Voice {
    pub fn chunk (&mut self, mut frames: usize) -> Option<Vec<Vec<f32>>> {
        // Create output buffer for each channel
        let mut chunk = vec![vec![];self.sample.channels.len()];
        // If it's not time to play yet, count down
        if self.after >= frames {
            self.after = self.after - frames;
            return Some(chunk)
        }
        // If the voice will start playing within the current buffer,
        // subtract the remaining number of wait frames.
        if self.after > 0 && self.after < frames {
            chunk = vec![vec![0.0;self.after];self.sample.channels.len()];
            frames = frames - self.after;
            self.after = 0;
        }
        if self.position < self.sample.end {
            let start = self.position.min(self.sample.end);
            let end   = (self.position + frames).min(self.sample.end);
            for (i, channel) in self.sample.channels.iter().enumerate() {
                chunk[i].extend_from_slice(&channel[start..end]);
            };
            self.position = self.position + frames;
            Some(chunk)
        } else {
            None
        }
    }
}