245 lines
7.9 KiB
Rust
245 lines
7.9 KiB
Rust
// Copyright (c) 2021 Weird Constructor <weirdconstructor@gmail.com>
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// This is a part of HexoDSP. Released under (A)GPLv3 or any later.
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// See README.md and COPYING for details.
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use crate::nodes::NodeAudioContext;
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use crate::dsp::{SAtom, ProcBuf, DspNode, LedPhaseVals};
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use crate::dsp::{out, at, inp, denorm}; //, inp, denorm, denorm_v, inp_dir, at};
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use super::helpers::Trigger;
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const RAMP_TIME_MS : f64 = 3.14;
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/// A simple amplifier
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#[derive(Debug, Clone)]
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pub struct Sampl {
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phase: f64,
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srate: f64,
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trig: Trigger,
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is_playing: bool,
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}
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impl Sampl {
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pub fn new() -> Self {
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Self {
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phase: 0.0,
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srate: 44100.0,
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trig: Trigger::new(),
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is_playing: false,
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}
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}
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pub const freq : &'static str =
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"Sampl freq\nPitch input for the sampler, giving the playback speed of the \
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sample.\nRange: (-1..1)\n";
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pub const trig : &'static str =
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"Sampl trig\nThe trigger input causes a resync of the playback phase \
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and triggers the playback if the 'pmode' is 'OneShot'";
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pub const offs : &'static str =
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"Sampl offs\nStart position offset.\nRange: (0..1)\n";
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pub const len : &'static str =
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"Sampl len\nLength of the sample, after the offset has been applied.\nRange: (0..1)\n";
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pub const sample : &'static str =
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"Sampl sample\nThe audio sample that is played back.\nRange: (-1..1)\n";
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pub const pmode : &'static str =
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"Sampl pmode\nThe playback mode of the sampler.\n\
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- 'Loop' constantly plays back the sample. You can reset/sync the phase \
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using the 'trig' input in this case.\n\
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- 'OneShot' plays back the sample if a trigger is received on 'trig' input.\n";
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pub const dclick : &'static str =
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"Sampl dclick\nIf this is enabled and the 'pmode' is 'OneShot' \
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this will enable short fade in and out ramps.\n\
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This if useful if you don't want to add an envelope just for \
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getting rid of the clicks if spos and epos are modulated.";
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pub const sig : &'static str =
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"Sampl sig\nSampler audio output\nRange: (-1..1)\n";
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}
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impl Sampl {
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#[inline]
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fn next_sample(&mut self, sr_factor: f64, speed: f64, sample_data: &[f32]) -> f32 {
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let sd_len = sample_data.len();
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if sd_len < 1 { return 0.0; }
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let i = self.phase.floor() as usize + sd_len;
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// Hermite interpolation, take from
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// https://github.com/eric-wood/delay/blob/main/src/delay.rs#L52
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//
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// Thanks go to Eric Wood!
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//
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// For the interpolation code:
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// MIT License, Copyright (c) 2021 Eric Wood
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let xm1 = sample_data[(i - 1) % sd_len];
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let x0 = sample_data[i % sd_len];
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let x1 = sample_data[(i + 1) % sd_len];
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let x2 = sample_data[(i + 2) % sd_len];
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let c = (x1 - xm1) * 0.5;
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let v = x0 - x1;
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let w = c + v;
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let a = w + v + (x2 - x0) * 0.5;
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let b_neg = w + a;
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let f = self.phase.fract();
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self.phase = (i % sd_len) as f64 + f + sr_factor * speed;
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let f = f as f32;
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(((a * f) - b_neg) * f + c) * f + x0
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}
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#[inline]
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fn play(&mut self, inputs: &[ProcBuf], nframes: usize,
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sample_data: &[f32], out: &mut ProcBuf, do_loop: bool,
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declick: bool)
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{
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let freq = inp::Sampl::freq(inputs);
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let trig = inp::Sampl::trig(inputs);
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let offs = inp::Sampl::offs(inputs);
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let len = inp::Sampl::len(inputs);
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let sample_srate = sample_data[0] as f64;
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let sample_data = &sample_data[1..];
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let sr_factor = sample_srate / self.srate;
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let ramp_sample_count = ((RAMP_TIME_MS * self.srate) / 1000.0).ceil() as usize;
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let ramp_inc = 1000.0 / (RAMP_TIME_MS * self.srate);
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let mut is_playing = self.is_playing;
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if do_loop {
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is_playing = true;
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}
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let mut prev_offs = -10.0;
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let mut prev_len = -10.0;
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let mut start_idx = 0;
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let mut end_idx_plus1 = sample_data.len();
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for frame in 0..nframes {
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let trig_val = denorm::Sampl::trig(trig, frame);
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let triggered = self.trig.check_trigger(trig_val);
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if triggered {
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self.phase = 0.0;
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is_playing = true;
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}
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if is_playing {
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let playback_speed =
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denorm::Sampl::freq(freq, frame) / 440.0;
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let prev_phase = self.phase;
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let cur_offs =
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denorm::Sampl::offs(offs, frame).abs().min(0.999999);
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if prev_offs != cur_offs {
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start_idx =
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(sample_data.len() as f32 * cur_offs)
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.floor() as usize;
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prev_offs = cur_offs;
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}
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let cur_len =
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denorm::Sampl::len(len, frame).abs().min(0.999999);
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if prev_len != cur_len {
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end_idx_plus1 =
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((sample_data.len() - start_idx) as f32 * cur_len)
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.ceil() as usize;
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prev_len = cur_len;
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}
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let sample_slice =
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&sample_data[start_idx..(start_idx + end_idx_plus1)];
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// next_sample mutates self.phase, so we need the current phase
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// that is used for looking up the sample from the audio data.
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let sample_idx = self.phase.floor() as usize;
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let mut s =
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self.next_sample(
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sr_factor,
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playback_speed as f64,
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sample_slice);
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if declick {
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let samples_to_end = sample_data.len() - sample_idx;
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let ramp_atten_factor =
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if sample_idx < ramp_sample_count {
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sample_idx as f64 * ramp_inc
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} else if samples_to_end < ramp_sample_count {
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1.0 - (samples_to_end as f64 * ramp_inc)
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} else {
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1.0
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};
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s *= ramp_atten_factor as f32;
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}
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out.write(frame, s);
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if !do_loop && prev_phase > self.phase {
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// played past end => stop playing.
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is_playing = false;
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}
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} else {
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out.write(frame, 0.0);
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}
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}
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self.is_playing = is_playing;
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}
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}
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impl DspNode for Sampl {
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fn outputs() -> usize { 1 }
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fn set_sample_rate(&mut self, srate: f32) { self.srate = srate.into(); }
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fn reset(&mut self) {
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self.trig.reset();
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}
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#[inline]
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fn process<T: NodeAudioContext>(
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&mut self, ctx: &mut T, atoms: &[SAtom], _params: &[ProcBuf],
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inputs: &[ProcBuf], outputs: &mut [ProcBuf], ctx_vals: LedPhaseVals)
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{
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let sample = at::Sampl::sample(atoms);
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let pmode = at::Sampl::pmode(atoms);
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let dclick = at::Sampl::dclick(atoms);
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let out = out::Sampl::sig(outputs);
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if let SAtom::AudioSample((_, Some(sample_data))) = sample {
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// 3 is for sample-sample-rate and at least 2 audio samples.
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if sample_data.len() < 3 {
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for frame in 0..ctx.nframes() {
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out.write(frame, 0.0);
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}
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return;
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}
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self.play(
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inputs,
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ctx.nframes(),
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&sample_data[..],
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out,
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pmode.i() == 0,
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dclick.i() == 1);
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} else {
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for frame in 0..ctx.nframes() {
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out.write(frame, 0.0);
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}
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}
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let last_frame = ctx.nframes() - 1;
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ctx_vals[0].set(out.read(last_frame));
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}
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}
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