96 lines
2.9 KiB
Rust
96 lines
2.9 KiB
Rust
// Copyright (c) 2021 Weird Constructor <weirdconstructor@gmail.com>
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// This file is a part of HexoDSP. Released under GPL-3.0-or-later.
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// See README.md and COPYING for details.
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const VALUE_SAMPLING_FILTER_SIZE : usize = 10;
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/// Accumulates the values for a single visible feedback value,
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/// like an LED ([crate::Matrix::led_value_for]) or the
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/// output feedbacks [crate::Matrix::out_fb_for] from the [crate::Matrix].
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#[derive(Debug, Clone, Copy)]
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pub struct VisualSamplingFilter {
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/// Holds a state bit, that is used to check if this
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/// filter needs to recalculate or not.
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recalc_state: bool,
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/// Current write head into the sample buffer.
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write_ptr: usize,
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/// Holds a set of the most recent samples to calculate
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/// the output.
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sample_buffer: [f32; VALUE_SAMPLING_FILTER_SIZE],
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/// Holds the last output, will only be recalculated
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/// when necessary.
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last_output: (f32, f32),
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}
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impl VisualSamplingFilter {
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pub fn new() -> Self {
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Self {
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recalc_state: false,
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write_ptr: 0,
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sample_buffer: [0.0; VALUE_SAMPLING_FILTER_SIZE],
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last_output: (0.0, 0.0),
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}
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}
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/// Used to check if we need to update this filter.
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#[inline]
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fn needs_recalc(&mut self, recalc_value: bool) -> bool {
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if self.recalc_state != recalc_value {
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self.recalc_state = recalc_value;
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true
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} else {
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false
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}
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}
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/// Retrieves the current output value of the filter.
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/// Negate the input for `recalc_value` one each frame,
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/// to reduce access to the `retrieve_fn` to be done only
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/// once per frame and per [VisualSamplingFilter].
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///
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///```
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/// use hexodsp::nodes::visual_sampling_filter::*;
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///
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/// let mut vsf = VisualSamplingFilter::new();
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///
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/// let inputs = [-0.87, -0.8, 0.2, 0.75, 0.5, 0.0, 0.22];
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/// let mut recalc = true;
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///
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/// let mut last_output = (0.0, 0.0);
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/// for ip in inputs {
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/// last_output = vsf.get(recalc, ip);
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/// recalc = !recalc;
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/// }
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///
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/// assert_eq!(last_output, (0.87, 0.75));
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///```
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pub fn get(&mut self, recalc_value: bool, sample: f32) -> (f32, f32) {
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if self.needs_recalc(recalc_value) {
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let write_ptr =
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(self.write_ptr + 1) % self.sample_buffer.len();
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self.write_ptr = write_ptr;
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self.sample_buffer[write_ptr] = sample;
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let mut neg_max : f32 = 0.0;
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let mut pos_max : f32 = 0.0;
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for v in self.sample_buffer.iter() {
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if *v >= 0.0 {
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pos_max = pos_max.max((*v).abs());
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} else {
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neg_max = neg_max.max((*v).abs());
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}
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}
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self.last_output = (neg_max, pos_max);
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}
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self.last_output
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}
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}
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