90 lines
2.6 KiB
Rust
90 lines
2.6 KiB
Rust
use std::time::Instant;
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use crate::grid::{Grid, NoteType};
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pub const LOOP_LENGTH: u32 = 16;
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pub struct Nome {
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/// Tempo in beats per minute
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pub tempo: u32,
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// A count _in beats_ of where we are in the loop
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timer: f32,
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/// Whether or not we're playing; false == paused
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pub playing: bool,
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// The instant of the last time we called tick()
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last_tick: Option<Instant>,
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/// The grids that we currently have going
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pub grids: Vec<Grid>,
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// Running count of windows created (for ids)
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window_counter: usize
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}
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impl Default for Nome {
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fn default() -> Self {
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Self {
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tempo: 90,
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timer: 0.0,
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playing: true,
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last_tick: None,
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grids: vec![],
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window_counter: 0
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}
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}
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}
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impl Nome {
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/// Call this every frame to update the timer / last tick based on the current instant
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/// and the tempo
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pub fn tick(&mut self) -> bool {
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let now = Instant::now();
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let old_beat = self.beat();
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if let Some(last) = self.last_tick && self.playing {
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let dt = (now - last).as_secs_f32();
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let bps = (self.tempo as f32) / 60.0;
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// Timer is an amount of time _in beats_ and some of those beats might have been for a
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// different tempo.
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// We know now a time delta in seconds and a conversion factor to turn that to beats, so:
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self.timer += dt * bps;
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// 16 beats in the loop, so timer should never be over 16:
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while self.timer > LOOP_LENGTH as f32 { self.timer -= LOOP_LENGTH as f32 }
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}
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// Playing or not, update last_tick so that the next frame adds the correct duration to timer
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self.last_tick = Some(now);
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// Did we enter a new beat?
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self.beat() != old_beat
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}
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/// Which beat (0..loop_length) we're on
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pub fn beat(&self) -> u32 {
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self.timer.floor() as u32
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}
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/// What fraction we are (0.0..1.0) through the loop
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/// (multiply by window width to find the x coord to draw the cursor line)
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pub fn ratio(&self) -> f32 {
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self.timer / LOOP_LENGTH as f32
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}
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pub fn add_window(&mut self, note_type: NoteType) {
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self.window_counter += 1;
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self.grids.push(Grid::for_note_type(note_type, self.window_counter));
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}
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pub fn notes_for_beat(&self) -> Vec<(String, u32)> {
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let mut notes = vec![];
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let beat = self.beat();
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for grid in self.grids.iter() {
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for note in grid.notes(beat).into_iter() {
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notes.push((grid.id.clone(), note))
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}
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}
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notes
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}
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} |