71 lines
1.3 KiB
Rust
71 lines
1.3 KiB
Rust
use std::{sync::LazyLock, time::Instant};
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static TIME_START: LazyLock<Instant> = LazyLock::new(Instant::now);
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pub fn get_micros() -> u64 {
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TIME_START.elapsed().as_micros() as u64
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}
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#[derive(Default)]
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pub struct Timestep {
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current_time_us: u64,
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accumulator: f32,
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time_micros: u64,
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ticks: u32,
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speed: f32,
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pub alpha: f32,
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delta: f32,
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loopnum: u8,
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}
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impl Timestep {
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pub fn new() -> Timestep {
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let mut timestep = Timestep {
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speed: 1.0,
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..Default::default()
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};
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timestep.reset();
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timestep
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}
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fn calculate_alpha(&mut self) {
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self.alpha = (self.accumulator / self.delta).clamp(0.0, 1.0);
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}
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pub fn set_tps(&mut self, tps: f32) {
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self.delta = 1000.0 / tps;
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}
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pub fn reset(&mut self) {
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self.current_time_us = get_micros();
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self.accumulator = 0.0;
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}
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pub fn on_tick(&mut self) -> bool {
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let newtime = get_micros();
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let frametime = newtime - self.current_time_us;
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self.time_micros += frametime;
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self.current_time_us = newtime;
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self.accumulator += frametime as f32 * self.speed / 1000.0;
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self.calculate_alpha();
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if self.accumulator >= self.delta {
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self.accumulator -= self.delta;
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self.loopnum += 1;
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self.ticks += 1;
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if self.loopnum > 5 {
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// cannot keep up!
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self.loopnum = 0;
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self.accumulator = 0.0;
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return false;
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}
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true
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} else {
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self.loopnum = 0;
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false
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}
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}
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}
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