50 lines
975 B
Rust
50 lines
975 B
Rust
use std::time::Instant;
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pub struct TimeStep {
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last_frame_time: Instant,
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// Milliseconds
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accum: u128,
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fps_num: u16,
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fps_den: u16,
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}
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impl TimeStep {
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pub fn new (fps_num: u16, fps_den: u16) -> Self {
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Self {
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last_frame_time: Instant::now (),
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accum: 0,
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fps_num,
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fps_den,
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}
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}
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// Automatically gets monotonic system time from Instant
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// If you need something fancy just rewrite this.
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// Returns: How many logics steps to run. Typically 0 or 1.
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pub fn step (&mut self) -> u16 {
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let frame_time = Instant::now ();
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let fps_num_128: u128 = self.fps_num.into ();
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let fps_den_128: u128 = self.fps_den.into ();
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self.accum += (frame_time - self.last_frame_time).as_millis () * fps_num_128;
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let mut result = 0;
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const MAX_FRAMES: u16 = 4;
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for _ in 0..MAX_FRAMES {
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if self.accum > fps_den_128 {
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result += 1;
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self.accum -= fps_den_128;
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}
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else {
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break;
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}
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}
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self.last_frame_time = frame_time;
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result
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}
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}
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