Struct frenderer::clock::Clock

pub struct Clock { /* private fields */ }

A data structure storing a time accumulator and some parameters for controlling the progression of game time. This implementation yields a fixed-timestep simulation loop following Fix Your Timestep! with optional improvements to smoothness and avoidance of death spirals based on Tyler Glaiel’s blog post.

Implementations

impl Clock

pub fn new(dt: f32, fudge_amount: f32, max_frames_per_tick: usize) -> Self

Creates a clock with the given target simulation frame rate.

fudge_amount, if non-zero, will “fudge” time intervals to nearby standard frame rates (e.g., 15hz, 30hz, 60hz, 120hz, 144hz) to smooth out small differences under vertical sync.

max_frames_per_tick limits the largest number of steps to simulate at once in order to avoid “death spirals” (where one slow frame causes multiple simulation steps, which delays the next frame, which then needs to make up for even more steps).

pub fn set_now(&mut self, instant: Instant)

Re-initialize the last-ticked time to the given instant and clear the accumulator. This might be useful when a new game level is loaded or at some other interval to limit drift between the fudged frame times and the actual wall-clock time.

pub fn now(&self) -> Instant

Returns the current time on the clock

pub fn tick(&mut self) -> usize

Tick the clock forward based on the time since it was last ticked. Returns how many timesteps to simulate based on the elapsed time.