Crate bevy_framepace

This is a bevy plugin that adds framepacing and framelimiting to improve input latency and power use.

How it works

This works by sleeping the app immediately before the event loop starts. In doing so, this minimizes the time from when user input is captured (start of event loop), to when the frame is presented on screen. Graphically, it looks like this:

          /-- latency --\             /-- latency --\
 sleep -> input -> render -> sleep -> input -> render
 \----- event loop -----/    \----- event loop -----/

One of the interesting benefits of this is that you can keep latency low even if the framerate is limited to a low value. Assuming you are able to reach the target frametime, there should be no difference in motion-to-photon latency when limited to 10fps or 120fps.

               same                                              same
          /-- latency --\                                   /-- latency --\
 sleep -> input -> render -> sleeeeeeeeeeeeeeeeeeeeeeeep -> input -> render
 \----- event loop -----/    \---------------- event loop ----------------/
          60 fps                           limited to 10 fps

Modules

debug

Adds diagnostic logging and a cursor for debugging.

Structs

FramePaceStats

Holds frame time measurements for framepacing diagnostics

FrameTimer

Tracks the instant of the end of the previous frame.

FramepacePlugin

Adds framepacing and framelimiting functionality to your App.

FramepaceSettings

Framepacing plugin configuration.

FrametimeLimit

Current frametime limit based on settings and monitor refresh rate.

Enums

Limiter

Configures the framelimiting technique for the app.