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Only call the request_repaint_callback at most once per frame (#2126)

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egui-winit adds new repaint events to the event loop on each call, and on some platforms this becomes very expensive.
This commit is contained in:
Emil Ernerfeldt 2022-10-10 10:47:20 +02:00 committed by GitHub
parent 0fe0c8115c
commit f4d2aa5b4a
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 24 additions and 7 deletions
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31
crates/egui/src/context.rs
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@ -46,17 +46,25 @@ struct ContextImpl {
output: PlatformOutput, output: PlatformOutput,
paint_stats: PaintStats, paint_stats: PaintStats,
/// the duration backend will poll for new events, before forcing another egui update /// the duration backend will poll for new events, before forcing another egui update
/// even if there's no new events. /// even if there's no new events.
repaint_after: std::time::Duration, repaint_after: std::time::Duration,
/// While positive, keep requesting repaints. Decrement at the end of each frame. /// While positive, keep requesting repaints. Decrement at the end of each frame.
repaint_requests: u32, repaint_requests: u32,
request_repaint_callback: Option<Box<dyn Fn() + Send + Sync>>, request_repaint_callback: Option<Box<dyn Fn() + Send + Sync>>,
/// used to suppress multiple calls to [`Self::request_repaint_callback`] during the same frame.
has_requested_repaint_this_frame: bool,
requested_repaint_last_frame: bool, requested_repaint_last_frame: bool,
} }
impl ContextImpl { impl ContextImpl {
fn begin_frame_mut(&mut self, new_raw_input: RawInput) { fn begin_frame_mut(&mut self, new_raw_input: RawInput) {
self.has_requested_repaint_this_frame = false; // allow new calls during the frame
self.memory.begin_frame(&self.input, &new_raw_input); self.memory.begin_frame(&self.input, &new_raw_input);
self.input = std::mem::take(&mut self.input) self.input = std::mem::take(&mut self.input)
@ -571,7 +579,10 @@ impl Context {
let mut ctx = self.write(); let mut ctx = self.write();
ctx.repaint_requests = 2; ctx.repaint_requests = 2;
if let Some(callback) = &ctx.request_repaint_callback { if let Some(callback) = &ctx.request_repaint_callback {
(callback)(); if !ctx.has_requested_repaint_this_frame {
(callback)();
ctx.has_requested_repaint_this_frame = true;
}
} }
} }
@ -850,12 +861,18 @@ impl Context {
self.read().repaint_after self.read().repaint_after
}; };
self.write().requested_repaint_last_frame = repaint_after.is_zero(); {
// make sure we reset the repaint_after duration. let ctx_impl = &mut *self.write();
// otherwise, if repaint_after is low, then any widget setting repaint_after next frame, ctx_impl.requested_repaint_last_frame = repaint_after.is_zero();
// will fail to overwrite the previous lower value. and thus, repaints will never
// go back to higher values. ctx_impl.has_requested_repaint_this_frame = false; // allow new calls between frames
self.write().repaint_after = std::time::Duration::MAX;
// make sure we reset the repaint_after duration.
// otherwise, if repaint_after is low, then any widget setting repaint_after next frame,
// will fail to overwrite the previous lower value. and thus, repaints will never
// go back to higher values.
ctx_impl.repaint_after = std::time::Duration::MAX;
}
let shapes = self.drain_paint_lists(); let shapes = self.drain_paint_lists();
FullOutput { FullOutput {