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Fix flickering (#9012)

Browse source 
See https://zed.dev/channel/gpui-536

Fixes https://github.com/zed-industries/zed/issues/9010
Fixes https://github.com/zed-industries/zed/issues/8883
Fixes https://github.com/zed-industries/zed/issues/8640
Fixes https://github.com/zed-industries/zed/issues/8598
Fixes https://github.com/zed-industries/zed/issues/8579
Fixes https://github.com/zed-industries/zed/issues/8363
Fixes https://github.com/zed-industries/zed/issues/8207


### Problem

After transitioning Zed to GPUI 2, we started noticing that interacting
with the mouse on many UI elements would lead to a pretty annoying
flicker. The main issue with the old approach was that hover state was
calculated based on the previous frame. That is, when computing whether
a given element was hovered in the current frame, we would use
information about the same element in the previous frame.

However, inspecting the previous frame tells us very little about what
should be hovered in the current frame, as elements in the current frame
may have changed significantly.

### Solution

This pull request's main contribution is the introduction of a new
`after_layout` phase when redrawing the window. The key idea is that
we'll give every element a chance to register a hitbox (see
`ElementContext::insert_hitbox`) before painting anything. Then, during
the `paint` phase, elements can determine whether they're the topmost
and draw their hover state accordingly.

We are also removing the ability to give an arbitrary z-index to
elements. Instead, we will follow the much simpler painter's algorithm.
That is, an element that gets painted after will be drawn on top of an
element that got painted earlier. Elements can still escape their
current "stacking context" by using the new `ElementContext::defer_draw`
method (see `Overlay` for an example). Elements drawn using this method
will still be logically considered as being children of their original
parent (for keybinding, focus and cache invalidation purposes) but their
layout and paint passes will be deferred until the currently-drawn
element is done.

With these changes we also reworked geometry batching within the
`Scene`. The new approach uses an AABB tree to determine geometry
occlusion, which allows the GPU to render non-overlapping geometry in
parallel.

### Performance

Performance is slightly better than on `main` even though this new
approach is more correct and we're maintaining an extra data structure
(the AABB tree).


![before_after](https://github.com/zed-industries/zed/assets/482957/c8120b07-1dbd-4776-834a-d040e569a71e)

Release Notes:

- Fixed a bug that was causing popovers to flicker.

---------

Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Thorsten <thorsten@zed.dev>
This commit is contained in:
Antonio Scandurra 2024-03-11 10:45:57 +01:00 • committed by GitHub
parent 9afd78b35e
commit 4700d33728
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
74 changed files with 6434 additions and 6301 deletions
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284
crates/gpui/src/view.rs
View file

@ -1,14 +1,16 @@
use crate::{
seal::Sealed, AnyElement, AnyModel, AnyWeakModel, AppContext, AvailableSpace, Bounds,
seal::Sealed, AfterLayoutIndex, AnyElement, AnyModel, AnyWeakModel, AppContext, Bounds,
ContentMask, Element, ElementContext, ElementId, Entity, EntityId, Flatten, FocusHandle,
FocusableView, IntoElement, LayoutId, Model, Pixels, Point, Render, Size, StackingOrder, Style,
TextStyle, ViewContext, VisualContext, WeakModel,
FocusableView, IntoElement, LayoutId, Model, PaintIndex, Pixels, Render, Style,
StyleRefinement, TextStyle, ViewContext, VisualContext, WeakModel,
};
use anyhow::{Context, Result};
use refineable::Refineable;
use std::{
any::{type_name, TypeId},
fmt,
hash::{Hash, Hasher},
ops::Range,
};
/// A view is a piece of state that can be presented on screen by implementing the [Render] trait.
@ -20,17 +22,15 @@ pub struct View<V> {
impl<V> Sealed for View<V> {}
#[doc(hidden)]
pub struct AnyViewState {
root_style: Style,
next_stacking_order_id: u16,
cache_key: Option<ViewCacheKey>,
element: Option<AnyElement>,
struct AnyViewState {
after_layout_range: Range<AfterLayoutIndex>,
paint_range: Range<PaintIndex>,
cache_key: ViewCacheKey,
}
#[derive(Default)]
struct ViewCacheKey {
bounds: Bounds<Pixels>,
stacking_order: StackingOrder,
content_mask: ContentMask<Pixels>,
text_style: TextStyle,
}
@ -90,22 +90,39 @@ impl<V: 'static> View<V> {
}
impl<V: Render> Element for View<V> {
type State = Option<AnyElement>;
type BeforeLayout = AnyElement;
type AfterLayout = ();
fn request_layout(
&mut self,
_state: Option<Self::State>,
cx: &mut ElementContext,
) -> (LayoutId, Self::State) {
cx.with_view_id(self.entity_id(), |cx| {
fn before_layout(&mut self, cx: &mut ElementContext) -> (LayoutId, Self::BeforeLayout) {
cx.with_element_id(Some(ElementId::View(self.entity_id())), |cx| {
let mut element = self.update(cx, |view, cx| view.render(cx).into_any_element());
let layout_id = element.request_layout(cx);
(layout_id, Some(element))
let layout_id = element.before_layout(cx);
(layout_id, element)
})
}
fn paint(&mut self, _: Bounds<Pixels>, element: &mut Self::State, cx: &mut ElementContext) {
cx.paint_view(self.entity_id(), |cx| element.take().unwrap().paint(cx));
fn after_layout(
&mut self,
_: Bounds<Pixels>,
element: &mut Self::BeforeLayout,
cx: &mut ElementContext,
) {
cx.set_view_id(self.entity_id());
cx.with_element_id(Some(ElementId::View(self.entity_id())), |cx| {
element.after_layout(cx)
})
}
fn paint(
&mut self,
_: Bounds<Pixels>,
element: &mut Self::BeforeLayout,
_: &mut Self::AfterLayout,
cx: &mut ElementContext,
) {
cx.with_element_id(Some(ElementId::View(self.entity_id())), |cx| {
element.paint(cx)
})
}
}
@ -203,16 +220,16 @@ impl<V> Eq for WeakView<V> {}
#[derive(Clone, Debug)]
pub struct AnyView {
model: AnyModel,
pub(crate) request_layout: fn(&AnyView, &mut ElementContext) -> (LayoutId, AnyElement),
cache: bool,
render: fn(&AnyView, &mut ElementContext) -> AnyElement,
cached_style: Option<StyleRefinement>,
}
impl AnyView {
/// Indicate that this view should be cached when using it as an element.
/// When using this method, the view's previous layout and paint will be recycled from the previous frame if [ViewContext::notify] has not been called since it was rendered.
/// The one exception is when [WindowContext::refresh] is called, in which case caching is ignored.
pub fn cached(mut self) -> Self {
self.cache = true;
pub fn cached(mut self, style: StyleRefinement) -> Self {
self.cached_style = Some(style);
self
}
@ -220,7 +237,7 @@ impl AnyView {
pub fn downgrade(&self) -> AnyWeakView {
AnyWeakView {
model: self.model.downgrade(),
layout: self.request_layout,
render: self.render,
}
}
@ -231,8 +248,8 @@ impl AnyView {
Ok(model) => Ok(View { model }),
Err(model) => Err(Self {
model,
request_layout: self.request_layout,
cache: self.cache,
render: self.render,
cached_style: self.cached_style,
}),
}
}
@ -246,113 +263,134 @@ impl AnyView {
pub fn entity_id(&self) -> EntityId {
self.model.entity_id()
}
pub(crate) fn draw(
&self,
origin: Point<Pixels>,
available_space: Size<AvailableSpace>,
cx: &mut ElementContext,
) {
cx.paint_view(self.entity_id(), |cx| {
cx.with_absolute_element_offset(origin, |cx| {
let (layout_id, mut rendered_element) = (self.request_layout)(self, cx);
cx.compute_layout(layout_id, available_space);
rendered_element.paint(cx)
});
})
}
}
impl<V: Render> From<View<V>> for AnyView {
fn from(value: View<V>) -> Self {
AnyView {
model: value.model.into_any(),
request_layout: any_view::request_layout::<V>,
cache: false,
render: any_view::render::<V>,
cached_style: None,
}
}
}
impl Element for AnyView {
type State = AnyViewState;
type BeforeLayout = Option<AnyElement>;
type AfterLayout = Option<AnyElement>;
fn request_layout(
&mut self,
state: Option<Self::State>,
cx: &mut ElementContext,
) -> (LayoutId, Self::State) {
cx.with_view_id(self.entity_id(), |cx| {
if self.cache
&& !cx.window.dirty_views.contains(&self.entity_id())
&& !cx.window.refreshing
{
if let Some(state) = state {
let layout_id = cx.request_layout(&state.root_style, None);
return (layout_id, state);
}
}
let (layout_id, element) = (self.request_layout)(self, cx);
let root_style = cx.layout_style(layout_id).unwrap().clone();
let state = AnyViewState {
root_style,
next_stacking_order_id: 0,
cache_key: None,
element: Some(element),
};
(layout_id, state)
})
fn before_layout(&mut self, cx: &mut ElementContext) -> (LayoutId, Self::BeforeLayout) {
if let Some(style) = self.cached_style.as_ref() {
let mut root_style = Style::default();
root_style.refine(style);
let layout_id = cx.request_layout(&root_style, None);
(layout_id, None)
} else {
cx.with_element_id(Some(ElementId::View(self.entity_id())), |cx| {
let mut element = (self.render)(self, cx);
let layout_id = element.before_layout(cx);
(layout_id, Some(element))
})
}
}
fn paint(&mut self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut ElementContext) {
cx.paint_view(self.entity_id(), |cx| {
if !self.cache {
state.element.take().unwrap().paint(cx);
return;
}
fn after_layout(
&mut self,
bounds: Bounds<Pixels>,
element: &mut Self::BeforeLayout,
cx: &mut ElementContext,
) -> Option<AnyElement> {
cx.set_view_id(self.entity_id());
if self.cached_style.is_some() {
cx.with_element_state::<AnyViewState, _>(
Some(ElementId::View(self.entity_id())),
|element_state, cx| {
let mut element_state = element_state.unwrap();
if let Some(cache_key) = state.cache_key.as_mut() {
if cache_key.bounds == bounds
&& cache_key.content_mask == cx.content_mask()
&& cache_key.stacking_order == *cx.stacking_order()
&& cache_key.text_style == cx.text_style()
{
cx.reuse_view(state.next_stacking_order_id);
return;
}
}
let content_mask = cx.content_mask();
let text_style = cx.text_style();
if let Some(mut element) = state.element.take() {
element.paint(cx);
} else {
let mut element = (self.request_layout)(self, cx).1;
element.draw(bounds.origin, bounds.size.into(), cx);
}
if let Some(mut element_state) = element_state {
if element_state.cache_key.bounds == bounds
&& element_state.cache_key.content_mask == content_mask
&& element_state.cache_key.text_style == text_style
&& !cx.window.dirty_views.contains(&self.entity_id())
&& !cx.window.refreshing
{
let after_layout_start = cx.after_layout_index();
cx.reuse_after_layout(element_state.after_layout_range.clone());
let after_layout_end = cx.after_layout_index();
element_state.after_layout_range = after_layout_start..after_layout_end;
return (None, Some(element_state));
}
}
state.next_stacking_order_id = cx
.window
.next_frame
.next_stacking_order_ids
.last()
.copied()
.unwrap();
state.cache_key = Some(ViewCacheKey {
bounds,
stacking_order: cx.stacking_order().clone(),
content_mask: cx.content_mask(),
text_style: cx.text_style(),
});
})
let after_layout_start = cx.after_layout_index();
let mut element = (self.render)(self, cx);
element.layout(bounds.origin, bounds.size.into(), cx);
let after_layout_end = cx.after_layout_index();
(
Some(element),
Some(AnyViewState {
after_layout_range: after_layout_start..after_layout_end,
paint_range: PaintIndex::default()..PaintIndex::default(),
cache_key: ViewCacheKey {
bounds,
content_mask,
text_style,
},
}),
)
},
)
} else {
cx.with_element_id(Some(ElementId::View(self.entity_id())), |cx| {
let mut element = element.take().unwrap();
element.after_layout(cx);
Some(element)
})
}
}
fn paint(
&mut self,
_bounds: Bounds<Pixels>,
_: &mut Self::BeforeLayout,
element: &mut Self::AfterLayout,
cx: &mut ElementContext,
) {
if self.cached_style.is_some() {
cx.with_element_state::<AnyViewState, _>(
Some(ElementId::View(self.entity_id())),
|element_state, cx| {
let mut element_state = element_state.unwrap().unwrap();
let paint_start = cx.paint_index();
if let Some(element) = element {
element.paint(cx);
} else {
cx.reuse_paint(element_state.paint_range.clone());
}
let paint_end = cx.paint_index();
element_state.paint_range = paint_start..paint_end;
((), Some(element_state))
},
)
} else {
cx.with_element_id(Some(ElementId::View(self.entity_id())), |cx| {
element.as_mut().unwrap().paint(cx);
})
}
}
}
impl<V: 'static + Render> IntoElement for View<V> {
type Element = View<V>;
fn element_id(&self) -> Option<ElementId> {
Some(ElementId::from_entity_id(self.model.entity_id))
}
fn into_element(self) -> Self::Element {
self
}
@ -361,10 +399,6 @@ impl<V: 'static + Render> IntoElement for View<V> {
impl IntoElement for AnyView {
type Element = Self;
fn element_id(&self) -> Option<ElementId> {
Some(ElementId::from_entity_id(self.model.entity_id))
}
fn into_element(self) -> Self::Element {
self
}
@ -373,7 +407,7 @@ impl IntoElement for AnyView {
/// A weak, dynamically-typed view handle that does not prevent the view from being released.
pub struct AnyWeakView {
model: AnyWeakModel,
layout: fn(&AnyView, &mut ElementContext) -> (LayoutId, AnyElement),
render: fn(&AnyView, &mut ElementContext) -> AnyElement,
}
impl AnyWeakView {
@ -382,8 +416,8 @@ impl AnyWeakView {
let model = self.model.upgrade()?;
Some(AnyView {
model,
request_layout: self.layout,
cache: false,
render: self.render,
cached_style: None,
})
}
}
@ -392,7 +426,7 @@ impl<V: 'static + Render> From<WeakView<V>> for AnyWeakView {
fn from(view: WeakView<V>) -> Self {
Self {
model: view.model.into(),
layout: any_view::request_layout::<V>,
render: any_view::render::<V>,
}
}
}
@ -412,15 +446,13 @@ impl std::fmt::Debug for AnyWeakView {
}
mod any_view {
use crate::{AnyElement, AnyView, ElementContext, IntoElement, LayoutId, Render};
use crate::{AnyElement, AnyView, ElementContext, IntoElement, Render};
pub(crate) fn request_layout<V: 'static + Render>(
pub(crate) fn render<V: 'static + Render>(
view: &AnyView,
cx: &mut ElementContext,
) -> (LayoutId, AnyElement) {
) -> AnyElement {
let view = view.clone().downcast::<V>().unwrap();
let mut element = view.update(cx, |view, cx| view.render(cx).into_any_element());
let layout_id = element.request_layout(cx);
(layout_id, element)
view.update(cx, |view, cx| view.render(cx).into_any_element())
}
}