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).
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 practice makes it difficult to locate todo!s in my code when I'm
working. Let's take out the bang if we want to keep doing this.
Release Notes:
- N/A
Reverts zed-industries/zed#7481
This would regress performance because we'd be using the standard
library's hash maps everywhere, so reverting for now.
With upcoming release of 1.76 I did a check of current +beta (which
seems to already be at 1.77). These would cause CI pipeline failures
once 1.77 is out.
Release Notes:
- N/A
This optimizes rendering time by saving computation of the layer_id and
comparison when inserting it into the `BTreeMaps`.
Co-authored-by: Antonio <antonio@zed.dev>
Before this change we wouldn't submit all possible primitives of the
same kind that are less-than the max order.
Result was that we would submit, say, 10 paths each in a separate batch
instead of actually batching them.
This was overly strict because even if the order of two different
primitives was the same, we could have still batched the 1st primitive
kind, if its implicit ordering was less than 2nd kind.
Example: say we have the following primitives and these orders
5x paths, order 3
2x sprites, order 3
Previously, we would submit 1 path, 1 path, 1 path, 1 path, 1 path, then
the sprites.
With this changes, we batch the 5 paths into one batch.
Co-authored-by: Antonio <antonio@zed.dev>
