This is another attempt to solve the same problem as
https://github.com/zed-industries/zed/pull/29718, while avoiding the
regression on Intel GPUs.
### Background
Currently, on main, all paths are first rendered to an intermediate
"atlas" texture, similar to what we use for rendering glyphs, but with
multi-sample antialiasing enabled. They are then drawn into our actual
frame buffer in a separate pass, via the "path sprite" shaders.
Notably, the intermediate texture acts as an "atlas" - the paths are
laid out in a non-overlapping way, so that each path could be copied to
an arbitrary position in the final scene. This non-overlapping approach
makes a lot sense for Glyphs (which are frequently re-used in multiple
places within a frame, and even across frames), but paths do not have
these properties.
* we clear the atlas every frame
* we rasterize each path separately. there is no deduping.
The problem with our current approach is that the path atlas textures
can end up using lots of VRAM if the scene contains many paths. This is
more of a problem in other apps that use GPUI than it is in Zed, but I
do think it's an issue for Zed as well. On Windows, I have hit some
crashes related to GPU memory.
In https://github.com/zed-industries/zed/pull/29718, @sunli829
simplified path rendering to just draw directly to the frame buffer, and
enabled msaa for the whole frame buffer. But apparently this doesn't
work well on Intel GPUs because MSAA is slow on those GPUs. So we
reverted that PR.
### Solution
With this PR, we rasterize paths to an intermediate texture with MSAA.
But rather than treating this intermediate texture like an *atlas*
(growing it in order to allocate non-overlapping rectangles for every
path), we simply use a single fixed-size, color texture that is the same
size as thew viewport. In this texture, we rasterize the paths in their
final screen position, allowing them to overlap. Then we simply blit
them from the resolved texture to the frame buffer.
### To do
* [x] Implement for Metal
* [x] Implement for Blade
* [x] Fix content masking for paths
* [x] Fix rendering of partially transparent paths
* [x] Verify that this performs well on Intel GPUs (help @notpeter 🙏 )
* [ ] Profile and optimize
Release Notes:
- N/A
---------
Co-authored-by: Junkui Zhang <364772080@qq.com>
Reverts zed-industries/zed#29718
We've noticed some issues with Zed on Intel-based Macs where typing has
become sluggish, and git bisect has seemed to point towards this PR.
Reverting for now, until we can understand why it is causing this issue.
Currently, the rendering path required creating a texture for each path,
which wasted a large amount of video memory. In our application, simply
drawing some charts resulted in video memory usage as high as 5G.
I removed the step of creating path textures and directly drew the paths
on the rendering target, adding post-processing global multi-sampling
anti-aliasing. Drawing paths no longer requires allocating any
additional video memory and also improves the performance of path
rendering.
Release Notes:
- N/A
---------
Co-authored-by: Jason Lee <huacnlee@gmail.com>
There's still a bit more work to do on this, but this PR is compiling
(with warnings) after eliminating the key types. When the tasks below
are complete, this will be the new narrative for GPUI:
- `Entity<T>` - This replaces `View<T>`/`Model<T>`. It represents a unit
of state, and if `T` implements `Render`, then `Entity<T>` implements
`Element`.
- `&mut App` This replaces `AppContext` and represents the app.
- `&mut Context<T>` This replaces `ModelContext` and derefs to `App`. It
is provided by the framework when updating an entity.
- `&mut Window` Broken out of `&mut WindowContext` which no longer
exists. Every method that once took `&mut WindowContext` now takes `&mut
Window, &mut App` and every method that took `&mut ViewContext<T>` now
takes `&mut Window, &mut Context<T>`
Not pictured here are the two other failed attempts. It's been quite a
month!
Tasks:
- [x] Remove `View`, `ViewContext`, `WindowContext` and thread through
`Window`
- [x] [@cole-miller @mikayla-maki] Redraw window when entities change
- [x] [@cole-miller @mikayla-maki] Get examples and Zed running
- [x] [@cole-miller @mikayla-maki] Fix Zed rendering
- [x] [@mikayla-maki] Fix todo! macros and comments
- [x] Fix a bug where the editor would not be redrawn because of view
caching
- [x] remove publicness window.notify() and replace with
`AppContext::notify`
- [x] remove `observe_new_window_models`, replace with
`observe_new_models` with an optional window
- [x] Fix a bug where the project panel would not be redrawn because of
the wrong refresh() call being used
- [x] Fix the tests
- [x] Fix warnings by eliminating `Window` params or using `_`
- [x] Fix conflicts
- [x] Simplify generic code where possible
- [x] Rename types
- [ ] Update docs
### issues post merge
- [x] Issues switching between normal and insert mode
- [x] Assistant re-rendering failure
- [x] Vim test failures
- [x] Mac build issue
Release Notes:
- N/A
---------
Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Cole Miller <cole@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Joseph <joseph@zed.dev>
Co-authored-by: max <max@zed.dev>
Co-authored-by: Michael Sloan <michael@zed.dev>
Co-authored-by: Mikayla Maki <mikaylamaki@Mikaylas-MacBook-Pro.local>
Co-authored-by: Mikayla <mikayla.c.maki@gmail.com>
Co-authored-by: joão <joao@zed.dev>
Release Notes:
- N/A
---
```
cargo run -p gpui --example painting
```
I added this demo to verify the detailed support of Path drawing in
GPUI.
Because of, when we actually used GPUI to draw a 2D line chart, we found
that the straight line Path#line_to did not support `anti-aliasing`, and
the drawn line looked very bad.
As shown in the demo image, if we zoom in on the image, we can clearly
see that all the lines are jagged.
I read and tried to make some appropriate adjustments to the functions
in Path, but since I have no experience in the graphics field, I still
cannot achieve anti-aliasing support so far.
I don't know if I used it wrong somewhere. I checked `curve_to` and
found that the curves drawn have anti-aliasing effects, as shown in the
arc part of the figure below.
<img width="1136" alt="image"
src="https://github.com/user-attachments/assets/4dfb7603-e746-43e9-b737-cff56b56329f">
