# Objective
- Fixes#20008 - Preconvert colors before sending them to the UI
gradients shader for better performance
## Solution
- Modified `prepare_gradient` in `gradient.rs` to convert colors from
`LinearRgba` to `Srgba` on the CPU before sending to the GPU
- Updated the gradient shader to remove per-pixel color space
conversions since colors are now pre-converted
- Added documentation to clarify that vertex colors are in sRGB space
This optimization reduces the number of power operations per pixel from
3 to 1:
- **Before**: Convert start color to sRGB, convert end color to sRGB,
mix, convert back to linear (3 pow operations per pixel)
- **After**: Colors pre-converted on CPU, mix in sRGB space, convert
back to linear (1 pow operation per pixel)
## Testing
- Verified that the UI gradient examples (`cargo run --example
gradients`) compile and render correctly
- The visual output should remain identical while performance improves,
especially for large gradient areas
- Changes maintain the same color interpolation behavior (mixing in sRGB
space)
To test:
1. Run `cargo run --example gradients` or `cargo run --example
stacked_gradients`
2. Verify gradients render correctly
---------
Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
# Objective
The names of the variants of `InterpolationColorSpace` don't match the
corresponding `Color` variants, which could be potentially confusing.
For instance, `Color` has an `Oklaba` variant, in
`InterpolationColorSpace` it's called `OkLab`.
## Solution
Rename variants of `InterpolationColorSpace` to mirror the variants of
Color.
# Objective
The false and true arguments for the select statement in `lerp_hue_long`
are misordered, resulting in it taking the wrong hue path:
## Solution
Swap the arguments around.
Also fixed another case I found during testing. The hue was interpolated
even when it is undefined for one of the endpoints (for example in a
gradient from black to yellow). In those cases it shouldn't interpolate,
instead it should return the hue of the other end point.
## Testing
I added a `linear_gradient` module to the testbed `ui` example, run
with:
```
cargo run --example testbed_ui
```
In the linear gradients screen (press space to switch) it shows a column
of red to yellow linear gradients. The last gradient in the column uses
the OKLCH long path, which should look like this:
matching the same gradient in CSS:
https://jsfiddle.net/fevshkdy/14/
if the correct hue path is chosen.
# Objective
Add interpolation in HSL and HSV colour spaces for UI gradients.
## Solution
Added new variants to `InterpolationColorSpace`: `Hsl`, `HslLong`,
`Hsv`, and `HsvLong`, along with mix functions to the `gradients` shader
for each of them.
#### Limitations
* Didn't include increasing and decreasing path support, it's not
essential and can be done in a follow up if someone feels like it.
* The colour conversions should really be performed before the colours
are sent to the shader but it would need more changes and performance is
good enough for now.
## Testing
```cargo run --example gradients```
# Objective
- for smallvec some crates specify default features false, other dont.
turns out we dont need them
## Solution
- remove
## Testing
- 3d_scene
# Objective
- Progress towards #19887.
## Solution
- Convert `FromWorld` impls into systems that run in `RenderStartup`.
- Move `UiPipeline` init to `build_ui_render` instead of doing it
separately in `finish`.
Note: I am making several of these systems pub so that users could order
their systems relative to them. This is to match the fact that these
types previously were FromWorld so users could initialize them.
## Testing
- Ran `ui_material`, `ui_texture_slice`, `box_shadow`, and `gradients`
examples and it still worked.
# Objective
Move Bevy UI's rendering into a dedicated crate.
Motivations:
* Allow the UI renderer to be used with other UI frameworks than
`bevy_ui`.
* Allow for using alternative renderers like Vello with `bevy_ui`.
* It's difficult for rendering contributors to make changes and
improvements to the UI renderer as it requires in-depth knowledge of the
UI implementation.
## Solution
Move the `render` and `ui_material` modules from `bevy_ui` into a new
crate `bevy_ui_render`.
## Testing
Important examples to check are `testbed_ui`, `testbed_full_ui`,
`ui_material`, `viewport_node` and `gradients`.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
