# Objective
- Rebase of https://github.com/bevyengine/bevy/pull/12561 , note that
this is blocked on "up-streaming
[iyes_perf_ui](https://crates.io/crates/iyes_perf_ui)" , but that work
seems to also be stalled
> Frame time is often more important to know than FPS but because of the
temporal nature of it, just seeing a number is not enough. Seeing a
graph that shows the history makes it easier to reason about
performance.
## Solution
> This PR adds a bar graph of the frame time history.
>
> Each bar is scaled based on the frame time where a bigger frame time
will give a taller and wider bar.
>
> The color also scales with that frame time where red is at or bellow
the minimum target fps and green is at or above the target maximum frame
rate. Anything between those 2 values will be interpolated between green
and red based on the frame time.
>
> The algorithm is highly inspired by this article:
https://asawicki.info/news_1758_an_idea_for_visualization_of_frame_times
## Testing
- Ran `cargo run --example fps_overlay --features="bevy_dev_tools"`
---------
Co-authored-by: IceSentry <c.giguere42@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Related to #19024.
## Solution
- This is a mix of several ways to get rid of weak handles. The primary
strategy is putting strong asset handles in resources that the rendering
code clones into its pipelines (or whatever).
- This does not handle every remaining case, but we are slowly clearing
them out.
## Testing
- `anti_aliasing` example still works.
- `fog_volumes` example still works.
# 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```
[Explanation](https://bevyengine.org/learn/contribute/helping-out/explaining-examples/)
for the 3d shapes example.
This shares a lot of detail with the [2d
shapes](https://github.com/bevyengine/bevy/pull/19211) example, so it's
similar in structure. The explanation for why asset handles are not
components has been copied over for now with minor adjustment, I'll do
another editing pass on this to make it match the surrounding context
and focus before taking it out of drafts.
---------
Co-authored-by: theotherphil <phil.j.ellison@gmail.com>
Co-authored-by: Carter Weinberg <weinbergcarter@gmail.com>
# Objective
- Fixes#13872 (also mentioned in #17167)
## Solution
- Added conditional padding fields to the shader uniform
## Alternatives
### 1- Use a UVec4
Replace the `u32` field in `MyExtension` by a `UVec4` and only use the
`x` coordinate.
(This was the original approach, but for consistency with the rest of
the codebase, separate padding fields seem to be preferred)
### 2- Don't fix it, unlist it
While the fix is quite simple, it does muddy the waters a tiny bit due
to `quantize_steps` now being a UVec4 instead of a simple u32. We could
simply remove this example from the examples that support WebGL2.
## Testing
- Ran the example locally on WebGL2 (and native Vulkan) successfully
# Objective
- make lights usable without bevy_render
## Solution
- make a new crate for lights to live in
## Testing
- 3d_scene, lighting, volumetric_fog, ssr, transmission, pcss,
light_textures
Note: no breaking changes because of re-exports, except for light
textures, which were introduced this cycle so it doesn't matter anyways