# Objective
Add a way to use the gizmo API in a retained manner, for increased
performance.
## Solution
- Move gizmo API from `Gizmos` to `GizmoBuffer`, ~ab~using `Deref` to
keep usage the same as before.
- Merge non-strip and strip variant of `LineGizmo` into one, storing the
data in a `GizmoBuffer` to have the same API for retained `LineGizmo`s.
### Review guide
- The meat of the changes are in `lib.rs`, `retained.rs`, `gizmos.rs`,
`pipeline_3d.rs` and `pipeline_2d.rs`
- The other files contain almost exclusively the churn from moving the
gizmo API from `Gizmos` to `GizmoBuffer`
## Testing
### Performance
Performance compared to the immediate mode API is from 65 to 80 times
better for static lines.
```
7900 XTX, 3700X
1707.9k lines/ms: gizmos_retained (21.3ms)
3488.5k lines/ms: gizmos_retained_continuous_polyline (31.3ms)
0.5k lines/ms: gizmos_retained_separate (97.7ms)
3054.9k lines/ms: bevy_polyline_retained_nan (16.8ms)
3596.3k lines/ms: bevy_polyline_retained_continuous_polyline (14.2ms)
0.6k lines/ms: bevy_polyline_retained_separate (78.9ms)
26.9k lines/ms: gizmos_immediate (14.9ms)
43.8k lines/ms: gizmos_immediate_continuous_polyline (18.3ms)
```
Looks like performance is good enough, being close to par with
`bevy_polyline`.
Benchmarks can be found here:
This branch:
https://github.com/tim-blackbird/line_racing/tree/retained-gizmos
Bevy 0.14: https://github.com/DGriffin91/line_racing
## Showcase
```rust
fn setup(
mut commands: Commands,
mut gizmo_assets: ResMut<Assets<GizmoAsset>>
) {
let mut gizmo = GizmoAsset::default();
// A sphere made out of one million lines!
gizmo
.sphere(default(), 1., CRIMSON)
.resolution(1_000_000 / 3);
commands.spawn(Gizmo {
handle: gizmo_assets.add(gizmo),
..default()
});
}
```
## Follow-up work
- Port over to the retained rendering world proper
- Calculate visibility and cull `Gizmo`s
# Objective
Several of our APIs (namely gizmos and bounding) use isometries on
current Bevy main. This is nicer than separate properties in a lot of
cases, but users have still expressed usability concerns.
One problem is that in a lot of cases, you only care about e.g.
translation, so you end up with this:
```rust
gizmos.cross_2d(
Isometry2d::from_translation(Vec2::new(-160.0, 120.0)),
12.0,
FUCHSIA,
);
```
The isometry adds quite a lot of length and verbosity, and isn't really
that relevant since only the translation is important here.
It would be nice if you could use the translation directly, and only
supply an isometry if both translation and rotation are needed. This
would make the following possible:
```rust
gizmos.cross_2d(Vec2::new(-160.0, 120.0), 12.0, FUCHSIA);
```
removing a lot of verbosity.
## Solution
Implement `From<Vec2>` and `From<Rot2>` for `Isometry2d`, and
`From<Vec3>`, `From<Vec3A>`, and `From<Quat>` for `Isometry3d`. These
are lossless conversions that fit the semantics of `From`.
This makes the proposed API possible! The methods must now simply take
an `impl Into<IsometryNd>`, and this works:
```rust
gizmos.cross_2d(Vec2::new(-160.0, 120.0), 12.0, FUCHSIA);
```
# Objective
- Solves the last bullet in and closes#14319
- Make better use of the `Isometry` types
- Prevent issues like #14655
- Probably simplify and clean up a lot of code through the use of Gizmos
as well (i.e. the 3D gizmos for cylinders circles & lines don't connect
well, probably due to wrong rotations)
## Solution
- go through the `bevy_gizmos` crate and give all methods a slight
workover
## Testing
- For all the changed examples I run `git switch main && cargo rr
--example <X> && git switch <BRANCH> && cargo rr --example <X>` and
compare the visual results
- Check if all doc tests are still compiling
- Check the docs in general and update them !!!
---
## Migration Guide
The gizmos methods function signature changes as follows:
- 2D
- if it took `position` & `rotation_angle` before ->
`Isometry2d::new(position, Rot2::radians(rotation_angle))`
- if it just took `position` before ->
`Isometry2d::from_translation(position)`
- 3D
- if it took `position` & `rotation` before ->
`Isometry3d::new(position, rotation)`
- if it just took `position` before ->
`Isometry3d::from_translation(position)`
# Objective
When trying to test a gizmos change I ran `cargo test -p bevy_gizmos`
and the output had a lot of noise from warnings and failed doc errors.
This was because I didn't have all of the features enabled.
## Solution
I admit this might be pedantic, and am happy if the concensus is to
reject it. Although it does reduce the lines of code, testing noise, and
the amount of code compiled. I don't think it affects the complexity of
public code, and it doesn't change much to the complexity of internal
code.
I've removed un-needed `bevy_render` imports in all of the gizmos docs
examples, there's probably other unnecessary ones there too, but I
haven't looked exhaustively. It isn't needed for those docs, and isn't
available except in a subset of `cfg` combinations.
I've also made several of the `use` statements slightly more specific. I
shouldn't have changed the public interfaces, except that
`GizmoMeshConfig` requires either `bevy_sprite` or `bevy_pbr`, as it
does nothing without them.
I've also avoided adding some systems and plugins in situations where
they can't work. An example of this is where the `light` module depends
on `all(feature = "bevy_pbr", feature = "bevy_render")`, but it has
`use` statements that only require `bevy_render`.
## Testing
During development I ran:
```
cargo check -p bevy_gizmos && cargo check -p bevy_gizmos --features=bevy_pbr && cargo check -p bevy_gizmos --features=bevy_sprite && cargo check -p bevy_gizmos --features=bevy_render
```
Afterwards I ran this just to be sure:
```
cargo check && cargo check --features=bevy_pbr && cargo check --features=bevy_sprite && cargo check --features=bevy_render
```
Finally I ran:
```
cargo test -p bevy_gizmos && cargo test -p bevy_gizmos --features=bevy_pbr && test check -p bevy_gizmos --features=bevy_sprite && cargo test -p bevy_gizmos --features=bevy_render
```
## Migration Guide
There shouldn't be any reason to migrate, although if for some reason
you use `GizmoMeshConfig` and `bevy_render` but not `bevy_pbr` or
`bevy_sprite` (such that it does nothing), then you will get an error
that it no longer exists.
