bevy/crates/bevy_gizmos/src/cross.rs
Tim d2a07f9f72
Retained Gizmos (#15473)
# 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
2024-12-04 21:21:06 +00:00

84 lines
2.6 KiB
Rust

//! Additional [`GizmoBuffer`] Functions -- Crosses
//!
//! Includes the implementation of [`GizmoBuffer::cross`] and [`GizmoBuffer::cross_2d`],
//! and assorted support items.
use crate::{gizmos::GizmoBuffer, prelude::GizmoConfigGroup};
use bevy_color::Color;
use bevy_math::{Isometry2d, Isometry3d, Vec2, Vec3};
impl<Config, Clear> GizmoBuffer<Config, Clear>
where
Config: GizmoConfigGroup,
Clear: 'static + Send + Sync,
{
/// Draw a cross in 3D with the given `isometry` applied.
///
/// If `isometry == Isometry3d::IDENTITY` then
///
/// - the center is at `Vec3::ZERO`
/// - the `half_size`s are aligned with the `Vec3::X`, `Vec3::Y` and `Vec3::Z` axes.
///
/// This should be called for each frame the cross needs to be rendered.
///
/// # Example
/// ```
/// # use bevy_gizmos::prelude::*;
/// # use bevy_math::prelude::*;
/// # use bevy_color::palettes::basic::WHITE;
/// fn system(mut gizmos: Gizmos) {
/// gizmos.cross(Isometry3d::IDENTITY, 0.5, WHITE);
/// }
/// # bevy_ecs::system::assert_is_system(system);
/// ```
pub fn cross(
&mut self,
isometry: impl Into<Isometry3d>,
half_size: f32,
color: impl Into<Color>,
) {
let isometry = isometry.into();
let color: Color = color.into();
[Vec3::X, Vec3::Y, Vec3::Z]
.map(|axis| axis * half_size)
.into_iter()
.for_each(|axis| {
self.line(isometry * axis, isometry * (-axis), color);
});
}
/// Draw a cross in 2D with the given `isometry` applied.
///
/// If `isometry == Isometry2d::IDENTITY` then
///
/// - the center is at `Vec3::ZERO`
/// - the `half_size`s are aligned with the `Vec3::X` and `Vec3::Y` axes.
///
/// This should be called for each frame the cross needs to be rendered.
///
/// # Example
/// ```
/// # use bevy_gizmos::prelude::*;
/// # use bevy_math::prelude::*;
/// # use bevy_color::palettes::basic::WHITE;
/// fn system(mut gizmos: Gizmos) {
/// gizmos.cross_2d(Isometry2d::IDENTITY, 0.5, WHITE);
/// }
/// # bevy_ecs::system::assert_is_system(system);
/// ```
pub fn cross_2d(
&mut self,
isometry: impl Into<Isometry2d>,
half_size: f32,
color: impl Into<Color>,
) {
let isometry = isometry.into();
let color: Color = color.into();
[Vec2::X, Vec2::Y]
.map(|axis| axis * half_size)
.into_iter()
.for_each(|axis| {
self.line_2d(isometry * axis, isometry * (-axis), color);
});
}
}