# Objective
A better alternative version of #10843.
Currently, Bevy has a single `Ray` struct for 3D. To allow better
interoperability with Bevy's primitive shapes (#10572) and some third
party crates (that handle e.g. spatial queries), it would be very useful
to have separate versions for 2D and 3D respectively.
## Solution
Separate `Ray` into `Ray2d` and `Ray3d`. These new structs also take
advantage of the new primitives by using `Direction2d`/`Direction3d` for
the direction:
```rust
pub struct Ray2d {
pub origin: Vec2,
pub direction: Direction2d,
}
pub struct Ray3d {
pub origin: Vec3,
pub direction: Direction3d,
}
```
and by using `Plane2d`/`Plane3d` in `intersect_plane`:
```rust
impl Ray2d {
// ...
pub fn intersect_plane(&self, plane_origin: Vec2, plane: Plane2d) -> Option<f32> {
// ...
}
}
```
---
## Changelog
### Added
- `Ray2d` and `Ray3d`
- `Ray2d::new` and `Ray3d::new` constructors
- `Plane2d::new` and `Plane3d::new` constructors
### Removed
- Removed `Ray` in favor of `Ray3d`
### Changed
- `direction` is now a `Direction2d`/`Direction3d` instead of a vector,
which provides guaranteed normalization
- `intersect_plane` now takes a `Plane2d`/`Plane3d` instead of just a
vector for the plane normal
- `Direction2d` and `Direction3d` now derive `Serialize` and
`Deserialize` to preserve ray (de)serialization
## Migration Guide
`Ray` has been renamed to `Ray3d`.
### Ray creation
Before:
```rust
Ray {
origin: Vec3::ZERO,
direction: Vec3::new(0.5, 0.6, 0.2).normalize(),
}
```
After:
```rust
// Option 1:
Ray3d {
origin: Vec3::ZERO,
direction: Direction3d::new(Vec3::new(0.5, 0.6, 0.2)).unwrap(),
}
// Option 2:
Ray3d::new(Vec3::ZERO, Vec3::new(0.5, 0.6, 0.2))
```
### Plane intersections
Before:
```rust
let result = ray.intersect_plane(Vec2::X, Vec2::Y);
```
After:
```rust
let result = ray.intersect_plane(Vec2::X, Plane2d::new(Vec2::Y));
```
d9aac887b5