# Objective
- There are several redundant imports in the tests and examples that are
not caught by CI because additional flags need to be passed.
## Solution
- Run `cargo check --workspace --tests` and `cargo check --workspace
--examples`, then fix all warnings.
- Add `test-check` to CI, which will be run in the check-compiles job.
This should catch future warnings for tests. Examples are already
checked, but I'm not yet sure why they weren't caught.
## Discussion
- Should the `--tests` and `--examples` flags be added to CI, so this is
caught in the future?
- If so, #12818 will need to be merged first. It was also a warning
raised by checking the examples, but I chose to split off into a
separate PR.
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
Currently in order to retrieve the inner values from direction types is
that you need to use the `Deref` trait or `From`/`Into`. `Deref` that is
currently implemented is an anti-pattern that I believe should be less
relied upon.
This pull-request add getters for retrieving the inner values for
direction types.
Advantages of getters:
- Let rust-analyzer to list out available methods for users to
understand better to on how to get the inner value. (This happens to me.
I really don't know how to get the value until I look through the source
code.)
- They are simple.
- Generally won't be ambiguous in most context. Traits such as
`From`/`Into` will require fully qualified syntax from time to time.
- Unsurprising result.
Disadvantages of getters:
- More verbose
Advantages of deref polymorphism:
- You reduce boilerplate for getting the value and call inner methods
by:
```rust
let dir = Dir3::new(Vec3::UP).unwrap();
// getting value
let value = *dir;
// instead of using getters
let value = dir.vec3();
// calling methods for the inner vector
dir.xy();
// instead of using getters
dir.vec3().xy();
```
Disadvantages of deref polymorphism:
- When under more level of indirection, it will requires more
dereferencing which will get ugly in some part:
```rust
// getting value
let value = **dir;
// instead of using getters
let value = dir.vec3();
// calling methods for the inner vector
dir.xy();
// instead of using getters
dir.vec3().xy();
```
[More detail
here](https://rust-unofficial.github.io/patterns/anti_patterns/deref.html).
Edit: Update information for From/Into trait.
Edit: Advantages and disadvantages.
## Solution
Add `vec2` method for Dir2.
Add `vec3` method for Dir3.
Add `vec3a` method for Dir3A.
# Objective
Rotating vectors is a very common task. It is required for a variety of
things both within Bevy itself and in many third party plugins, for
example all over physics and collision detection, and for things like
Bevy's bounding volumes and several gizmo implementations.
For 3D, we can do this using a `Quat`, but for 2D, we do not have a
clear and efficient option. `Mat2` can be used for rotating vectors if
created using `Mat2::from_angle`, but this is not obvious to many users,
it doesn't have many rotation helpers, and the type does not give any
guarantees that it represents a valid rotation.
We should have a proper type for 2D rotations. In addition to allowing
for potential optimization, it would allow us to have a consistent and
explicitly documented representation used throughout the engine, i.e.
counterclockwise and in radians.
## Representation
The mathematical formula for rotating a 2D vector is the following:
```
new_x = x * cos - y * sin
new_y = x * sin + y * cos
```
Here, `sin` and `cos` are the sine and cosine of the rotation angle.
Computing these every time when a vector needs to be rotated can be
expensive, so the rotation shouldn't be just an `f32` angle. Instead, it
is often more efficient to represent the rotation using the sine and
cosine of the angle instead of storing the angle itself. This can be
freely passed around and reused without unnecessary computations.
The two options are either a 2x2 rotation matrix or a unit complex
number where the cosine is the real part and the sine is the imaginary
part. These are equivalent for the most part, but the unit complex
representation is a bit more memory efficient (two `f32`s instead of
four), so I chose that. This is like Nalgebra's
[`UnitComplex`](https://docs.rs/nalgebra/latest/nalgebra/geometry/type.UnitComplex.html)
type, which can be used for the
[`Rotation2`](https://docs.rs/nalgebra/latest/nalgebra/geometry/type.Rotation2.html)
type.
## Implementation
Add a `Rotation2d` type represented as a unit complex number:
```rust
/// A counterclockwise 2D rotation in radians.
///
/// The rotation angle is wrapped to be within the `]-pi, pi]` range.
pub struct Rotation2d {
/// The cosine of the rotation angle in radians.
///
/// This is the real part of the unit complex number representing the rotation.
pub cos: f32,
/// The sine of the rotation angle in radians.
///
/// This is the imaginary part of the unit complex number representing the rotation.
pub sin: f32,
}
```
Using it is similar to using `Quat`, but in 2D:
```rust
let rotation = Rotation2d::radians(PI / 2.0);
// Rotate vector (also works on Direction2d!)
assert_eq!(rotation * Vec2::X, Vec2::Y);
// Get angle as degrees
assert_eq!(rotation.as_degrees(), 90.0);
// Getting sin and cos is free
let (sin, cos) = rotation.sin_cos();
// "Subtract" rotations
let rotation2 = Rotation2d::FRAC_PI_4; // there are constants!
let diff = rotation * rotation2.inverse();
assert_eq!(diff.as_radians(), PI / 4.0);
// This is equivalent to the above
assert_eq!(rotation2.angle_between(rotation), PI / 4.0);
// Lerp
let rotation1 = Rotation2d::IDENTITY;
let rotation2 = Rotation2d::FRAC_PI_2;
let result = rotation1.lerp(rotation2, 0.5);
assert_eq!(result.as_radians(), std::f32::consts::FRAC_PI_4);
// Slerp
let rotation1 = Rotation2d::FRAC_PI_4);
let rotation2 = Rotation2d::degrees(-180.0); // we can use degrees too!
let result = rotation1.slerp(rotation2, 1.0 / 3.0);
assert_eq!(result.as_radians(), std::f32::consts::FRAC_PI_2);
```
There's also a `From<f32>` implementation for `Rotation2d`, which means
that methods can still accept radians as floats if the argument uses
`impl Into<Rotation2d>`. This means that adding `Rotation2d` shouldn't
even be a breaking change.
---
## Changelog
- Added `Rotation2d`
- Bounding volume methods now take an `impl Into<Rotation2d>`
- Gizmo methods with rotation now take an `impl Into<Rotation2d>`
## Future use cases
- Collision detection (a type like this is quite essential considering
how common vector rotations are)
- `Transform` helpers (e.g. return a 2D rotation about the Z axis from a
`Transform`)
- The rotation used for `Transform2d` (#8268)
- More gizmos, maybe meshes... everything in 2D that uses rotation
---------
Co-authored-by: Tristan Guichaoua <33934311+tguichaoua@users.noreply.github.com>
Co-authored-by: Robert Walter <robwalter96@gmail.com>
Co-authored-by: IQuick 143 <IQuick143cz@gmail.com>
# Objective
`Dir3` and `Dir3A` can be rotated using `Quat`s. However, if enough
floating point error accumulates or (more commonly) the rotation itself
is degenerate (like not normalized), the resulting direction can also
become denormalized.
Currently, with debug assertions enabled, it panics in these cases with
the message `rotated.is_normalized()`. This error message is unclear,
doesn't give information about *how* it is denormalized (like is the
length too large, NaN, or something else), and is overall not very
helpful. Panicking for small-ish error might also be a bit too strict,
and has lead to unwanted crashes in crates like `bevy_xpbd` (although it
has also helped in finding actual bugs).
The error message should be clearer and give more context, and it
shouldn't cause unwanted crashes.
## Solution
Change the `debug_assert!` to a warning for small error with a (squared
length) threshold of 2e-4 and a panic for clear error with a threshold
of 2e-2. The warnings mention the direction type and the length of the
denormalized vector.
Here's what the error and warning look like:
```
Error: `Dir3` is denormalized after rotation. The length is 1.014242.
```
```
Warning: `Dir3A` is denormalized after rotation. The length is 1.0001414.
```
I gave the same treatment to `new_unchecked`:
```
Error: The vector given to `Dir3::new_unchecked` is not normalized. The length is 1.014242.
```
```
Warning: The vector given to `Dir3A::new_unchecked` is not normalized. The length is 1.0001414.
```
---
## Discussion
### Threshold values
The thresholds are somewhat arbitrary. 2e-4 is what Glam uses for the
squared length in `is_normalized` (after I corrected it in
bitshifter/glam-rs#480), and 2e-2 is just what I thought could be a
clear sign of something being critically wrong. I can definitely tune
them if there are better thresholds though.
### Logging
`bevy_math` doesn't have `bevy_log`, so we can't use `warn!` or
`error!`. This is why I made it use just `eprintln!` and `panic!` for
now. Let me know if there's a better way of logging errors in
`bevy_math`.
# Objective
Bevy's `Dir3` and `Dir3A` only implement `Mul<f32>` and not vice versa,
and `Dir2` can not be multiplied by `f32` at all. They all should
implement multiplication both ways, just like Glam's vector types.
## Solution
Implement `Mul<Dir2>`, `Mul<Dir3>`, and `Mul<Dir3A>` for `f32`, and
`Mul<f32>` for `Dir2`.
# Objective
Split up from #12017, rename Bevy's direction types.
Currently, Bevy has the `Direction2d`, `Direction3d`, and `Direction3dA`
types, which provide a type-level guarantee that their contained vectors
remain normalized. They can be very useful for a lot of APIs for safety,
explicitness, and in some cases performance, as they can sometimes avoid
unnecessary normalizations.
However, many consider them to be inconvenient to use, and opt for
standard vector types like `Vec3` because of this. One reason is that
the direction type names are a bit long and can be annoying to write (of
course you can use autocomplete, but just typing `Vec3` is still nicer),
and in some intances, the extra characters can make formatting worse.
The naming is also inconsistent with Glam's shorter type names, and
results in names like `Direction3dA`, which (in my opinion) are
difficult to read and even a bit ugly.
This PR proposes renaming the types to `Dir2`, `Dir3`, and `Dir3A`.
These names are nice and easy to write, consistent with Glam, and work
well for variants like the SIMD aligned `Dir3A`. As a bonus, it can also
result in nicer formatting in a lot of cases, which can be seen from the
diff of this PR.
Some examples of what it looks like: (copied from #12017)
```rust
// Before
let ray_cast = RayCast2d::new(Vec2::ZERO, Direction2d::X, 5.0);
// After
let ray_cast = RayCast2d::new(Vec2::ZERO, Dir2::X, 5.0);
```
```rust
// Before (an example using Bevy XPBD)
let hit = spatial_query.cast_ray(
Vec3::ZERO,
Direction3d::X,
f32::MAX,
true,
SpatialQueryFilter::default(),
);
// After
let hit = spatial_query.cast_ray(
Vec3::ZERO,
Dir3::X,
f32::MAX,
true,
SpatialQueryFilter::default(),
);
```
```rust
// Before
self.circle(
Vec3::new(0.0, -2.0, 0.0),
Direction3d::Y,
5.0,
Color::TURQUOISE,
);
// After (formatting is collapsed in this case)
self.circle(Vec3::new(0.0, -2.0, 0.0), Dir3::Y, 5.0, Color::TURQUOISE);
```
## Solution
Rename `Direction2d`, `Direction3d`, and `Direction3dA` to `Dir2`,
`Dir3`, and `Dir3A`.
---
## Migration Guide
The `Direction2d` and `Direction3d` types have been renamed to `Dir2`
and `Dir3`.
## Additional Context
This has been brought up on the Discord a few times, and we had a small
[poll](https://discord.com/channels/691052431525675048/1203087353850364004/1212465038711984158)
on this. `Dir2`/`Dir3`/`Dir3A` was quite unanimously chosen as the best
option, but of course it was a very small poll and inconclusive, so
other opinions are certainly welcome too.
---------
Co-authored-by: IceSentry <c.giguere42@gmail.com>
# Objective
Split up from #12017, add an aligned version of `Direction3d` for SIMD,
and move direction types out of `primitives`.
## Solution
Add `Direction3dA` and move direction types into a new `direction`
module.
---
## Migration Guide
The `Direction2d`, `Direction3d`, and `InvalidDirectionError` types have
been moved out of `bevy::math::primitives`.
Before:
```rust
use bevy::math::primitives::Direction3d;
```
After:
```rust
use bevy::math::Direction3d;
```
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
