bevy/crates/bevy_math/src/isometry.rs
Joona Aalto 21b78b5990
Implement From translation and rotation for isometries (#15733)
# 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);
```
2024-10-08 16:09:28 +00:00

687 lines
21 KiB
Rust

//! Isometry types for expressing rigid motions in two and three dimensions.
use crate::{Affine2, Affine3, Affine3A, Dir2, Dir3, Mat3, Mat3A, Quat, Rot2, Vec2, Vec3, Vec3A};
use core::ops::Mul;
#[cfg(feature = "approx")]
use approx::{AbsDiffEq, RelativeEq, UlpsEq};
#[cfg(feature = "bevy_reflect")]
use bevy_reflect::{std_traits::ReflectDefault, Reflect};
#[cfg(all(feature = "bevy_reflect", feature = "serialize"))]
use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
/// An isometry in two dimensions, representing a rotation followed by a translation.
/// This can often be useful for expressing relative positions and transformations from one position to another.
///
/// In particular, this type represents a distance-preserving transformation known as a *rigid motion* or a *direct motion*,
/// and belongs to the special [Euclidean group] SE(2). This includes translation and rotation, but excludes reflection.
///
/// For the three-dimensional version, see [`Isometry3d`].
///
/// [Euclidean group]: https://en.wikipedia.org/wiki/Euclidean_group
///
/// # Example
///
/// Isometries can be created from a given translation and rotation:
///
/// ```
/// # use bevy_math::{Isometry2d, Rot2, Vec2};
/// #
/// let iso = Isometry2d::new(Vec2::new(2.0, 1.0), Rot2::degrees(90.0));
/// ```
///
/// Or from separate parts:
///
/// ```
/// # use bevy_math::{Isometry2d, Rot2, Vec2};
/// #
/// let iso1 = Isometry2d::from_translation(Vec2::new(2.0, 1.0));
/// let iso2 = Isometry2d::from_rotation(Rot2::degrees(90.0));
/// ```
///
/// The isometries can be used to transform points:
///
/// ```
/// # use approx::assert_abs_diff_eq;
/// # use bevy_math::{Isometry2d, Rot2, Vec2};
/// #
/// let iso = Isometry2d::new(Vec2::new(2.0, 1.0), Rot2::degrees(90.0));
/// let point = Vec2::new(4.0, 4.0);
///
/// // These are equivalent
/// let result = iso.transform_point(point);
/// let result = iso * point;
///
/// assert_eq!(result, Vec2::new(-2.0, 5.0));
/// ```
///
/// Isometries can also be composed together:
///
/// ```
/// # use bevy_math::{Isometry2d, Rot2, Vec2};
/// #
/// # let iso = Isometry2d::new(Vec2::new(2.0, 1.0), Rot2::degrees(90.0));
/// # let iso1 = Isometry2d::from_translation(Vec2::new(2.0, 1.0));
/// # let iso2 = Isometry2d::from_rotation(Rot2::degrees(90.0));
/// #
/// assert_eq!(iso1 * iso2, iso);
/// ```
///
/// One common operation is to compute an isometry representing the relative positions of two objects
/// for things like intersection tests. This can be done with an inverse transformation:
///
/// ```
/// # use bevy_math::{Isometry2d, Rot2, Vec2};
/// #
/// let circle_iso = Isometry2d::from_translation(Vec2::new(2.0, 1.0));
/// let rectangle_iso = Isometry2d::from_rotation(Rot2::degrees(90.0));
///
/// // Compute the relative position and orientation between the two shapes
/// let relative_iso = circle_iso.inverse() * rectangle_iso;
///
/// // Or alternatively, to skip an extra rotation operation:
/// let relative_iso = circle_iso.inverse_mul(rectangle_iso);
/// ```
#[derive(Copy, Clone, Default, Debug, PartialEq)]
#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(
feature = "bevy_reflect",
derive(Reflect),
reflect(Debug, PartialEq, Default)
)]
#[cfg_attr(
all(feature = "serialize", feature = "bevy_reflect"),
reflect(Serialize, Deserialize)
)]
pub struct Isometry2d {
/// The rotational part of a two-dimensional isometry.
pub rotation: Rot2,
/// The translational part of a two-dimensional isometry.
pub translation: Vec2,
}
impl Isometry2d {
/// The identity isometry which represents the rigid motion of not doing anything.
pub const IDENTITY: Self = Isometry2d {
rotation: Rot2::IDENTITY,
translation: Vec2::ZERO,
};
/// Create a two-dimensional isometry from a rotation and a translation.
#[inline]
pub fn new(translation: Vec2, rotation: Rot2) -> Self {
Isometry2d {
rotation,
translation,
}
}
/// Create a two-dimensional isometry from a rotation.
#[inline]
pub fn from_rotation(rotation: Rot2) -> Self {
Isometry2d {
rotation,
translation: Vec2::ZERO,
}
}
/// Create a two-dimensional isometry from a translation.
#[inline]
pub fn from_translation(translation: Vec2) -> Self {
Isometry2d {
rotation: Rot2::IDENTITY,
translation,
}
}
/// Create a two-dimensional isometry from a translation with the given `x` and `y` components.
#[inline]
pub fn from_xy(x: f32, y: f32) -> Self {
Isometry2d {
rotation: Rot2::IDENTITY,
translation: Vec2::new(x, y),
}
}
/// The inverse isometry that undoes this one.
#[inline]
pub fn inverse(&self) -> Self {
let inv_rot = self.rotation.inverse();
Isometry2d {
rotation: inv_rot,
translation: inv_rot * -self.translation,
}
}
/// Compute `iso1.inverse() * iso2` in a more efficient way for one-shot cases.
///
/// If the same isometry is used multiple times, it is more efficient to instead compute
/// the inverse once and use that for each transformation.
#[inline]
pub fn inverse_mul(&self, rhs: Self) -> Self {
let inv_rot = self.rotation.inverse();
let delta_translation = rhs.translation - self.translation;
Self::new(inv_rot * delta_translation, inv_rot * rhs.rotation)
}
/// Transform a point by rotating and translating it using this isometry.
#[inline]
pub fn transform_point(&self, point: Vec2) -> Vec2 {
self.rotation * point + self.translation
}
/// Transform a point by rotating and translating it using the inverse of this isometry.
///
/// This is more efficient than `iso.inverse().transform_point(point)` for one-shot cases.
/// If the same isometry is used multiple times, it is more efficient to instead compute
/// the inverse once and use that for each transformation.
#[inline]
pub fn inverse_transform_point(&self, point: Vec2) -> Vec2 {
self.rotation.inverse() * (point - self.translation)
}
}
impl From<Isometry2d> for Affine2 {
#[inline]
fn from(iso: Isometry2d) -> Self {
Affine2 {
matrix2: iso.rotation.into(),
translation: iso.translation,
}
}
}
impl From<Vec2> for Isometry2d {
#[inline]
fn from(translation: Vec2) -> Self {
Isometry2d::from_translation(translation)
}
}
impl From<Rot2> for Isometry2d {
#[inline]
fn from(rotation: Rot2) -> Self {
Isometry2d::from_rotation(rotation)
}
}
impl Mul for Isometry2d {
type Output = Self;
#[inline]
fn mul(self, rhs: Self) -> Self::Output {
Isometry2d {
rotation: self.rotation * rhs.rotation,
translation: self.rotation * rhs.translation + self.translation,
}
}
}
impl Mul<Vec2> for Isometry2d {
type Output = Vec2;
#[inline]
fn mul(self, rhs: Vec2) -> Self::Output {
self.transform_point(rhs)
}
}
impl Mul<Dir2> for Isometry2d {
type Output = Dir2;
#[inline]
fn mul(self, rhs: Dir2) -> Self::Output {
self.rotation * rhs
}
}
#[cfg(feature = "approx")]
impl AbsDiffEq for Isometry2d {
type Epsilon = <f32 as AbsDiffEq>::Epsilon;
fn default_epsilon() -> Self::Epsilon {
f32::default_epsilon()
}
fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool {
self.rotation.abs_diff_eq(&other.rotation, epsilon)
&& self.translation.abs_diff_eq(other.translation, epsilon)
}
}
#[cfg(feature = "approx")]
impl RelativeEq for Isometry2d {
fn default_max_relative() -> Self::Epsilon {
Self::default_epsilon()
}
fn relative_eq(
&self,
other: &Self,
epsilon: Self::Epsilon,
max_relative: Self::Epsilon,
) -> bool {
self.rotation
.relative_eq(&other.rotation, epsilon, max_relative)
&& self
.translation
.relative_eq(&other.translation, epsilon, max_relative)
}
}
#[cfg(feature = "approx")]
impl UlpsEq for Isometry2d {
fn default_max_ulps() -> u32 {
4
}
fn ulps_eq(&self, other: &Self, epsilon: Self::Epsilon, max_ulps: u32) -> bool {
self.rotation.ulps_eq(&other.rotation, epsilon, max_ulps)
&& self
.translation
.ulps_eq(&other.translation, epsilon, max_ulps)
}
}
/// An isometry in three dimensions, representing a rotation followed by a translation.
/// This can often be useful for expressing relative positions and transformations from one position to another.
///
/// In particular, this type represents a distance-preserving transformation known as a *rigid motion* or a *direct motion*,
/// and belongs to the special [Euclidean group] SE(3). This includes translation and rotation, but excludes reflection.
///
/// For the two-dimensional version, see [`Isometry2d`].
///
/// [Euclidean group]: https://en.wikipedia.org/wiki/Euclidean_group
///
/// # Example
///
/// Isometries can be created from a given translation and rotation:
///
/// ```
/// # use bevy_math::{Isometry3d, Quat, Vec3};
/// # use std::f32::consts::FRAC_PI_2;
/// #
/// let iso = Isometry3d::new(Vec3::new(2.0, 1.0, 3.0), Quat::from_rotation_z(FRAC_PI_2));
/// ```
///
/// Or from separate parts:
///
/// ```
/// # use bevy_math::{Isometry3d, Quat, Vec3};
/// # use std::f32::consts::FRAC_PI_2;
/// #
/// let iso1 = Isometry3d::from_translation(Vec3::new(2.0, 1.0, 3.0));
/// let iso2 = Isometry3d::from_rotation(Quat::from_rotation_z(FRAC_PI_2));
/// ```
///
/// The isometries can be used to transform points:
///
/// ```
/// # use approx::assert_relative_eq;
/// # use bevy_math::{Isometry3d, Quat, Vec3};
/// # use std::f32::consts::FRAC_PI_2;
/// #
/// let iso = Isometry3d::new(Vec3::new(2.0, 1.0, 3.0), Quat::from_rotation_z(FRAC_PI_2));
/// let point = Vec3::new(4.0, 4.0, 4.0);
///
/// // These are equivalent
/// let result = iso.transform_point(point);
/// let result = iso * point;
///
/// assert_relative_eq!(result, Vec3::new(-2.0, 5.0, 7.0));
/// ```
///
/// Isometries can also be composed together:
///
/// ```
/// # use bevy_math::{Isometry3d, Quat, Vec3};
/// # use std::f32::consts::FRAC_PI_2;
/// #
/// # let iso = Isometry3d::new(Vec3::new(2.0, 1.0, 3.0), Quat::from_rotation_z(FRAC_PI_2));
/// # let iso1 = Isometry3d::from_translation(Vec3::new(2.0, 1.0, 3.0));
/// # let iso2 = Isometry3d::from_rotation(Quat::from_rotation_z(FRAC_PI_2));
/// #
/// assert_eq!(iso1 * iso2, iso);
/// ```
///
/// One common operation is to compute an isometry representing the relative positions of two objects
/// for things like intersection tests. This can be done with an inverse transformation:
///
/// ```
/// # use bevy_math::{Isometry3d, Quat, Vec3};
/// # use std::f32::consts::FRAC_PI_2;
/// #
/// let sphere_iso = Isometry3d::from_translation(Vec3::new(2.0, 1.0, 3.0));
/// let cuboid_iso = Isometry3d::from_rotation(Quat::from_rotation_z(FRAC_PI_2));
///
/// // Compute the relative position and orientation between the two shapes
/// let relative_iso = sphere_iso.inverse() * cuboid_iso;
///
/// // Or alternatively, to skip an extra rotation operation:
/// let relative_iso = sphere_iso.inverse_mul(cuboid_iso);
/// ```
#[derive(Copy, Clone, Default, Debug, PartialEq)]
#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(
feature = "bevy_reflect",
derive(Reflect),
reflect(Debug, PartialEq, Default)
)]
#[cfg_attr(
all(feature = "serialize", feature = "bevy_reflect"),
reflect(Serialize, Deserialize)
)]
pub struct Isometry3d {
/// The rotational part of a three-dimensional isometry.
pub rotation: Quat,
/// The translational part of a three-dimensional isometry.
pub translation: Vec3A,
}
impl Isometry3d {
/// The identity isometry which represents the rigid motion of not doing anything.
pub const IDENTITY: Self = Isometry3d {
rotation: Quat::IDENTITY,
translation: Vec3A::ZERO,
};
/// Create a three-dimensional isometry from a rotation and a translation.
#[inline]
pub fn new(translation: impl Into<Vec3A>, rotation: Quat) -> Self {
Isometry3d {
rotation,
translation: translation.into(),
}
}
/// Create a three-dimensional isometry from a rotation.
#[inline]
pub fn from_rotation(rotation: Quat) -> Self {
Isometry3d {
rotation,
translation: Vec3A::ZERO,
}
}
/// Create a three-dimensional isometry from a translation.
#[inline]
pub fn from_translation(translation: impl Into<Vec3A>) -> Self {
Isometry3d {
rotation: Quat::IDENTITY,
translation: translation.into(),
}
}
/// Create a three-dimensional isometry from a translation with the given `x`, `y`, and `z` components.
#[inline]
pub fn from_xyz(x: f32, y: f32, z: f32) -> Self {
Isometry3d {
rotation: Quat::IDENTITY,
translation: Vec3A::new(x, y, z),
}
}
/// The inverse isometry that undoes this one.
#[inline]
pub fn inverse(&self) -> Self {
let inv_rot = self.rotation.inverse();
Isometry3d {
rotation: inv_rot,
translation: inv_rot * -self.translation,
}
}
/// Compute `iso1.inverse() * iso2` in a more efficient way for one-shot cases.
///
/// If the same isometry is used multiple times, it is more efficient to instead compute
/// the inverse once and use that for each transformation.
#[inline]
pub fn inverse_mul(&self, rhs: Self) -> Self {
let inv_rot = self.rotation.inverse();
let delta_translation = rhs.translation - self.translation;
Self::new(inv_rot * delta_translation, inv_rot * rhs.rotation)
}
/// Transform a point by rotating and translating it using this isometry.
#[inline]
pub fn transform_point(&self, point: impl Into<Vec3A>) -> Vec3A {
self.rotation * point.into() + self.translation
}
/// Transform a point by rotating and translating it using the inverse of this isometry.
///
/// This is more efficient than `iso.inverse().transform_point(point)` for one-shot cases.
/// If the same isometry is used multiple times, it is more efficient to instead compute
/// the inverse once and use that for each transformation.
#[inline]
pub fn inverse_transform_point(&self, point: impl Into<Vec3A>) -> Vec3A {
self.rotation.inverse() * (point.into() - self.translation)
}
}
impl From<Isometry3d> for Affine3 {
#[inline]
fn from(iso: Isometry3d) -> Self {
Affine3 {
matrix3: Mat3::from_quat(iso.rotation),
translation: iso.translation.into(),
}
}
}
impl From<Isometry3d> for Affine3A {
#[inline]
fn from(iso: Isometry3d) -> Self {
Affine3A {
matrix3: Mat3A::from_quat(iso.rotation),
translation: iso.translation,
}
}
}
impl From<Vec3> for Isometry3d {
#[inline]
fn from(translation: Vec3) -> Self {
Isometry3d::from_translation(translation)
}
}
impl From<Vec3A> for Isometry3d {
#[inline]
fn from(translation: Vec3A) -> Self {
Isometry3d::from_translation(translation)
}
}
impl From<Quat> for Isometry3d {
#[inline]
fn from(rotation: Quat) -> Self {
Isometry3d::from_rotation(rotation)
}
}
impl Mul for Isometry3d {
type Output = Self;
#[inline]
fn mul(self, rhs: Self) -> Self::Output {
Isometry3d {
rotation: self.rotation * rhs.rotation,
translation: self.rotation * rhs.translation + self.translation,
}
}
}
impl Mul<Vec3A> for Isometry3d {
type Output = Vec3A;
#[inline]
fn mul(self, rhs: Vec3A) -> Self::Output {
self.transform_point(rhs)
}
}
impl Mul<Vec3> for Isometry3d {
type Output = Vec3;
#[inline]
fn mul(self, rhs: Vec3) -> Self::Output {
self.transform_point(rhs).into()
}
}
impl Mul<Dir3> for Isometry3d {
type Output = Dir3;
#[inline]
fn mul(self, rhs: Dir3) -> Self::Output {
self.rotation * rhs
}
}
#[cfg(feature = "approx")]
impl AbsDiffEq for Isometry3d {
type Epsilon = <f32 as AbsDiffEq>::Epsilon;
fn default_epsilon() -> Self::Epsilon {
f32::default_epsilon()
}
fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool {
self.rotation.abs_diff_eq(other.rotation, epsilon)
&& self.translation.abs_diff_eq(other.translation, epsilon)
}
}
#[cfg(feature = "approx")]
impl RelativeEq for Isometry3d {
fn default_max_relative() -> Self::Epsilon {
Self::default_epsilon()
}
fn relative_eq(
&self,
other: &Self,
epsilon: Self::Epsilon,
max_relative: Self::Epsilon,
) -> bool {
self.rotation
.relative_eq(&other.rotation, epsilon, max_relative)
&& self
.translation
.relative_eq(&other.translation, epsilon, max_relative)
}
}
#[cfg(feature = "approx")]
impl UlpsEq for Isometry3d {
fn default_max_ulps() -> u32 {
4
}
fn ulps_eq(&self, other: &Self, epsilon: Self::Epsilon, max_ulps: u32) -> bool {
self.rotation.ulps_eq(&other.rotation, epsilon, max_ulps)
&& self
.translation
.ulps_eq(&other.translation, epsilon, max_ulps)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{vec2, vec3, vec3a};
use approx::assert_abs_diff_eq;
use core::f32::consts::{FRAC_PI_2, FRAC_PI_3};
#[test]
fn mul_2d() {
let iso1 = Isometry2d::new(vec2(1.0, 0.0), Rot2::FRAC_PI_2);
let iso2 = Isometry2d::new(vec2(0.0, 1.0), Rot2::FRAC_PI_2);
let expected = Isometry2d::new(vec2(0.0, 0.0), Rot2::PI);
assert_abs_diff_eq!(iso1 * iso2, expected);
}
#[test]
fn inverse_mul_2d() {
let iso1 = Isometry2d::new(vec2(1.0, 0.0), Rot2::FRAC_PI_2);
let iso2 = Isometry2d::new(vec2(0.0, 0.0), Rot2::PI);
let expected = Isometry2d::new(vec2(0.0, 1.0), Rot2::FRAC_PI_2);
assert_abs_diff_eq!(iso1.inverse_mul(iso2), expected);
}
#[test]
fn mul_3d() {
let iso1 = Isometry3d::new(vec3(1.0, 0.0, 0.0), Quat::from_rotation_x(FRAC_PI_2));
let iso2 = Isometry3d::new(vec3(0.0, 1.0, 0.0), Quat::IDENTITY);
let expected = Isometry3d::new(vec3(1.0, 0.0, 1.0), Quat::from_rotation_x(FRAC_PI_2));
assert_abs_diff_eq!(iso1 * iso2, expected);
}
#[test]
fn inverse_mul_3d() {
let iso1 = Isometry3d::new(vec3(1.0, 0.0, 0.0), Quat::from_rotation_x(FRAC_PI_2));
let iso2 = Isometry3d::new(vec3(1.0, 0.0, 1.0), Quat::from_rotation_x(FRAC_PI_2));
let expected = Isometry3d::new(vec3(0.0, 1.0, 0.0), Quat::IDENTITY);
assert_abs_diff_eq!(iso1.inverse_mul(iso2), expected);
}
#[test]
fn identity_2d() {
let iso = Isometry2d::new(vec2(-1.0, -0.5), Rot2::degrees(75.0));
assert_abs_diff_eq!(Isometry2d::IDENTITY * iso, iso);
assert_abs_diff_eq!(iso * Isometry2d::IDENTITY, iso);
}
#[test]
fn identity_3d() {
let iso = Isometry3d::new(vec3(-1.0, 2.5, 3.3), Quat::from_rotation_z(FRAC_PI_3));
assert_abs_diff_eq!(Isometry3d::IDENTITY * iso, iso);
assert_abs_diff_eq!(iso * Isometry3d::IDENTITY, iso);
}
#[test]
fn inverse_2d() {
let iso = Isometry2d::new(vec2(-1.0, -0.5), Rot2::degrees(75.0));
let inv = iso.inverse();
assert_abs_diff_eq!(iso * inv, Isometry2d::IDENTITY);
assert_abs_diff_eq!(inv * iso, Isometry2d::IDENTITY);
}
#[test]
fn inverse_3d() {
let iso = Isometry3d::new(vec3(-1.0, 2.5, 3.3), Quat::from_rotation_z(FRAC_PI_3));
let inv = iso.inverse();
assert_abs_diff_eq!(iso * inv, Isometry3d::IDENTITY);
assert_abs_diff_eq!(inv * iso, Isometry3d::IDENTITY);
}
#[test]
fn transform_2d() {
let iso = Isometry2d::new(vec2(0.5, -0.5), Rot2::FRAC_PI_2);
let point = vec2(1.0, 1.0);
assert_abs_diff_eq!(vec2(-0.5, 0.5), iso * point);
}
#[test]
fn inverse_transform_2d() {
let iso = Isometry2d::new(vec2(0.5, -0.5), Rot2::FRAC_PI_2);
let point = vec2(-0.5, 0.5);
assert_abs_diff_eq!(vec2(1.0, 1.0), iso.inverse_transform_point(point));
}
#[test]
fn transform_3d() {
let iso = Isometry3d::new(vec3(1.0, 0.0, 0.0), Quat::from_rotation_y(FRAC_PI_2));
let point = vec3(1.0, 1.0, 1.0);
assert_abs_diff_eq!(vec3(2.0, 1.0, -1.0), iso * point);
}
#[test]
fn inverse_transform_3d() {
let iso = Isometry3d::new(vec3(1.0, 0.0, 0.0), Quat::from_rotation_y(FRAC_PI_2));
let point = vec3(2.0, 1.0, -1.0);
assert_abs_diff_eq!(vec3a(1.0, 1.0, 1.0), iso.inverse_transform_point(point));
}
}