Derive PartialEq, Serialize, Deserialize and Reflect on primitives (#11514)

# Objective

- Implement common traits on primitives

## Solution

- Derive PartialEq on types that were missing it.
- Derive Copy on small types that were missing it.
- Derive Serialize/Deserialize if the feature on bevy_math is enabled.
- Add a lot of cursed stuff to the bevy_reflect `impls` module.

Author: NiseVoid

crates/bevy_math/src/primitives/dim2.rs

@@ -80,7 +80,8 @@ impl std::ops::Neg for Direction2d {
 }
 
 /// A circle primitive
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Circle {
     /// The radius of the circle
     pub radius: f32,
@@ -115,7 +116,8 @@ impl Circle {
 }
 
 /// An ellipse primitive
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Ellipse {
     /// Half of the width and height of the ellipse.
     ///
@@ -160,7 +162,8 @@ impl Ellipse {
 
 /// An unbounded plane in 2D space. It forms a separating surface through the origin,
 /// stretching infinitely far
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Plane2d {
     /// The normal of the plane. The plane will be placed perpendicular to this direction
     pub normal: Direction2d,
@@ -184,7 +187,8 @@ impl Plane2d {
 /// An infinite line along a direction in 2D space.
 ///
 /// For a finite line: [`Segment2d`]
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Line2d {
     /// The direction of the line. The line extends infinitely in both the given direction
     /// and its opposite direction
@@ -194,7 +198,8 @@ impl Primitive2d for Line2d {}
 
 /// A segment of a line along a direction in 2D space.
 #[doc(alias = "LineSegment2d")]
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Segment2d {
     /// The direction of the line segment
     pub direction: Direction2d,
@@ -241,9 +246,11 @@ impl Segment2d {
 /// A series of connected line segments in 2D space.
 ///
 /// For a version without generics: [`BoxedPolyline2d`]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Polyline2d<const N: usize> {
     /// The vertices of the polyline
+    #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     pub vertices: [Vec2; N],
 }
 impl<const N: usize> Primitive2d for Polyline2d<N> {}
@@ -270,7 +277,8 @@ impl<const N: usize> Polyline2d<N> {
 /// in a `Box<[Vec2]>`.
 ///
 /// For a version without alloc: [`Polyline2d`]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct BoxedPolyline2d {
     /// The vertices of the polyline
     pub vertices: Box<[Vec2]>,
@@ -294,7 +302,8 @@ impl BoxedPolyline2d {
 }
 
 /// A triangle in 2D space
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Triangle2d {
     /// The vertices of the triangle
     pub vertices: [Vec2; 3],
@@ -367,7 +376,8 @@ impl Triangle2d {
 
 /// A rectangle primitive
 #[doc(alias = "Quad")]
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Rectangle {
     /// Half of the width and height of the rectangle
     pub half_size: Vec2,
@@ -400,9 +410,11 @@ impl Rectangle {
 /// A polygon with N vertices.
 ///
 /// For a version without generics: [`BoxedPolygon`]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Polygon<const N: usize> {
     /// The vertices of the `Polygon`
+    #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     pub vertices: [Vec2; N],
 }
 impl<const N: usize> Primitive2d for Polygon<N> {}
@@ -429,7 +441,8 @@ impl<const N: usize> Polygon<N> {
 /// in a `Box<[Vec2]>`.
 ///
 /// For a version without alloc: [`Polygon`]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct BoxedPolygon {
     /// The vertices of the `BoxedPolygon`
     pub vertices: Box<[Vec2]>,
@@ -453,7 +466,8 @@ impl BoxedPolygon {
 }
 
 /// A polygon where all vertices lie on a circle, equally far apart.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct RegularPolygon {
     /// The circumcircle on which all vertices lie
     pub circumcircle: Circle,

crates/bevy_math/src/primitives/dim3.rs

@@ -84,7 +84,8 @@ impl std::ops::Neg for Direction3d {
 }
 
 /// A sphere primitive
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Sphere {
     /// The radius of the sphere
     pub radius: f32,
@@ -120,7 +121,8 @@ impl Sphere {
 
 /// An unbounded plane in 3D space. It forms a separating surface through the origin,
 /// stretching infinitely far
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Plane3d {
     /// The normal of the plane. The plane will be placed perpendicular to this direction
     pub normal: Direction3d,
@@ -144,7 +146,8 @@ impl Plane3d {
 /// An infinite line along a direction in 3D space.
 ///
 /// For a finite line: [`Segment3d`]
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Line3d {
     /// The direction of the line
     pub direction: Direction3d,
@@ -153,7 +156,8 @@ impl Primitive3d for Line3d {}
 
 /// A segment of a line along a direction in 3D space.
 #[doc(alias = "LineSegment3d")]
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Segment3d {
     /// The direction of the line
     pub direction: Direction3d,
@@ -200,9 +204,11 @@ impl Segment3d {
 /// A series of connected line segments in 3D space.
 ///
 /// For a version without generics: [`BoxedPolyline3d`]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Polyline3d<const N: usize> {
     /// The vertices of the polyline
+    #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     pub vertices: [Vec3; N],
 }
 impl<const N: usize> Primitive3d for Polyline3d<N> {}
@@ -229,7 +235,8 @@ impl<const N: usize> Polyline3d<N> {
 /// in a `Box<[Vec3]>`.
 ///
 /// For a version without alloc: [`Polyline3d`]
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct BoxedPolyline3d {
     /// The vertices of the polyline
     pub vertices: Box<[Vec3]>,
@@ -253,7 +260,8 @@ impl BoxedPolyline3d {
 }
 
 /// A cuboid primitive, more commonly known as a box.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Cuboid {
     /// Half of the width, height and depth of the cuboid
     pub half_size: Vec3,
@@ -285,7 +293,8 @@ impl Cuboid {
 }
 
 /// A cylinder primitive
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Cylinder {
     /// The radius of the cylinder
     pub radius: f32,
@@ -306,7 +315,8 @@ impl Cylinder {
 
 /// A capsule primitive.
 /// A capsule is defined as a surface at a distance (radius) from a line
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Capsule {
     /// The radius of the capsule
     pub radius: f32,
@@ -327,7 +337,8 @@ impl Capsule {
 }
 
 /// A cone primitive.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Cone {
     /// The radius of the base
     pub radius: f32,
@@ -339,7 +350,8 @@ impl Primitive3d for Cone {}
 /// A conical frustum primitive.
 /// A conical frustum can be created
 /// by slicing off a section of a cone.
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct ConicalFrustum {
     /// The radius of the top of the frustum
     pub radius_top: f32,
@@ -370,6 +382,7 @@ pub enum TorusKind {
 
 /// A torus primitive, often representing a ring or donut shape
 #[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
 pub struct Torus {
     /// The radius of the tube of the torus
     #[doc(

crates/bevy_math/src/primitives/mod.rs

@@ -6,6 +6,8 @@ mod dim2;
 pub use dim2::*;
 mod dim3;
 pub use dim3::*;
+#[cfg(feature = "serialize")]
+mod serde;
 
 /// A marker trait for 2D primitives
 pub trait Primitive2d {}

crates/bevy_math/src/primitives/serde.rs

@@ -0,0 +1,63 @@
+//! This module defines serialization/deserialization for const generic arrays.
+//! Unlike serde's default behavior, it supports arbitrarily large arrays.
+//! The code is based on this github comment:
+//! <https://github.com/serde-rs/serde/issues/1937#issuecomment-812137971>
+
+pub(crate) mod array {
+    use serde::{
+        de::{SeqAccess, Visitor},
+        ser::SerializeTuple,
+        Deserialize, Deserializer, Serialize, Serializer,
+    };
+    use std::marker::PhantomData;
+
+    pub fn serialize<S: Serializer, T: Serialize, const N: usize>(
+        data: &[T; N],
+        ser: S,
+    ) -> Result<S::Ok, S::Error> {
+        let mut s = ser.serialize_tuple(N)?;
+        for item in data {
+            s.serialize_element(item)?;
+        }
+        s.end()
+    }
+
+    struct GenericArrayVisitor<T, const N: usize>(PhantomData<T>);
+
+    impl<'de, T, const N: usize> Visitor<'de> for GenericArrayVisitor<T, N>
+    where
+        T: Deserialize<'de>,
+    {
+        type Value = [T; N];
+
+        fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+            formatter.write_str(&format!("an array of length {}", N))
+        }
+
+        #[inline]
+        fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+        where
+            A: SeqAccess<'de>,
+        {
+            let mut data = Vec::with_capacity(N);
+            for _ in 0..N {
+                match (seq.next_element())? {
+                    Some(val) => data.push(val),
+                    None => return Err(serde::de::Error::invalid_length(N, &self)),
+                }
+            }
+            match data.try_into() {
+                Ok(arr) => Ok(arr),
+                Err(_) => unreachable!(),
+            }
+        }
+    }
+
+    pub fn deserialize<'de, D, T, const N: usize>(deserializer: D) -> Result<[T; N], D::Error>
+    where
+        D: Deserializer<'de>,
+        T: Deserialize<'de>,
+    {
+        deserializer.deserialize_tuple(N, GenericArrayVisitor::<T, N>(PhantomData))
+    }
+}

crates/bevy_reflect/Cargo.toml

@@ -12,7 +12,9 @@ readme = "README.md"
 [features]
 default = []
 # When enabled, provides Bevy-related reflection implementations
-bevy = ["glam", "smallvec", "bevy_math", "smol_str"]
+bevy = ["smallvec", "bevy_math", "smol_str"]
+glam = ["dep:glam"]
+bevy_math = ["glam", "dep:bevy_math"]
 smallvec = []
 # When enabled, allows documentation comments to be accessed via reflection
 documentation = ["bevy_reflect_derive/documentation"]