Feature flag to add repr(c) to bevy types

Cargo.toml

@@ -348,6 +348,9 @@ ios_simulator = ["bevy_internal/ios_simulator"]
 # Enable built in global state machines
 bevy_state = ["bevy_internal/bevy_state"]
 
+# Enable C style struct representation to allow passing built-in types over FFI
+repr_c = ["bevy_internal/repr_c"]
+
 [dependencies]
 bevy_internal = { path = "crates/bevy_internal", version = "0.15.0-dev", default-features = false }
 

crates/bevy_internal/Cargo.toml

@@ -195,6 +195,13 @@ ios_simulator = ["bevy_pbr?/ios_simulator", "bevy_render?/ios_simulator"]
 # Enable built in global state machines
 bevy_state = ["dep:bevy_state"]
 
+# Enable C style struct representation to allow passing built-in types over FFI
+repr_c = [
+  "bevy_transform/repr_c",
+  "bevy_math/repr_c",
+  "bevy_reflect/repr_c"
+]
+
 [dependencies]
 # bevy
 bevy_a11y = { path = "../bevy_a11y", version = "0.15.0-dev" }

crates/bevy_math/Cargo.toml

@@ -52,6 +52,11 @@ debug_glam_assert = ["glam/debug-glam-assert"]
 # Enable the rand dependency for shape_sampling
 rand = ["dep:rand", "dep:rand_distr", "glam/rand"]
 
+repr_c = [
+  "glam/scalar-math",
+  "bevy_reflect/repr_c"
+]
+
 [lints]
 workspace = true
 

crates/bevy_math/src/affine3.rs

@@ -7,6 +7,7 @@ use bevy_reflect::Reflect;
 /// significant performance impact. Convert to `glam::Affine3A` to do
 /// non-trivial calculations.
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Affine3 {
     /// Scaling, rotation, shears, and other non-translation affine transforms
     pub matrix3: Mat3,

crates/bevy_math/src/aspect_ratio.rs

@@ -8,6 +8,7 @@ use bevy_reflect::Reflect;
 /// An `AspectRatio` is the ratio of width to height.
 #[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug, PartialEq))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct AspectRatio(f32);
 
 impl AspectRatio {

crates/bevy_math/src/bounding/bounded2d/mod.rs

@@ -32,6 +32,7 @@ pub trait Bounded2d {
 #[doc(alias = "BoundingRectangle")]
 #[derive(Clone, Copy, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Aabb2d {
     /// The minimum, conventionally bottom-left, point of the box
     pub min: Vec2,

crates/bevy_math/src/bounding/bounded3d/mod.rs

@@ -35,6 +35,7 @@ pub trait Bounded3d {
 /// A 3D axis-aligned bounding box
 #[derive(Clone, Copy, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Aabb3d {
     /// The minimum point of the box
     pub min: Vec3A,

crates/bevy_math/src/bounding/raycast2d.rs

@@ -7,6 +7,7 @@ use bevy_reflect::Reflect;
 /// A raycast intersection test for 2D bounding volumes
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct RayCast2d {
     /// The ray for the test
     pub ray: Ray2d,
@@ -105,6 +106,7 @@ impl IntersectsVolume<BoundingCircle> for RayCast2d {
 /// An intersection test that casts an [`Aabb2d`] along a ray.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct AabbCast2d {
     /// The ray along which to cast the bounding volume
     pub ray: RayCast2d,
@@ -143,6 +145,7 @@ impl IntersectsVolume<Aabb2d> for AabbCast2d {
 /// An intersection test that casts a [`BoundingCircle`] along a ray.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct BoundingCircleCast {
     /// The ray along which to cast the bounding volume
     pub ray: RayCast2d,

crates/bevy_math/src/bounding/raycast3d.rs

@@ -7,6 +7,7 @@ use bevy_reflect::Reflect;
 /// A raycast intersection test for 3D bounding volumes
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct RayCast3d {
     /// The origin of the ray.
     pub origin: Vec3A,
@@ -100,6 +101,7 @@ impl IntersectsVolume<BoundingSphere> for RayCast3d {
 /// An intersection test that casts an [`Aabb3d`] along a ray.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct AabbCast3d {
     /// The ray along which to cast the bounding volume
     pub ray: RayCast3d,
@@ -143,6 +145,7 @@ impl IntersectsVolume<Aabb3d> for AabbCast3d {
 /// An intersection test that casts a [`BoundingSphere`] along a ray.
 #[derive(Clone, Debug)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Debug))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct BoundingSphereCast {
     /// The ray along which to cast the bounding volume
     pub ray: RayCast3d,

crates/bevy_math/src/compass.rs

@@ -23,6 +23,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Deserialize, Serialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub enum CompassQuadrant {
     /// Corresponds to [`Dir2::Y`] and [`Dir2::NORTH`]
     North,

crates/bevy_math/src/direction.rs

@@ -92,6 +92,7 @@ pub type Direction3d = Dir3;
     reflect(Serialize, Deserialize)
 )]
 #[doc(alias = "Direction2d")]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Dir2(Vec2);
 impl Primitive2d for Dir2 {}
 
@@ -345,6 +346,7 @@ impl approx::UlpsEq for Dir2 {
     reflect(Serialize, Deserialize)
 )]
 #[doc(alias = "Direction3d")]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Dir3(Vec3);
 impl Primitive3d for Dir3 {}
 
@@ -551,6 +553,7 @@ impl approx::UlpsEq for Dir3 {
     reflect(Serialize, Deserialize)
 )]
 #[doc(alias = "Direction3dA")]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Dir3A(Vec3A);
 impl Primitive3d for Dir3A {}
 

crates/bevy_math/src/float_ord.rs

@@ -22,6 +22,7 @@ use bevy_reflect::Reflect;
     derive(Reflect),
     reflect(Debug, PartialEq, Hash)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct FloatOrd(pub f32);
 
 impl PartialOrd for FloatOrd {

crates/bevy_math/src/lib.rs

@@ -25,6 +25,9 @@ mod rects;
 mod rotation2d;
 #[cfg(feature = "rand")]
 pub mod sampling;
+
+// mod quat;
+
 pub use compass::{CompassOctant, CompassQuadrant};
 
 pub use affine3::*;
@@ -58,4 +61,4 @@ pub mod prelude {
     };
 }
 
-pub use glam::*;
+pub use glam::*;

crates/bevy_math/src/primitives/dim2.rs

@@ -20,6 +20,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Circle {
     /// The radius of the circle
     pub radius: f32,
@@ -107,6 +108,7 @@ impl Measured2d for Circle {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Arc2d {
     /// The radius of the circle
     pub radius: f32,
@@ -274,6 +276,7 @@ impl Arc2d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct CircularSector {
     /// The arc defining the sector
     #[cfg_attr(feature = "serialize", serde(flatten))]
@@ -413,6 +416,7 @@ impl CircularSector {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct CircularSegment {
     /// The arc defining the segment
     #[cfg_attr(feature = "serialize", serde(flatten))]

crates/bevy_math/src/primitives/dim3.rs

@@ -20,6 +20,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Sphere {
     /// The radius of the sphere
     pub radius: f32,
@@ -92,6 +93,7 @@ impl Measured3d for Sphere {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Plane3d {
     /// The normal of the plane. The plane will be placed perpendicular to this direction
     pub normal: Dir3,
@@ -164,6 +166,7 @@ impl Plane3d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct InfinitePlane3d {
     /// The normal of the plane. The plane will be placed perpendicular to this direction
     pub normal: Dir3,
@@ -226,6 +229,7 @@ impl InfinitePlane3d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Line3d {
     /// The direction of the line
     pub direction: Dir3,
@@ -241,6 +245,7 @@ impl Primitive3d for Line3d {}
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Segment3d {
     /// The direction of the line
     pub direction: Dir3,
@@ -300,6 +305,7 @@ impl Segment3d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Polyline3d<const N: usize> {
     /// The vertices of the polyline
     #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
@@ -331,6 +337,7 @@ impl<const N: usize> Polyline3d<N> {
 /// For a version without alloc: [`Polyline3d`]
 #[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct BoxedPolyline3d {
     /// The vertices of the polyline
     pub vertices: Box<[Vec3]>,
@@ -366,6 +373,7 @@ impl BoxedPolyline3d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Cuboid {
     /// Half of the width, height and depth of the cuboid
     pub half_size: Vec3,
@@ -458,6 +466,7 @@ impl Measured3d for Cuboid {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Cylinder {
     /// The radius of the cylinder
     pub radius: f32,
@@ -536,6 +545,7 @@ impl Measured3d for Cylinder {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Capsule3d {
     /// The radius of the capsule
     pub radius: f32,
@@ -606,6 +616,7 @@ impl Measured3d for Capsule3d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Cone {
     /// The radius of the base
     pub radius: f32,
@@ -684,6 +695,7 @@ impl Measured3d for Cone {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct ConicalFrustum {
     /// The radius of the top of the frustum
     pub radius_top: f32,
@@ -736,6 +748,7 @@ pub enum TorusKind {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Torus {
     /// The radius of the tube of the torus
     #[doc(
@@ -847,6 +860,7 @@ impl Measured3d for Torus {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Triangle3d {
     /// The vertices of the triangle.
     pub vertices: [Vec3; 3],
@@ -1040,6 +1054,7 @@ impl Measured2d for Triangle3d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Tetrahedron {
     /// The vertices of the tetrahedron.
     pub vertices: [Vec3; 4],

crates/bevy_math/src/primitives/mod.rs

@@ -18,6 +18,7 @@ pub trait Primitive3d {}
 /// The winding order for a set of points
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 #[doc(alias = "Orientation")]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub enum WindingOrder {
     /// A clockwise winding order
     Clockwise,

crates/bevy_math/src/ray.rs

@@ -16,6 +16,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Deserialize, Serialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Ray2d {
     /// The origin of the ray.
     pub origin: Vec2,
@@ -65,6 +66,7 @@ impl Ray2d {
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Deserialize, Serialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Ray3d {
     /// The origin of the ray.
     pub origin: Vec3,

crates/bevy_math/src/rects/irect.rs

@@ -25,6 +25,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct IRect {
     /// The minimum corner point of the rect.
     pub min: IVec2,

crates/bevy_math/src/rects/rect.rs

@@ -25,6 +25,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Rect {
     /// The minimum corner point of the rect.
     pub min: Vec2,

crates/bevy_math/src/rects/urect.rs

@@ -25,6 +25,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     all(feature = "serialize", feature = "bevy_reflect"),
     reflect(Serialize, Deserialize)
 )]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct URect {
     /// The minimum corner point of the rect.
     pub min: UVec2,

crates/bevy_math/src/rotation2d.rs

@@ -42,6 +42,7 @@ use bevy_reflect::{ReflectDeserialize, ReflectSerialize};
     reflect(Serialize, Deserialize)
 )]
 #[doc(alias = "rotation", alias = "rotation2d", alias = "rotation_2d")]
+#[cfg_attr(feature = "repr_c", repr(C))]
 pub struct Rot2 {
     /// The cosine of the rotation angle in radians.
     ///