New circular primitives: Arc2d, CircularSector, CircularSegment (#13482)

# Objective

Adopted #11748

## Solution

I've rebased on main to fix the merge conflicts. ~~Not quite ready to
merge yet~~

* Clippy is happy and the tests are passing, but...
* ~~The new shapes in `examples/2d/2d_shapes.rs` don't look right at
all~~ Never mind, looks like radians and degrees just got mixed up at
some point?
* I have updated one doc comment based on a review in the original PR.

---------

Co-authored-by: Alexis "spectria" Horizon <spectria.limina@gmail.com>
Co-authored-by: Alexis "spectria" Horizon <118812919+spectria-limina@users.noreply.github.com>
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Ben Harper <ben@tukom.org>

Author: 5 people

Cargo.toml

@@ -423,6 +423,17 @@ description = "Renders a 2d mesh"
 category = "2D Rendering"
 wasm = true
 
+[[example]]
+name = "mesh2d_arcs"
+path = "examples/2d/mesh2d_arcs.rs"
+doc-scrape-examples = true
+
+[package.metadata.example.mesh2d_arcs]
+name = "Arc 2D Meshes"
+description = "Demonstrates UV-mapping of the circular segment and sector primitives"
+category = "2D Rendering"
+wasm = true
+
 [[example]]
 name = "mesh2d_manual"
 path = "examples/2d/mesh2d_manual.rs"

crates/bevy_math/Cargo.toml

@@ -18,6 +18,7 @@ approx = { version = "0.5", optional = true }
 rand = { version = "0.8", features = [
   "alloc",
 ], default-features = false, optional = true }
+smallvec = { version = "1.11" }
 
 [dev-dependencies]
 approx = "0.5"
@@ -26,6 +27,8 @@ rand = "0.8"
 rand_chacha = "0.3"
 # Enable the approx feature when testing.
 bevy_math = { path = ".", version = "0.14.0-dev", features = ["approx"] }
+glam = { version = "0.27", features = ["approx"] }
+
 
 [features]
 default = ["rand"]

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

@@ -234,7 +234,7 @@ impl std::ops::Mul<Dir2> for Rotation2d {
     }
 }
 
-#[cfg(feature = "approx")]
+#[cfg(any(feature = "approx", test))]
 impl approx::AbsDiffEq for Dir2 {
     type Epsilon = f32;
     fn default_epsilon() -> f32 {
@@ -245,7 +245,7 @@ impl approx::AbsDiffEq for Dir2 {
     }
 }
 
-#[cfg(feature = "approx")]
+#[cfg(any(feature = "approx", test))]
 impl approx::RelativeEq for Dir2 {
     fn default_max_relative() -> f32 {
         f32::EPSILON
@@ -256,7 +256,7 @@ impl approx::RelativeEq for Dir2 {
     }
 }
 
-#[cfg(feature = "approx")]
+#[cfg(any(feature = "approx", test))]
 impl approx::UlpsEq for Dir2 {
     fn default_max_ulps() -> u32 {
         4