Add optimized is_in_half_space_identity, contains_aabb_identity, and intersects_obb_identity

crates/bevy_camera/src/primitives.rs

@@ -130,6 +130,16 @@ impl Aabb {
         let signed_distance = p_normal.dot(aabb_center_world) + half_space.d();
         signed_distance > r
     }
+
+    /// Optimized version of [`Self::is_in_half_space`] when the AABB is already in world space.
+    /// Use this when `world_from_local` would be the identity transform.
+    #[inline]
+    pub fn is_in_half_space_identity(&self, half_space: &HalfSpace) -> bool {
+        let p_normal = half_space.normal();
+        let r = self.half_extents.abs().dot(p_normal.abs());
+        let signed_distance = p_normal.dot(self.center) + half_space.d();
+        signed_distance > r
+    }
 }
 
 impl From<Sphere> for Aabb {
@@ -348,6 +358,18 @@ impl Frustum {
         }
         true
     }
+
+    /// Optimized version of [`Self::contains_aabb`] when the AABB is already in world space.
+    /// Use this when `world_from_local` would be [`Affine3A::IDENTITY`].
+    #[inline]
+    pub fn contains_aabb_identity(&self, aabb: &Aabb) -> bool {
+        for half_space in &self.half_spaces {
+            if !aabb.is_in_half_space_identity(half_space) {
+                return false;
+            }
+        }
+        true
+    }
 }
 
 pub struct CubeMapFace {
@@ -740,4 +762,36 @@ mod tests {
         );
         assert!(!frustum.contains_aabb(&aabb, &model));
     }
+
+    #[test]
+    fn test_identity_optimized_equivalence() {
+        let cases = vec![
+            (
+                Aabb {
+                    center: Vec3A::ZERO,
+                    half_extents: Vec3A::splat(1.0),
+                },
+                HalfSpace::new(Vec4::new(1.0, 0.0, 0.0, -0.5)),
+            ),
+            (
+                Aabb {
+                    center: Vec3A::new(2.0, -1.0, 0.5),
+                    half_extents: Vec3A::new(1.0, 2.0, 0.5),
+                },
+                HalfSpace::new(Vec4::new(1.0, 1.0, 1.0, -1.0).normalize()),
+            ),
+            (
+                Aabb {
+                    center: Vec3A::new(1.0, 1.0, 1.0),
+                    half_extents: Vec3A::ZERO,
+                },
+                HalfSpace::new(Vec4::new(0.0, 0.0, 1.0, -2.0)),
+            ),
+        ];
+        for (aabb, half_space) in cases {
+            let general = aabb.is_in_half_space(&half_space, &Affine3A::IDENTITY);
+            let identity = aabb.is_in_half_space_identity(&half_space);
+            assert_eq!(general, identity,);
+        }
+    }
 }