Treat zero-angle rotation as identity when axis is invalid

crates/store/re_types/definitions/rerun/components/rotation_axis_angle.fbs

@@ -2,7 +2,8 @@ namespace rerun.components;
 
 /// 3D rotation represented by a rotation around a given axis.
 ///
-/// If normalization of the rotation axis fails the rotation is treated as an invalid transform.
+/// If normalization of the rotation axis fails the rotation is treated as an invalid transform, unless the
+/// angle is zero in which case it is treated as an identity.
 table RotationAxisAngle (
   "attr.rust.derive": "Default, Copy, PartialEq",
   "attr.rust.repr": "transparent"
@@ -12,7 +13,8 @@ table RotationAxisAngle (
 
 /// 3D rotation represented by a rotation around a given axis that doesn't propagate in the transform hierarchy.
 ///
-/// If normalization of the rotation axis fails the rotation is treated as an invalid transform.
+/// If normalization of the rotation axis fails the rotation is treated as an invalid transform, unless the
+/// angle is zero in which case it is treated as an identity.
 table PoseRotationAxisAngle (
   "attr.rust.derive": "Default, Copy, PartialEq",
   "attr.rust.repr": "transparent"

crates/store/re_types/definitions/rerun/datatypes/rotation_axis_angle.fbs

@@ -10,7 +10,8 @@ table RotationAxisAngle (
   ///
   /// This is not required to be normalized.
   /// However, if normalization of the rotation axis fails (typically due to a zero vector)
-  /// the rotation is treated as an invalid transform.
+  /// the rotation is treated as an invalid transform, unless the angle is zero in which case
+  /// it is treated as an identity.
   axis: rerun.datatypes.Vec3D (order: 100);
 
   /// How much to rotate around the axis.

crates/store/re_types/src/components/pose_rotation_axis_angle_ext.rs

@@ -19,9 +19,14 @@ impl TryFrom<PoseRotationAxisAngle> for glam::Affine3A {
 
     #[inline]
     fn try_from(val: PoseRotationAxisAngle) -> Result<Self, Self::Error> {
-        glam::Vec3::from(val.0.axis)
-            .try_normalize()
-            .map(|normalized| Self::from_axis_angle(normalized, val.0.angle.radians()))
-            .ok_or(())
+        // 0 degrees around any axis is an identity transform.
+        if val.angle.radians == 0. {
+            Ok(Self::IDENTITY)
+        } else {
+            glam::Vec3::from(val.0.axis)
+                .try_normalize()
+                .map(|normalized| Self::from_axis_angle(normalized, val.0.angle.radians()))
+                .ok_or(())
+        }
     }
 }