You mean particles in view coordinates, rather than world coordinates. This would be possible, but it's rarely needed, so I'm not sure if it's worth an new particle flag.

You can solve this problem already in world coordinates, in the particle function:

- get the distance vector from the camera to the particle
- rotate this vector by the same euler angle you added to the camera angle.
- get the distance vector from the rotated vector to the original vector
- add this new distance vector to the particle position.

This should keep your particles in front of the camera regardless of the rotation.