The existing code was copied from the ellipse light case. But this computation simplifies for the disk case, removing the need of `inversesqrt`. Pull Request: https://projects.blender.org/blender/blender/pulls/108616
The existing code was copied from the ellipse light case. But this computation simplifies for the disk case, removing the need of `inversesqrt`. Pull Request: https://projects.blender.org/blender/blender/pulls/108616