v2.1

Move with keys "wasdqe" , mouse left click and mouse scroll.

1. Fixed bug when psi->0.
2. Add 16x super sampling so stars won't flash when moving.
3. The whole frame is 2x brighter.

v2.0

Move with keys "wasdqe" , mouse left click and mouse scroll.

1. In places where the light is strongly curved (r->1), the sampling resolution is greatly improved, making the rendering more accurate.
2. It can render light that rotates more times at a distance from the black hole (maximum 2 rotations).

v1.0

Move with keys "wasdqe" , mouse left click and mouse scroll.