Improve orbit visibility

```
/* TODO: Improve orbit visibility (like p4_ArcanePropagation_PointOrbit) */
```

https://github.com/dishmint/ArcanePropagation/blob/176399cd05f0fd6277d2e0bdcbace6d0d617ed07/p4_ArcanePropagatorGUI/data/blueline.glsl#L5