A plugin for creating a realistically rotating celestial sphere with stars around the game world in Unreal Engine 4.
Sky with 50000 stars along with a wireframe view of the geometry.
Obviously you don't need to have that many stars if you're aiming for a realistic sky because the human eye can see only 9096 stars. Star sphere geometry with said amount of stars. There is no visual difference with realistic brightness values.
A small demo video on youtube.
A demo project can be found on the demo branch, it should work with UE 4.26.
The plugin consists of two main classes. The first is an actor component that rotates the owning actor as sidereal time advances. The second one is an actor that creates a star sphere around the actor and rotates itself using the previously mentioned rotation component.
This component rotates the owning actor by calculating the local sidereal angle for the given latitude, longitude and time.
The rotation rate is tied to time and it can be increased by increasing the TimeScale property.
This actor offers the ability to generate a star sphere procedurally around this actor with a desired maximum number of stars.
The star geometry itself is either a simple triangle or a quad, this can be changed by changing the Geometry property of the actor.
The generation process stores the star's magnitude and colour temperature in Kelvins in a secondary UV map of the mesh. This data
can in turn be used in the material of the mesh.
Stars' data can be found under the resources folder.
Source of this data is https://github.com/astronexus/HYG-Database.
You can obviously use any kind of data, as long as it can be massaged into the FStar struct.
The star coordinates are in J2000.0 epoch and equinox.