Crashes on Linux

```
Exception in thread "Render Thread" java.lang.IllegalStateException: GroundData hasn't been initialized yet.
    at snowworld.Environment.tick(Environment.java:54)
    at snowworld.World.render(World.java:116)
    at java.base/java.lang.Thread.run(Thread.java:832)
```

Tested on both java 15 and 8 (openjdk)