Cube mesh, voxel world inspired from https://threejsfundamentals.org/threejs/lessons/threejs-voxel-geometry.html
Terrain generation inspired from
- https://notch.tumblr.com/post/3746989361/terrain-generation-part-1
- https://codepen.io/ptc24/pen/BpXbOW?editors=0010#0 & (using same noise generation algorithm from here https://cdn.rawgit.com/josephg/noisejs/master/perlin.js)