Better Terrain Mesh Conversion

[martindevans]

The terrain can be covnerted to a mesh with far less vertices/more detail than a simple grid.

References:

• http://graphics.pixar.com/library/LOD2002/4-terrain.pdf

[probable-basilisk]

https://twvideo01.ubm-us.net/o1/vault/GDC2014/Presentations/Kloetzli_John_Advanced_Visual_Effects.pdf http://casual-effects.blogspot.com/2014/04/fast-terrain-rendering-with-continuous.html https://www.iquilezles.org/www/articles/terrainmarching/terrainmarching.htm