OpenGL test - real 3D terrain + soft shadows + cubemap

Small OpenGL test. 3D view of Castel di Sangro italy.

DEM map downloaded from Copernicus:
https://land.copernicus.eu/

Cubemap used: 'Miramax' by Jockum Skoglund (hipshot), link: https://opengameart.org/content/miramar-skybox
licensed under the creative commons CC BY 3.0 license: https://creativecommons.org/licenses/by/3.0/