Experiment1 - terrain deformation

navigation - wasd, 

rotation - q,e

zoom - scroll mousewheel

The three buttons to the left are:  raise/lower terrain, flatten terrain, add tree.

When raise/lower is selected (default), left mouse button raises terrain and right mouse button lowers it. 

when flatten is selected, left mouse button flattens upwards, right mouse button flattens downwards.

when add tree is selected, left mouse button adds a new tree if there's no colliding tree and the terrain inclination allows it, right mouse button removes all existing trees that collide with the new tree - they are marked in red.

Code: https://bitbucket.org/nihohit/godgame

Credits: 

Low poly trees - https://goo.gl/je8K7S .