Good question RandomDude. i forget water.
Use it for water problem;
http://mirror.pantharay.com/vegetation.c
(right click&save as)




@S3an; No. invisible flag for performance. Maybe you are right just for demo. But you use 4000/5000 entities and smooth land,performance very low(if you close invisible/visible function). Look at the Jungle Demo .(walk and fly play)

Thanks for all nice comment.