What's the most efficient way of creating shadows for object on a isometric terrain with OpenGL and JOGL? Note that this terrain is not flat and is not heightmap generated. Think it as another model. However objects' shadows on other objects is just nice to have.Objects must drop shadows just on the terrain.
Projective shadow mapping is a very common technique, almost inexpensive on current hardware and used in most of AAA video games around. The nice thing is that you can cast shadows on any object, regardless of their shape, and you can easily obtain soft shadows with a number of techniques, e.g. percentage closer filtering (PCF).