I am trying to get a shaded area in my scene, but I have no Idea how to go about it.
My scene is made out of Quads with a Sprite/Diffuse Shader all located at z=0.
My main camera is orthographic and it is located at z= -20.
The light that I am currently using for illuminating all the scene is a directional light located at z=-30.
Here is a illustration of the shaded area that I would like to have ( sorry for the very poor quality ):
Any directions on how to go about this will be greatly appreciated.