If you tiled it in the world and rendered it, the camera rays would look something like below, but your triangle-count would be huge:

So instead, in this technique you just pick the direction that the camera is looking in (or some other arbitrary choice of direction that looks good), and render a single "tile" of grass to a texture, using an orthographic projection in that direction.

Do you have to render a new "tile" for each angle of sloped terrain, since the camera is looking at the grass at a different angle?

[quote name='riuthamus' timestamp='1358563079' post='5023078']
We do not need anything epic, in fact i dont mind going with a 5/6 polygon model of planes that are slightly bent. Like i said my goal is to make something like firefall. The major question is how to put a shadow under them ( doesnt need to reflect the texture just an ambient blur ) and how to render light on them. And if there are methods to render it better that would help as well. Your engine looks impressive.

[/quote]

Then you just need to make a decision based on what features you are going to implement beside grass. Is there enough space that mid-level system can go with more geometry than add some and if not then go with textured planes and apply some sin and cos functions in the shader to get them waving. When it comes to shadows I did not put enough research into it to say if there is a simple or better method as rendering it with your shadowmaps. And for lighting just use double-sided lighting.