More Grass, Denser Grass

The CodeMasters blog entry made me think again about my Grass rendering using a Geometry Shader. I had followed the suggestions from Outerra to generate my grass but CodeMasters suggested combining this approach with simple billboards.

Instead of each geometry shader triangle strip representing a single blade of grass, why not just output a quad with a nicely detailed, colourful, texture. The textured quad might represent 5 or 10 blades of grass, rotated and scaled. This is a massive increase in grass density with better art, than the Outerra model.

With a bit of texture atlasing of various textures I could generate a very varied meadow with only some basic changes to my shader – and use less vertexes per location as well. Although the end result is clearly more “billboard” than “geometry” it still achieves a much higher density of foliage.

Here is the outcome with a four texture atlas




This is animated in the normal way using some perlin noise textures to generate movement. The density of the grass is overwhelming here – it looks like a forest. Changing the texture atlas to something more “grassy”;



Mmm. Thats nice.


Meadows underplating shadowed trees, distant ocean and mountains. 80 fps.


One thought on “More Grass, Denser Grass

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s