Basic Multitexturing

A large forested scene would likely require many different forest map textures that describe tree placement and type.  For one, if there are distinctive features in the texture, it would be quite noticeable that the texture repeats.  Secondly, forests vary in relation to aspect, terrain type, and elevation.  Thus this system should support basic multi texturing (based off of Riemer's terrain tutorial) that supports dynamic or terrain based forests. 

Scene with many forest types - Helena National Forest, Montana

The young forest, beetle kill, and fields could potentially be described via the modification map, but in this area some forests are more dense, and tree types vary depending on aspect.  There is support for differences accounting for age, roads and cut blocks via the modification texture, as well as in a value in the terrain vertices which defines whether or not the ground is forested.

Deer Lodge National Forest, Montana

Inspired by some of the beautiful forests of the Rocky Mountains, I decided to see if this system could also be used to render similar rock formations and mixed forests.  With not too much effort I was able to implement a similar scene supporting multi texturing and different tree types (in this case, one tree and one type of rock)

Here 4 different textures were used, one describing a mixed forest/rock, dense forest, sparse forest, and only rock formations.

These are the 4 textures used.  The red channel describes feature height, the blue channel defines forest or rock, and the green channel is noise used for dynamic texturing.  As you can imagine, many possible forest types could be created by creating simple noise based textures.

 Here only two feature types are used, the Forest Color and Forest Texture images are split for the trees and rocks.  Potentially many feature types, tree species, kinds of rock etc could be represented through this system.  Though there are some potential problems when merging different Forest Maps for Multi texturing, as well as with transitions between types.  Some solutions to these problems will be explored later.

But even so, this process can successfully implement basic mutlitextured mixed forests