In texture generation is used random fractal terrain generation algorithm 
[http://www.gameprogrammer.com/fractal.html].

In 1 dimension algorithm starts with one straight line. Then it affects to that 
line's midpoint with some random multiplied with H-value. After those first steps 
it simply calls itself to both parts of line changing H-value smaller.

Two dimensional version (programmed to the code) needs step for point's between 
last density and step diagonal to last density's points, otherwise quite similar 
to 1 dimensional version.

Version of algorithm in our code is decided to be coded as iterative.