//SLUGens released under the GNU GPL as extensions for SuperCollider 3, by Nick Collins, http://composerprogrammer.com/index.html
Specify a surface z(x,y) via a buffer and scan it from the x and y inputs.
Your surface is a two dimensional array, but specified via a one dimensional buffer. The convention is exhibited below; note that you have to pass in the surface dimensions as well.
audio rate scanning instructions. Both values must be in the range 0.0 to 1.0, or they are wrapped into this range.