This shader creates a simulated wood texture on a surface. It uses two colors, one as the base (often lighter) color of the wood and one as the color of the (often darker) rings in it. The rings is put into the base color about the x-axis and are then distorted using noise() and turbulence(). A similar pattern is repeated at regular intervals to create an illusion of logs or boards.
ambient is a value between 0.0 and 1.0 which determines how much of the base color of a surface that is visible when it is not illuminated by any light source.
specular is a value between 0.0 and 1.0 which is the fraction of color specularly reflected.
c3 is the shininess of the surface where 0.0 is the most dull and 1.0 is the most shiny.
scale describes how much the texture coordinates should be scaled before applying the wood texture. The larger the scaling, the smaller the area of the wood texture associated with a given area of the surface. A large number results in a very fine pattern, a small number yields a coarse pattern. You will have to experiment some to get this right.
basecolor is a list containing the red, green and blue values for the wood base. Each being a number between 0.0 and 1.0.
ringcolor is a list containing the red, green and blue values for the wood rings.
opacity describes the opacity of a surface. 0.0 means totally transparent, 1.0 means totally opaque. May be a list of red, green and blue opacity values or a single value to be used for all color channels. Optional, default is 1.0.