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Syntax :function Width, Height { FUNCTION_BODY }
Not a real pattern, but listed here for convenience. This keyword defines a new 'internal' bitmap image type. The
pixels of the image are derived from the Function_Body, with Function_Body either being a regular function, a pattern
function or a pigment function. In case of a pigment function the output image will be in color, in case of a pattern
or regular function the output image will be grayscale. All variants of grayscale pigment functions are available
using the regular function syntax, too. In either case the image will use 16 bit per component
Note: functions are evaluated on the x-y plane. This is different from the pattern
image type for the reason that it makes using uv functions easier.
Width and Height specify the resolution of the resulting 'internal' bitmap image. The image is taken from the
square region <0,0,0>, <1,1,0>
The function statement can be used wherever an image specifier like tga or png
may be used. Some uses include creating heightfields from procedural textures or wrapping a slice of a 3d texture or
function around a cylinder or extrude it along an axis.
Examples:
plane {
y, -1
pigment {
image_map {
function 10,10 {
pigment { checker 1,0 scale .5 }
}
}
rotate x*90
}
}
height_field {
function 200,200 {
pattern {
bozo
}
}
translate -0.5
scale 10
pigment {rgb 1}
}
Note: that for height fields and other situations where color is not needed it is
easier to use function n,n {pattern{...}} than function n,n {pigment{...}}. The pattern
functions are returning a scalar, not a color vector, thus a pattern is grayscale.
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