The RenderMan Interface - Paul Bourke

15.5 String Functions
string concat ( string a, b, ... )
Concatenates two or more strings into a single string.
void printf ( string pattern, val1, val2,..., valn )
Print the values of the specified variables on the standard output stream of the renderer
(much like the printf function in C. pattern uses ”%f”, ”%p”, ”%c”, ”%m”, and ”%s”
to indicate float, point, color, matrix, and string, respectively. A vector or normal may
also be printed using ”%p”.
string format ( string pattern, val1, val2,..., valn )
Does a formatted string creation under the control of pattern. This function is similar
to the C function sprintf(). As with the Shading Language printf function, ”%f”, ”%p”,
”%c”, ”%m”, and ”%s” to indicate float, point, color, matrix, and string, respectively.
float match ( string pattern, subject )
Does a string pattern match on subject. Returns 1.0 if the pattern exists anywhere
within subject, and 0.0 if the pattern does not exist within subject. pattern can be
any regular expression, as described in the POSIX manual page on regex()(3X), with
the following exception: the $n notation does not work, as there are no return values
from this function. Note that the pattern does not need to start in the first character of
the subject string, unless the pattern begins with the ˆ (beginning of string) character.
15.6 Shading and Lighting Functions
In this section, built-in shading and lighting functions are defined.
color
ambient()
ambient returns the total amount of ambient light incident upon the surface. An
ambient light source is one in which there is no directional component, that is, a light
which does not have an illuminate or a solar statement.
color
diffuse( normal N )
{
color C = 0;
illuminance( P, N, PI/2 )
C += Cl * normalize(L).N;
return C;
}
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