Prman Functions

Front 1

noise(p)

Back 1

float
Perlin noise of a float or point

Front 2

xcomp(p)

Back 2

float
X component of a point

Front 3

ycomp(p)

Back 3

float
Y component of a point

Front 4

zcomp(p)

Back 4

float
Z component of a point

Front 5

setxcomp(p,v)

Back 5

----------------------
Set X component of a point to the value of v

Front 6

setycomp(p,v)

Back 6

----------------------
Set Y component of a point to the value of v

Front 7

setzcomp(p,v)

Back 7

----------------------
Set Z component of a point to the value of v

Front 8

texture( "name", s, t )

Back 8

float, color
Return a color or a float from a texture

Front 9

length(V)

Back 9

float
Euclidean length of vector V

Front 10

calculateNormal(P)

Back 10

vector
Returns the new surface normal at P

Front 11

normalize(V)

Back 11

vector
Returns unitized V

Front 12

faceforward(V,I)

Back 12

Return V flipped to point opposite I
Used for fixing aliasing - SC25 - RenderMan for Everyone

and face direction - RenderMan Shading Language Guide

Front 13

diffuse(N)

Back 13

float
Returns sum of all diffuse contributions to normal N

Front 14

pow( x, y )

Back 14

float
x to the yth power

Front 15

mod( v, b )

Back 15

float
modulo( v, b )

Front 16

mix( c0, c1, t )

Back 16

color
(1.-t)*c0 + t*c1
Uses t as a blending value between c0 and c1

Front 17

smoothstep(min, max, val )

Back 17

float
0. if v < min, 1. if v > max, else smooth interpolation from 0 to 1.

Front 18

specular( N, eye, roughness )
typically written as:
specular( Nn, V, roughness )

Back 18

float
Returns sum of all specular components to normal N and eye position eye

Front 19

ceiling( v )

Back 19

float
Smallest integer >= v

Front 20

floor( v )

Back 20

float
Largest integer <= v

Front 21

round( v )

Back 21

float
Closest integer to v