The RenderMan Interface - Paul Bourke

through the interface. Any place where user data is used and would normally require a
preceeding RiDeclare, it is also legal to use an in-line declaration.
The storage modifiers vertex, varying, uniform, and constant are discussed in the section on
Uniform and Varying Variables in Part II and in Section 5, Geometric Primitives. All procedure
parameter tokens and shader variable name tokens named in this document are standard
and are predefined by all implementations of the RenderMan Interface. In addition,
a particular implementation may predeclare other variables for use with implementationspecific
options, geometry, etc.
Whenever a point, vector, normal, matrix, or hpoint variable is passed through the Render-
Man Interface to shaders, the values are assumed to be relative to the current coordinate
system. This is sometimes referred to as object coordinates. Different coordinate systems
are discussed in the Camera section.
Whenever colors are passed through the RenderMan Interface, they are expected to have
a number of floats equal to the number of color samples being used by the interface. This
defaults to 3, but can be changed by the user (see the section on Additional options).
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