The RenderMan Interface - Paul Bourke

The standard types are ”hidden” and ”null”. ”hidden”, which is the default, performs
standard hidden-surface computations. The hider ”null” performs no pixel computation
and hence produces no output. Other implementation-specific hidden-surface
algorithms can also be selected using this routine; for example, an implementation
may choose to support type ”paint”, which might draw the objects in the order in
which they are defined.
RIB BINDING
Hider type ...parameterlist...
EXAMPLE
RiHider ”paint”
Rendering programs compute color values in some spectral color space. This implies that
multiplying two colors corresponds to interpreting one of the colors as a light and the
other as a filter and passing light through the filter. Adding two colors corresponds to
adding two lights. The default color space is NTSC-standard RGB; this color space has
three samples. Color values of 0 are interpreted as black (or transparent) and values of 1
are interpreted as white (or opaque), although values outside this range are allowed.
RiColorSamples ( RtInt n, RtFloat nRGB[], RtFloat RGBn[] )
This function controls the number of color components or samples to be used in specifying
colors. By default, n is 3, which is appropriate for RGB color values. Setting
n to 1 forces the rendering program to use only a single color component. The array
nRGB is an n by 3 transformation matrix that is used to convert n component colors
to 3 component NTSC-standard RGB colors. This is needed if the rendering program
cannot handle multiple components. The array RGBn is a 3 by n transformation matrix
that is used to convert 3 component NTSC-standard RGB colors to n component
colors. This is mainly used for transforming constant colors specified as color triples
in the Shading Language to the representation being used by the RenderMan Interface.
Calling this procedure effectively redefines the type RtColor to be
typedef RtFloat RtColor [n];
After a call to RiColorSamples, all subsequent color arguments are assumed to be
this size.
If the Spectral Color capability is not supported by a particular implementation, that
implementation will still accept multiple component colors, but will immediately
convert them to RGB color space and do all internal calculations with 3 component
colors.
RIB BINDING
ColorSamples nRGB RGBn
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