The RenderMan Interface - Paul Bourke

Name Type Storage Class Description
P point varying Surface position
dPdu vector varying Derivitive of surface position along u
dPdv vector varying Derivitive of surface position along v
N normal varying Surface shading normal
Ng normal varying Surface geometric normal
I vector varying Incident ray direction
E point uniform Position of the eye
u,v float varying Surface parameters
du,dv float varying Change in surface parameters
s,t float varying Surface texture coordinates
ncomps float uniform Number of color components
time float uniform Current shutter time
dtime float uniform The amount of time covered by this shading
sample.
dPdtime vector varying How the surface position P is changing
per unit time, as described by motion
blur in the scene.
P point varying Displaced surface position
N normal varying Displaced surface shading normal
Table 12.4: Predefined Displacement Shader Variables
Name Type Storage Class Description
P point varying Pixel raster position
Ci color varying Pixel color
Oi color varying Pixel opacity
alpha float uniform Fractional pixel coverage
ncomps float uniform Number of color components
time float uniform Shutter open time.
dtime float uniform The amount of time the shutter was open.
Ci color varying Output pixel color
Oi color varying Output pixel opacity
Table 12.5: Predefined Imager Shader Variables
124