shadowspot - Spot light shader with shadow map capability
Light "shadowspot" "intensity" n "lightcolor" c "from" p "to" p "coneangle" n "conedeltaangle" n "beamdistribution" n "shadowname" s "samples" n "width" n
float intensity=1.0 color lightcolor=[1 1 1] point from=[0 0 0] to=[0 0 1] float coneangle=radians(30), conedeltaange=radians(5), beamdistribution=2 float samples=16, width=1 string shadowname=""
This light is a spotlight with an optional shadow map parameter shadowname. If shadowname is "", the light is a normal spotlight.
The parameter samples controls the sampling rate for filtering the shadow map, as shown in Table 15.1 of the RenderMan Interface Specification, Version 3.1. Higher values will produce less noisy-looking shadows, but will take significantly longer. You can produce a (very noisy) test shadow very rapidly by setting samples to 1.
The width parameter controls overfiltering in the s and t directions, as is also shown in Table 15.1 of the Interface Specification. Higher values will give shadows more blurry edges, which can be used either as an effect or to hide the jagged edges of a low-resolution shadow map.
The intensity of the light varies from 0 (off) to any positive value (usually 1) representing the light at full intensity. The lightcolor parameter is an RGB triple representing the color of light emitted by the source.
The from parameter represents the position of the light source in space and to the direction it is shining.
The coneangle and conedeltaangle parameters specify the distribution of the light as a cone-shaped beam, whose intensity falls off with the angle from the center of the cone. The falloff from the cone center is a square-law falloff (cosine of this angle raised to the power 2) by default, but can be changed to a higher (or lower) power by setting the beamdistribution parameter.
The spotlight shader in the RenderMan Interface Specification.
Pixar Animation Studios