This file contains source for Houdini shaders for the RenderMan(TM) Renderer.

Included are:
	attenlight	- an attenuated point light source
	attenspot	- an attenuated spot light source
	attenshadow	- an attenuated point light source with shadows
	attenshadowspot	- an attenuated spot light source with shadows
	h_distantlight	- a distant light source
	h_distantshadow - a distant shadow casting light source

The distant light source shaders are used if the light source has an
orthographic projection in Houdini.

These light shaders are automatically used by Houdini according to certain
information.  If the "Shadow" picture string for a light is filled in,
the shadow shaders will be used.  If the cone angle channels exist, then
the spot light shaders will be used:

    Ortho    Shadow    Cone	Shader Choice
    -----    ------    -----	-------------
     No	       No	No	attenlight
     No	       No	Yes	attenspot
     No	       Yes	No	attenshadow
     No	       Yes	Yes	attenshadowspot
     Yes       No	No	h_distantlight
     Yes       No	Yes	attenspot(*)
     Yes       Yes	No	h_distantshadow
     Yes       Yes	Yes	attenshadowspot(*)

  (*) We do not provide shaders to emulate distant spot-lights.
