| Realistic Illumination, IDL & OpenGL [message #37828] |
Fri, 30 January 2004 14:06  |
nasalmon
Messages: 33
Registered: August 2003
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Could someone please help me with problems of illumination in IDL.
For Object Graphics to emulate reality, illumination must be
accurately represented. Take for example an outdoor scene, where sky
background emission above and up-welling emission below bathes an
object in different intensities from all directions. Can this be
accurately described in IDL or OpenGL?
In IDL Object Graphics there is the possibility to bring in the
"light" by way of obj_new "IDLgrLight". However, this can only be:
type 0) Ambient; 1) point source; 2) collimated beam; 3) spot light
(apertured). The number of lights is limited to 8. Is this
illumination limited by IDL or the OpenGL on which IDL operates?
Gereral illumination in an outdoor environment has something of an
angular distribution, for an overcast day at least. This might be
represented in an alt-azimuth coordinate system; large amount of
emission at zenith, with some kind of distribution coming down to the
horizon, with some up-welling illumination from the ground. This could
be either simulated by a very large number of point sources or ambient
illumination with some angular distribution on it. Are there plans to
introduce this kind of "light" into IDL in future versions?
many thanks,
Neil
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