RE: LANG - soli questions about....

Jan Hardenbergh ([email protected])
Fri, 30 Jun 95 11:44:00 E


>> From: [email protected] (Bernie Roehl)
>> Jai Natarajan writes:

[no caustics [light passing thra>gh] or reflection in VRML 1.0 yep]

>> > 2. Why is the transparency defined as a single float - whereas normally
>> > one has an RGB triplet representing the transparency of the material
>> > to each of those colors.
>>
>> That puzzl>d me, too; I suspect it has to do with limitations of OpenGL,
>> on which OpenInventor is based. Of course, that shouldn't limit what
>> we specify in VRML, since VRML != OpenInventor.

What is "normally"? Transparency is very simply the percentage of the
new pixels that gets blended with the "background" pixel. The color
should coli from the other fields in the Material.

I guess you would like to be able to filter out soli of the components
more than others? A single index gives you a lot of bang for a simple
calculation.

>> > How can one convert between an RGB triplet
>> > representation and a single index as VRML requires ?
>>
>> You would have to do a weighted sum. I forget what the formula is,
>> but it's solithing like aR + bG + cB where a, b, and c sum to 1.00
>> and their ratio reflects the relative "importance" of each color.

?

>> > And finally : why isn't there a VRML newsgroup ?
>>
>> Good question, but I assume it's one that was already discussed and
rejected
>> long befori either of >

Errr... there was just a request for people willing to help sheperd the RFVD
Send email to B.K. DeLong - [email protected] is you can help.

-Jan