Mark Baranowski (baranowski++at++marklynn.demon.co.uk)
Wed, 18 Jun 1997 09:18:14 GMT
<snip>
>> > You could set the object Emissive, so no lights are applied to it using
>> > the PFMPASS_EMISSIVE_PASS bit in the PFTRAV_MULTIPASS flag, and set the
>> > material of the toy to be emissive.=20
>>
>> You have me slightly confused. I thought this *would* introduce
>> another rendering pass on the toy (which is definitely what I don't
>> want). Are you saying that the toy would only be rendered once in this
>> situation?
>>
>> If so, I do not want the toy to glow in the dark, so would have to
>> make the emmisive properties small. Would the toy still be illuminated
>> by other light sources (I anticipate having one other infinite light
>> source in the scene).
>>
> No, the toy will not have any light source applied to it. the result
> will be the same as if you turn off lights in performer. You will have
> to change the colors of the object, using pfColortable for example.
> the object will be rendered once after the multipass algorithm that
> will be applied on all non emissive objects.
> If you want to do something specific, you will have to use bins,
> and pfDrawBins, and do your own multipass algorithm.
If the toy is not illuminated by the other (infinite) light source
then I don't think the emissive material approach you describe is
suitable for us.
I was hoping to avoid having to implement our own projected texture
approach, as Performer does it anyway. Does anyone else have any
suggestions?
Am I correct in assuming that using the normal PROJTEX pfLightsource
behaviour will result in the toy being rendered twice (even though it
is not textured)?
Just in case we end up having to do something specific ourselves, is
there a description of the algorithm for projected textures anywhere?
(we haven't got the example gl code which used to be under
/usr/people/4Dgifts on our machines).
Thanks again for any help.
--
Mark Baranowski at work (baranowski++at++marklynn.demon.co.uk)
Pera, VR Division. Melton Mowbray, Leics. LE13 0PB. UK.
Tel: +44 (0)1664 501501, Fax: +44 (0)1664 501553
All opinions expressed are my own and should not be viewed
as representing my employer unless stated otherwise.
===================================List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
Submissions: info-performer++at++sgi.com
Admin. requests: info-performer-request++at++sgi.com
This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:55:28 PDT