David Cooper (davec++at++division.demon.co.uk)
Sat, 20 Nov 93 14:57:14 GMT
I am using Performer 1.1
1) Is there a way to modify the zwritemask from within performer or do I
have to use a pre/post render callback approach ? With the callback method
would there be any other implications ? How could I minimise the impact of
this mode change if I have a number of geosets that require a modified
zwritemask ?
2) If I want to switch blendfunction on/off dynamically for a number of geosets
depending on a variable set per frame, what is the most performance efficent
way to do this ? The blendfunction may be the only common feature between the
geosets. Would changing the geostate of a parent node while in cull work
reliably when in multiprocess mode ?
3) If I have dynamically changing geometry, performance wise is it better to
write the code in GL or to modify geosets at cull time ? Is there a way to
lock out the render process to allow safe changing of geosets dynamically,
in a multiprocess environment ?
4) When running an a RE what does performer do with the ms alpha mask ? If I
was to modify this dynamically would there be any Performer implications ?
5) Again in a multiprocess environment what would happen if a cull callback
was to delete its node ? Would this throw the app out of skew ?
6) Is the pfChanData structure the only multiprocess buffered data available ?
Is it possible to use pfNodeTravFuncs data in shared memory to communicate
bewteen associated cull and render callbacks - assuming of course that there
is a way to buffer the data.
7) Is there a way to prepage texture into texture memory dynamically, to avoid
having the huge delay on the first drawing of every texture? Without
having the luxury of being able to load/draw every texture at init time ? I
don't care if it is unsupported or unreliable, anything would be better than
the current situation.
8) Our virtual reality systems operate in a different coordinate
frame from Performer, it is not possible to modify our existing system as it
encompasses a lot of hardware/software (tracking, sound, collison detection,
etc) some from external suppliers. This gives me a number of headaches and
makes it very difficult to use some Performer functions including pfESky and
pfBillboards which use the eye heading, roll, and pitch to operate. Is there
any way to get performer to change its coord frame? Simply rotating/translating
the channel viewpoint does not appear to work - the sky flies all over the
place when you change orientation.
If one doesn't exist how about a user settable flag to indicate
what coord system your using. After all, Performer doesn't agree with GL,
and SGI worked for 10 years to get GL accepted as a standard. Theres a lot of
code out there aimed at the GL coord system, and it can be a pain to convert.
David Cooper
Division Ltd
UK
This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:50:06 PDT