From: Alexander Lechner (alexander.lechner++at++vertigo-systems.de)
Date: 10/14/2004 07:04:51
Hi all!
In our VR Framework we make heavy use of pfNode draw callbacks (to achieve
special effects, set stencil, etc.).
I once stumbled across the pfChannel manpage where it states that
¨Sorting by state is limited to the scope of a transformation (pfDCS or pfSCS)
or a node with draw callbacks, i.e. - pfGeoSets affected by different
transformations or draw callbacks are not
sorted together. However, range sorting spans both transformation and draw
callback boundaries. Thus a range-sorted scene graph with many
transformations and expensive draw callbacks may suffer reduced performance
due to an increased number of transformation and draw callback changes.¨
- Does this mean that if I put a drawcallback into my pfScene, all rendered
geosets are not sorted by their pfGeoState?
- Does this mean that it if I have
GeoSet 1 with GeoState 1 and Texture A
GeoSet 2 with GeoState 2 and Texture B
GeoSet 3 with GeoState 1 and Texture A
that these will not be sorted when they are located under different DCSs?
This will burden a heavy texture object switch if they are rendered 1,2,3
instead of 1,3 and then 2.
- What if, in the last example, the geosets are located under the same DCS,
but each of their pfGeodes has a draw callback? Sort or no sort?
Thanks in advance, looking forward to PF 3.2!
Alex
-- Alexander.Lechner ++at++ vertigo-systems.de Engelbertstraße 30 | phone: +49-221-2405472 D-50674 Köln | fax: +49-221-34892616
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