Sorting of transparent geometry not right

New Message Reply Date view Thread view Subject view Author view

From: MLM Veraart (Veraart++at++fel.tno.nl)
Date: 02/11/2000 09:19:29


Hello,

In my application I have a problem with the sorting of transparent
geometry.
I have two types of transparent geometry, one is white and the other
is black.
Both are put explicitly in the transparent bin.
They are there because if I call pfDrawBin(PFSORT_TRANS_BIN) only
the transparent polygons are drawn. The terrain is not there.
The sort order for the channel transparent bin are set to BACK_TO_FRONT

The white polygons are completely drawn in the pfGeode node callback.
The black polygons have a node callback that enables a pfSprite,
[the pfBillboard had a bug that it could not render more then about 10
polygons, maybe because if you let the graphics pipe do the
transformation your polygons are lost. For the pfSprite I had to set
the CPU transform range to a high polygon count.]

If both types of geometry is partial transparent then I see the
following strange effects
  o I can't see the black geometry behind the white geometry
  o when putting a few white geometrys in line,
    depending on the viewpoint (all infront) the sorting/drawing is
    sometimes ok and sometimes wrong (further away is invisible)

The sorting of the black geometrys is done always back to front.

Can anybody give me a clue how to solve these artifacts.

I use Performer 2.2.6 on a Onyx IR.

The choosing of the pfSprite for the billboard was because an older
version of Performer had the billboard bug. I haven't tried if 2.2.6
still has the bug because rewriting would be a lot of time and a
billboard does not allow a changing number of polygons.

Mario Veraart


New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Fri Feb 11 2000 - 09:21:35 PST

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.