>From the documentation (javadoc for View.java):
Transparency sorting policy - specifies whether and how
transparent objects are sorted. Sorting multiple transparent
objects is necessary to avoid artifacts caused by overlapping
transparent objects. There are two transparency sorting
policies:
TRANSPARENCY_SORT_NONE - no depth sorting of transparent
objects is performed (this is the default). Transparent objects
are drawn after opaque objects, but are not sorted from back to
front.
TRANSPARENCY_SORT_GEOMETRY - transparent objects are
depth-sorted on a per-geometry basis. Each geometry object of
each transparent Shape3D node is drawn from back to front. Note
that this policy will not split geometry into smaller pieces,
so intersecting or intertwined objects may not be sorted
correctly. The method used for determining which geometry is
closer is implementation dependent.
So that should answer your question about triangles within a geometry
(they are not sorted).
As for two concentric spheres, since the centroid is used to sort, it
will not necessarily work correctly. More to the point, concentric
spheres are a case of intertwined objects, which cannot be resolved
without breaking the geometry up. Further, there is no way to
depth-sort even a single sphere correctly without breaking up the
geometry, unless you turn on back face culling. A single sphere has
triangles that overlap each other and would require the sphere to be
broken up into multiple geometries so the individual triangles (or
patches) could be sorted.
--
Kevin Rushforth
Java 3D Team
Sun Microsystems
[EMAIL PROTECTED]
>Date: Thu, 20 Dec 2001 14:22:34 +0100
>From: "Dipl. Ing. Paul Szawlowski" <[EMAIL PROTECTED]>
>To: Kevin Rushforth <[EMAIL PROTECTED]>, Java 3D
<[EMAIL PROTECTED]>
>Subject: Re: [JAVA3D] Still a transparency sorting problem in Java3D1.3Beta?
>
>
>
>Kevin Rushforth schrieb:
>
>> >Can you please give a short description how depth sorting is done (what
>> coordinate
>> >is taken for comparing the depth, ...) ?
>>
>> The centroid of each geometry object is used for comparing depth.
>
>Do you only sort geometries, but not the triangles (or quads) within a geometry
?
>What happens if I have 2 transparent concentric spheres with different
diameters
>(each a seperate shape). Will you get that configuration right ?
>
>regards
>Paul
>
>PS: If there is a description of the capabilities of depth sorted transparency
>(what it does and what it does not), please point me to that description, so I
>don't have to bother you anymore with my questions.
>Unfortunatly I cannot test the 1.3 version because of the FireGL bug.
>
>
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