Re: [JAVA3D] Another transparency question

[Daniel Selman]

David,

I ran some tests, and I *think* it is working, though its always hard to be
100% sure!

I created a Quad with per-vertex colors:

Black               Blue
Alpha 1.0           Alpha 0.8


Red                 Green
Alpha 0.0           Alpha 0.2

And set the following attributes:
Transparency 0.8, NICEST
TextureAttributes: Modulate
Material: null

Screen shots (attached)
1) without a texture
2) with a texture (no alpha in texture)
3) with a texture (alpha in texture)

Sincerely,

Daniel Selman

[EMAIL PROTECTED]

Tornado Labs Ltd.
http://www.tornadolabs.com



-----Original Message-----
From: Discussion list for Java 3D API
[mailto:[EMAIL PROTECTED]]On Behalf Of David
Sent: Saturday, December 23, 2000 11:29 AM
To: [EMAIL PROTECTED]
Subject: Another transparency question


Is it possible to set the vertex alphas, then modulate a texture with alphas
to merge the two alpha componants?  So lets say I have a texture with a
solid circle, where the circle has texels of alpha 1, but the space around
the circle has texel alphas of 0.  Now I map this to a plane, where the
geometry is defined with COLOR_4.  All the vertices of colors of white, with
alpha of 1, except one vertex right in the middle, which has an alpha of
0.5.  Now I modulate the texture onto the plane, such that the circle is
centered in the middle of the plane.  I would expect the texels of the
texture to modulate all 4 parts of the color with the vertex, producing a
blended 50 percent transparency in the center.

But it looks like the TransparencyAttributes are overwriting my vertex
alpha, leaving the circle solid.  In other words, in order to render my
texture with its alphas, I have to use transparency attributes, which
overwrite my vertex alphas.  Seems to anyway.

Any thoughts?

Dave Yazel

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screen1.jpg

screen2.jpg

screen3.jpg