Hi Yazel

> One of the issues with J3D 1.2.1 was that you could not do an add and a
> subtract in one pass.  So for example bump mapping you often want to lighten

Well this is still the rule. You can only add, subtract, multiply,
interpolate or dot3 but not a combination between these. And only
interpolation uses 3 sources. (Couldn't think of a good use for this one
yet, though it's fancy idea) That's because it seems it only uses
one combiner (this could be the limitation in OpenGL1.3 not sure haven't
read the specification of it yet. The problem I see when you try to
support more, they only work on a limited range of hardware which I think
is not the way J3D wants to go). What's new in J3D1.3 is add,subtract,
interpolate and dot3 and you can have different sources. If you want more
hardware-close-level but still some scenegraph functionality you should
rather go for OpenSceneGraph (not to be mistaken with OpenSG) but it's
C++.

> one part and darken another part.  So what we would do is use a lighter
> material and then apply a "darken" multiply, where a value of 1 would leave

That rather sounds like an extrem fake of bump mapping I would say :)

> applied the material brighten) and 0.6 would leave it shadowed.  The reason
> we did this was that multitexturing could only multiply.

Well now it can do more.

> So when I spoke of limitations I was refering to your comment that only one
> register combiner is used.  I was wondering what types of things we could do
> with one register combiner, versus the types of techniques which would
> require more than one.

A lot more. Look at latest Geforce3 or ATI R8500 technical demos, they use
upto 8 combiners. But they are still very very limited. So I say wait for
J3D1.4 :)

EOF,
 J.D.

--
Explore SRT with the help of Java3D
(http://wwwvis.informatik.uni-stuttgart.de/relativity/minkowski)
(http://www.antiflash.net/java3d/relativity (mirror)

===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA3D-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".

Reply via email to