Hi Matthias,
On Mon, 2004-08-23 at 03:34, Matthias Biedermann wrote:
Hi folks,
we have some material (Cg shader) assigned to a bunch of objects or
different parts of an object, respectively. However, some of the shader's
uniform parameters need to be changed for the different objects, that is
to say, the model matrix (not the modelview!) for the geometry.
Duplicating the whole material for every node is not an option due to its
memory consumption (textures...).
Is there a way to have every node below the material change its parameters
independently? Something like registering enter/leave functions? How can
this be accomplished then?
No, that would pretty badly clash with the basic design, I'd rather
avoid if possible.
Or can the material be split into a shared "texture-part" and individual
"shaderprogram-parts"...?
Matthias already mentioned that, and yes, it will work. It will be more
expensive than having a single material, but the actual state changes
will be much simplified (identical Chunks don't do anything when used in
multiple materials). Right now you can't share the ProgramChunks, as
they store the parameters, so you need to have copies of those, which is
not free.
I can see two solutions: 1) build smarts into the ProgramChunk so that
it shares the actual program IDs when the programs are the same.
Requires a central registry (which I don't like much), and might be
tricky. 2) Split the parameters off from the ProgramChunk into a
separate ProgramParameterChunk, which can then be used independent of
the program. Andreas, what do you think?
The real solution for your problem would be the ability to add Chunks on
a per-object basis. It's in my head, but not in code yet, so for now you
will not get around having multiple materials.
Yours
Dirk
Hi,
I wrote a extra ParameterChunk for GLSL with my test scene (500 cubes) I
got a nice speed improvement.
500 SHLChunks : 32 fps
1 SHLChunk and 500 ParameterChunks : 71 fps
1 SHLChunk : 85 fps
Andreas
--
Andreas Zieringer [EMAIL PROTECTED]
Fraunhofer IGD - A4 phone +49 (0)6151 155 289
Fraunhoferstr. 5 fax +49 (0)6151 155 196
D-64283 Darmstadt www.igd.fhg.de/www/igd-a4
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