Hi all,
My goal is to replace shader generator with shader composer, so I spent
a few days playing with it. It proved to be very flexible and powerful
tool but unfortunately, it lacks the support for a key feature I would
consider necessary, and that is support for the "position state".
Putting it differently, shader composer is "blind" for position state
attributes (Light, ClipPlane, TexGen) stored within LightSource,
ClipNode and TexGenNode. I was able to workaround the problem with cull
calbacks or with custom cull visitor where I'm able to identify
"positioned uniform" multiply it with model-view matrix and then force
shader composer to accept the uniform and ShaderComponent attached to
the state attribure. Unfortnatelly, this workaround introduced some
unnecessary code complications and problems with uniform management and
that is why I strongly feel that the solution should be integrated into
OSG core.
I believe the implementation of such a feature should be straightforward
task and since I might be able to post the core solution @submissions
for a review, I am asking you for advice on how user interface should
look. I have two ideas for now:
1. easy to implement solution dedicated to LightSource, ClipNode and
TexGenNode. In addition to LightSource::setLight we could introduce two
new methods: LightSource::addPositionedUniform(name, VecX) that will be
collected into PositionalStateContainer and get special treatment with
model-view matrix before applied at RenderStage and
LightSource::addUniform(osg::Uniform*) to set other non-poisitioned
uniforms that won't be multiplied but applied in a same way before any
other attribure.
2. general soution by introducing two new types of uniforms:
osg::PositionedUniform and "global? scene?" uniform, Both can be set at
any StateSet and will be applied at RenderStage before any other attribure.
3. both solutions: First dedicated and after that general solution which
will replace internal logic of LightSource and others leaving the
interface as is.
4. ?
Best Regards
Robert Milharcic
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
