Bob,
Its hard for me to imagine how one could get the effect of lightening
instead of dimming. But maybe color material set in vertices
(GL_COLOR_MATERIAL) may be involved somehow. This attribute is not handled
by vertex shaders. But its handled by fixed pipeline.You may look at the
shaders code ( stored inside osgShadow\src\StandardShadowMap.cpp ). All
classed derived from StandardShadowMap (Lispsm included) may work bit
differenet than other techniques because they define Vertex Shader. If your
fixed pipeline lighting setup is different than what is assumed in SSM
vertex shader we may see some issues not observable with other techniques
(which only use Fragment Shaders). SSM vertex shader assumes that we have
one light and separately compute and pass diffuse and ambient components to
fragment shader. If ambient is passed separately, fragment shader may
properly remove only diffuse component in shadowed areas keeping ambient
untouched.
Cheers,
Wojtek
Cheers,
Wojtek
----- Original Message -----
From: "Bob Holcomb" <[email protected]>
To: <[email protected]>
Sent: Wednesday, April 08, 2009 2:34 AM
Subject: [osg-users] osgShadow and model alpha textures
Hello,
I'm adding osgShadow to an existing osg project and I'm getting some weird
results with PSSM (Parallel Split Shadow Maps). They don't seem to be
respecting the alpha channel of my model's texture. For example, I have
helicopter model who's rotor system is represented by a quad and a texture
of the blades which is mostly transparent. When rendering before adding
osgShadow it looked fine. After adding osgShadow the translucent part is
white (but the shadows projected on the ground look pretty good!). This
only affects the items under the shadowedScene node, any geometry not
under that node is rendered correctly.
I've also tried the Light Space Perspective Map technique and found that
the self shadowing looks great, but the projected texture on the ground
actually makes the ground lighter instead of darker. If anybody has any
info on either of these issues I would also appreciate the help. Thanks!
Cheers,
Bob
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=9871#9871
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