Hi Jacob, You spotted the fix that should already be in CVS, as I came across this very same problem a couple of weeks back.
The reason for the alpha not being active is that osgvolume just created the scene to drop in to the opaque bin and eroneously never enabled the glAlphaFunc/osg::AlphaFunc. The only reason why this originally work is that the OSG used to default to enable alphafunc for both the opaque and transparent bins, but now only does it for the transparent bin. Robert. On 11/28/06, Jacob Foshee <[EMAIL PROTECTED]> wrote:
To whom it may concern: I think I found a solution to the alpha-blending problem. I changed the following 2 lines in createModel(): > stateset->setMode(GL_BLEND,osg::StateAttribute::ON); > stateset->setAttribute(new osg::AlphaFunc(osg::AlphaFunc::GREATER,alphaFuncValue)); > to: > stateset->setAttributeAndModes(new osg::BlendFunc, osg::StateAttribute::ON ); > osg::AlphaFunc* alphaFunc = new osg::AlphaFunc; > alphaFunc->setFunction(osg::AlphaFunc::GEQUAL,alphaFuncValue); > stateset->setAttributeAndModes( alphaFunc, osg::StateAttribute::ON ); > Now alpha blending is behaving as expected. On 11/27/06, Jacob Foshee < [EMAIL PROTECTED]> wrote: > Howdy, > I cannibalized the osgvolume example to do some volume rendering for > my application. > > The only function I changed was the main() function (primarily because > it is not my main function, and my data has already been loaded). I > only have one channel in my data, so I set desiredPixelFormat to > GL_LUMINANCE. > > I ran into 2 problems: > > - alphaFuncValue seems to be ineffective. No matter what I set the > alpha cut-off value to, I get the same results in my rendering. > Blending is working, but it seems to behave as if alphaFuncValue is > 0.0. > > - The corners of the volume get clipped off at certain angles. As a > remedy, I pass a cube size of 1.5 to createCube() rather than 1.0. Is > there a better solution? > > Thanks! And Kudos to the author (I think it was Robert) for making it > so easy to get up and running w/ volume rendering. > > Jacob > _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
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