Re: [Opensg-users] Antialiasing

[Andreas K. <ko...@hl...>]

Hi!

On Wed, 2004-06-23 at 15:01, si...@ti... wrote:
> I've got some problems when I try to use antialiasing.
> I add the follow chunks to every MaterialGroup node of the scenegraph.
> 
>     osg::PolygonChunkPtr poly=osg::PolygonChunk::create();
>     osg::BlendChunkPtr blend=osg::BlendChunk::create();
> 
>     beginEditCP(blend); 
>         blend->setSrcFactor(GL_SRC_ALPHA);
>         blend->setDestFactor(GL_ONE_MINUS_SRC_ALPHA); 
>         blend->setColor(osg::Color4f(0,0,0,0));
>     endEditCP(blend);
> 
>     beginEditCP(poly); 
>         poly->setSmooth(true);
>     endEditCP(poly);
> 
> So the model appears with some transparent lines: that lines are the wireframe
> 
> but I don't want to see the wireframe. 
> If I change the DestFactor to GL_ONE, the model becomes transparent.Do you
> 
> know how to solve this problem? Is there another way to use antialiasing
> with 
> OpenSG?

Normally you do antialiasing by selecting a multisampling GL-context.
Then you can do the following:

void setMultisampling(bool on) {

#if !defined(GL_MULTISAMPLE_SGIS) && !defined(GL_MULTISAMPLE_ARB)
#ifndef _WIN32
#warning "No Multisampling support detected, disabling"
#endif
#else

  if (multisampling) {
#ifdef GL_MULTISAMPLE_SGIS
    glEnable(GL_MULTISAMPLE_SGIS);
#endif //GL_MULTISAMPLE_SGIS
#ifdef GL_MULTISAMPLE_ARB
    glEnable(GL_MULTISAMPLE_ARB);
#endif //GL_MULTISAMPLE_ARB
  } else {
#ifdef GL_MULTISAMPLE_SGIS
    glDisable(GL_MULTISAMPLE_SGIS);
#endif //GL_MULTISAMPLE_SGIS
#ifdef GL_MULTISAMPLE_ARB
    glDisable(GL_MULTISAMPLE_ARB);
#endif //GL_MULTISAMPLE_ARB
  }
#endif //!defined(GL_MULTISAMPLE_SGIS) && !defined(GL_MULTISAMPLE_ARB)
}


also, often you have to set an environment variable, in the NVIDIA
(under Linux) case __GL_FSAA_MODE (see the NVIDIA docs)

-- 
Andreas Kopecki                High Performance Computing Center (HLRS)
                               Visualisation Department
Tel. ++49-711-6855789          Allmandring 30a, D-70550 Stuttgart

ko...@hl...                                      http://www.hlrs.de/
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