[osg-users] Show part of geometry which intersects a specific area

[Ali Ozdin]

Hi Robert,

Did you examine my sample code? 
I dont set mode GL_CLIP_PLANEi to my subgraph in the sample. I am only using createClipBox function like in the osgClip example.

Do you think sample code I have sent to you seems to work right?

If the sample code I have sent to you seems right; what is your advice?






robertosfield wrote:
> Hi Ali,
> 
> When you put nodes underneath a ClipNode those nodes should inherit
> the required GL_CLIP_PLANEi, so in theory it should work right,
> however, as I've never mixed osgText with clipping I can only say I
> don't see a reason in principle when it wouldn't work.  If you put the
> subgraphs you want to clip in a different subgraph you'll need to set
> the GL_CLIP_PLANEi.
> 
> Robert.
> 
> On 28 March 2018 at 08:46, Ali Ozdin <> wrote:
> 
> > Hi Robert,
> > 
> > Firstly, I am using osg 3.4.1. However I dont enable any GL_CLIP_PLANEi but all geometry in geodeForgeomRight works well except osgText geometries. Sample code is below:
> > 
> > 
> > Code:
> > 
> > osg::ClipNode* clipped_subgraph;
> > osg::ref_ptr<osg::Geode> geodeForgeomRight;
> > 
> > osg::ref_ptr<osgText::Text> bottomAltitudeText = new  osgText::Text;
> > osg::Vec3 position( (SCREEN_WIDTH * 0.64) + bigLineLength, (i/2)*lineBreak, 0.0f);
> > std::string timesFont("fonts/arial.ttf");
> > bottomAltitudeText->setAlignment(osgText::TextBase::AlignmentType::LEFT_CENTER);
> > bottomAltitudeText->setFont(timesFont);
> > bottomAltitudeText->setColor( osg::Vec4f(0.f, 255.f,0.f,1.f) );
> > bottomAltitudeText->setPosition(position);
> > bottomAltitudeText->setText("hello world" );
> > bottomAltitudeText->setCharacterSize(15.0);
> > geodeForgeomRight->addDrawable( bottomAltitudeText.get() );
> > 
> > 
> > osg::ref_ptr<osg::MatrixTransform> mt = new osg::MatrixTransform();
> > mt->addChild(geodeForgeomRight.get());
> > 
> > clipped_subgraph = new osg::ClipNode;
> > double xMin,yMin, zMin, xMax, yMax, zMax;
> > xMin = (SCREEN_WIDTH * 0.64);
> > yMin = SCREEN_HEIGHT*0.6 - 17*lineBreak;
> > zMin = 0.0f;
> > xMax = geodeForgeomRight.get()->getBoundingBox().xMax();
> > yMax = SCREEN_HEIGHT*0.6;
> > zMax = 0.0f;
> > osg::BoundingBox bb(xMin,yMin, zMin, xMax, yMax, zMax);
> > clipped_subgraph->createClipBox(bb);
> > clipped_subgraph->addChild(mt);
> > 
> > clipped_subgraph->setCullingActive(true);
> > mt->setUpdateCallback(new AltitudeCallBack());
> > 
> > 
> > 
> > 
> > Best regards,
> > 
> > 
> > robertosfield wrote:
> > 
> > > Hi Ali,
> > > I haven't tested this specific combination of features, but in
> > > principle it should be just a case of enabling the GL_CLIP_PLANEi mode
> > > for the text subgraphs.
> > > 
> > > Which version of the OSG are you using and what GL versions?
> > > 
> > > The new osgText implementation in master/OSG-3.6 branch uses shaders
> > > so out of the box, looking at the shader I don't see any setting of
> > > the gl_ClipVertex so this could be a problem.  I will look into this.
> > > 
> > > Robert.
> > > _______________________________________________
> > > osg-users mailing list
> > > 
> > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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> > 
> > 
> > 
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