Hi Robert,
Thank you for responding. I've been experimenting for hours, with the
'opengl programming guide' on my desk, but no luck.
In my small test program the initial view distance to the centre of my
scene is about 250.
I would expect the following to work but is does NOT:
fog->setMode(Fog::LINEAR);
fog->setStart(200.f); fog->setEnd(300.f);
The fog looks 'ok' on my example when I use negative start/end values
(but I dont understand why it works):
fog->setMode(Fog::LINEAR);
fog->setStart(-200.f);
For the exponential mode I would expect this to work, but it does not
(nor does any other density)
fog->setMode(Fog::EXP);
fog->setDensity(.00277); // e^(-250. * .00277) = .5
Any clue? any hint? A simple working example (code or osg-file)?
anybody?
Thanks,
Hans,
> Hi Hans,
>
> Fog most likely will be working correctly, just the values
> involved need tweaking. The best thing to do is read up on
> OpenGL Fog settings, the OSG just passes the settings it has
> on to OpenGL. osg::Fog is effectively glFog, all the
> variable and naming conventions are the same.
>
> Robert.
>
> On Nov 12, 2007 12:25 PM, Elbers, H.P. <[EMAIL PROTECTED]> wrote:
> >
> >
> > Hello All,
> >
> > I'm new to osg, and trying to use Fog...
> >
> > I get no fog at all, unless I use LINEAR mode with negative
> start and
> > end values, wich I find strange: I would expect that
> positive values
> > are required. If I try EXP mode, I cannot get any fog at al.
> >
> > Am I overlooking something obvious?
> > Please help!
> >
> > Hans Elbers
> >
> > ==========================================================
> > I'm using OSG 2.2 on linux, installed in a default way.
> > Here is a small test example (with red fog):
> >
> > I compile like this:
> > g++ -c -g main.cpp -o main.o
> > g++ -o osgtest -g main.o -losg -losgViewer -losgSim
> >
> > main.cpp:
> > ==========================================================
> > #include <osg/Group>
> > #include <osg/Fog>
> > #include <osgDB/ReadFile>
> > #include <osg/MatrixTransform>
> > #include <osg/PositionAttitudeTransform> #include
> <osgViewer/Viewer>
> > #include <osgGA/TrackballManipulator>
> >
> > using namespace osg;
> > using namespace std;
> >
> > int main(int argc, char *argv[]) {
> > osgViewer::Viewer viewer;
> > Group *world = new Group();
> >
> > StateSet *state= world->getOrCreateStateSet();
> >
> > Fog *fog =
> dynamic_cast<Fog*>(state->getAttribute(StateAttribute::FOG));
> > if (!fog) fog = new Fog;
> > fog->setColor(osg::Vec4(1.,0.,0., 1.));
> > fog->setDensity(0.15f);
> >
> > // ====> FOG works !?!?!
> > fog->setMode(Fog::LINEAR); fog->setStart(-200.f);
> > fog->setEnd(-300.f);
> >
> > // ====> NO FOG !?!?!?
> > //fog->setMode(Fog::LINEAR); fog->setStart(200.f);
> fog->setEnd(300.f);
> > //fog->setMode(Fog::EXP); fog->setStart(200.f);
> fog->setEnd(300.f);
> >
> > state->setAttributeAndModes(fog,StateAttribute::ON);
> >
> > Node *obj = osgDB::readNodeFile("obj.osg");
> > if (obj) for (int i=-5; i<=5; i++) for (int j=-5; j<=5; j++) {
> > PositionAttitudeTransform *T = new PositionAttitudeTransform();
> > world->addChild(T);
> > T->setPosition(Vec3(10.*i, 10.*j, 0.));
> > T->addChild(obj);
> > }
> >
> > viewer.setSceneData(world);
> > osgGA::TrackballManipulator *manip = new
> osgGA::TrackballManipulator();
> > viewer.setCameraManipulator(manip);
> > viewer.realize();
> >
> > viewer.run();
> > }
> > ==========================================================
> >
> >
> > obj.osg contains a small cube:
> > ==========================================================
> > Group {
> > UniqueID Group_0
> > DataVariance UNSPECIFIED
> > name "root"
> > nodeMask 0xffffffff
> > cullingActive TRUE
> > num_children 1
> > Geode {
> > UniqueID Geode_7
> > DataVariance UNSPECIFIED
> > name "geode19"
> > nodeMask 0xffffffff
> > cullingActive TRUE
> > num_drawables 1
> > ShapeDrawable {
> > UniqueID ShapeDrawable_8
> > DataVariance UNSPECIFIED
> > Box {
> > DataVariance UNSPECIFIED
> > Center 0 0 0
> > HalfLengths .5 .5 .5
> > Rotation 0 0 0 1
> > }
> > useDisplayList FALSE
> > useVertexBufferObjects TRUE
> > color 1 1 1 1
> > }
> > }
> > }
> > ==========================================================
> > _______________________________________________
> > osg-users mailing list
> > [email protected]
> >
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.
> > org
> >
> >
> _______________________________________________
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>
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