[osg-users] Absolutely dark scene

[Fernan]

Hi,

first of all a greeting to everyone, because I'm new around here.

I am developing an application that need to be done at night and become 
completely dark scene, but I can not.

I do not know how to remove the whole lighting of the scene, it is made at 
night, but there is always some light.

How can I create a totally dark scene?
Thanks a lot.

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Re: [osg-users] Absolutely dark scene

[Fernan]

Hi Robert,

thanks for reply.

I initialize my system as follows:

--

// construct the viewer.
osgViewer::Viewer viewer;
viewer.setLightingMode (osg::View::HEADLIGHT);

// Configura el visor para aparecer en una ventana
viewer.setUpViewInWindow (100, 100, 800, 600, 0);

// Pone el manejador de eventos de ratón (se hace por defecto dentro del 
run() del viewer, pero 
// aquí es necesario crearlo antes para poder ponerle la posición por 
defecto de la cámara
viewer.setCameraManipulator(new osgGA::TrackballManipulator());

// Pone la posición por defecto de la cámara
osgGA::MatrixManipulator* pCameraManip = viewer.getCameraManipulator();
if (pCameraManip != NULL)
{
  pCameraManip-setHomePosition (osg::Vec3 (0.0, -600.0, 8.0), osg::Vec3 
(0.0, 0.0, 8.0), osg::Vec3 (0.0, 0.0, 1.0));
}

// create a model from the images.
osg::Group* pRoot = new osg::Group();

// Create a new light, and set the light number according to our parameter.
osg::Light* pLight = new osg::Light();
pLight-setLightNum (0);
pLight-setAmbient (osg::Vec4d (0.0, 0.0, 0.0, 1.0));
pLight-setDiffuse (osg::Vec4d (0.0, 0.0, 0.0, 1.0)); 
pLight-setSpecular (osg::Vec4d (0.0, 0.0, 0.0, 1.0)); 
osg::LightSource* pLightsource = new osg::LightSource();
pLightsource-setLight (pLight);
pLightsource-setStateSetModes (*pRoot-getOrCreateStateSet(), 
osg::StateAttribute::ON);
pRoot-addChild (pLightsource);




With this, the scene get a little dark, but it is not totally black.
There is always a little light, so objects that I add to the scene can be seen.

These objects are ships and what I want is to see their lights and not ships 
due to it is night.

Would that be possible?

Thanks.

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Re: [osg-users] Absolutely dark scene

[Fernan]

Hi Robert,

Thank you for your help.
I've achieved my purpose.

Following your instructions I realized that my problems were two:

1) On the one hand, the scene by default sets the AmbientIntensity as follows:

osg::LightModel* lightmodel = new osg::LightModel;
lightmodel-setAmbientIntensity(osg::Vec4(0.1f,0.1f,0.1f,1.0f));
_globalStateSet-setAttributeAndModes(lightmodel, 
osg::StateAttribute::ON);

And due this the scene was always a little light.
Then I set this value to zero in my application after create the scene:

osg::LightModel* lightmodel = new osg::LightModel;
lightmodel-setAmbientIntensity(osg::Vec4(0.0f,0.0f,0.0f,1.0f));
_globalStateSet-setAttributeAndModes(lightmodel, 
osg::StateAttribute::ON);

And I got all the elements of the scene appear dark unless sea.

2) On the other, I realized that I was applying to the sea surface an 
OSG::Material with Emission value set to nonzero. Once I set the zero value to 
this parameter, all to be completely dark in my scene.

--

I leave here my solution in order to it can help someone with same problem.

Thanks a lot again for your help.

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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=8627#8627





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