[osg-users] [build] Why Restoring OpenGL currentState is not working with OpenGLES2 but working with GLES1

[Koduri Lakshmi]

Hi,

I am using a 3rd party lib(QCAR) with OSG on Android. This lib clears OpenGLES graphics context every time after rendering a frame. So the model renders only once (first time) and disappears on the viewer. So to preserve graphics context i did as follows

---> Created Embeded View
---> Captured current Graphics context as follws


Code:
m_lastStateSet = new osg::StateSet();
_viewer->getCamera()->getGraphicsContext()->getState()->captureCurrentState(*m_lastStateSet.get());



---> In RendererFrame function
---> Restore graphics context as follows


Code:
osgState = _viewer->getCamera()->getGraphicsContext()->getState();
osgState->reset();
osgState->apply(m_lastStateSet.get());



---> render Frame Code

----> Save the current state of the graphics context as follows

Code:
_viewer->getCamera()->getGraphicsContext()->getState()->captureCurrentState(*m_lastStateSet.get());



This works fine with OpenGLES1. The same is not working if I build the same code with OpenGLES2 version.

Can you please help me what could be the mistake.

Here is the complete code

OSG INIT Function


Code:
void OsgApp::initOsgWindow(int sW,int sH)
{
_viewer = new osgViewer::Viewer();
embeddedWindow=_viewer->setUpViewerAsEmbeddedInWindow(x, y, width, height);
_root = new osg::Group();

_viewer->realize();
_state = _root->getOrCreateStateSet();
_state->setMode(GL_LIGHTING, osg::StateAttribute::ON);
_state->setMode(GL_DEPTH_TEST, osg::StateAttribute::ON);
_state->setMode(GL_CULL_FACE, osg::StateAttribute::ON);

//_viewer->setSceneData(_root.get());


_viewer->addEventHandler(new osgViewer::StatsHandler);
_viewer->addEventHandler(new osgGA::StateSetManipulator(_viewer->getCamera()->getOrCreateStateSet()));
_viewer->addEventHandler(new osgViewer::ThreadingHandler);
_viewer->addEventHandler(new osgViewer::LODScaleHandler);


_manipulator = new osgGA::KeySwitchMatrixManipulator;

_manipulator->addMatrixManipulator( '1', "Trackball", new osgGA::TrackballManipulator() );
_manipulator->addMatrixManipulator( '2', "Flight", new osgGA::FlightManipulator() );
_manipulator->addMatrixManipulator( '3', "Drive", new osgGA::DriveManipulator() );
_manipulator->addMatrixManipulator( '4', "Terrain", new osgGA::TerrainManipulator() );
_manipulator->addMatrixManipulator( '5', "Orbit", new osgGA::OrbitManipulator() );
_manipulator->addMatrixManipulator( '6', "FirstPerson", new osgGA::FirstPersonManipulator() );
_manipulator->addMatrixManipulator( '7', "Spherical", new osgGA::SphericalManipulator() );

_viewer->setCameraManipulator( _manipulator.get() );

_viewer->getViewerStats()->collectStats("scene", true);



_viewer->getCamera()->setViewport(0,0,sW, sH);

_viewer->getCamera()->setClearMask(GL_DEPTH_BUFFER_BIT );



modelSwitch=new osg::Switch;


LOG("READING Model_0");
readModels("/mnt/sdcard/test/0.osg",MODEL_1);


_root->addChild(modelSwitch.get());

_viewer->setSceneData(NULL);
_viewer->setSceneData(_root.get());
_manipulator->getNode();
_viewer->home();

_viewer->getDatabasePager()->clear();
_viewer->getDatabasePager()->registerPagedLODs(_root.get());
_viewer->getDatabasePager()->setUpThreads(3, 1);
_viewer->getDatabasePager()->setTargetMaximumNumberOfPageLOD(2);
_viewer->getDatabasePager()->setUnrefImageDataAfterApplyPolicy(true, true);

[color=red][b]m_lastStateSet = new osg::StateSet();
_viewer->getCamera()->getGraphicsContext()->getState()->captureCurrentState(*m_lastStateSet.get()); [/b][/color]
}




Renderer Function


Code:
void OsgApp::renderer(osg::Matrix mat)
{

[color=red] [b]osgState = _viewer->getCamera()->getGraphicsContext()->getState();
osgState->reset();
osgState->apply(m_lastStateSet.get()); [/b][/color]


renderModel_1(mat);


_viewer->frame();
[color=red][b]_viewer->getCamera()->getGraphicsContext()->getState()->captureCurrentState(*m_lastStateSet.get()); [/b] [/color]


}


...


Thank you!

Cheers,
Koduri

------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=51032#51032




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[Koduri Lakshmi]

Hi,

The error is not with the previous post code.

When I added the following code then the model is displayed.


Code:
mtForMarker[idx]=new osg::MatrixTransform();

osg::Shader * vshader = new osg::Shader(osg::Shader::VERTEX, gVertexShader );
osg::Shader * fshader = new osg::Shader(osg::Shader::FRAGMENT, gFragmentShader );

osg::Program * prog = new osg::Program;
prog->addShader ( vshader );
prog->addShader ( fshader );

mtForMarker[idx]->getOrCreateStateSet()->setAttribute ( prog );

mtForMarker[idx]->addChild(loadedModel[idx].get());
modelSwitch->addChild(mtForMarker[idx].get());


osgViewer::Viewer::Windows windows;
_viewer->getWindows(windows);
for(osgViewer::Viewer::Windows::iterator itr = windows.begin();itr != windows.end();++itr)
{
(*itr)->getState()->setUseModelViewAndProjectionUniforms(true);
(*itr)->getState()->setUseVertexAttributeAliasing(true);
}



This code I added from osgAndroidOpenGLES2 example.

As I am new to OSG I have two doubts

1) Why should I add the shaders in OpenGLES2 to display model. If I remove this code then the model is not displayed. OpenGLES1 dosnt have this shaders.

2) If I add this code then the textures are not applied to my model. I got model from 3DS MAX. How can I get textures?

Can you please guide me how to get textures? If shaders are necessary to render model on Android then how can I handle textures (or any others) ? Is there any tutorial to handle this in Android?

...


Thank you!

Cheers,
Koduri

------------------
Read this topic online here:

http://forum.openscenegraph.org/viewtopic.php?p=51112#51112