how a hud-camera respond to the resize event;

Jeremy Moles

2008-05-06 13:37:03 UTC

osgWidget handles this by using a custom EventHandler:

http://code.google.com/p/osgwidget/source/browse/trunk/src/ViewerEventHandlers.cpp#165

...the idea being that it's generally the case you want to adjust your
orthographic display by responding to the RESIZE event, and that you'll
almost never get the results you want otherwise (at least in my
experience :)).

Post by Wu Xiaodong
All. I try to render a hud-text;
I created a hud text in a geode and added it to a
slave-camera. It's good. but when i resize the view and set a new
position to the text bases on the new window rect. The text's position
seems based on the old window rect when when the slave-camera is
created.
when created, window rect is (0,0, 100,100) and the text
position is : 50,50, it's good;
when resize the window to rect (0,0,200,200) and i try to set
the text position (100,100); I hope the text should be in the center
of window, but it's out of the window range and I can see it in the
view.
how can I fix my problem?
Thanks.
xiaodong
the codes is following.
if( _hudCamera.valid() ) _hudCamera.release();
_hudCamera = new osg::Camera;
_hudCamera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
osg::ref_ptr<osg::Camera> camera = this->getCamera();
//update the main camera;
osg::ref_ptr<osg::GraphicsContext::Traits> traits;
if( camera.valid() )
{
osg::ref_ptr<osg::GraphicsContext> context =
camera->getGraphicsContext();
if( context.valid() )
{
traits =
const_cast<osg::GraphicsContext::Traits*>( context->getTraits() );
if( traits.valid() )
{
_hudCamera->setGraphicsContext( context.get() );
_hudCamera->setViewport(0,0,traits->width,
traits->height );
}
}
}
if( traits.valid() ) {
_hudCamera->setProjectionMatrixAsOrtho2D(0,traits->width,0,traits->height);
_hudCamera->setViewMatrix(osg::Matrix::identity());
_hudCamera->setRenderOrder(osg::Camera::POST_RENDER);
_hudCamera->setClearMask(GL_DEPTH_BUFFER_BIT);
std::string timesFont("fonts/times.ttf");
turn lighting off for the text and disable depth test to
ensure its always ontop.
osg::Vec3 position( 10.0f,traits->height/2.0,0.0f);
osg::Geode* geode = new osg::Geode();
osg::StateSet* stateset = geode->getOrCreateStateSet();
stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
stateset->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
//--
stateset->setRenderBinDetails(11, "RenderBin");
_hudCamera->addChild( geode );
osgText::Text* text = new osgText::Text;
geode->addDrawable( text );
text->setFont(timesFont);
std::stringstream ss;
ss<<"width:"<<traits->width<<"Height:"<<traits->height<<std::endl;
std::string str;
ss>>str;
std::wstring wstr(str.begin(), str.end());
text->setText( wstr.data() );
text->setPosition(position);
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
--
Xiaodong Wu
吴晓东
"'Xiao' means the time and the view when the sun rises and 'dong'
means the east in Chinese"
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