Hi All,
I'm struggling to understand how to properly offset a slave in
osgViewer, and still have the perspectives line up for tiled and
CAVE-like displays.
For example, I have one OSG window to render the "left corner" of a
CAVE. The window has 2 cameras: The "left" camera has a viewport that
covers the left half of the window and is rotated -90 degrees. The
"center" camera has a viewport that covers the right half of the window
and is not rotated.
left camera:
viewer.addSlave(camera.get(), pMatrix,
osg::Matrix::rotate(osg::inDegrees(-90), 0,1,0));
center camera:
viewer.addSlave(camera.get(), pMatrix, osg::Matrix::());
How do I compute the correct pMatrix to ensure that the frustums line up
in a seamless fashion (ie, objects do not disappear or become duplicated)?
Note that through trial and error, I have found a pMatrix that works:
pMatrix = osg::Matrixd::scale( viewportWidthRatio * traits->width /
3150, 1, 1 );
But I don't understand why I have to scale by 3150? It seems that it's
related to the size of the viewport... so in my case my full window
width is 2048, so I have: 0.5 * 2048 / 3150 = 0.325. Why this value?
Also, in case it's important, the master camera is attached to a
NodeTrackerManipulator that I define like this:
nodeTracker = new osgGA::NodeTrackerManipulator();
nodeTracker->setTrackerMode(
osgGA::NodeTrackerManipulator::NODE_CENTER_AND_ROTATION );
nodeTracker->setRotationMode(
osgGA::NodeTrackerManipulator::ELEVATION_AZIM );
nodeTracker->setHomePosition(osg::Vec3d(0,0,0), osg::Vec3d(0,1,0),
osg::Vec3d(0,0,1));
The other question I have: what if the left view is not rotated, but
planar to the center? ie, the eye looks directly forward through the
center camera, and the left camera shows a translated and thus distorted
view? What is the proper way to set my pMatrix for that? Obviously it's
not just a scaling operation and requires skewing.
Any insight would be greatly appreciated!
Thanks in advance,
-Mike Wozniewski
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