Hi all, I'm having fun learning about rotation about an arbitrary axis and it's not working as I expected it to at all.
I am using the code from the Trackball manipulator to construct a "local" origin at a point that is actually @ the edge of my earth sphere. It goes like this: osg::Vec3d Up(0,0,1); osg::Vec3d focalPt(x,y,z); osg::Vec3d x_axis = Up ^ focalPt; // up cross focal should give "x-axis"? osg::Vec3d y_axis = x_axis ^ focalPt;// should be y-axis?? osg::Vec3d z_axis = x_axis ^ y_axis; I can construct the "x-axis" w/o a prob and I can rotate about it - though it LOOKS LIKE A PITCH that I am actually performing and not a ROLL. This behavior is very strange to me. :( To actually perform the rotate, I do the following: osg::Quat q(AngleOfRotation, x_axis); osg::Matrixd mtxd = osg::Matrixd::rotate(q) * OriginalPositionMatrixd; The mtxd computed is the correct rotation about the x-axis but, again, it appears to be a PITCH instead of a ROLL. OriginalPositionMatrixd is computed as follows: osg::Vec3d ov3d = s_paxNode->getPosition(); osg::Quat q = s_paxNode->getAttitude(); osg::Matrixd mtxdR; mtxdR.makeRotate(q); osg::Matrixd mtxdT; mtxdT.makeTranslate(ov3d); osg::Matrixd OriginalPositionMatrixd = mtxdR * mtxdT; //order matters!!!! MY PROBLEM: when I attempt to rotate about "y-axis" or "z-axis" which I think are local to the focalPt, the rotation is totally wrong. It rotates in an completely unexpected way. Would someone please explain to me how to properly construct a local origin at my focal point so that I can rotate my model, which is at that point, around the local x,y and z axes? I am on the surface of the Earth, too, and I want to actually rotate my model about it's "z-axis" so as to change the azimuth the model is facing. Note: whether the axes are normalized or not seems to make no difference though I think that that should make a difference. ... Thank you very much! Cheers, Allen ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=20288#20288 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
