Hi, I don't know if you already found the solution to your problem, but this is how you can calculate the camera position in worldspace:
Code: vec4 cameraPos_wordspace = osg_ViewMatrixInverse * vec4(0.0, 0.0, 0.0, 1.0); The rotation and scale factors can be found in the first three rows and columns of a matrix, so if you only want to compute a rotation and scale it is sufficient to use a 3x3 matrix. But to mathematically compute a translation of a vector you need to use a 4x4 matrix. The vector needs to be expanded to the 4th dimension, as-well to make it compatible with the matrix for multiplication. Here is how it works: Code: M * v = v' <==> 1 0 0 tx * x = 1*x + 0*y + 0*z + tx * 1 0 1 0 ty * y = 0*x + 1*y + 0*z + ty * 1 0 0 1 tz * z = 0*x + 0*y + 1*z + tz * 1 0 0 0 1 * 1 = 0*x + 0*y + 0*z + 1*1 (These are the rows of a matrix not individual equations, I wasn't able to format it in a good way, sorry) no if we simplify this we get: Code: x+tx = y+ty z+tz 1 As we can see it all boils down to adding an offset the the original vector. For the rest of your computations you can just ignore the w component of the vector. I hope I was able to shed some light on the dark ;) Thank you! Cheers, Marcel ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=56677#56677 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
