Hey Steven, Your magnification is modifying the FOV of the view frustum, and thus is best understood as an angular magnification. This statement:
atan(_left /_nearClip) /_magnification takes the left half of your horizontal field of view and scales it by your magnification value. Keep in mind, the actual value of your _magnification variable may not directly correspond to a proper angular magnification value (more detail here: http://en.wikipedia.org/wiki/Magnification#Magnification_as_a_number_.28optical_magnification.29 ). These pages may help too: https://forums.epicgames.com/threads/811228-Avoiding-FOV-for-doing-ZOOM http://en.wikipedia.org/wiki/Perspective_distortion_(photography) Alex -----Original Message----- From: osg-users [mailto:[email protected]] On Behalf Of Steven Powers Sent: Thursday, May 22, 2014 1:22 PM To: [email protected] Subject: [osg-users] Angular magnification Currently I am simulating magnification by manipulating the projection matrix like this: Code: left = nearClip * tan(atan(_left /_nearClip)/_magnification); right = nearClip * tan(atan(_right /_nearClip)/_magnification); top = nearClip * tan(atan(_top /_nearClip)/_magnification); bottom = nearClip * tan(atan(_bottom/_nearClip)/_magnification); _camera->setProjectionMatrixAsFrustum(left,right,bottom,top,nearClip,farClip); I've been posed a question as to whether this method of magnification is angular or linear. Does anyone know the answer to this question? Cheers, Steven ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=59535#59535 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
