[osg-users] zoom and orthographic projections
I'm calling osg::Camera::setProjectionMatrixAsOrtho() and I'm getting an orthographic projection (this is, if I look directly at the face of a cube in wireframe, all I see is a square). I can rotate and pan, but zoom isn't working (I'm dragging the right mouse button). I want to allow the user to toggle between perspective and orthographic projections. Obviously I need to do more than just set the projection matrix, but I'm not sure where to start looking for clues. I've been searching on setProjectionMatrixAsOrtho. What should I be looking for? Thanks, Cory Riddell ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] zoom and orthographic projections
TrackballManipulator doesn't support zoom, it only supports moving the viewpoint forwards backwards, which has no visible effect in ortho. You'll need to create an event handler and have it modify the camera projection matrix. Paul Martz Skew Matrix Software On Mar 26, 2009, at 8:35 AM, Cory Riddell c...@codeware.com wrote: I'm calling osg::Camera::setProjectionMatrixAsOrtho() and I'm getting an orthographic projection (this is, if I look directly at the face of a cube in wireframe, all I see is a square). I can rotate and pan, but zoom isn't working (I'm dragging the right mouse button). I want to allow the user to toggle between perspective and orthographic projections. Obviously I need to do more than just set the projection matrix, but I'm not sure where to start looking for clues. I've been searching on setProjectionMatrixAsOrtho. What should I be looking for? Thanks, Cory Riddell ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] zoom and orthographic projections
Zoom in ortho is done by shrinking or expanding the view volume defined by the left right top bottom planes. Paul Martz Skew Matrix Software On Mar 26, 2009, at 8:35 AM, Cory Riddell c...@codeware.com wrote: I'm calling osg::Camera::setProjectionMatrixAsOrtho() and I'm getting an orthographic projection (this is, if I look directly at the face of a cube in wireframe, all I see is a square). I can rotate and pan, but zoom isn't working (I'm dragging the right mouse button). I want to allow the user to toggle between perspective and orthographic projections. Obviously I need to do more than just set the projection matrix, but I'm not sure where to start looking for clues. I've been searching on setProjectionMatrixAsOrtho. What should I be looking for? Thanks, Cory Riddell ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] zoom and orthographic projections
Hi Cory, Orthographics views don't function like perspective ones, when you move near to the center, nothing actually changes w.r.t your view. This is normal and what you shoudl expect. If you want to simulate a perspective view by moving the left, right, top and bottom values of the projection matrix in then it kinda works, but and this is a HUGE BUT, you then hit issues what to do about the near and far plane. Soon you'll be trying your really hard to just and get get a orthographic view and perspective to kinda work the same but you'll never get to where you want to get to, perhaps some day after a few weeks of trying you might just come to realization that it can't be done, orthographic views just should never be used like perspetive one. So... rather than waste much of your life, and much of our time trying to support you give up now. Learn that orthographic views are best kept for external views of models where the whole model can be seen, or map views where no issues with the near/far planes exist. Once you get to this point life will be good once more. Robert. On Thu, Mar 26, 2009 at 2:35 PM, Cory Riddell c...@codeware.com wrote: I'm calling osg::Camera::setProjectionMatrixAsOrtho() and I'm getting an orthographic projection (this is, if I look directly at the face of a cube in wireframe, all I see is a square). I can rotate and pan, but zoom isn't working (I'm dragging the right mouse button). I want to allow the user to toggle between perspective and orthographic projections. Obviously I need to do more than just set the projection matrix, but I'm not sure where to start looking for clues. I've been searching on setProjectionMatrixAsOrtho. What should I be looking for? Thanks, Cory Riddell ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] zoom and orthographic projections
Hi Robert, Our app is a CAD app and all the views are external views of the model. I don't have any near/far plane issues. At first I thought I could simulate an orthographic view by moving the camera very far away then zooming in, but no. Anyway, I won't post to the list about this anymore. But your explanation (and Paul's explanation) of how orthographic views work was helpful. Thanks. Cory Robert Osfield wrote: Hi Cory, Orthographics views don't function like perspective ones, when you move near to the center, nothing actually changes w.r.t your view. This is normal and what you shoudl expect. If you want to "simulate" a perspective view by moving the left, right, top and bottom values of the projection matrix in then it "kinda" works, but and this is a HUGE BUT, you then hit issues what to do about the near and far plane. Soon you'll be trying your really hard to just and get get a orthographic view and perspective to kinda work the same but you'll never get to where you want to get to, perhaps some day after a few weeks of trying you might just come to realization that it can't be done, orthographic views just should never be used like perspetive one. So... rather than waste much of your life, and much of our time trying to support you give up now. Learn that orthographic views are best kept for external views of models where the whole model can be seen, or map views where no issues with the near/far planes exist. Once you get to this point life will be good once more. Robert. On Thu, Mar 26, 2009 at 2:35 PM, Cory Riddell c...@codeware.com wrote: I'm calling osg::Camera::setProjectionMatrixAsOrtho() and I'm getting an orthographic projection (this is, if I look directly at the face of a cube in wireframe, all I see is a square). I can rotate and pan, but zoom isn't working (I'm dragging the right mouse button). I want to allow the user to toggle between perspective and orthographic projections. Obviously I need to do more than just set the projection matrix, but I'm not sure where to start looking for clues. I've been searching on setProjectionMatrixAsOrtho. What should I be looking for? Thanks, Cory Riddell ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] zoom and orthographic projections
Sorry for my curt response before -- it was from my cell. Zooming in orthographic projection is not only possible, it's easy, and for an OpenGL implementation example, I'll direct you to the OpenGL Distilled example code: http://code.google.com/p/ogld/. See the Viewing example, setProjection() method. The Viewing example allows you to switch between perspective and orthographic. You can change the alt/az of the eye and zoom(*) in either projection mode. There are good code comments there describing how the code mimics a change in eye distance while in orthographic projection. (*) In perspective, the code allows you to move the eye forwards or backwards without changing the FOV, so this is not a zoom in the strict definition of the word, it is just a camera pan along the view vector. In ortho, on the other hand, it is a true zoom (the FOV is shrunk or expanded), as panning the eye along the view vector obviously has no effect in ortho. Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com http://www.skew-matrix.com/ +1 303 859 9466 _ From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Robert Osfield Sent: Thursday, March 26, 2009 8:48 AM To: OpenSceneGraph Users Subject: Re: [osg-users] zoom and orthographic projections Hi Cory, Orthographics views don't function like perspective ones, when you move near to the center, nothing actually changes w.r.t your view. This is normal and what you shoudl expect. If you want to simulate a perspective view by moving the left, right, top and bottom values of the projection matrix in then it kinda works, but and this is a HUGE BUT, you then hit issues what to do about the near and far plane. Soon you'll be trying your really hard to just and get get a orthographic view and perspective to kinda work the same but you'll never get to where you want to get to, perhaps some day after a few weeks of trying you might just come to realization that it can't be done, orthographic views just should never be used like perspetive one. So... rather than waste much of your life, and much of our time trying to support you give up now. Learn that orthographic views are best kept for external views of models where the whole model can be seen, or map views where no issues with the near/far planes exist. Once you get to this point life will be good once more. Robert. On Thu, Mar 26, 2009 at 2:35 PM, Cory Riddell c...@codeware.com wrote: I'm calling osg::Camera::setProjectionMatrixAsOrtho() and I'm getting an orthographic projection (this is, if I look directly at the face of a cube in wireframe, all I see is a square). I can rotate and pan, but zoom isn't working (I'm dragging the right mouse button). I want to allow the user to toggle between perspective and orthographic projections. Obviously I need to do more than just set the projection matrix, but I'm not sure where to start looking for clues. I've been searching on setProjectionMatrixAsOrtho. What should I be looking for? Thanks, Cory Riddell ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
