Kaiser, Hagen (CT) wrote:
It is in radians.
But do you know something about those diffent Up-Vectors?
Well, the default "camera" orientation for OpenGL (i.e. when the
model-view matrix is the identity matrix) is to have the camera at the
origin, with Y being up, and the camera looking down the negative
Z-axis. This also applies to the MatrixManipulator classes. So if a
manipulator returns the identity matrix the view will have Y up.
However, the manipulator classes in OSG seem to default (i.e. home
position when pressing the space bar) to return a matrix in which Z is
up. So the matrix they return includes as a first step a rotation around
the X around by 90 degrees to turn Y up in Z up. More confusing is the
fact that the _inverse matrix_ returned by a matrix manipulator is
actually used as the model-view matrix.
Hmm, I hope I got this all correct, it's so easy to make a mistake with
this stuff...
BTW, you don't have to use a matrix manipulator, as it seems you want
full control over the view orientation (and assuming mouse interaction
is unwanted). In that case you can do
viewer->getCamera()->setViewMatrix(...)
within the frame loop and set your desired model-view matrix there.
Paul
-----Ursprüngliche Nachricht-----
Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Paul Melis
Gesendet: Freitag, 6. Juni 2008 16:36
An: OpenSceneGraph Users
Betreff: Re: [osg-users] Positioning the viewers camera
Kaiser, Hagen (CT) wrote:
Thanks for the idea,
But that doesnt seem to bring me any furhter.
Coordinates are somthing like 500, -5,50 so making this all minus
brings me so far away, that i cant see anything anymore
This is what I found in atutorial about that problem:
To position a camera manually, we can use the viewer class
setViewByMatrix() method. This call should be placed between the
viewer.update and viewer.frame calls within the simulation loop. The
following guidelines are useful:
* Producer and all classes below osgGA::MatrixManipulator (in
terms of abstraction) use 'Y' up coordinates. All others
-including the Viewer class matrix manipulators - use 'Z' up.
* The inverse of a position/orientation matrix can be used to
orient a camera.
This correseponds to my makeTranslate call, I think.
Just a check: is the rotation value you apply in degrees or radians?
makeRotate() expects a value in radians...
Paul
------------------------------------------------------------------------
*Von:* [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] *Im Auftrag von
*Alejandro Segovia
*Gesendet:* Freitag, 6. Juni 2008 16:24
*An:* OpenSceneGraph Users
*Betreff:* Re: [osg-users] Positioning the viewers camera
Hello,
On Fri, Jun 6, 2008 at 11:10 AM, Kaiser, Hagen (CT)
<[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:
Hello everyone,
I am desparately trying to position a viewers camera manually and
correctly.
My give data give me a Position Vector a RotationAxis and a
Rotation Angle.
And a float that is named fieldofView.
Here is how I implement it:
osgGA::TrackballManipulator* man =
(osgGA::TrackballManipulator*)this->viewer->getCameraManipulator();
osg::Matrix trans;
trans.makeTranslate(osg::Vec3(position.x(),position.y(),position.z()));
osg::Matrix rot;
rot.makeRotate(Angle,osg::Vec3(Axis.x,Axis.y,Axis.z)));
osg::Matrix cam = rot*trans;
this->viewer->setByMatrix(cam)
}
But I never get the right position or rotation.
After testing around, I noticed the following:
Changing
trans.makeTranslate(...
to trans.makeTranslate(osg::Vec3(position.x,* -position.z,
position.y*));
Have you tried making a translation of (-x, -y, -z) instead? Remember
that placing the camera at some point P is actually applying a
translation of -P to the whole world.
cam = rot*trans seems fine.
Let me know how it went.
Alejandro.-
--
[EMAIL PROTECTED]
http://varrojo.linuxuruguay.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
_______________________________________________
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
