Matthew,

Geodetic coordinates (lat,lon,alt) are typically mapped into some sort
of Cartesian coordinate system (x,y,z) (i.e. geocentric coordinates).
Setting the view matrix will operate in the latter CS.

The projection matrix does not control where you are looking. The view
matrix determines that. The projection matrix controls the viewing
frustum. Perhaps a review of the OpenGL transformation pipeline is
appropriate here.

Orientation (h,p,r) and position are concatenated together to form the
view matrix. This topic has been discussed on how to manually set the
view matrix to your liking.

If you need some code snippets to get started, that can be provided...:)

-Shayne 

-----Original Message-----
From: osg-users-boun...@lists.openscenegraph.org
[mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Matthew
Runo
Sent: Monday, January 02, 2012 10:18 AM
To: osg-users@lists.openscenegraph.org
Subject: [osg-users] Newbie Questions re: Camera control (I think)

Hi,

I found the CameraControl wiki page, but it has a warning that it's out
of date.. and I don't know how to update it to the osgViewer class
because I can't get to the documentation (that, and I'm reasonably new
to C++).

- Given a point in 3d space with World Coordinates (eg, Latitude,
Longitude, Altitude), how can I position the viewer at that point? I'm
thinking that I need to create a matrix with my points in it, and then
call camera.setViewMatrix(..). Is that correct? How do I convert my
world coordinates into coordinates that will work in the camera?

- Once I'm at that point, do I use camera.setProjectionMatrix to control
where I'm looking? For example, say I want to look due North at lat 26,
long -119, altitude 52.  

- Given a set of rotations that should happen to the camera (roll 3
degrees right, pitch 4 degrees up, etc), are those best handled by
looking at the examples from osgGA::FirstPersonManipulator and going
from there by building up a Matrix to use somewhere to rotate the
camera's view?

As of right now I've been tinkering with the code for the various
implementations of the osgGA::FirstPersonManipulator and learning quite
a bit - I just wanted to get these questions in my mind cleared up. I'm
sorry that they're so basic =\

Thank you very much for your help, and for this community full of
knowledge!

Thank you again,
Matthew

------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=44529#44529





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