On Mon, Oct 18, 2010 at 10:23 PM, Cory Riddell <c...@codeware.com
<mailto:c...@codeware.com>> wrote:
I've been plowing through this and I can almost get what I need, I
just don't entirely understand a couple of things.
Is it safe to think of the view matrix as the camera position and
orientation? By doing so, I think I understand
SphericalManipulator::getMatrix() method. It returns:
As was mentioned recently, the view matrix is actually the inverse of
camera position and orientation in the world. You can also think of it
as the position and orientation of the world in eye space. The
"matrix" returned by the manipulator classes is the camera pose; the
matrix returned by getInverseMatrix() is the view matrix.
return osg::Matrixd::translate(osg::Vec3d(0.0, 0.0, m_distance))*
osg::Matrixd::rotate(M_PI_2-m_elevation, 1.0, 0.0, 0.0)*
osg::Matrixd::rotate(M_PI_2+m_heading, 0.0, 0.0, 1.0)*
osg::Matrixd::translate(m_center);
This manipulator has two parameters - heading and elevation.
Heading is the angle from the x-axis in the x-y plane and
elevation is the angle from the x-y plane (pi/2 would give you the
z-axis).
If I want the x-axis to be up rather than the z-axis, I add an
additional rotation:
return osg::Matrixd::translate(osg::Vec3d(0.0, 0.0, m_distance))*
osg::Matrixd::rotate(M_PI_2-m_elevation, 1.0, 0.0, 0.0)*
osg::Matrixd::rotate(M_PI_2+m_heading, 0.0, 0.0, 1.0)*
osg::Matrixd::rotate(M_PI_2, 0.0, 1.0, 0.0)* // NEW!
osg::Matrixd::translate(m_center);
Am I tinkering with the right stuff here? (I've also made the
appropriate change to my getInverseMatrix() method.)
Yes, that looks fine.
Tim
It's feeling ok, but I do need to make more changes to the
manipulators code that handles pans.
Cory
On 10/15/2010 5:03 PM, Cory Riddell wrote:
I have been using the SphericalManipulator and it works really
well for my application.
One thing I would like to do is change which direction is up. The
default is Z == up. Sometimes I want X to be up. If I understand
the code, I need to make fairly extensive modifications to the
existing manipulator. Before I start down that road, I just
wanted to ask if that sounds right. I'm hoping I'm not missing
some place where I obviously just need to apply some
transformation matrix.
I actually want my entire scene to go sideways, not just orbit up
and down on my screen rather than right and left. For example, if
I were modeling a pencil (coaxial the z axis), I sometimes want
it standing on end, and sometimes lying on its side on my screen.
I think I'm asking a question that has been asked before:
http://www.mail-archive.com/osg-users@lists.openscenegraph.org/msg33695.html
Cory
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