[osg-users] LookAt() function parameter meanings..

Rowley, Marlin R marlin.r.rowley at lmco.com
Mon Aug 13 07:07:10 PDT 2018


I'm very confused by the parameters passed into this function.  I am going over some of the legacy code and saw this line of code:

osg::Matrixd frustumView;
frustumView.makeLookAt(VIEW_POS, mDirection, mUp);

saw the docs, it's described like this:

void makeLookAt(const Vec3d& eye,const Vec3d& center,const Vec3d& up);

So in this context, I would think that "eye" represents the look vector.  However, it seems to work like a position vector.  The "center" parameter expects a direction vector (0, -1, 0) where the look vector is along the -yaxis.

This matrix will not translate to OpenGL properly since it's coordinate system is based off of a right handed coordinate frame.


  1.  Am I interpreting these parameters properly?
  2.  How would I convert this system to the OpenGL right-handed system?

Marlin Rowley
Software Engineer, Staff
[cid:image002.jpg at 01D39374.DEC5A2E0]
Missiles and Fire Control
972-603-1931 (office)
214-926-0622 (mobile)
marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>

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