[osg-users] What coordinate system does OSG use?

Rowley, Marlin R marlin.r.rowley at lmco.com
Tue Apr 10 12:03:18 PDT 2018


Hello,

I'm very confused by this coordinate system.  It appears that our conventional left-handed and right-handed systems are NOT used, which causes havoc with the OpenGL coordinate frame.

It seems like getting the view matrix at the origin looking down what would be a left-handed +z-axis but rotated 90-degress about the x-axis so that z is pointing up seems to be the coordinate frame.

In a function call for getting the view matrix from a camera, for example. You get these values for the matrix (assuming it's column-major order)

Mat[2] : [0, -1, 0] <== LOOK
Mat[1]: [0, 0, 1] <==UP
Mat[0]: [1, 0, 0] <== RIGHT

This is confusing me with getting transforms and moving them into the vertex shaders.

-M

----------------------------------------
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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