Hello all,

I've been struggeling for some while to understand whats in an OpenGL matrix after applying a rotation, and I can't seem to figure it out. :-(

This is my program :

glLoadIdentity
glRotatef,degtorad(22.5),0,0,+1.0
glTranslatef,10.0, 0,0
glGetFloatv,GL_MODELVIEW_MATRIX

This is the resulting matrix :

+0.924 +0.383(1) +0.000 +0.000
-0.383(2) +0.924 +0.000 +0.000
+0.000 +0.000 +1.000 +0.000
+9.239 +3.827 +0.000 +1.000

The X,Y and Z coordinates are as expected, indicating a (geometric) rotation
in quardrant #0 (top-right), starting at +X, going counter-clockwise.

The problem is the Z-axis rotation. The cells (1) and (2) look to be
reversed from all the documentation I could find (about applying a rotation
by hand).

It *could* be indicating a left-hand rotation, but when I check the result
(in a game - the only constant I have) the object in case does a counter-clockwise rotation, which indicates a right-hand rotation.

It simply doesn't match up. Help ?


Also, when I do not apply any rotation (keep, apart from the coordinates, an identity matrix) the object seems to point (and move) North, instead of East (over the +X axis).

It makes me feel as if my programs OpenGL coordinate system is off somehow,
but can't seem to find any documentation as to how/why and how to fix it. Again, help ?

Regards,
Rudy Wieser

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