How to get camera up vector from roll, pitch, and yaw?

Question

I need to get an up vector for a camera (to get the right look) from a roll, pitch, and yaw angles (in degrees). I've been trying different things for a couple hours and have had no luck :(. Any help here would be appreciated!

Answer 1

Roll, Pitch and Yaw define a rotation in 3 axis. from these angles you can construct a 3x3 transformation matrix which express this rotation (see here how)
After you have this matrix you take your regular up vector, say (0,1,0) if 'up' is the Y axis and multiply it with the matrix. What you'll get is the transformed up vector.

Edit-
Applying the transformation to (0,1,0) is the same thing as taking the middle row. The 3 rows of the matrix make up an orthogonal base of the rotated system. Mind you that a 3D graphic API uses 4x4 matrices. So to make a 4x4 matrix out of the 3x3 rotation matrix you need to add a '1' at M[3][3] (the corner) and zeros at the rest like so:

r r r 0
r r r 0 
r r r 0
0 0 0 1