Quarternion to radians (SOLVED)

Questions
1

Has anyone written a function to do the opposite of vmath.quat_rotation_z? That is, convert a quaternion to radians of the z-axis.

My code uses radians but when getting the rotation of a GO, it is returned as a quaternion (which I don’t know how to use).

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2

If you are only rotating in 2D, it should be:

local a = 2 * math.acos(q.w)

If the rotation happens around a (normalised) axis (x,y,z) with angle t radians, the individual elements are:

local s = sin(0.5*t)
local c = cos(0.5*t)
local q = vmath.quat(s*x, s*y, s*z, c)

I can recommend using quaternions instead of radians, it can simplify things after the initial learning bump.

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