How does the rotation angle using a rotation matrix correspond to a degree

Question

I am trying to rotate a box in java using a rotation matrix.

(I am using the LWJGL and Slick 2D libraries)

my code to rotate 1 point around the center point is this:

point1X = (float) (centerX * Math.cos(rotation) - centerY * Math.sin(rotation));
point1Y = (float) (centerX * Math.sin(rotation) + centerY * Math.cos(rotation));

Right now I just update the rotation every update like so:

rotation += delta * 0.001;

This works great except the rotation number does not seem to correspond to a degree from 0˚ to 360˚

Is there a formula or something that will translate the rotation number to a readable degree and vice versa?

Answer 1

Normally, trig functions expect their arguments to be in radians, not degrees.

2*pi radians = 360 degrees.