If I could get these I can easily make a frustum culling function that is simple and should work.
How can I take the field of view and get the vertical and horizontal angles of the view frustum?
Assuming a typical projection matrix as generated by e.g.
glFrustum, the eye-space plane equations are:
x/z = -(m-1)/m(left)
x/z = -(m+1)/m(right)
y/z = -(m-1)/m(bottom)
y/z = -(m+1)/m(top)
The angles are the arctangents of those values.
If the projection is centred (e.g. as created by
gluPerspective or similar), m and m will be zero, so the plane equations become ±1/m and ±1/m and the angles are fovX=2*atan(1/m), fovY=2*atan(1/m).