NAME

       s3d_angle_to_cam - calculate angle between vector and cam

SYNOPSIS

       #include <s3d.h>

       float s3d_angle_to_cam(const float obj_pos[], const float cam_pos[], float *angle_rad);

DESCRIPTION

       Given obj_pos and cam_pos in the format float[3], angle_rad about which angle the object
       should be rotated around the y-axis so that it faces the camera. This might become handy
       if you have some text floating in space and want it to face the camera.
       http://en.wikipedia.org/wiki/Vector_(spatial)

AUTHOR

       Simon Wunderlich
           Author of s3d