;rotates any vector about the z-axis by an angle theta, where ;clockwise is from x towards y, just like the azimuth angle in spc ;theta is in RADIANS!! ; ; Created by: Robert Lillis (rlillis@SSL.Berkeley.edu) pro rotate_z, theta, x, y, z, x1, y1, z1 x1 = x*cos(theta) - y*sin(theta) y1 = y*cos(theta) + x*sin(theta) z1 = z end