;polarxy2c.lsp -- conversion from XY to polar (in prep for Sisyphus)
;Bruce Shapiro   10/1/17 (from polarxy2.lsp) 
;L/R mirror correction

(defun c:makepolar ( / bm sset i  )
  (setq bm (getvar "blipmode"))
  (setvar "blipmode" 0)
  (setq Pi 3.14159)

  (setq sset (ssget))
  (setq i 0)
  (while (ssname sset i)
    (setq ename (ssname sset i))
    (setq alist (entget ename))
    (do_pline)
    (setq i (1+ i))
  );end while

  (setvar "blipmode" bm)
  (command "_regen")
  
);end c:test()

;*********************************
(defun do_pline ()

   (setq next (entnext ename))   ;now, deal with vertices
   (setq alist (entget next))

;initialize theta_old and theta_accum:  
   (setq vert (cdr (assoc 10 alist)))
   (setq x (car vert)   ;get x,y,z coords
             y (cadr vert) 
	     theta_old (* (atan y x) 1)
             theta_accum theta_old
   )
;(print theta_old)
;(print theta_accum)
;(getstring)
(while (/= (cdr (assoc 0 alist)) "SEQEND")
     (progn    
       (setq vert (cdr (assoc 10 alist)))
       (setq x (car vert)   ;get x,y,z coords
             y (cadr vert) 
	     theta_new (* (atan y x) 1)
             r (sqrt (+ (* x x)(* y y)))
       )
       (setq d_theta (- theta_old theta_new))
       (if ( > d_theta Pi) (setq d_theta (- d_theta (* 2 Pi))))
       (if ( < d_theta (- Pi)) (setq d_theta (+ d_theta (* 2 Pi))))
       (setq theta_accum (+ theta_accum d_theta))
;(print theta_new)
;(print d_theta)
;(print theta_accum)

;(getstring)      
       (setq newvert (list theta_accum r 0 ))
       (setq theta_old theta_new) 
       (setq alist 		;change vertex xyz values
            (subst
               (cons 10 newvert)
               (assoc 10 alist)
               alist
            )
       )
       (entmod alist)
     );end progn
     (setq next (entnext next))   
     (setq alist (entget next))
   ); end while
);end do_pline()     

;*************************************
(prompt "\nMakepolar to execute")(princ)