;Cycloid First cut    2-7-98
;;cycloid1.lsp
(defun C:cycloid()			;Main routine
	(setup_cycloid)				;set up 
	(setq counter 0)
	;(alert "\nTo start, hit reutrn key and move cursor horizontally.")
	(while (setq pnt_tmp (cadr (grread T)) )	;continuous mouse tracking
		(get_value)
		(if (>= counter 1) (clear_lines))			
		(command "_.insert" "cycle" pnt_center 1.0 1.0 angle_tmp)
		(command "explode" (entlast))
		(setq counter (1+ counter))
	)
	(setvar "blipmode" sblip)
	(setvar "cmdecho" scmde)
)
;;;
;;;	Cycloid_curve
;;;
(defun c:cycloid_curve()
	(setup_cycloid_curve)				;set up 
	(make_jpg)
	(make_jpg)
	(make_jpg)
	(setq theta_0 0
		theta_end (* 2 pi)
		ndiv 150
		del_theta (/ (- theta_end theta_0) ndiv)
		pnt_old '(0 0)
		count 0
	)
	(repeat (1+ ndiv)
		(entdel old_circle)
		(setq theta (+ theta_0 (* count del_theta))
			x (- theta (sin theta))
			y (- 1 (cos theta))
			pnt_new (list x y)
			pnt_center (list theta 1)
			pnt_across (plt pnt_new pnt_center 2.0)
		)
		(make_circle_1 "0" 8 pnt_center radius)
			(setq old_circle (entlast))
		(make_pt "layer1" 1 pnt_new)
		(make_line_1 "layer2" 2 pnt_old pnt_new)
		(make_line_1 "layer3" 3 pnt_center pnt_new)
		;(make_line_1 "layer3" 3 pnt_new pnt_across)
		(setq count (1+ count)
			pnt_old pnt_new
		)
		(make_jpg)
		(command "_.delay" 150)	
	)
	(make_pt "0" 0 pnt_center)

	(make_jpg)
	(make_jpg)
	(make_jpg)
	(make_jpg)
	(reset_sysvar)
)
;;;
;;;
(defun c:cycloid_area()
	(setup_cycloid_curve)				;set up 
	(make_jpg)
	(make_jpg)
	(make_jpg)
	(setq theta_0 0
		theta_end (* 2 pi)
		ndiv 150
		del_theta (/ (- theta_end theta_0) ndiv)
		pnt_old '(0 0)
		pnt_base_old '(0 0)
		area_sum 0
		count 0
	)
	(repeat (1+ ndiv)
		(entdel old_circle)
		(setq theta (+ theta_0 (* count del_theta))
			x (- theta (sin theta))
			y (- 1 (cos theta))
			pnt_new (list x y)
			pnt_center (list theta 1)
			pnt_across (plt pnt_new pnt_center 2.0)
			pnt_base_new (list x 0)
			del_h (distance pnt_base_new pnt_base_old)
			area_sum (+ area_sum (* del_h y))
		)
		(make_circle_1 "0" 8 pnt_center radius)
			(setq old_circle (entlast))
		(make_pt "layer1" 1 pnt_new)
		;(make_line_1 "layer2" 2 pnt_old pnt_new)
		(make_line_1 "layer3" 3 pnt_base_new pnt_new)
		;(make_line_1 "layer3" 3 pnt_new pnt_across)
		(setq count (1+ count)
			pnt_old pnt_new
			pnt_base_old pnt_base_new
		)
		(make_jpg)
		(command "_.delay" 150)	
	)
	(make_pt "0" 0 pnt_center)

	(make_jpg)
	(make_jpg)
	(make_jpg)
	(make_jpg)
	(reset_sysvar)
	(setq result (/ area_sum 3.))
)
;;;
;compute translation & angle values from pnt_tmp
(defun get_value()
	(setq x_tmp (car pnt_tmp))
	(setq angle_tmp (- (rtd x_tmp)))
	(setq pnt_center (list x_tmp 0))
)
;clear construction lines
(defun clear_lines( )
	(setq block_set (ssget "X" (list (cons -4 "<OR")(cons 8 "layer1")(cons 8 "layer8")
					  (cons -4 "OR>")) ))
	(setq n (sslength block_set))
	(setq nminus (- n 3))
	;repeat for all circle  & line elements
	(setq index 0)
	(repeat nminus       
            (entdel (ssname block_set index)) 
	    (setq index (1+ index))
	)
)	
;
;setup_cycloid
(defun setup_cycloid()
	(setq sblip (getvar "blipmode"))
	(setq scmde (getvar "cmdecho"))
	(setvar "blipmode" 0)
	(setvar "cmdecho" 0)
	;(set_layer)
	(setvar "PDMODE" 32)
	(setvar "PDSIZE" 0.15)
	
	(setq pnt_init '(0 0)
 	      radius 1 )
	      	     
	(command "_.line" '(-10 -1) '(10 -1) "" )
	;layer 8
	(make_circle_1 "layer8" 8 pnt_init radius)
	(make_pt "layer8" 8 pnt_init)
	
	;layer 5
	(make_pt "layer5" 5 '(0 1))
	(make_pt "layer3" 3 '(0 0.5))
	(make_pt "layer2" 2 '(0 1.45))
	
	;layer 1
	(make_line_1 "layer1" 1 pnt_init '(0 1))
		
	(command "_.layer" "_set" "0" "")

	(command "_.zoom" "_EXTENT")
	(command "_.regen")
	(setq pnt_uprr '( 1.5  1.5)
	      pnt_lowl '(-1.5 -0.5))
	(setq set_1 (ssget "C" pnt_uprr pnt_lowl ))	;select entity set for block
	(alert "\nHit return ley to start. Move mouse slowly along X-axis")
	(command "_.block" "cycle" pnt_init set_1 pause)	;block definition
)
;;;
;setup_cycloid_curve
(defun setup_cycloid_curve()
	(setup_sysvar)
	(setvar "PDMODE" 32)
	(setvar "PDSIZE" 0.05)
	
	(setq pnt_init '(0 1)
		pnt_org '(0 0)
		pnt_x '(7.2 0)
		pnt_y '(0 2.25)
		pnt_left '(-1.1 0)
		chr_size 0.2
 	      radius 1 
		lower_left  '(-1.3 -0.4)
		upper_right '(7.5  2.75)
	)
	      	     
	(make_line_1 "0" 8 pnt_org pnt_y)
	(make_line_1 "0" 8 pnt_left pnt_x)
	(mark_id pnt_x "X" 1 chr_size) 
	(mark_id pnt_y "Y" 1 chr_size) 
	(mark_id pnt_org "O" 4 chr_size) 
	;layer 8
	(make_circle_1 "layer8" 8 pnt_init radius)
	(make_circle_1 "layer8" 8 pnt_init radius)
		(setq old_circle (entlast))
	(make_pt "0" 0 pnt_init)
	
	;	(command "_.zoom" "_W" lower_left upper_right)
	(command "_.zoom" "_E")
	(command "_.regen")
	
)