; Change list:
; Toggle extrusion while keeping smooth movement
; Modify to se x0 and xf to arbitrary functions of step or another parameter

G21 (mm)
G90 (Absolute distance mode)
G55 (Machine Plane Coordinates) 
G64 (Turn off exact stop check)
M5 (Stop the spindle if it's left on)

; Variables for controlling the model

; #<_speed> = 1100 (450)(300)
#<_speed> = 1100 (450)(300)
#<_mss> = 1  (1.28) (Margin Speed Scalar: the return speed on the margin)

#<_ccws> = 0.0006 ;extrude: extruder motor counter clockwise from top (0.005 to 0.007) 
#<_cws> = 0.005 (extruder back up, used before inter-layer pauses)

#<_corners> = 0 (1 extrude on corners, 0 no extrude on corners)
#<_margin> = 8
#<_lo> = 2 ; loop offset, used to prevent errors from turn-arounds at row ends	

#<_pause> = .0001 (wait time, used at corners)

;work dimensions
#<_l> = 36 (mm length)
#<_width> = 36 (mm width)
#<_delta> = .75 (mm inter-row&column spacing)
#<_layerH> = .08 (mm layer height)

;coordinates
; #<_z0> = 2  (Initial Height of Needle Tip) (5)
; #<_z0> = 1  (Initial Height of Needle Tip) (5)

#<_zz> = 2

#<_x0> = 0 (initial x)
#<_xx> = #<_x0> (x)

#<_y0> = 0 (initial y)
#<_yy> = #<_y0> (y) 

;counters
#<_zstep> = 0
#<_step> = 0

;counter maximums
#<_layers> = 20

#<_ystepf> = FIX[#<_l>/#<_delta>](_____-[#<_l> MOD #<_delta>]/#<_delta>])
#<_xstepf> = FIX[#<_width>/#<_delta>]([_____-[#<_width> MOD #<_delta>]/#<_delta>])

;#<_yy> = [#<_yy> + #<_l> + 20]     ;position purge routine (y)
#<_xx> = [#<_xx> - #<_width>+7] ;position purge routine (x)
G0 X[#<_xx>] Y[#<_yy>] Z10         ;position purge routine

M3 S0.005                            ;literal purge
o100 while [#<_step> LE 0]         ;'timer' for purge
	;#<_yy> = [#<_yy> + #<_delta>] (shows iterations for debugging)
	#<_xx> = [#<_xx> + 0.25*#<_width>*[2*[#<_step> MOD 2]-1]]    ;remind linuxcnc how to dance
	G1 X[#<_xx>] F#<_speed>                                     ;travel (the real time filler)
	#<_step>=[#<_step> + 1]                                     ;linuxcnc doesn't like infinity...
o100 endwhile

M4 S0.05                            ;back up extruder to relieve excess pressure 
o101 while [#<_step> LE 0]         ;'timer' for purge
	;#<_yy> = [#<_yy> + #<_delta>] (shows iterations for debugging)
	#<_xx> = [#<_xx> + 0.25*#<_width>*[2*[#<_step> MOD 2]-1]]    ;remind linuxcnc how to dance
	G1 X[#<_xx>] F#<_speed>                                     ;travel (the real time filler)
	#<_step>=[#<_step> + 1]                                     ;linuxcnc doesn't like infinity...
o101 endwhile
M3

S#<_ccws>       ;slow down the extruder and allow the pressure to equilibrate
o105 while [#<_step> LE 35]
	;G1 X[#<_xx> - #<_margin>*[2*[#<_step> MOD 2]-1]] F#<_speed> ;margin code (equilibration)
	;G0 Y[#<_yy>] F#<_speed>                                     ;margin code (equilibration)
	;G1 X[#<_xx>] F#<_speed>                                     ;margin code (equilibration)
	;#<_yy> = [#<_yy> + #<_delta>] (shows iterations for debugging)
	#<_xx> = [#<_xx> + 0.5*#<_width>*[2*[#<_step> MOD 2]-1]]
	G1 X[#<_xx>] F#<_speed>
	#<_step>=[#<_step> + 1]
o105 endwhile
#<_xx> = #<_x0> ;reset variables assumed to have previously stated initial values
#<_yy> = #<_y0> ;reset variables assumed to have previously stated initial values
#<_step> = 0    ;reset variables assumed to have previously stated initial values
M5

G1 X[#<_xx>] Y[#<_yy>] Z[#<_zz>] F#<_speed>
M3 S#<_ccws>
o110 while [#<_zstep> LE FIX[[#<_layers> - 1]/2]] (4)
		
	;G1 Y[#<_yy> + #<_margin>+5] F#<_speed>
	;G1 X[#<_x0> - #<_margin>-5] F#<_speed>

	;G1 Y[#<_y0>]  F#<_speed>
	#<_xx> = [#<_l> + #<_margin>*0.5]
	#<_yy> = [#<_y0> + [[0.5*#<_delta>]*[#<_zstep> MOD 2]]] ; causes layers to stager
	
	o115 while[#<_step> LE [[#<_ystepf>/2]-1]]
		#<_step> = [#<_step> + 1]
		o120 if [#<_corners> EQ 0]
			(M5) (Causes stop in spite of G64 will need something else.)
		o120 endif
		;G4 P#<_pause>		
		G1 X[[#<_xx> - #<_width> - [#<_margin>]]] F#<_speed>
		#<_yy> = [#<_yy>+[0.5*#<_l>]]
		
		G4 P[#<_pause>]
		;margin
		G0 Y[#<_yy>] X[[#<_xx> - #<_width> - [#<_margin>]*1.5]] F[#<_speed> * #<_mss>]
		G4 P#<_pause>
		
		G1 X[#<_xx> ] F#<_speed>
		#<_yy> = [#<_yy>-[[0.5*#<_l>]-#<_delta>]]
		
		G4 P#<_pause>
		;margin
		G0 Y[#<_yy>] X[#<_xx> + [#<_margin>/2]] F[#<_speed>*#<_mss>]
		G4 P#<_pause>
	o115 endwhile	

	#<_zz> = [#<_zz>+#<_layerH>]
	G0 Z[#<_zz>]
	;#<_step> = 0
	#<_xx> = #<_x0>
	#<_xx> = [#<_x0> + [[0.5*#<_delta>]*[#<_zstep> MOD 2]]] ; causes layers to stager
	#<_yy> = [#<_y0> - #<_margin>]	
	
;These three lines may turn out to be important	
	;G1 X[#<_x0> - #<_margin>-5] Y[#<_yy> + #<_margin>+5] F#<_speed>
	;G1 X[#<_x0> - #<_margin>-5] Y[#<_yy> + #<_margin>+5] F#<_speed>
	;G1 Y[#<_y0>] F#<_speed>

	#<_step> = 0

	o125 while[#<_step> LE [[#<_xstepf>/2]-1]]
		#<_step> = [#<_step> + 1]
		o130 if [#<_corners> EQ 0]
			(M5)  (Causes stop in spite of G64)
		o130 endif
		;G4 P#<_pause>		
		G1 Y[[#<_yy> + #<_l> +[#<_margin>*1.5]]] F#<_speed>
		#<_xx> = [#<_xx>+[0.5*#<_width>]]
		
		G4 P[#<_pause>/2]
		;margin		
		G0 X[#<_xx>] Y[[#<_yy> + #<_l> + [2*#<_margin>]]] F[#<_speed>*#<_mss>]

		;G4 P#<_pause>		
		G1 Y[#<_yy> + [#<_margin>/2]] F#<_speed>
		
		#<_xx> = [#<_xx>-[[0.5*#<_width>]-#<_delta>]]
		
		G4 P#<_pause>
		;margin		
		G0 X[#<_xx>] Y[#<_yy>] F[#<_speed>*#<_mss>]
		
	o125 endwhile
		
	#<_zz> = [#<_zz>+#<_layerH>]
	G0 Z[#<_zz>]
	#<_step> = 0
	
	(z++)

#<_zstep> = [#<_zstep> + 1]	
o110 endwhile	
G0 X-20 Y-20 Z 20
M5

M30