; poly_frame - perimeter cut of a regular polygon.
; apothem = flat-to-flat distance / 2 (center to midpoint of edge).
; rotation in degrees: 0 places first vertex on +X axis, CCW positive.
; Requires globals: #<_z_top>, #<_z_bot>
; Requires tool loaded (uses #5410 for diameter)
; Optional global:  #<_z_clearance>
o<poly_frame> sub
	; o<poly_frame> call [mode] [x][y] [n_sides] [apothem] [rotation] [fincut]
	; #1=mode #2=x #3=y #4=n_sides #5=apothem #6=rotation #7=fincut

	#<M_CONVENTIONAL> = [FIX[#1/1] MOD 2 EQ 1]
	#<M_OUTSIDE>      = [FIX[#1/8] MOD 2 EQ 1]
	#<M_CLIMB>        = [FIX[#1/1] MOD 2 EQ 0]
	#<M_INSIDE>       = [FIX[#1/8] MOD 2 EQ 0]

	G90
	G90.1
	M101
	G17

	#<td> = #5410
	#<tr> = [#<td>/2]
	o1 if [EXISTS[#<_z_clearance>]]
		#<z_clearance> = #<_z_clearance>
	o1 else
		#<z_clearance> = #<_z_top>
	o1 endif

	o10 if [#<M_INSIDE>]
		#<effective_apothem> = [#5 - #<tr> - #7]
	o10 else
		#<effective_apothem> = [#5 + #<tr> + #7]
	o10 endif

	#<R> = [#<effective_apothem> / COS[180/#4]]
	#<step_angle> = [360/#4]

	o11 if [[#<M_INSIDE> AND #<M_CLIMB>] OR [#<M_OUTSIDE> AND #<M_CONVENTIONAL>]]
		#<dir> = 1
	o11 else
		#<dir> = -1
	o11 endif

	G0 Z#<z_clearance>

	#<x0> = [#2 + #<R>*COS[#6]]
	#<y0> = [#3 + #<R>*SIN[#6]]
	G0 X#<x0> Y#<y0>
	G0 Z#<_z_top>
	G1 Z#<_z_bot>

	#<i> = 1
	o20 while [#<i> LE #4]
		#<ang> = [#6 + #<dir>*#<i>*#<step_angle>]
		G1 X[#2 + #<R>*COS[#<ang>]] Y[#3 + #<R>*SIN[#<ang>]]
		#<i> = [#<i> + 1]
	o20 endwhile

	G0 Z#<z_clearance>

o<poly_frame> endsub

M2