Index: bloat.sh
===================================================================
--- bloat.sh	(revision 19442)
+++ bloat.sh	(revision 19443)
@@ -22,7 +22,7 @@
 }
 
 # offset-shift an edge using the neighbour edges
-function edge_shift(POLY, bloat, n0    ,x0,y0,xp,yp,x1,y1,xn,yn, dx,dy,l,nx,ny  ,ax,ay,al,a1l,a1x,a1y)
+function edge_shift(POLY, NX, NY, bloat, n0    ,x0,y0,xp,yp,x1,y1,xn,yn, dx,dy,l,nx,ny  ,ax,ay,al,a1l,a1x,a1y)
 {
 	x0 = POLY[n0, "x"]
 	y0 = POLY[n0, "y"]
@@ -33,14 +33,8 @@
 	xp = POLY[pwrap(POLY, n0-1), "x"]
 	yp = POLY[pwrap(POLY, n0-1), "y"]
 
-	# targe edge normal
-	dx = x1 - x0
-	dy = y1 - y0
-	l = sqrt(dx*dx + dy*dy)
-	dx /= l
-	dy /= l
-	nx = -dy
-	ny = dx
+	nx = NX[n0]
+	ny = NY[n0]
 
  # previous edge offset
 	ax = x0 - xp
@@ -77,13 +71,29 @@
 }
 
 # offset shift the target edge or all edges
-function poly_bloat(POLY, bloat,   n)
+function poly_bloat(POLY, bloat,   n,NX,NY,x0,y0,x1,y1,dx,dy,l)
 {
+	for(n = 0; n < POLY["len"]; n++) {
+		x0 = POLY[n, "x"]
+		y0 = POLY[n, "y"]
+		x1 = POLY[pwrap(POLY, n+1), "x"]
+		y1 = POLY[pwrap(POLY, n+1), "y"]
+
+		# targe edge normal
+		dx = x1 - x0
+		dy = y1 - y0
+		l = sqrt(dx*dx + dy*dy)
+		dx /= l
+		dy /= l
+		NX[n] = -dy
+		NY[n] = dx
+	}
+
 	if (target_edge == "")
 		for(n = 0; n < POLY["len"]; n++)
-			edge_shift(POLY, bloat, n)
+			edge_shift(POLY, NX, NY, bloat, n)
 	else
-			edge_shift(POLY, bloat, target_edge)
+			edge_shift(POLY, NX, NY, bloat, target_edge)
 }
 
 ### loader