mesh: introduce calc_sigmas (nfc)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/meshscad b/meshscad
index d56754498ac53bfb97f2276060177241c932ebf9..7e109f01aaf683816f38eda1c6ff23c7ae9f3d2c 100755 (executable)
--- a/meshscad
+++ b/meshscad
@@ -36,6 +36,9 @@ def points_round_wire(p, norm, acrs, sigmas):
     r = p + wire/nomsize * delta
     yield r
 
+def calc_sigmas(ss):
+  return [ (s + 0.5)/ns * tau for s in ss ]
+
 def make_moebius(objname):
   print('module %s(){' % objname)
   # wires:
@@ -63,7 +66,7 @@ def make_moebius(objname):
   for v in range(0, nv):
     for w in range(0, nw+1):
       for s in range(0, ns):
-        sigmas = [ (s + sx + 0.5)/ns * tau for sx in 0,1 ]
+        sigmas = calc_sigmas([s + sx for sx in (0,1)])
         #print('VWS',v,w,s, sigmas, file=sys.stderr)
         if not w % each_w:
           extents[w % nw].quad([ cnr for cnr in qc(v,w,sigmas,False) ])