From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 4 Nov 2017 22:00:45 +0000 (+0000)
Subject: Twirler; add extra_zeta
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=659f23b40638b4db9bd2a9a49b092c4c4e584a8a;p=moebius3.git

Twirler; add extra_zeta

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

diff --git a/moebius.py b/moebius.py
index 944ea9b..3b7ad46 100644
--- a/moebius.py
+++ b/moebius.py
@@ -42,8 +42,8 @@ class Twirler(ParametricCircle):
     tw._cycles = cycles
     tw._begin_zeta = begin_zeta
     tw._axis = np.cross(r0, r1)
-  def dirn(tw, theta):
-    zeta = tw._begin_zeta + theta * tw._cycles
+  def dirn(tw, theta, extra_zeta=0):
+    zeta = tw._begin_zeta + theta * tw._cycles + extra_zeta
     r = tw.radius(theta)
     return cos(zeta) * r + sin(zeta) * tw._axis