bugfixes

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

diff --git a/check.py b/check.py
index 9d903f7b41d08ea8b935df1927750c5b7ee52c64..21c33d1643cc956866633b75d5fbefb51cd93358 100644 (file)
--- a/check.py
+++ b/check.py
@@ -1,12 +1,13 @@
 from visual import *
 from bezier import BezierSegment
+from moebius import Moebius
+import numpy as np
 
-b = BezierSegment([ [0,0,3],
-                    [0,1,4],
-                    [1,1,5],
-                    [1,0,6],
-                    ])
+n_u = 10
+
+m = Moebius(10)
 
 ts = arange(0, 1, 0.1)
 
-curve( pos = [ b.point_at_t(t) for t in ts ] )
+for ix_u in range(0, n_u+1):
+  curve( pos = [ m.point(ix_u, t) for t in ts ] )

diff --git a/moebius.py b/moebius.py
index 38e3cb8d9e7d3c75f04c4f140004915f54e42dc9..7240248e82684d517944de2d3bbc375d6ffd4e16 100644 (file)
--- a/moebius.py
+++ b/moebius.py
@@ -1,14 +1,17 @@
 
 import numpy as np
+from numpy import cos, sin
+
+from bezier import BezierSegment
 
 tau = np.pi * 2
 
-origin =  (0,0,0)
-unit_x = (1,0,0)
-unit_y = (0,1,0)
-unit_z = (0,0,1)
+origin = np.array((0,0,0))
+unit_x = np.array((1,0,0))
+unit_y = np.array((0,1,0))
+unit_z = np.array((0,0,1))
 
-def ParametricCircle:
+class ParametricCircle:
   def __init__(pc, c, r0, r1):
     ''' circle centred on c
         with theta=0 point at c+r0
@@ -21,7 +24,7 @@ def ParametricCircle:
   def point(pc, theta):
     return pc._c + pc.radius(theta)
 
-def Twirler(ParametricCircle):
+class Twirler(ParametricCircle):
   def __init__(tw, c, r0, r1, cycles, begin_zeta):
     ''' circle centred on c, etc.
         but with an orientation at each point, orthogonal to
@@ -37,20 +40,21 @@ def Twirler(ParametricCircle):
     tw._axis = np.cross(r0, r1)
   def dirn(tw, theta):
     zeta = tw._begin_zeta + theta * tw._cycles
-    r = radius(tw, theta)
-    return cos(zeta) * r + sin(zeta) * pc._axis
+    r = tw.radius(theta)
+    return cos(zeta) * r + sin(zeta) * tw._axis
 
 class Moebius:
-  def __init__(m, n_u):
-    m._edge    = Twirler(origin,  unit_z, unit_x, 2, 0)
-    m._midline = Twirler(-unit_z, unit_z, unit_y, 1, 0)
-    m._beziers = [ self._bezier(u) for u in np.linspace(0, 1, n_u) ]
-  def _bezier(u):
+  def __init__(m, n_u): # ix_u will be in [0, n_u>
+    m.edge    = Twirler(origin,  unit_z, unit_x, 2, 0)
+    m.midline = Twirler(-unit_z, unit_z, unit_y, 1, 0)
+    m._beziers = [ m._bezier(u) for u in np.linspace(0, 1, n_u) ]
+  def _bezier(m,u):
     theta = u * tau
     cp = [None] * 4
-    cp[0] =               m._edge   .point(theta)
-    cp[1] = cp[0] + 0.5 * m._edge   .dirn (theta)
-    cp[3] =               m._midline.point(theta*2)
-    cp[2] = cp[3] + 0.5 * m._midline.dirn (theta*2)
-    return BezierSegmentcp)
-    
+    cp[0] =               m.edge   .point(theta)
+    cp[1] = cp[0] + 0.5 * m.edge   .dirn (theta)
+    cp[3] =               m.midline.point(theta*2)
+    cp[2] = cp[3] + 0.5 * m.midline.dirn (theta*2)
+    return BezierSegment(cp)
+  def point(m, ix_u, t):
+    return m._beziers[ix_u].point_at_t(t)