pylint of drape.py

 Addresses BruceSherwood#76

site-packages/visual/examples/drape.py

@@ -1,94 +1,100 @@
-from visual import *
-
-print("""
+#!/usr/bin/env python
+#coding:utf-8
+""" Drape Demo
 Click to place spheres under falling string.
 Right button drag or Ctrl-drag to rotate view.
 Middle button drag or Alt-drag to zoom in or out.
   On a two-button mouse, middle is left + right.
-""")
+"""
+from __future__ import print_function, division
+#from visual import *
+import visual as vp
+
+print(__doc__)
 
 # David Scherer
 
-scene.title = "Drape"
-restlength = 0.02
-m = 0.010 * restlength
-g = 9.8
-dt = 0.002
-k = 3
-damp = (1-0)**dt
-nspheres = 3
-floor = 0
+vp.scene.title = "Drape"
+RESTLENGTH = 0.02
+M = 0.010 * RESTLENGTH
+G = 9.8
+DT = 0.002
+K = 3
+DAMP = (1-0)**DT
+NSPHERES = 3
+FLOOR = 0
 
 # Create the stringy thing:
-band = curve( x = arange(-1,1,restlength), 
-              y = 1,
-              radius = 0.02
-            )
+BAND = vp.curve(
+    x=vp.arange(-1, 1, RESTLENGTH),
+    y=1,
+    radius=0.02
+)
 
-band.p = band.pos * 0
+BAND.p = BAND.pos * 0
 
-scene.range = 1.5
-scene.autoscale = 0
+vp.scene.range = 1.5
+vp.scene.autoscale = 0
 
 # Let the user position obstacles:
-spheres = []
-for i in range(nspheres):   
-    s = sphere( pos = scene.mouse.getclick().pos,  #(i*0.6 - 0.7,0.5 + i*0.1,0),
-                radius = 0.25, 
-                color = (abs(sin(i)),cos(i)**2,(i%10)/10.0) )
-    spheres.append( s )
+SPHERES = []
+for i in range(NSPHERES):
+    S = vp.sphere(pos=vp.scene.mouse.getclick().pos, #(i*0.6 - 0.7, 0.5 + i*0.1, 0),
+                  radius=0.25,
+                  color=(abs(vp.sin(i)), vp.cos(i)**2, (i%10)/10.0))
+    SPHERES.append(S)
 
 while True:
-  rate(1.0 / dt)
+    vp.rate(1.0 / DT)
 
-  if scene.mouse.clicked:
-    i = len(spheres)
-    s = sphere( pos = scene.mouse.getclick().pos,
-                radius = 0.25, 
-                color = (abs(sin(i)),cos(i)**2,(i%10)/10.0) )
-    spheres.append( s )
+    if vp.scene.mouse.clicked:
+        i = len(SPHERES)
+        S = vp.sphere(pos=vp.scene.mouse.getclick().pos,
+                      radius=0.25,
+                      color=(abs(vp.sin(i)), vp.cos(i)**2, (i%10)/10.0))
+        SPHERES.append(S)
 
-  if floor:
-    below = less(band.pos[:,1],-1)
-    band.p[:,1] = where( below, 0, band.p[:,1] )
-    band.pos[:,1] = where( below, -1, band.pos[:,1] )
+    if FLOOR:
+        BELOW = vp.less(BAND.pos[:, 1], -1)
+        BAND.p[:, 1] = vp.where(BELOW, 0, BAND.p[:, 1])
+        BAND.pos[:, 1] = vp.where(BELOW, -1, BAND.pos[:, 1])
 
-  # need a more physical way to make 'damped springs' than this!
-  band.p = band.p * damp
+    # need a more physical way to make 'damped springs' than this!
+    BAND.p = BAND.p * DAMP
 
-  #band.p[0] = 0   # nail down left endpoint
-  #band.p[-1] = 0  # nail down right endpoint
+    #band.p[0] = 0   # nail down left endpoint
+    #band.p[-1] = 0  # nail down right endpoint
 
-  band.pos = band.pos + band.p/m*dt
+    BAND.pos = BAND.pos + BAND.p/M*DT
 
-  #gravity
-  band.p[:,1] = band.p[:,1] - m * g * dt
+    #gravity
+    BAND.p[:, 1] = BAND.p[:, 1] - M * G * DT
 
-  # force[n] is the force on point n from point n+1 (to the right):
-  length = (band.pos[1:] - band.pos[:-1])
-  dist = sqrt(sum(length*length,-1))
-  force = k * ( dist - restlength )
-  force = length/dist[:,newaxis] * force[:,newaxis]
+    # force[n] is the force on point n from point n+1 (to the right):
+    LENGTH = (BAND.pos[1:] - BAND.pos[:-1])
+    DIST = vp.sqrt(vp.sum(LENGTH*LENGTH, -1))
+    FORCE = K * (DIST - RESTLENGTH)
+    FORCE = LENGTH/DIST[:, vp.newaxis] * FORCE[:, vp.newaxis]
 
-  band.p[:-1] = band.p[:-1] + force*dt
-  band.p[1:] = band.p[1:] - force*dt
+    BAND.p[:-1] = BAND.p[:-1] + FORCE*DT
+    BAND.p[1:] = BAND.p[1:] - FORCE*DT
 
-  # color based on "stretch":  blue -> white -> red
-  c = clip( dist/restlength * 0.5, 0, 2 )
+    # color based on "stretch":  blue -> white -> red
+    C = vp.clip(DIST/RESTLENGTH * 0.5, 0, 2)
 
-  #   blue (compressed) -> white (relaxed) -> red (tension)
-  band.red[1:] = where( less(c,1), c, 1 )
-  band.green[1:] = where( less(c,1), c, 2-c )
-  band.blue[1:] = where( less(c,1), 1, 2-c )
+    #   blue (compressed) -> white (relaxed) -> red (tension)
+    BAND.red[1:] = vp.where(vp.less(C, 1), C, 1)
+    BAND.green[1:] = vp.where(vp.less(C, 1), C, 2-C)
+    BAND.blue[1:] = vp.where(vp.less(C, 1), 1, 2-C)
 
-  for s in spheres:
-    dist = mag( band.pos - s.pos )[:,newaxis]
-    inside = less( dist, s.radius )
-    if sometrue(inside):
-        R = ( band.pos - s.pos ) / dist
-        surface = s.pos + (s.radius)*R
+    for S in SPHERES:
+        DIST = vp.mag(BAND.pos - S.pos)[:, vp.newaxis]
+        inside = vp.less(DIST, S.radius)
+        if vp.sometrue(inside):
+            R = (BAND.pos - S.pos) / DIST
+            surface = S.pos + (S.radius)*R
 
-        band.pos = surface*inside + band.pos*(1-inside)
+            BAND.pos = surface*inside + BAND.pos*(1-inside)
 
-        pdotR = sum(asarray(band.p)*asarray(R),-1)
-        band.p = band.p - R*pdotR[:,newaxis]*inside
+            pdotR = vp.sum(vp.asarray(BAND.p)*vp.asarray(R), -1)
+            BAND.p = BAND.p - R*pdotR[:, vp.newaxis]*inside