def next(self):
frame_info, posicions = self.frames.next()
walls = posicions[self.sys_info.phys_size:]
ywalls = [y for x,y in walls]
ymax, ymin = max(ywalls), min(ywalls)
toTriangulate = [(x,y) for x,y in posicions if ymin < y < ymax]
trian = Triangulation(toTriangulate)
dislos = trian.dislocations()
dislos = [dislocate(f,s) for f,s in dislos if
f not in walls and
s not in walls]
return frame_info, dislos, toTriangulate[:self.sys_info.phys_size], \
walls
