nojhan/ubergeekism
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

bugfix convex hull: the hull can contains straight tangents

Browse source
This commit is contained in:
Johann Dreo 2014-04-07 15:09:35 +02:00
commit 4504f89d30
1 changed files with 11 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

17
hull.py
View file

@ -98,21 +98,26 @@ def right_tangent(hull, p):
return icenter return icenter
# If the tangent touches the left point in the window. # If the tangent touches the left point in the window.
elif ( c_side == TURN_LEFT and ( l_next == TURN_RIGHT or l_prev == l_next) ) \ elif c_side == TURN_LEFT and ( l_next == TURN_RIGHT or l_prev == l_next ) \
or ( c_side == TURN_RIGHT and c_prev == TURN_RIGHT ): or c_side == TURN_RIGHT and c_prev == TURN_RIGHT:
# Do not consider points at the RIGHT of the center. # Do not consider points at the RIGHT of the center.
iright = icenter iright = icenter
# If the tangent touches the right point in the window. # If the tangent touches the right point in the window,
else: # but this is not the last possible tangent.
elif icenter+1 < iright:
# Do not consider points at the LEFT of the center. # Do not consider points at the LEFT of the center.
ileft = icenter + 1 ileft = icenter+1
# Switch sides: if the turn toward the point before the center # Switch sides: if the turn toward the point before the center
# was to the right, search to the left and conversely. # was to the right, search to the left and conversely.
l_prev = -1 * c_next l_prev = -1 * c_next
# Update the turn to the next left point. # Update the turn to the next left point.
l_next = turn( p, hull[ileft], hull[ at(ileft+1) ] ) l_next = turn( p, hull[ileft], hull[ at(ileft+1) ] )
# There is no more possible tangent, the hull contains a straight segment.
else:
return ileft
return ileft return ileft
@ -177,7 +182,7 @@ def convex_hull(points):
LOG( "Guess",guess) LOG( "Guess",guess)
hulls = [] hulls = []
for i in range(0, len(points), guess): for i in range(0, len(points), guess):
LOG(".") # LOG(".")
# Split the points into chunks of (roughly) the guess. # Split the points into chunks of (roughly) the guess.
chunk = points[i:i + guess] chunk = points[i:i + guess]
# Find the corresponding convex hull of these chunks. # Find the corresponding convex hull of these chunks.