def check_all(points, lines):
crosses = []
for i in xrange(len(lines)):
s1 = points[lines[i,0]], points[lines[i,1]]
p11 = lines[i,0]
p12 = lines[i,1]
for j in xrange(i+1, len(lines)):
p21 = lines[j,0]
p22 = lines[j,1]
#print "segment 1:",p11, p12
#print "segment 2:",p21, p22
if (p11 == p21 and p12 == p22) or (p11 == p22 and p12 == p21): # they are the same two points:
#print "segments are the same"
crosses.append( (i, j) )
break # no need to check further
elif p11 == p21:
#print "first point matches first point"
break
elif p11 == p22:
#print "first point matches second point"
break
elif p12 == p21:
#print "second point matches first point"
break
elif p12 == p22:
#print "second point matches second point"
break
s2 = points[lines[j,0]], points[lines[j,1]]
if segment_cross(s1, s2):
crosses.append( (i,j) )
return crosses
def test_segment_cross_no():
S1 = ((0.0, 0.0), (10.0, 10.0))
for S2 in [ ((10.0, 0.0), (10.0, -10.0)),
((-1.0, 0.0), ( 0.0, -1.0)),
((11.0, 9.0), ( 9.0, -11.0)),
(( 5.0, 5.00000000000001), ( 0.0, 5.0)),
]:
assert not segment_cross(S1, S2)
def test_segment_cross_yes():
S1 = ( (0.0, 0.0), (10.0, 10.0) )
for S2 in [ ( (10.0, 0.0), ( 0.0, 10.0) ),
( ( 0.0, 0.0), ( 1.0, 0.0) ),
( (10.0, 10.0), (20.0, 10.0) ), # just touch the end
( (10.0, 10.0), (20.0, 10.0) ),
(( 5.0, 5.0), ( 0.0, 5.0)),
]:
print S1, S2
assert segment_cross(S1, S2)
