def checkLoS(self, points):
"""Determine line of sight between all points in the list by constructing a line segment for the two points
in question and comparing it for intersection with line segments in the BSP tree
:param points: a list of Point objects
:return: a list of lists, n by n, an entry at [i][j] tells wether point i and point j have line of sight with each other
"""
LoS = []
for point in points:
LoS.append(['X'] * len(points))
for FromIndex, FromPoint in enumerate(points):
for ToIndex, ToPoint in enumerate(points):
# if LoS is not determined
if (FromIndex != ToIndex) and (LoS[FromIndex][ToIndex] == 'X'):
# Assume there is LoS
LoS[FromIndex][ToIndex] = 'T'
LoS[ToIndex][FromIndex] = 'T'
SightSegment = LineSegment(
points[FromIndex], points[ToIndex])
# Point to root node
stack = [self.tree]
IsIntersection = False
# NumOfIntersections = 0
NumOfTraversals = 0
while len(stack) != 0 and IsIntersection == False:
TreePointer = stack.pop()
NumOfTraversals += 1
compareLoS = TreePointer.data[0].compare(SightSegment)
if compareLoS == 'P':
if SightSegment.split(TreePointer.data[0]) is not None:
LoS[FromIndex][ToIndex] = 'F'
LoS[ToIndex][FromIndex] = 'F'
else:
if TreePointer.left is not None:
stack.append(TreePointer.left)
if TreePointer.right is not None:
stack.append(TreePointer.right)
elif compareLoS == 'F':
if TreePointer.left is not None:
stack.append(TreePointer.left)
elif compareLoS == 'B':
if TreePointer.right is not None:
stack.append(TreePointer.right)
distance = points[FromIndex].getDistance(points[ToIndex])
if IsIntersection:
print(('Distance: %0.1f' % distance) +
', # of traversals(F): ' + str(NumOfTraversals))
else:
print(('Distance: %0.1f' % distance) +
', # of traversals(T): ' + str(NumOfTraversals))
return LoS
def generateRandomScene(
n,
width,
height,
MinLength=50,
MaxLength=300,
isUniform=True):
"""
Randomnly generates a list of non intersecting line segments
:param n: int, Number of line segments
:param width: int, our area width
:param height: int, our area height
:param MinLength: float, Minimum possible length of a line segment
:param MaxLength: float, Maximum possible length of a line segment
:param isUniform: boolean, whether the position of line segments should be generated with uniform distributed random number or with powerlaw distribution
:return: a list of line segments
"""
Lines = []
for i in range(n):
Done = False
while not Done:
P2x = -1
P2y = -1
c = 0
if isUniform:
P1x = int(round(np.random.uniform(0, width)))
P1y = int(round(np.random.uniform(0, height)))
Distance = np.random.uniform(MinLength, MaxLength)
while not 0 <= P2x <= width:
c = np.random.uniform(-1, 1)
P2x = P1x + int(round(c * Distance))
while not 0 <= P2y <= height:
P2y = P1y + \
int(round(sign(np.random.uniform(-1, 1)) * (1 - (abs(c))) * Distance))
else:
P1x = int(round(np.random.power(3.0) * width))
P1y = int(round(np.random.power(3.0) * height))
Distance = np.random.uniform(MinLength, MaxLength)
while not 0 <= P2x <= width:
c = np.random.uniform(-1, 1)
P2x = P1x + int(round(c * Distance))
while not 0 <= P2y <= height:
P2y = P1y + \
int(round(sign(np.random.uniform(-1, 1)) * (1 - (abs(c))) * Distance))
r = round(generateRandom(1, 1))
if r == 0:
r = -1
NewLine = LineSegment(Point(P1x, P1y), Point(P2x, P2y), r)
IsIntersection = False
for line in Lines:
if NewLine.split(line) is not None:
IsIntersection = True
break
if not IsIntersection:
Lines.append(NewLine)
Done = True
return Lines