def CalculateAverageGraphEdgeLength(graph):
"""
Determines the average length of the edges in a navGraph (using the
distance between the source & target node positions (not the cost of the
edge as represented in the graph, which may account for all sorts of
other factors such as terrain type, gradients etc)
:param graph:
:return:
"""
totalLength = 0
numberOfEdgesCounted = 0
for node in graph.Nodes:
if node.Index != -1:
for edge in graph.GetNodeEdges(node.Index):
# Increment edge counter
numberOfEdgesCounted += 1
# Add length of edge to total length
totalLength += Vector2D.Vec2DDistance(
graph.GetNode(edge.From).Position,
graph.GetNode(edge.To).Position)
return totalLength / numberOfEdgesCounted
def WeightNavGraphNodeEdges(graph, nodeIndex, weight):
"""
Given a cost value and an index to a valid node this function examines
all a node's edges, calculates their length, and multiplies the value
with the weight. Useful for setting terrain costs.
:param graph:
:param nodeIndex:
:param weight:
:return:
"""
# Make sure the node is present
if nodeIndex > graph.NumberOfNodes():
raise Exception("Invalid node index")
# Set the cost for each edge
for edge in graph.GetNodeEdges(nodeIndex):
# Calculate the distance between nodes
distance = Vector2D.Vec2DDistance(
graph.GetNode(edge.From).Position,
graph.GetNode(edge.To).Position)
# Set the cost of this edge
graph.SetEdgeCost(edge.From, edge.To, distance * weight)
# If not a digraph, set the cost of the parallel edge to be the same
if not graph.IsDigraph:
graph.SetEdgeCost(edge.To, edge.From, distance * weight)
def Calculate(graph, nodeIndex1, nodeIndex2):
"""
Calculate the straight line distance from node nodeIndex1 to node nodeIndex2
:param graph:
:param nodeIndex1:
:param nodeIndex2:
:return:
"""
return Vector2D.Vec2DDistance(
graph.GetNode(nodeIndex1).Position,
graph.GetNode(nodeIndex2).Position) * uniform(0.9, 1.1)
def test_SpecifyThatTheDistanceBetweenTwoVectorsCanBeCalculatedUsingAStaticMethod(
self):
v1 = Vector2D(1, 0)
v2 = Vector2D(1, 3)
self.assertAlmostEqual(3.0, Vector2D.Vec2DDistance(v1, v2), places=3)
