node.obstacle module¶

Module obstacle contains a obstacle class to encapsulate a list of polygons describing static obstacle on the simulation area or map. It also provide useful methods to test whether a line crosses any obstacle, and number of obstacles crossed if required.

Note

Although the coordinates of obstacles can be float or integer type, it is strongly recommended to use integer for speed consideration.
Implementing this class in Python isn’t efficient, suggest using shapely package or use Cython to compile _LSI functions into C language.

Note

Created by: CH Foh (2022)

class node.obstacle.Obstacle¶

Bases: object

This class provides storage to keep polygons as obstacles and useful methods if check if a line has crossed any obstacle, and how many.

Methods

`add_poly`(polygon)	This method adds a polygon as an obstacle.
`add_rect`(x, y, w, h)	This method adds a rectangle as an obstacle.
`get_list`()	This method returns a list containing all obstacle polygons.
`is_crossed`(point1, point2)	This method tests whether the given line crosses any obstacle.
`num_crossed`(point1, point2)	This method counts the number of obstacles that the given line has crossed.
`remove`(polygon)	This method removes an obstacle from the existing list.

__init__()¶: Initialize self. See help(type(self)) for accurate signature.

get_list()¶

This method returns a list containing all obstacle polygons.

Returns

List: The list of all obstacle polygons.

add_poly(polygon)¶

This method adds a polygon as an obstacle.

Parameters

polygonlist of a pair of float or int (be consistent) as (x,y): The vertices of the polygon describing the obstacle.

add_rect(x, y, w, h)¶

This method adds a rectangle as an obstacle.

Parameters

xint: The left coordinate of the obstacle.
yint: The top coordinate of the obstacle.
wint: The width of the obstacle.
hint: The heightof the obstacle.

remove(polygon)¶

This method removes an obstacle from the existing list.

Parameters

polygonlist of float or int (be consistent): The polygon to be removed. For this method to be effective, the exact same polygon object must have been added into the list earlier.

is_crossed(point1, point2) → bool¶

This method tests whether the given line crosses any obstacle. It does not tell how many obstacles the line crosses.

Note

This isn’t an efficient implementation, suggest using shapely package or compile this class into C language using Cython.

Parameters

point1float or int: One end of the line.
point2float or int: Another end of the line.

Returns

bool: It returns whether the given line specified by point1 and point2 has crossed any obstacle.

num_crossed(point1, point2) → int¶

This method counts the number of obstacles that the given line has crossed. To test whether a line has crossed any obstacle, use is_crossed() method instead for efficiency.

Parameters

point1float or int: One end of the line.
point2float or int: Another end of the line.

Returns

int: The number of obstacles that the given line has crossed.