dijkstra-map

Python implementation to create a Dijkstra map (distance map)

Usage

Just import the flood function from the flood module. To use it the first parameter is an input 2D array that will have 0's in the start positions where you want the flooding to begin, the other elements can have any other value. Optionally, you can give another map with walls, and it has to be of the same size and a binary 2D array where True means walls; you can also give a limit, if you have something like a maximum distance (for example if you want to convert to an image you can set limit to 255 and the elements that are further than that will be set to 255).

Example:

import numpy as np
from dijkstra_map import dijkstra_map

input_map = np.array(
    [
        [1, 1, 1, 0],
        [1, 0, 1, 1],
        [1, 0, 1, 1],
        [1, 1, 1, 1]
    ],
    dtype=int
)

walls_map = np.array(
    [
        [0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 1, 0]
    ],
    dtype=int
)

output_map = dijkstra_map(input_map, walls_map)
print(output_map)

That would print:

[[1 1 1 0]
 [1 0 1 1]
 [1 0 0 2]
 [1 1 0 3]]

Note that wall elements are set to 0 when limit is not given. If we use a limit, they will take that value, for example:

import numpy as np
from dijkstra_map import dijkstra_map

input_map = np.array(
    [
        [1, 1, 1, 0],
        [1, 0, 1, 1],
        [1, 0, 1, 1],
        [1, 1, 1, 1]
    ],
    dtype=int
)

walls_map = np.array(
    [
        [0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 1, 0]
    ],
    dtype=int
)

output_map = dijkstra_map(input_map, walls_map, limit=2)
print(output_map)

Will give:

[[1 1 1 0]
 [1 0 1 1]
 [1 0 2 2]
 [1 1 2 2]]

Dependencies

This project works with Python and the external library numpy. To install it run:

python -m pip install -r requirements.txt

Examples

Path-finding

In this example game we have a 2D grid with the player represented as a blue circle and 3 enemies as other circles that chase the player. Path finding for the enemies is implemented using a dijkstra map that is recalculated on each update call.

Testing

To run the tests use unittest in this way:

python -m unittest -v tests

This will run every test in the tests module, if you add new tests make sure to import them into the __init__.py file inside the tests folder.