This library provides a pathfinding mechanism based on vectors field.
You can find a working example here : Live Example
Download the package with yarn
yarn add FlowField
or npm with npm install FlowField
import flowfield from FlowField;
//create the flowfield
const FF = flowfield.create(2, 20, 20); //Create a grid of 10x10
FF.setTarget([2,2]); //add a target
FF.addObstacle([3,3]);
FF.addObstacle([7,2]);
const path = FF.getPathFromCoordinates([8,9]); //return array of position to reach the target in [2,2] from [8,9];
-
Flowfield : Object containing the Grid and all the following methods.
-
Grid :
Array<Array<Cell>>
. -
Cell :
Object
containing several attributes- distance :
Number
- number of cells between the current cell and the target - direction :
Array<Number>
- normalized direction from the cell to the target - obstacle :
boolean
- describing whether the cell is an obstacle
- distance :
- create
create( step: number, height: number, width: number): FlowField Object
Create a flowfield based on step
, height
and number
.
The size of the grid it is about to create is simply [height/step ,width/step
].
For example,
flowfield.create(2, 10, 10)
will create a grid of5 x 5
cells.
-
setTarget
setTarget(position: Array<number>) : Grid
Set the target of the flowfield
-
setObstacle
setObstacle(position: Array<number>) : Grid
Given the position provided, adds an obstacle on the flowfield. This cell will be therefore avoided to calculate path.
-
removeObstacle
removeObstacle(position: Array<number>) : Grid
If the cell at the given position is an obstacle, set it back as a regular cell. Does nothing otherwise.
-
getPathFromCoordinates
getPathFromCoordinates(position: Array<number>) : Array<Array<Number>>
Given a position, returns an array containing the coordinates of the path to go from the given cell to the target of the flowfield.
-
getGrid
getGrid() : Array<Array<Object>>
Returns the entire grid.
-
getImmutableGrid
getImmutableGrid : List<List<Map>>
Returns the Immutable object representing the grid. Might be relevant if Immutable.js is used in your project
-
getCell
getCell(position: Array<number>) : Object
From the position provided, it returns the object representing the cell.
-
getCellFromRealWorldCoordinates
getCellFromRealWorldCoordinates(position: Array<number>) : Cell
From the "real world coordinates" position provided, it returns the object representing the cell.
For example, with a
flowfield.create(2, 10, 10)
,getCell(3,3) will return the cell located in [1,1] in the grid space.
.
- setObstacleFromWorldCoordinates
Same as before except that it takes "real world coordinates". Meaning that the conversion to the grid system will be done automatically based on the step parameter provided at the Flowfield creation.
- removeObstacleFromWorldCoordinates
Same as before but with "real world coordinates".
To run them :
yarn test
Just trying to get a 100% coverage...
- Code refactoring to remove duplications
- Tests cleaning to improve readability
- Deal with some edge cases where not the fastest way is not chosen (based on how the next cell to go is chosen based on a distance comparison to the target). One possibility would be a post-process on the path calculated.
- make the
step
parameter optionnal. - use a caching method to store paths to save computing time as long as the grid is not modified (e.g. no new target/obstacles)
- usage of web workers as an option to release main thread.
Feel free to help and improve this library by opening a PR. As said previously, this is a first version that matches my use cases for now but I'm open to improvements :)
We use SemVer for versioning. For the versions available, see the tags on this repository.
- Gaël Servaud - Initial work - My profile
This project is licensed under the ISC License.