# Module `ROT.FOV.Recursive`

Recursive Shadowcasting Field of View calculator.

The Recursive shadow casting algorithm developed by Ondřej Žára for rot.js. See http://roguebasin.roguelikedevelopment.org/index.php?title=Recursive_Shadowcasting_in_JavaScript

## Functions

 init (lightPassesCallback, options) Constructor. compute (x, y, R, callback) Compute. compute180 (x, y, R, dir, callback) Compute 180. compute90 (x, y, R, dir, callback) Compute 90.

## Functions

init (lightPassesCallback, options)
Constructor. Called with ROT.FOV.Recursive:new()

### Parameters:

• lightPassesCallback function A function with two parameters (x, y) that returns true if a map cell will allow light to pass through
• options Options
• topology int Direction for light movement Accepted values: (4 or 8)
compute (x, y, R, callback)
Compute. Get visibility from a given point

### Parameters:

• x int x-position of center of FOV
• y int y-position of center of FOV
• R int radius of FOV (i.e.: At most, I can see for R cells)
• callback A function that is called for every cell in view. Must accept four parameters.
• x int x-position of cell that is in view
• y int y-position of cell that is in view
• r int The cell's distance from center of FOV
• visibility boolean Indicates if the cell is seen
compute180 (x, y, R, dir, callback)
Compute 180. Get visibility from a given point for a 180 degree arc

### Parameters:

• x int x-position of center of FOV
• y int y-position of center of FOV
• R int radius of FOV (i.e.: At most, I can see for R cells)
• dir int viewing direction (use ROT.DIR index for values)
• callback A function that is called for every cell in view. Must accept four parameters.
• x int x-position of cell that is in view
• y int y-position of cell that is in view
• r int The cell's distance from center of FOV
• visibility boolean Indicates if the cell is seen
compute90 (x, y, R, dir, callback)
Compute 90. Get visibility from a given point for a 90 degree arc

### Parameters:

• x int x-position of center of FOV
• y int y-position of center of FOV
• R int radius of FOV (i.e.: At most, I can see for R cells)
• dir int viewing direction (use ROT.DIR index for values)
• callback A function that is called for every cell in view. Must accept four parameters.
• x int x-position of cell that is in view
• y int y-position of cell that is in view
• r int The cell's distance from center of FOV
• visibility boolean Indicates if the cell is seen
generated by LDoc 1.4.6 Last updated 2017-07-19 18:43:03