fov-2d

Test whether a point is in an observer's field-of-view.

Given the location, heading, and field-of-view (as an angle) of an observer's eye, determine whether the target is visible (the blue triangle).

Installation

npm install fov-2d

Example

var inFov = require('fov-2d')

var enemy = [0, 0]
var enemyFacing = [1, 0]
var enemyFov = Math.PI / 3  // 60 degrees
var player = [100, 0]
var crate = [0, 10]

var testPlayer = inFov(enemy, enemyFacing, enemyFov, player)
var testCrate = inFov(enemy, enemyFacing, enemyFov, crate)

console.log(testPlayer)
console.log(testCrate)

outputs

true
false

Usage

var fov = require('fov-2d')

var visible = fov(eyePos, eyeFacing, eyeFov, targetPos)

• eyePos - origin of the eye [x, y]
• eyeFacing - the direction the eye is facing, given by a 2d vector
• eyeFov - the angle, in radians, of the eye's field-of-view
• targetPos - origin of the target the eye is trying to test the visibility of

Returns true if the target is within the eye's FOV, and false otherwise.

More

This module can be readily combined with modules like raycast-2d-tilemap to check for solid tiles in a tilemap to determine visibility.