imclab / spatial-trigger

enter/exit events for bounding boxes based on events from spatial-events

spatial-trigger

given a spatial event emitter and an axis aligned bounding box, return a new event emitter that emits enter and exit events when spatial events indicate that something has passed into the bounding box.

var trigger = require('spatial-trigger')
  , aabb = require('aabb-3d')
  , SPEE = require('spatial-events')
  , spee = new SPEE

trigger(spee, aabb([0, 0, 0], [4, 4, 4]), 'point')
  .on('enter', function() { console.log('entered box') })
  .on('exit', function() { console.log('exited box') })

spee.emit('point', [-4, -4, -4])
spee.emit('point', [-2, -2, -2])
spee.emit('point', [+0, +0, +0]) // 'entered box'
spee.emit('point', [+2, +2, +2])
spee.emit('point', [+4, +4, +4])
spee.emit('point', [+6, +6, +6]) // 'exited box'

API

ee = trigger(spatial_ee, boundingBox[, eventName='position'])

attaches one infinite listener to spatial_ee and one at boundingBox for eventName (which defaults to 'position' if not given), and returns an event emitter that emits 'enter' and 'exit' events.

Events

enter

enter events happen whenever the positions emitted by spatial_ee cross into the given bounding box. When an event triggers the enter event, its arguments will be forwarded to enter listeners.

exit

exit events happen whenever the positions emitted by spatial_ee leave the given bounding box. When an event triggers the exit event, its arguments will be forwarded to exit listeners.

License

MIT