whydoidoit/sendmessage

Introduction

An alternative to events in PlayCanvas. Entities gain extra methods to broadcast messages to scripts on entities in the hierarchy:

broadcast on or below the Entity.

sendUpwards on or above the Entity.

send on the Entity.

This works like the methods in Unity and removes the need for binding and unbinding event listeners. And discovering objects on which bindings could be made in the first place. The cost is not insignificant if there are a lot of objects beneath the entity and broadcast is called. This would be quite unusual though. It's for events. Don't call it every frame, if you want to do that then you have something else up with your code.

Installation

npm install --save playcanvas-sendmessage

Usage

import 'playcanvas-sendmessage'

...

//Script One - some kind of collision detection sensor on a sub object

ScriptOne.prototype.trigger = function(otherObject) {
    this.entity.sendUpwards('detected', this.name, otherObject, this);
};

//Script Two - the player control script

ScriptTwo.prototype.detected = function(sensorName, detectedObject, sensor) {
    if(sensorName === 'autoFirePoint' && detectedObject.tags.has('enemy')) {
        this.releaseTheDogsOfWar(detectedObject, sensor.getPosition());
    }
};
 
 

Requirements

Requires PlayCanvas Engine to be running on the page. Uses ES6/Babel/PlayCanvas template.