Plugin management

[romainberger]

The point of releasing this module and extracting it from the website is to allow the creation of plugins. I'm alone here but I've never worked on a module that would allow plugin so I'll dump ideas on how this could work hoping someone with more experience can review this

Here is a first idea of how this could work:

var voxelPainter = require('voxel-painter-core')
  , plugin = require('voxel-plugin-to-do-stuff')

var painter = voxelPainter({container: '#container'})

// load the plugin in the voxel-painter instance
painter.loadPlugin(plugin)

The core module would then provide hooks (pre and post) on most methods. The plugin could for example try to do something after a voxel has been added:

// plugin snippet
module.exports = function() {
  var nbrOfVoxel

  this.postAddVoxel = function() {
    nbrOfVoxel++
    // do something interesting here
  }
}

So the core module loadPlugin method would store the plugin, then on every hook iterate on the plugins registered. If they have a method corresponding to the hook, run it.

The hook could provides informations and variables. For example for a hook called before adding a voxel:

// plugin module snippet
function preAddVoxel(x, y, z, c) {
  // x, y, z and c would be the infos given by the core module 
  // on the position and color of the voxel to be add
}

The issue could be that if the plugin can modify these values they need to be returned.

[romainberger]

Other solution with streams (Gist: https://gist.github.com/romainberger/9117621)

Basically the core module would load the plugins and everything would use streams to emit / watch events.

// Core module
var Stream = require('stream')
  , pluginStream = new Stream()

// [...]

  /**
   * Load a plugin
   */
  exports.loadPlugin = function(plugin) {
    plugins.push(plugin)
    return plugin(pluginStream)
  }

   // [...]
   // then in the methods, emit events from the stream
   function addVoxel(x, y, z, c) {
     pluginStream.emit('addVoxel', [x, y, z, c])
     // [...]
   }

In the module, watch the stream given

var Stream = require('stream')
  , stream = new Stream()
  , numberVoxel = 0

var voxelCount = function(studio) {
  studio.on('addVoxel', function() {
    numberVoxel++
    stream.emit('addVoxel', numberVoxel)
  })

  return stream
}

module.exports = voxelCount

then load the plugin, in this example the module also returns a stream to trigger stuffs

voxelCount = studio.loadPlugin(voxelCount)
voxelCount.on('addVoxel', function(number) {
  console.log(number+' voxels in the canvas')
})