Updated comments

dist/vizicities.js

@@ -4732,6 +4732,23 @@ return /******/ (function(modules) { // webpackBootstrap
 	
 	var _three2 = _interopRequireDefault(_three);
 	
+	// TODO: Consider keeping a single TileLayer / LOD instance running by default
+	// that keeps a standard LOD grid for other layers to utilise, rather than
+	// having to create their own, unique LOD grid and duplicate calculations when
+	// they're going to use the same grid setup anyway
+	//
+	// It still makes sense to be able to have a custom LOD grid for some layers as
+	// they may want to customise things, maybe not even using a quadtree at all!
+	//
+	// Perhaps it makes sense to split out the quadtree stuff into a singleton and
+	// pass in the necessary parameters each time for the calculation step.
+	//
+	// Either way, it seems silly to force layers to have to create a new LOD grid
+	// each time and create extra, duplicated processing every frame.
+	
+	// TODO: Allow passing in of options to define min/max LOD and a distance to use
+	// for culling tiles beyond that distance.
+	
 	// DONE: Prevent tiles from being loaded if they are further than a certain
 	// distance from the camera and are unlikely to be seen anyway
 	
@@ -6847,7 +6864,7 @@ return /******/ (function(modules) { // webpackBootstrap
 	
 	  // Initialise without requiring new keyword
 	
-	  // Request data for the various tile provider
+	  // Request data for the tile
 	
 	  _createClass(ImageTile, [{
 	    key: 'requestTileAsync',

src/layer/tile/ImageTile.js

@@ -7,7 +7,7 @@ class ImageTile extends Tile {
     super(quadcode, path, layer);
   }
 
-  // Request data for the various tile provider
+  // Request data for the tile
   requestTileAsync() {
     // Making this asynchronous really speeds up the LOD framerate
     setTimeout(() => {

src/layer/tile/ImageTileLayer.js

@@ -35,6 +35,14 @@ import THREE from 'three';
 // reach a ready state (eg. cancel image requests, etc). Need to ensure that the
 // images are re-requested when the tile is next in scene (even if from cache)
 
+// TODO: Consider not performing an LOD calculation on every frame, instead only
+// on move end so panning, orbiting and zooming stays smooth. Otherwise it's
+// possible for performance to tank if you pan, orbit or zoom rapidly while all
+// the LOD calculations are being made and new tiles requested.
+//
+// Pending tiles should continue to be requested and output to the scene on each
+// frame, but no new LOD calculations should be made.
+
 class ImageTileLayer extends TileLayer {
   constructor(path, options) {
     // Cache 1000 tiles

src/layer/tile/TileLayer.js

@@ -2,6 +2,23 @@ import Layer from '../Layer';
 import TileCache from './TileCache';
 import THREE from 'three';
 
+// TODO: Consider keeping a single TileLayer / LOD instance running by default
+// that keeps a standard LOD grid for other layers to utilise, rather than
+// having to create their own, unique LOD grid and duplicate calculations when
+// they're going to use the same grid setup anyway
+//
+// It still makes sense to be able to have a custom LOD grid for some layers as
+// they may want to customise things, maybe not even using a quadtree at all!
+//
+// Perhaps it makes sense to split out the quadtree stuff into a singleton and
+// pass in the necessary parameters each time for the calculation step.
+//
+// Either way, it seems silly to force layers to have to create a new LOD grid
+// each time and create extra, duplicated processing every frame.
+
+// TODO: Allow passing in of options to define min/max LOD and a distance to use
+// for culling tiles beyond that distance.
+
 // DONE: Prevent tiles from being loaded if they are further than a certain
 // distance from the camera and are unlikely to be seen anyway