Allow geometries to use a shared vertex array

The ol.geom.SharedVertices structure represents a flattened array of vertex coordinates.  This is intended to support optimal WebGL rendering.

src/ol/geom/point.js

@@ -2,30 +2,45 @@ goog.provide('ol.geom.Point');
 
 goog.require('goog.asserts');
 goog.require('ol.Extent');
-goog.require('ol.geom.Coordinate');
 goog.require('ol.geom.Geometry');
 goog.require('ol.geom.GeometryType');
+goog.require('ol.geom.SharedVertices');
+goog.require('ol.geom.Vertex');
 
 
 
 /**
  * @constructor
  * @extends {ol.geom.Geometry}
- * @param {ol.geom.Coordinate} coordinates Coordinates array (e.g. [x, y]).
+ * @param {ol.geom.Vertex} coordinates Coordinates array (e.g. [x, y]).
+ * @param {ol.geom.SharedVertices=} opt_shared Shared vertices.
  */
-ol.geom.Point = function(coordinates) {
-
+ol.geom.Point = function(coordinates, opt_shared) {
   goog.base(this);
 
+  var vertices = opt_shared,
+      dimension;
+
+  if (!goog.isDef(vertices)) {
+    dimension = coordinates.length;
+    vertices = new ol.geom.SharedVertices({dimension: dimension});
+  }
+
   /**
-   * @type {Array}
+   * @type {ol.geom.SharedVertices}
    */
-  this.coordinates = coordinates;
+  this.vertices = vertices;
+
+  /**
+   * @type {string}
+   * @private
+   */
+  this.sharedId_ = vertices.add([coordinates]);
 
   /**
    * @type {number}
    */
-  this.dimension = coordinates.length;
+  this.dimension = vertices.getDimension();
   goog.asserts.assert(this.dimension >= 2);
 
   /**
@@ -38,22 +53,53 @@ ol.geom.Point = function(coordinates) {
 goog.inherits(ol.geom.Point, ol.geom.Geometry);
 
 
+/**
+ * @param {number} dim Coordinate dimension.
+ * @return {number} The coordinate value.
+ */
+ol.geom.Point.prototype.get = function(dim) {
+  return this.vertices.get(this.sharedId_, 0, dim);
+};
+
+
 /**
  * @inheritDoc
  */
 ol.geom.Point.prototype.getBounds = function() {
   if (goog.isNull(this.bounds_)) {
-    var x = this.coordinates[0],
-        y = this.coordinates[1];
+    var x = this.get(0),
+        y = this.get(1);
     this.bounds_ = new ol.Extent(x, y, x, y);
   }
   return this.bounds_;
 };
 
 
+/**
+ * @inheritDoc
+ * @return {ol.geom.Vertex} Coordinates array.
+ */
+ol.geom.Point.prototype.getCoordinates = function() {
+  var coordinates = new Array(this.dimension);
+  for (var i = 0; i < this.dimension; ++i) {
+    coordinates[i] = this.get(i);
+  }
+  return coordinates;
+};
+
+
 /**
  * @inheritDoc
  */
 ol.geom.Point.prototype.getType = function() {
   return ol.geom.GeometryType.POINT;
 };
+
+
+/**
+ * Get the identifier used to mark this point in the shared vertices structure.
+ * @return {string} The identifier.
+ */
+ol.geom.Point.prototype.getSharedId = function() {
+  return this.sharedId_;
+};