Trim buffers after populating

js/data/bucket.js

@@ -107,6 +107,7 @@ Bucket.prototype.addFeatures = function() {
     for (var i = 0; i < this.features.length; i++) {
         this.addFeature(this.features[i]);
     }
+    this.trimBuffers();
 };
 
 /**
@@ -179,6 +180,12 @@ Bucket.prototype.destroy = function(gl) {
     }
 };
 
+Bucket.prototype.trimBuffers = function() {
+    for (var bufferName in this.buffers) {
+        this.buffers[bufferName].trim();
+    }
+};
+
 /**
  * Get the name of the method used to add an item to a buffer.
  * @param {string} shaderName The name of the shader that will use the buffer

js/data/bucket/symbol_bucket.js

@@ -228,6 +228,8 @@ SymbolBucket.prototype.addFeatures = function(collisionTile, stacks, icons) {
     }
 
     this.placeFeatures(collisionTile, this.collisionDebug);
+
+    this.trimBuffers();
 };
 
 SymbolBucket.prototype.addFeature = function(lines, shapedText, shapedIcon) {

js/data/buffer.js

@@ -96,7 +96,7 @@ Buffer.prototype.bind = function(gl) {
     if (!this.buffer) {
         this.buffer = gl.createBuffer();
         gl.bindBuffer(type, this.buffer);
-        gl.bufferData(type, this.arrayBuffer.slice(0, this.length * this.itemSize), gl.STATIC_DRAW);
+        gl.bufferData(type, this.arrayBuffer, gl.STATIC_DRAW);
 
         // dump array buffer once it's bound to gl
         this.arrayBuffer = null;
@@ -173,12 +173,18 @@ Buffer.prototype.validate = function(args) {
     assert(argIndex === args.length);
 };
 
+Buffer.prototype.trim = function() {
+    this.capacity = align(this.itemSize * this.length, Buffer.CAPACITY_ALIGNMENT);
+    this.arrayBuffer = this.arrayBuffer.slice(0, this.capacity);
+    this._refreshViews();
+};
+
 Buffer.prototype._resize = function(capacity) {
-    var old = this.views.UNSIGNED_BYTE;
+    var oldUByteView = this.views.UNSIGNED_BYTE;
     this.capacity = align(capacity, Buffer.CAPACITY_ALIGNMENT);
     this.arrayBuffer = new ArrayBuffer(this.capacity);
     this._refreshViews();
-    this.views.UNSIGNED_BYTE.set(old);
+    this.views.UNSIGNED_BYTE.set(oldUByteView);
 };
 
 Buffer.prototype._refreshViews = function() {

test/js/data/buffer.test.js

@@ -71,5 +71,18 @@ test('Buffer', function(t) {
         t.end();
     });
 
+    t.test('trims', function(t) {
+        var buffer = create();
+        var capacityInitial = buffer.capacity;
+
+        buffer.push(1, 1, 1);
+        t.equal(buffer.capacity, capacityInitial);
+
+        buffer.trim();
+        t.equal(buffer.capacity, buffer.itemSize);
+
+        t.end();
+    });
+
     t.end();
 });