1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
10 * A helper function to abbreviate getElementById.
12 * @param {string} elementId The id to get.
15 function $(elementId) {
16 return document.getElementById(elementId);
22 * @return {string} MIME type
24 function PNaClmimeType() {
25 return 'application/x-pnacl';
29 * Check if the browser supports PNaCl.
33 function browserSupportsPNaCl() {
34 var mimetype = PNaClmimeType();
35 return navigator.mimeTypes[mimetype] !== undefined;
39 * Get the URL for Google Cloud Storage.
41 * @param {string} name The relative path to the file.
44 function getDataURL(name) {
45 var revision = 229855;
46 var baseUrl = 'http://commondatastorage.googleapis.com/gonacl/demos/publish/';
47 return baseUrl + revision + '/earth/' + name;
51 * Create the Native Client <embed> element as a child of the DOM element
54 * @param {string} name The name of the example.
55 * @param {number} width The width to create the plugin.
56 * @param {number} height The height to create the plugin.
57 * @param {Object} attrs Dictionary of attributes to set on the module.
59 function createNaClModule(name, width, height, attrs) {
60 var moduleEl = document.createElement('embed');
61 moduleEl.setAttribute('name', 'nacl_module');
62 moduleEl.setAttribute('id', 'nacl_module');
63 moduleEl.setAttribute('width', width);
64 moduleEl.setAttribute('height', height);
65 moduleEl.setAttribute('path', '');
66 moduleEl.setAttribute('src', getDataURL(name + '.nmf'));
67 moduleEl.setAttribute('type', PNaClmimeType());
69 // Add any optional arguments
71 for (var key in attrs) {
72 moduleEl.setAttribute(key, attrs[key]);
76 // The <EMBED> element is wrapped inside a <DIV>, which has both a 'load'
77 // and a 'message' event listener attached. This wrapping method is used
78 // instead of attaching the event listeners directly to the <EMBED> element
79 // to ensure that the listeners are active before the NaCl module 'load'
81 var listenerDiv = $('listener');
82 listenerDiv.appendChild(moduleEl);
86 * Add the default event listeners to the element with id "listener".
88 function attachDefaultListeners() {
89 var listenerDiv = $('listener');
90 listenerDiv.addEventListener('load', moduleDidLoad, true);
91 listenerDiv.addEventListener('error', moduleLoadError, true);
92 listenerDiv.addEventListener('progress', moduleLoadProgress, true);
93 listenerDiv.addEventListener('message', handleMessage, true);
94 listenerDiv.addEventListener('crash', handleCrash, true);
99 * Called when the Browser can not communicate with the Module
101 * This event listener is registered in attachDefaultListeners above.
103 * @param {Object} event
105 function handleCrash(event) {
106 if (naclModule.exitStatus == -1) {
107 updateStatus('CRASHED');
109 updateStatus('EXITED [' + naclModule.exitStatus + ']');
114 * Called when the NaCl module is loaded.
116 * This event listener is registered in attachDefaultListeners above.
118 function moduleDidLoad() {
119 var bar = $('progress');
122 naclModule = $('nacl_module');
128 * Hide the status field and progress bar.
130 function hideStatus() {
131 $('statusField').style.display = 'none';
132 $('progress').style.display = 'none';
136 * Called when the plugin fails to load.
138 * @param {Object} event
140 function moduleLoadError(event) {
141 updateStatus('Load failed.');
145 * Called when the plugin reports progress events.
147 * @param {Object} event
149 function moduleLoadProgress(event) {
150 $('progress').style.display = 'block';
152 var loadPercent = 0.0;
153 var bar = $('progress');
155 if (event.lengthComputable && event.total > 0) {
156 loadPercent = event.loaded / event.total * 100.0;
158 // The total length is not yet known.
161 bar.value = loadPercent;
165 * If the element with id 'statusField' exists, then set its HTML to the status
168 * @param {string} opt_message The message to set.
170 function updateStatus(opt_message) {
171 var statusField = $('statusField');
173 statusField.style.display = 'block';
174 statusField.textContent = opt_message;
179 * Send the current value of the element threadCount to the NaCl module.
181 * @param {number} threads The number of threads to use to render.
183 function setThreadCount(threads) {
184 var value = parseInt($('threadCount').value);
185 naclModule.postMessage({'message': 'set_threads',
190 * Add event listeners after the NaCl module has loaded. These listeners will
191 * forward messages to the NaCl module via postMessage()
193 function attachListeners() {
194 $('threadCount').addEventListener('change', setThreadCount);
195 $('zoomRange').addEventListener('change',
197 var value = parseFloat($('zoomRange').value);
198 naclModule.postMessage({'message' : 'set_zoom',
201 $('lightRange').addEventListener('change',
203 var value = parseFloat($('lightRange').value);
204 naclModule.postMessage({'message' : 'set_light',
210 * Load a texture and send pixel data down to NaCl module.
211 * @param {string} name
213 function loadTexture(name) {
214 // Load image from jpg, decompress into canvas.
215 var img = new Image();
216 img.onload = function() {
217 var graph = document.createElement('canvas');
218 graph.width = img.width;
219 graph.height = img.height;
220 var context = graph.getContext('2d');
221 context.drawImage(img, 0, 0);
222 var imageData = context.getImageData(0, 0, img.width, img.height);
223 // Send NaCl module the raw image data obtained from canvas.
224 naclModule.postMessage({'message' : 'texture',
227 'height' : img.height,
228 'data' : imageData.data.buffer});
230 // A cross-origin request to an image is "tainted", and cannot be read into a
231 // canvas without specifying this. See
232 // https://developer.mozilla.org/en-US/docs/HTML/CORS_Enabled_Image
233 img.crossOrigin = 'Anonymous';
234 img.src = getDataURL(name);
238 * Handle a message coming from the NaCl module.
239 * @param {Object} message_event
241 function handleMessage(message_event) {
242 if (message_event.data['message'] == 'set_zoom') {
244 var zoom = message_event.data['value'];
245 $('zoomRange').value = zoom;
246 } else if (message_event.data['message'] == 'set_light') {
248 var light = message_event.data['value'];
249 $('lightRange').value = light;
250 } else if (message_event.data['message'] == 'request_textures') {
251 // NaCl module is requesting a set of textures.
252 var names = message_event.data['names'];
253 for (var i = 0; i < names.length; i++)
254 loadTexture(names[i]);
259 * Listen for the DOM content to be loaded. This event is fired when parsing of
260 * the page's document has finished.
262 document.addEventListener('DOMContentLoaded', function() {
263 updateStatus('Loading...');
264 if (!browserSupportsPNaCl()) {
265 updateStatus('Browser does not support PNaCl or PNaCl is disabled');
266 } else if (naclModule == null) {
267 createNaClModule('earth', 480, 480);
268 attachDefaultListeners();
270 // It's possible that the Native Client module onload event fired
271 // before the page's onload event. In this case, the status message
272 // will reflect 'SUCCESS', but won't be displayed. This call will
273 // display the current message.
274 updateStatus('Waiting.');