/*
* Copyright 2010, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @fileoverview This file contains functions every webgl program will need
* a version of one way or another.
*
* Instead of setting up a context manually it is recommended to
* use. This will check for success or failure. On failure it
* will attempt to present an approriate message to the user.
*
* gl = WebGLUtils.setupWebGL(canvas);
*
* For animated WebGL apps use of setTimeout or setInterval are
* discouraged. It is recommended you structure your rendering
* loop like this.
*
* function render() {
* window.requestAnimFrame(render, canvas);
*
* // do rendering
* ...
* }
* render();
*
* This will call your rendering function up to the refresh rate
* of your display but will stop rendering if your app is not
* visible.
*/
WebGLUtils = function () {
/**
* Creates the HTLM for a failure message
* @param {string} canvasContainerId id of container of th
* canvas.
* @return {string} The html.
*/
var makeFailHTML = function (msg) {
return '' +
'<table style="background-color: #8CE; width: 100%; height: 100%;"><tr>' +
'<td align="center">' +
'<div style="display: table-cell; vertical-align: middle;">' +
'<div style="">' + msg + '</div>' +
'</div>' +
'</td></tr></table>';
};
/**
* Mesasge for getting a webgl browser
* @type {string}
*/
var GET_A_WEBGL_BROWSER = '' +
'This page requires a browser that supports WebGL.<br/>' +
'<a href="http://get.webgl.org">Click here to upgrade your browser.</a>';
/**
* Mesasge for need better hardware
* @type {string}
*/
var OTHER_PROBLEM = '' +
"It doesn't appear your computer can support WebGL.<br/>" +
'<a href="http://get.webgl.org/troubleshooting/">Click here for more information.</a>';
/**
* Creates a webgl context. If creation fails it will
* change the contents of the container of the <canvas>
* tag to an error message with the correct links for WebGL.
* @param {Element} canvas. The canvas element to create a
* context from.
* @param {WebGLContextCreationAttributes} opt_attribs Any
* creation attributes you want to pass in.
* @param {function(msg)} opt_onError An function to call
* if there is an error during creation.
* @return {WebGLRenderingContext} The created context.
*/
var setupWebGL = function (canvas, opt_attribs, opt_onError) {
function handleCreationError(msg) {
var container = canvas.parentNode;
if (container) {
var str = window.WebGLRenderingContext ?
OTHER_PROBLEM :
GET_A_WEBGL_BROWSER;
if (msg) {
str += "<br/><br/>Status: " + msg;
}
container.innerHTML = makeFailHTML(str);
}
};
opt_onError = opt_onError || handleCreationError;
if (canvas.addEventListener) {
canvas.addEventListener("webglcontextcreationerror", function (event) {
opt_onError(event.statusMessage);
}, false);
}
var context = create3DContext(canvas, opt_attribs);
if (!context) {
if (!window.WebGLRenderingContext) {
opt_onError("");
}
}
return context;
};
/**
* Creates a webgl context.
* @param {!Canvas} canvas The canvas tag to get context
* from. If one is not passed in one will be created.
* @return {!WebGLContext} The created context.
*/
var create3DContext = function (canvas, opt_attribs) {
var names = ["webgl", "experimental-webgl", "webkit-3d", "moz-webgl"];
var context = null;
for (var ii = 0; ii < names.length; ++ii) {
try {
context = canvas.getContext(names[ii], opt_attribs);
} catch (e) { }
if (context) {
break;
}
}
return context;
}
return {
create3DContext: create3DContext,
setupWebGL: setupWebGL
};
}();
/**
* Provides requestAnimationFrame in a cross browser way.
*/
window.requestAnimFrame = (function () {
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function (/* function FrameRequestCallback */ callback, /* DOMElement Element */ element) {
window.setTimeout(callback, 1000 / 60);
};
})();