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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>WebGL Fundamentals Module: webgl-utils</title>
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<h1 class="page-title">Module: webgl-utils</h1>
<section>
<header>
<h2>
webgl-utils
</h2>
</header>
<article>
<div class="container-overview">
<dl class="details">
</dl>
</div>
<h3 class="subsection-title">Methods</h3>
<dl>
<dt>
<h4 class="name" id="createAttribsFromArrays"><span class="type-signature"> </span>createAttribsFromArrays<span class="signature">(gl, arrays, <span class="optional">opt_mapping</span>)</span><span class="type-signature"> → {Object.<string, <a href="module-webgl-utils.html#AttribInfo">module:webgl-utils.AttribInfo</a>>}</span></h4>
</dt>
<dd>
<div class="description">
<p>Creates a set of attribute data and WebGLBuffers from set of arrays</p>
<p>Given</p>
<pre><code> var arrays = {
position: { numComponents: 3, data: [0, 0, 0, 10, 0, 0, 0, 10, 0, 10, 10, 0], },
texcoord: { numComponents: 2, data: [0, 0, 0, 1, 1, 0, 1, 1], },
normal: { numComponents: 3, data: [0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1], },
color: { numComponents: 4, data: [255, 255, 255, 255, 255, 0, 0, 255, 0, 0, 255, 255], type: Uint8Array, },
indices: { numComponents: 3, data: [0, 1, 2, 1, 2, 3], },
};</code></pre>
<p>returns something like</p>
<pre><code> var attribs = {
a_position: { numComponents: 3, type: gl.FLOAT, normalize: false, buffer: WebGLBuffer, },
a_texcoord: { numComponents: 2, type: gl.FLOAT, normalize: false, buffer: WebGLBuffer, },
a_normal: { numComponents: 3, type: gl.FLOAT, normalize: false, buffer: WebGLBuffer, },
a_color: { numComponents: 4, type: gl.UNSIGNED_BYTE, normalize: true, buffer: WebGLBuffer, },
};</code></pre>
</div>
<h5>Parameters:</h5>
<table class="params table table-striped">
<thead>
<tr>
<th>Name</th>
<th>Type</th>
<th>Argument</th>
<th class="last">Description</th>
</tr>
</thead>
<tbody>
<tr>
<td class="name"><code>gl</code></td>
<td class="type">
<span class="param-type">WebGLRenderingContext</span>
</td>
<td class="attributes">
</td>
<td class="description last"><p>The webgl rendering context.</p></td>
</tr>
<tr>
<td class="name"><code>arrays</code></td>
<td class="type">
<span class="param-type">Object.<string, (array|typedarray)></span>
</td>
<td class="attributes">
</td>
<td class="description last"><p>The arrays</p></td>
</tr>
<tr>
<td class="name"><code>opt_mapping</code></td>
<td class="type">
<span class="param-type">Object.<string, string></span>
</td>
<td class="attributes">
<optional><br>
</td>
<td class="description last"><p>mapping from attribute name to array name.
if not specified defaults to "a_name" -> "name".</p></td>
</tr>
</tbody>
</table>
<dl class="details">
</dl>
<h5>Returns:</h5>
<div class="param-desc">
<p>the attribs</p>
</div>
<dl>
<dt>
Type
</dt>
<dd>
<span class="param-type">Object.<string, <a href="module-webgl-utils.html#AttribInfo">module:webgl-utils.AttribInfo</a>></span>
</dd>
</dl>
</dd>
<dt>
<h4 class="name" id="createAttributeSetters"><span class="type-signature"> </span>createAttributeSetters<span class="signature">(program)</span><span class="type-signature"> → {Object.<string, function()>}</span></h4>
</dt>
<dd>
<div class="description">
<p>Creates setter functions for all attributes of a shader
program. You can pass this to <a href="module-webgl-utils.html#setBuffersAndAttributes"><code>module:webgl-utils.setBuffersAndAttributes</code></a> to set all your buffers and attributes.</p>
</div>
<h5>Parameters:</h5>
<table class="params table table-striped">
<thead>
<tr>
<th>Name</th>
<th>Type</th>
<th class="last">Description</th>
</tr>
</thead>
<tbody>
<tr>
<td class="name"><code>program</code></td>
<td class="type">
<span class="param-type">WebGLProgram</span>
</td>
<td class="description last"><p>the program to create setters for.</p></td>
</tr>
</tbody>
</table>
<dl class="details">
<dt class="tag-see">See:</dt>
<dd class="tag-see">
<ul>
<li><a href="module-webgl-utils.html#setAttributes"><code>module:webgl-utils.setAttributes</code></a> for example</li>
</ul>
</dd>
</dl>
<h5>Returns:</h5>
<div class="param-desc">
<p>an object with a setter for each attribute by name.</p>
</div>
<dl>
<dt>
Type
</dt>
<dd>
<span class="param-type">Object.<string, function()></span>
</dd>
</dl>
</dd>
<dt>
<h4 class="name" id="createAugmentedTypedArray"><span class="type-signature"> </span>createAugmentedTypedArray<span class="signature">(numComponents, numElements, opt_type)</span><span class="type-signature"> → {ArrayBuffer}</span></h4>
</dt>
<dd>
<div class="description">
<p>creates a typed array with a <code>push</code> function attached
so that you can easily <em>push</em> values.</p>
<p><code>push</code> can take multiple arguments. If an argument is an array each element
of the array will be added to the typed array.</p>
<p>Example:</p>
<pre><code>var array = createAugmentedTypedArray(3, 2); // creates a Float32Array with 6 values
array.push(1, 2, 3);
array.push([4, 5, 6]);
// array now contains [1, 2, 3, 4, 5, 6]</code></pre>
<p>Also has <code>numComponents</code> and <code>numElements</code> properties.</p>
</div>
<h5>Parameters:</h5>
<table class="params table table-striped">
<thead>
<tr>
<th>Name</th>
<th>Type</th>
<th class="last">Description</th>
</tr>
</thead>
<tbody>
<tr>
<td class="name"><code>numComponents</code></td>
<td class="type">
<span class="param-type">number</span>
</td>
<td class="description last"><p>number of components</p></td>
</tr>
<tr>
<td class="name"><code>numElements</code></td>
<td class="type">
<span class="param-type">number</span>
</td>
<td class="description last"><p>number of elements. The total size of the array will be <code>numComponents * numElements</code>.</p></td>
</tr>
<tr>
<td class="name"><code>opt_type</code></td>
<td class="type">
<span class="param-type">constructor</span>
</td>
<td class="description last"><p>A constructor for the type. Default = <code>Float32Array</code>.</p></td>
</tr>
</tbody>
</table>
<dl class="details">
</dl>
<h5>Returns:</h5>
<div class="param-desc">
<p>A typed array.</p>
</div>
<dl>
<dt>
Type
</dt>
<dd>
<span class="param-type">ArrayBuffer</span>
</dd>
</dl>
</dd>
<dt>
<h4 class="name" id="createBufferInfoFromArrays"><span class="type-signature"> </span>createBufferInfoFromArrays<span class="signature">(gl, arrays, <span class="optional">opt_mapping</span>)</span><span class="type-signature"> → {<a href="module-webgl-utils.html#BufferInfo">module:webgl-utils.BufferInfo</a>}</span></h4>
</dt>
<dd>
<div class="description">
<p>Creates a BufferInfo from an object of arrays.</p>
<p>This can be passed to <a href="module-webgl-utils.html#setBuffersAndAttributes"><code>module:webgl-utils.setBuffersAndAttributes</code></a> and to
<code>module:webgl-utils:drawBufferInfo</code>.</p>
<p>Given an object like</p>
<pre><code>var arrays = {
position: { numComponents: 3, data: [0, 0, 0, 10, 0, 0, 0, 10, 0, 10, 10, 0], },
texcoord: { numComponents: 2, data: [0, 0, 0, 1, 1, 0, 1, 1], },
normal: { numComponents: 3, data: [0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1], },
indices: { numComponents: 3, data: [0, 1, 2, 1, 2, 3], },
};</code></pre>
<p> Creates an BufferInfo like this</p>
<pre><code>bufferInfo = {
numElements: 4, // or whatever the number of elements is
indices: WebGLBuffer, // this property will not exist if there are no indices
attribs: {
a_position: { buffer: WebGLBuffer, numComponents: 3, },
a_normal: { buffer: WebGLBuffer, numComponents: 3, },
a_texcoord: { buffer: WebGLBuffer, numComponents: 2, },
},
};</code></pre>
<p> The properties of arrays can be JavaScript arrays in which case the number of components
will be guessed.</p>
<pre><code>var arrays = {
position: [0, 0, 0, 10, 0, 0, 0, 10, 0, 10, 10, 0],
texcoord: [0, 0, 0, 1, 1, 0, 1, 1],
normal: [0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1],
indices: [0, 1, 2, 1, 2, 3],
};</code></pre>
<p> They can also by TypedArrays</p>
<pre><code>var arrays = {
position: new Float32Array([0, 0, 0, 10, 0, 0, 0, 10, 0, 10, 10, 0]),
texcoord: new Float32Array([0, 0, 0, 1, 1, 0, 1, 1]),
normal: new Float32Array([0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1]),
indices: new Uint16Array([0, 1, 2, 1, 2, 3]),
};</code></pre>
<p> Or augmentedTypedArrays</p>
<pre><code>var positions = createAugmentedTypedArray(3, 4);
var texcoords = createAugmentedTypedArray(2, 4);
var normals = createAugmentedTypedArray(3, 4);
var indices = createAugmentedTypedArray(3, 2, Uint16Array);
positions.push([0, 0, 0, 10, 0, 0, 0, 10, 0, 10, 10, 0]);
texcoords.push([0, 0, 0, 1, 1, 0, 1, 1]);
normals.push([0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1]);
indices.push([0, 1, 2, 1, 2, 3]);
var arrays = {
position: positions,
texcoord: texcoords,
normal: normals,
indices: indices,
};</code></pre>
<p>For the last example it is equivalent to</p>
<pre><code>var bufferInfo = {
attribs: {
a_position: { numComponents: 3, buffer: gl.createBuffer(), },
a_texcoods: { numComponents: 2, buffer: gl.createBuffer(), },
a_normals: { numComponents: 3, buffer: gl.createBuffer(), },
},
indices: gl.createBuffer(),
numElements: 6,
};
gl.bindBuffer(gl.ARRAY_BUFFER, bufferInfo.attribs.a_position.buffer);
gl.bufferData(gl.ARRAY_BUFFER, arrays.position, gl.STATIC_DRAW);
gl.bindBuffer(gl.ARRAY_BUFFER, bufferInfo.attribs.a_texcoord.buffer);
gl.bufferData(gl.ARRAY_BUFFER, arrays.texcoord, gl.STATIC_DRAW);
gl.bindBuffer(gl.ARRAY_BUFFER, bufferInfo.attribs.a_normal.buffer);
gl.bufferData(gl.ARRAY_BUFFER, arrays.normal, gl.STATIC_DRAW);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufferInfo.indices);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, arrays.indices, gl.STATIC_DRAW);</code></pre>
</div>
<h5>Parameters:</h5>
<table class="params table table-striped">
<thead>
<tr>
<th>Name</th>
<th>Type</th>
<th>Argument</th>
<th class="last">Description</th>
</tr>
</thead>
<tbody>
<tr>
<td class="name"><code>gl</code></td>
<td class="type">
<span class="param-type">WebGLRenderingContext</span>
</td>
<td class="attributes">
</td>
<td class="description last"><p>A WebGLRenderingContext</p></td>
</tr>
<tr>
<td class="name"><code>arrays</code></td>
<td class="type">
<span class="param-type">Object.<string, (array|object|typedarray)></span>
</td>
<td class="attributes">
</td>
<td class="description last"><p>Your data</p></td>
</tr>
<tr>
<td class="name"><code>opt_mapping</code></td>
<td class="type">
<span class="param-type">Object.<string, string></span>
</td>
<td class="attributes">
<optional><br>
</td>
<td class="description last"><p>an optional mapping of attribute to array name.
If not passed in it's assumed the array names will be mapped to an attibute
of the same name with "a_" prefixed to it. An other words.</p>
<pre><code> var arrays = {
position: ...,
texcoord: ...,
normal: ...,
indices: ...,
};
bufferInfo = createBufferInfoFromArrays(gl, arrays);</code></pre>
<p> Is the same as</p>
<pre><code> var arrays = {
position: ...,
texcoord: ...,
normal: ...,
indices: ...,
};
var mapping = {
a_position: "position",
a_texcoord: "texcoord",
a_normal: "normal",
};
bufferInfo = createBufferInfoFromArrays(gl, arrays, mapping);</code></pre></td>
</tr>
</tbody>
</table>
<dl class="details">
</dl>
<h5>Returns:</h5>
<div class="param-desc">
<p>A BufferInfo</p>
</div>
<dl>
<dt>
Type
</dt>
<dd>
<span class="param-type"><a href="module-webgl-utils.html#BufferInfo">module:webgl-utils.BufferInfo</a></span>
</dd>
</dl>
</dd>
<dt>
<h4 class="name" id="createBuffersFromArrays"><span class="type-signature"> </span>createBuffersFromArrays<span class="signature">({WebGLRenderingContext), arrays)</span><span class="type-signature"> → {Object.<string, WebGLBuffer>}</span></h4>
</dt>
<dd>
<div class="description">
<p>Creates buffers from typed arrays</p>
<p>Given something like this</p>
<pre><code>var arrays = {
positions: [1, 2, 3],