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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<base href="../../../" />
<script src="page.js"></script>
<link type="text/css" rel="stylesheet" href="page.css" />
</head>
<body>
<h1>[name]</h1>
<p class="desc">
This class stores data for an attribute (such as vertex positions, face
indices, normals, colors, UVs, and any custom attributes ) associated with
a [page:BufferGeometry], which allows for more efficient passing of data
to the GPU. See that page for details and a usage example. When working
with vector-like data, the <i>.fromBufferAttribute( attribute, index )</i>
helper methods on [page:Vector2.fromBufferAttribute Vector2],
[page:Vector3.fromBufferAttribute Vector3],
[page:Vector4.fromBufferAttribute Vector4], and
[page:Color.fromBufferAttribute Color] classes may be helpful.
</p>
<h2>Constructor</h2>
<h3>[name]( [param:TypedArray array], [param:Integer itemSize], [param:Boolean normalized] )</h3>
<p>
[page:TypedArray array] -- Must be a
[link:https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/TypedArray TypedArray]. Used to instantiate the buffer. <br />
This array should have
<code>
itemSize * numVertices
</code>
elements, where numVertices is the number of vertices in the associated
[page:BufferGemetry BufferGeometry].<br /><br />
[page:Integer itemSize] -- the number of values of the array that should
be associated with a particular vertex. For instance, if this attribute is
storing a 3-component vector (such as a position, normal, or color), then
itemSize should be 3.
<br /><br />
[page:Boolean normalized] -- (optional) Applies to integer data only.
Indicates how the underlying data in the buffer maps to the values in the
GLSL code. For instance, if [page:TypedArray array] is an instance of
UInt16Array, and [page:Boolean normalized] is true, the values `0 -
+65535` in the array data will be mapped to 0.0f - +1.0f in the GLSL
attribute. An Int16Array (signed) would map from -32768 - +32767 to -1.0f
- +1.0f. If [page:Boolean normalized] is false, the values will be
converted to floats unmodified, i.e. 32767 becomes 32767.0f.
</p>
<h2>Properties</h2>
<h3>[property:TypedArray array]</h3>
<p>The [page:TypedArray array] holding data stored in the buffer.</p>
<h3>[property:Integer count]</h3>
<p>
Represents the number of items this buffer attribute stores. It is internally computed by dividing the [page:BufferAttribute.array array]'s length by the
[page:BufferAttribute.itemSize itemSize]. Read-only property.
</p>
<h3>[property:Number gpuType]</h3>
<p>
Configures the bound GPU type for use in shaders. Either [page:BufferAttribute THREE.FloatType] or [page:BufferAttribute THREE.IntType], default is [page:BufferAttribute THREE.FloatType].
Note: this only has an effect for integer arrays and is not configurable for float arrays. For lower precision float types, see [page:BufferAttributeTypes THREE.Float16BufferAttribute].
</p>
<h3>[property:Boolean isBufferAttribute]</h3>
<p>Read-only flag to check if a given object is of type [name].</p>
<h3>[property:Integer itemSize]</h3>
<p>
The length of vectors that are being stored in the
[page:BufferAttribute.array array].
</p>
<h3>[property:String name]</h3>
<p>Optional name for this attribute instance. Default is an empty string.</p>
<h3>[property:Boolean needsUpdate]</h3>
<p>
Flag to indicate that this attribute has changed and should be re-sent to
the GPU. Set this to true when you modify the value of the array.<br /><br />
Setting this to true also increments the [page:BufferAttribute.version version].
</p>
<h3>[property:Boolean normalized]</h3>
<p>
Indicates how the underlying data in the buffer maps to the values in the
GLSL shader code. See the constructor above for details.
</p>
<h3>[property:Function onUploadCallback]</h3>
<p>
A callback function that is executed after the Renderer has transferred
the attribute array data to the GPU.
</p>
<h3>[property:Object updateRange]</h3>
<p>
Object containing:<br />
[page:Integer offset]: Default is `0`. Position at which to start
update.<br />
[page:Integer count]: Default is `-1`, which means don't use update
ranges. <br /><br />
This can be used to only update some components of stored vectors (for
example, just the component related to color).
</p>
<h3>[property:Usage usage]</h3>
<p>
Defines the intended usage pattern of the data store for optimization
purposes. Corresponds to the `usage` parameter of
[link:https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/bufferData WebGLRenderingContext.bufferData](). Default is [page:BufferAttributeUsage StaticDrawUsage]. See usage [page:BufferAttributeUsage constants] for all
possible values. <br /><br />
Note: After the initial use of a buffer, its usage cannot be changed.
Instead, instantiate a new one and set the desired usage before the next
render.
</p>
<h3>[property:Integer version]</h3>
<p>
A version number, incremented every time the
[page:BufferAttribute.needsUpdate needsUpdate] property is set to true.
</p>
<h2>Methods</h2>
<h3>[method:this applyMatrix3]( [param:Matrix3 m] )</h3>
<p>
Applies matrix [page:Matrix3 m] to every Vector3 element of this
BufferAttribute.
</p>
<h3>[method:this applyMatrix4]( [param:Matrix4 m] )</h3>
<p>
Applies matrix [page:Matrix4 m] to every Vector3 element of this
BufferAttribute.
</p>
<h3>[method:this applyNormalMatrix]( [param:Matrix3 m] )</h3>
<p>
Applies normal matrix [page:Matrix3 m] to every Vector3 element of this
BufferAttribute.
</p>
<h3>[method:this transformDirection]( [param:Matrix4 m] )</h3>
<p>
Applies matrix [page:Matrix4 m] to every Vector3 element of this
BufferAttribute, interpreting the elements as a direction vectors.
</p>
<h3>[method:BufferAttribute clone]()</h3>
<p>Return a copy of this bufferAttribute.</p>
<h3>[method:this copy]( [param:BufferAttribute bufferAttribute] )</h3>
<p>Copies another BufferAttribute to this BufferAttribute.</p>
<h3>[method:this copyArray]( array )</h3>
<p>
Copy the array given here (which can be a normal array or TypedArray) into
[page:BufferAttribute.array array].<br /><br />
See
[link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/set TypedArray.set] for notes on requirements if copying a TypedArray.
</p>
<h3>[method:this copyAt] ( [param:Integer index1], [param:BufferAttribute bufferAttribute], [param:Integer index2] )</h3>
<p>Copy a vector from bufferAttribute[index2] to [page:BufferAttribute.array array][index1].</p>
<h3>[method:Number getComponent]( [param:Integer index], [param:Integer component] ) </h3>
<p>Returns the given component of the vector at the given index.</p>
<h3>[method:Number getX]( [param:Integer index] )</h3>
<p>Returns the x component of the vector at the given index.</p>
<h3>[method:Number getY]( [param:Integer index] )</h3>
<p>Returns the y component of the vector at the given index.</p>
<h3>[method:Number getZ]( [param:Integer index] )</h3>
<p>Returns the z component of the vector at the given index.</p>
<h3>[method:Number getW]( [param:Integer index] )</h3>
<p>Returns the w component of the vector at the given index.</p>
<h3>[method:this onUpload]( [param:Function callback] )</h3>
<p>
Sets the value of the onUploadCallback property.<br /><br />
In the [example:webgl_buffergeometry WebGL / Buffergeometry] this is used
to free memory after the buffer has been transferred to the GPU.
</p>
<h3>[method:this set] ( [param:Array value], [param:Integer offset] )</h3>
<p>
value -- an [page:Array] or [page:TypedArray] from which to copy values.
<br />
offset -- (optional) index of the [page:BufferAttribute.array array] at
which to start copying.<br /><br />
Calls
[link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/set TypedArray.set]( [page:Array value], [page:Integer offset] ) on the
[page:BufferAttribute.array array].<br /><br />
In particular, see that page for requirements on [page:Array value] being
a [page:TypedArray].
</p>
<h3>[method:this setUsage] ( [param:Usage value] )</h3>
<p>
Set [page:BufferAttribute.usage usage] to value. See usage
[page:BufferAttributeUsage constants] for all possible input values.
<br /><br />
Note: After the initial use of a buffer, its usage cannot be changed.
Instead, instantiate a new one and set the desired usage before the next
render.
</p>
<h3>[method:Number setComponent]( [param:Integer index], [param:Integer component], [param:Float value] ) </h3>
<p>Sets the given component of the vector at the given index.</p>
<h3>[method:this setX]( [param:Integer index], [param:Float x] )</h3>
<p>Sets the x component of the vector at the given index.</p>
<h3>[method:this setY]( [param:Integer index], [param:Float y] )</h3>
<p>Sets the y component of the vector at the given index.</p>
<h3>[method:this setZ]( [param:Integer index], [param:Float z] )</h3>
<p>Sets the z component of the vector at the given index.</p>
<h3>[method:this setW]( [param:Integer index], [param:Float w] )</h3>
<p>Sets the w component of the vector at the given index.</p>
<h3>[method:this setXY]( [param:Integer index], [param:Float x], [param:Float y] )</h3>
<p>Sets the x and y components of the vector at the given index.</p>
<h3>[method:this setXYZ]( [param:Integer index], [param:Float x], [param:Float y], [param:Float z] )</h3>
<p>Sets the x, y and z components of the vector at the given index.</p>
<h3>[method:this setXYZW]( [param:Integer index], [param:Float x], [param:Float y], [param:Float z], [param:Float w] )
</h3>
<p>Sets the x, y, z and w components of the vector at the given index.</p>
<h2>Source</h2>
<p>
[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]
</p>
</body>
</html>