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<!DOCTYPE html>
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<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.<br /><br />
Data is stored as vectors of any length (defined by [page:BufferAttribute.itemSize itemSize]),
and in general in the methods outlined below if passing in an index, this is automatically
multiplied by the vector length.
</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:BufferGeometry 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 -32767 - +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>
Stores the [page:BufferAttribute.array array]'s length divided by the [page:BufferAttribute.itemSize itemSize].<br /><br />
If the buffer is storing a 3-component vector (such as a position, normal, or color),
then this will count the number of such vectors stored.
</p>
<h3>[property:Boolean isBufferAttribute]</h3>
<p>
Used to check whether this or derived classes are BufferAttributes. Default is *true*.<br /><br />
You should not change this, as it used internally for optimisation.
</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 *THREE.StaticDrawUsage*.
</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:BufferAttribute clone]() </h3>
<p>Return a copy of this bufferAttribute.</p>
<h3>[method:BufferAttribute copy]( [param:BufferAttribute bufferAttribute] )</h3>
<p>Copies another BufferAttribute to this BufferAttribute.</p>
<h3>[method:BufferAttribute 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:null 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:BufferAttribute copyColorsArray]( [param:Array colors] ) </h3>
<p>Copy an array representing RGB color values into [page:BufferAttribute.array array].</p>
<h3>[method:BufferAttribute copyVector2sArray]( [param:Array vectors] ) </h3>
<p>Copy an array representing [page:Vector2]s into [page:BufferAttribute.array array].</p>
<h3>[method:BufferAttribute copyVector3sArray]( [param:Array vectors] ) </h3>
<p>Copy an array representing [page:Vector3]s into [page:BufferAttribute.array array].</p>
<h3>[method:BufferAttribute copyVector4sArray]( [param:Array vectors] ) </h3>
<p>Copy an array representing [page:Vector4]s into [page:BufferAttribute.array array].</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:null 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:BufferAttribute 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:BufferAttribute setUsage] ( [param:Usage value] ) </h3>
<p>Set [page:BufferAttribute.usage usage] to value.</p>
<h3>[method:BufferAttribute setX]( [param:Integer index], [param:Float x] ) </h3>
<p>Sets the x component of the vector at the given index.</p>
<h3>[method:BufferAttribute setY]( [param:Integer index], [param:Float y] ) </h3>
<p>Sets the y component of the vector at the given index.</p>
<h3>[method:BufferAttribute setZ]( [param:Integer index], [param:Float z] ) </h3>
<p>Sets the z component of the vector at the given index.</p>
<h3>[method:BufferAttribute setW]( [param:Integer index], [param:Float w] ) </h3>
<p>Sets the w component of the vector at the given index.</p>
<h3>[method:BufferAttribute 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:BufferAttribute 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:BufferAttribute 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>
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