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