javascript
/
three.js
镜像自地址 https://github.com/tazdij/three.js.git


			
				
					
						
						
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		<h1>[name]</h1>

		<p class="desc">
			This buffer attribute class does not construct a VBO. Instead, it uses
			whatever VBO is passed in constructor and can later be altered via the
			*buffer* property.<br /><br />
			It is required to pass additional params alongside the VBO. Those are:
			the GL context, the GL data type, the number of components per vertex,
			the number of bytes per component, and the number of vertices.<br /><br />
			The most common use case for this class is when some kind of GPGPU
			calculation interferes or even produces the VBOs in question.
		</p>

		<h2>Constructor</h2>
		<h3>[name]( [param:WebGLBuffer buffer], [param:GLenum type], [param:Integer itemSize], [param:Integer elementSize], [param:Integer count] )</h3>
		<p>
		*buffer* — Must be a <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebGLBuffer" target="_blank">WebGLBuffer</a>.
		<br />
		*type* — One of <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants#Data_types" target="_blank">WebGL Data Types</a>.
		<br />
		*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 />
		*elementSize* — 1, 2 or 4. The corresponding size (in bytes) for the given "type" param.
		<ul>
			<li>gl.FLOAT: 4</li>
			<li>gl.UNSIGNED_SHORT: 2</li>
			<li>gl.SHORT: 2</li>
			<li>gl.UNSIGNED_INT: 4</li>
			<li>gl.INT: 4</li>
			<li>gl.BYTE: 1</li>
			<li>gl.UNSIGNED_BYTE: 1</li>
		</ul>
		*count* — The expected number of vertices in VBO.
		</p>

		<h2>Properties</h2>

		<h3>[property:WebGLBuffer buffer]</h3>
		<p>
			The current <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebGLBuffer" target="_blank">WebGLBuffer</a> instance.
		</p>

		<h3>[property:Integer count]</h3>
		<p>
			The expected number of vertices in VBO.
		</p>

		<h3>[property:Integer itemSize]</h3>
		<p>
			How many values make up each item (vertex).
		</p>

		<h3>[property:Integer elementSize]</h3>
		<p>
			Stores the corresponding size in bytes for the current *type* property value.
		</p>
		<p>
			See above (constructor) for a list of known type sizes.
		</p>

		<h3>[property:GLenum type]</h3>
		<p>
			A <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/Constants#Data_types" target="_blank">WebGL Data Type</a>
			describing the underlying VBO contents.
		</p>
		<p>
			Set this property together with *elementSize*. The recommended way is
			using the *setType* method.
		</p>

		<h3>[property:Boolean isGLBufferAttribute]</h3>
		<p>
			Read-only. Always *true*.
		</p>

		<h2>Methods</h2>

		<h3>[method:null setBuffer]( buffer ) </h3>
		<p>Sets the *buffer* property.</p>

		<h3>[method:null setType]( type, elementSize ) </h3>
		<p>Sets the both *type* and *elementSize* properties.</p>

		<h3>[method:null setItemSize]( itemSize ) </h3>
		<p>Sets the *itemSize* property.</p>

		<h3>[method:null setCount]( count ) </h3>
		<p>Sets the *count* property.</p>

		<h3>[property:Integer version]</h3>
		<p>
		A version number, incremented every time the needsUpdate property is set to true.
		</p>

		<h3>[property:Boolean needsUpdate]</h3>
		<p>
		Default is *false*. Setting this to true increments [page:GLBufferAttribute.version version].
		</p>

		<h2>Source</h2>
		<p>
			[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]
		</p>
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