GLBufferAttribute
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.
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.
The most common use case for this class is when some kind of GPGPU calculation interferes or even produces the VBOs in question.
Constructor
GLBufferAttribute( buffer : WebGLBuffer, type : GLenum, itemSize : Integer, elementSize : Integer, count : Integer )
buffer — Must be a WebGLBuffer.
type — One of WebGL Data Types.
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.
elementSize — 1, 2 or 4. The corresponding size (in bytes) for the given "type" param.
- gl.FLOAT: 4
- gl.UNSIGNED_SHORT: 2
- gl.SHORT: 2
- gl.UNSIGNED_INT: 4
- gl.INT: 4
- gl.BYTE: 1
- gl.UNSIGNED_BYTE: 1
Properties
.buffer : WebGLBuffer
The current WebGLBuffer instance.
.count : Integer
The expected number of vertices in VBO.
.itemSize : Integer
How many values make up each item (vertex).
.elementSize : Integer
Stores the corresponding size in bytes for the current type property value.
See above (constructor) for a list of known type sizes.
.type : GLenum
A WebGL Data Type describing the underlying VBO contents.
Set this property together with elementSize. The recommended way is using the setType method.
.isGLBufferAttribute : Boolean
Read-only. Always true.
Methods
.setBuffer ( buffer ) : null
Sets the buffer property.
.setType ( type, elementSize ) : null
Sets the both type and elementSize properties.
.setItemSize ( itemSize ) : null
Sets the itemSize property.
.setCount ( count ) : null
Sets the count property.
.version : Integer
A version number, incremented every time the needsUpdate property is set to true.
.needsUpdate : Boolean
Default is false. Setting this to true increments version.