Chapter 388: BufferNode

Core Idea

A special type of uniform node which represents array-like data as uniform buffers. The access usually happens via element() which returns an instance of ArrayElementNode. For example:

In general, it is recommended to use the more managed UniformArrayNode since it handles more input types and automatically cares about buffer paddings.

Key Concepts

• bufferCount : number: The uniform node that holds the value of the reference node.
• bufferType : string: The data type of the buffer.
• isBufferNode : boolean (readonly): This flag can be used for type testing.
• updateRanges : Array.<{start: number, count: number}>: An array of update ranges.

Code Examples

const bufferNode = buffer( array, 'mat4', count );
const matrixNode = bufferNode.element( index ); // access a matrix from the buffer

• What it demonstrates: Typical usage of BufferNode.

Reference Tables

Constructor

Signature
new BufferNode( value : Array.<number>, bufferType : string, bufferCount : number )

Properties

Property	Description
.bufferCount : number	The uniform node that holds the value of the reference node.
.bufferType : string	The data type of the buffer.
.isBufferNode : boolean (readonly)	This flag can be used for type testing.
.updateRanges : Array.<{start: number, count: number}>	An array of update ranges.

Methods

Method	Description
.addUpdateRange( start : number, count : number )	Adds a range of data in the data array to be updated on the GPU.
.clearUpdateRanges()	Clears the update ranges.
.getElementType( builder : NodeBuilder ) : string	The data type of the buffer elements.
.getInputType( builder : NodeBuilder ) : string	Overwrites the default implementation to return a fixed value 'buffer'.

Key Takeaways

1. BufferNode extends: EventDispatcher → Node → InputNode → UniformNode
2. Most relevant properties: bufferCount, bufferType, isBufferNode, updateRanges.
3. Key methods: addUpdateRange, clearUpdateRanges, getElementType, getInputType.

Connects To

• EventDispatcher: parent class
• Node: parent class
• InputNode: parent class
• UniformNode: parent class
• Source: src/nodes/accessors/BufferNode.js