WebGLRenderingContext: bufferData() method

The WebGLRenderingContext.bufferData() method of the WebGL API initializes and creates the buffer object's data store.

Syntax

bufferData(target, size, usage)
bufferData(target, srcData, usage)

Parameters

target

A GLenum specifying the binding point (target). Possible values:

gl.ARRAY_BUFFER: Buffer containing vertex attributes, such as vertex coordinates, texture coordinate data, or vertex color data.
gl.ELEMENT_ARRAY_BUFFER: Buffer used for element indices.

When using a WebGL 2 context, the following values are available additionally:

gl.COPY_READ_BUFFER: Buffer for copying from one buffer object to another.
gl.COPY_WRITE_BUFFER: Buffer for copying from one buffer object to another.
gl.TRANSFORM_FEEDBACK_BUFFER: Buffer for transform feedback operations.
gl.UNIFORM_BUFFER: Buffer used for storing uniform blocks.
gl.PIXEL_PACK_BUFFER: Buffer used for pixel transfer operations.
gl.PIXEL_UNPACK_BUFFER: Buffer used for pixel transfer operations.

size

A GLsizeiptr setting the size in bytes of the buffer object's data store.

srcData Optional

An ArrayBuffer, SharedArrayBuffer, a TypedArray or a DataView that will be copied into the data store. If null, a data store is still created, but the content is uninitialized and undefined.

usage

A GLenum specifying the intended usage pattern of the data store for optimization purposes. Possible values:

gl.STATIC_DRAW: The contents are intended to be specified once by the application, and used many times as the source for WebGL drawing and image specification commands.
gl.DYNAMIC_DRAW: The contents are intended to be respecified repeatedly by the application, and used many times as the source for WebGL drawing and image specification commands.
gl.STREAM_DRAW: The contents are intended to be specified once by the application, and used at most a few times as the source for WebGL drawing and image specification commands.

When using a WebGL 2 context, the following values are available additionally:

gl.STATIC_READ: The contents are intended to be specified once by reading data from WebGL, and queried many times by the application.
gl.DYNAMIC_READ: The contents are intended to be respecified repeatedly by reading data from WebGL, and queried many times by the application.
gl.STREAM_READ: The contents are intended to be specified once by reading data from WebGL, and queried at most a few times by the application
gl.STATIC_COPY: The contents are intended to be specified once by reading data from WebGL, and used many times as the source for WebGL drawing and image specification commands.
gl.DYNAMIC_COPY: The contents are intended to be respecified repeatedly by reading data from WebGL, and used many times as the source for WebGL drawing and image specification commands.
gl.STREAM_COPY: The contents are intended to be specified once by reading data from WebGL, and used at most a few times as the source for WebGL drawing and image specification commands.

Return value

None (undefined).

Exceptions

A gl.OUT_OF_MEMORY error is thrown if the context is unable to create a data store with the given size.
A gl.INVALID_VALUE error is thrown if size is negative.
A gl.INVALID_ENUM error is thrown if target or usage are not one of the allowed enums.

Examples

Using bufferData

const canvas = document.getElementById("canvas");
const gl = canvas.getContext("webgl");
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, 1024, gl.STATIC_DRAW);

Getting buffer information

To check the current buffer usage and buffer size, use the WebGLRenderingContext.getBufferParameter() method.

gl.getBufferParameter(gl.ARRAY_BUFFER, gl.BUFFER_SIZE);
gl.getBufferParameter(gl.ARRAY_BUFFER, gl.BUFFER_USAGE);

Getting size of a typed array

To calculate size parameter for a typed array.

const dataArray = new Float32Array([1, 2, 3, 4]);
const sizeInBytes = dataArray.length * dataArray.BYTES_PER_ELEMENT;

Specifications

Specification
WebGL Specification # 5.14.5

Browser compatibility

BCD tables only load in the browser