WebGLRenderingContext.bufferSubData()

The WebGLRenderingContext.bufferSubData() method of the WebGL API updates a subset of a buffer object's data store.

Syntax

// WebGL1
bufferSubData(target, offset)
bufferSubData(target, offset, srcData)

// WebGL2
bufferSubData(target, dstByteOffset, srcOffset)
bufferSubData(target, dstByteOffset, srcData, srcOffset)
bufferSubData(target, dstByteOffset, srcData, srcOffset, length)

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.

dstByteOffset

A GLintptr specifying an offset in bytes where the data replacement will start.

srcData Optional

An ArrayBuffer, SharedArrayBuffer or one of the ArrayBufferView typed array types that will be copied into the data store.

srcOffset

A GLuint specifying the element index offset where to start reading the buffer.

length Optional

A GLuint defaulting to 0.

Return value

None (undefined).

Exceptions

  • A gl.INVALID_VALUE error is thrown if the data would be written past the end of the buffer or if data is null.
  • A gl.INVALID_ENUM error is thrown if target is not one of the allowed enums.

Examples

Using bufferSubData

var canvas = document.getElementById('canvas');
var gl = canvas.getContext('webgl');
var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, 1024, gl.STATIC_DRAW);
gl.bufferSubData(gl.ARRAY_BUFFER, 512, data);

Specifications

Specification
WebGL Specification
# 5.14.5

Browser compatibility

BCD tables only load in the browser

See also