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WebGLRenderingContext: bufferSubData() method

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

Syntax

js

// 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, a DataView, or a TypedArray 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

js

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);
gl.bufferSubData(gl.ARRAY_BUFFER, 512, data);

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
bufferSubData 9 12 4 11 12 5.1 4.4.3 25 4 12 8 1.5

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/bufferSubData