The WebGLRenderingContext.bufferSubData()
method of the WebGL API updates a subset of a buffer object's data store.
Syntax
void gl.bufferSubData(target, offset, data);
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.
- offset
- A
GLintptr
specifying an offset in bytes where the data replacement will start. - data Optional
- An
ArrayBuffer
,SharedArrayBuffer
or one of theArrayBufferView
typed array types that will be copied into the data store.
Return value
None.
Exceptions
- A
gl.INVALID_VALUE
error is thrown if the data would be written past the end of the buffer or ifdata
isnull
. - A
gl.INVALID_ENUM
error is thrown iftarget
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 | Status | Comment |
---|---|---|
WebGL 1.0 The definition of 'bufferSubData' in that specification. |
Recommendation | Initial definition for WebGL. |
OpenGL ES 2.0 The definition of 'glBufferSubData' in that specification. |
Standard | Man page of the OpenGL ES 2 API. |
OpenGL ES 3.0 The definition of 'glBufferSubData' in that specification. |
Standard | Man page of the (similar) OpenGL ES 3 API. Adds new target buffers:gl.COPY_READ_BUFFER ,gl.COPY_WRITE_BUFFER ,gl.TRANSFORM_FEEDBACK_BUFFER ,gl.UNIFORM_BUFFER ,gl.PIXEL_PACK_BUFFER ,gl.PIXEL_UNPACK_BUFFER . |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 9 | 12 | 4.0 (2.0) | 11 | 12 | 5.1 |
WebGL 2 | No support [2] | No support | Nightly build [1] | No support | No support | No support |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | ? | 25 | 4.0 (2.0) | 1.0 | ? | 12 | 8.0 |
WebGL 2 | No support | No support | No support | No support | No support | No support | No support |
[1] WebGL 2 is enabled by default in Firefox Nightly. To enable it in a release version of Firefox, set the preference webgl.enable-prototype-webgl2
to true
in about:config.
[2] To use an experimental implementation of WebGL 2 in Chrome, you have to start Chrome with the runtime flag --enable-unsafe-es3-apis
.