This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The WebGL2RenderingContext.getBufferSubData()
method of the WebGL 2 API reads data from a buffer binding point and writes them to an ArrayBuffer
or SharedArrayBuffer
.
Syntax
void gl.getBufferSubData(target, srcByteOffset, ArrayBufferView dstData, optional dstOffset, optional 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.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.
srcByteOffset
- A
GLintptr
specifying the byte offset from which to start reading from the buffer. dstData
- An
ArrayBuffer
orSharedArrayBuffer
to which to write the buffer data. - srcOffset Optional
- A
GLuint
specifying the element index offset where to start reading the buffer. length
Optional- A
GLuint
defaulting to 0.
Return value
None.
Exceptions
An INVALID_VALUE
error is generated if:
offset
+returnedData.byteLength
would extend beyond the end of the bufferreturnedData
isnull
offset
is less than zero.
An INVALID_OPERATION
error is generated if:
- zero is bound to
target
target
isTRANSFORM_FEEDBACK_BUFFER
, and any transform feedback object is currently active.
Examples
var buffer = gl.createBuffer(); gl.bindBuffer(gl.ARRAY_BUFFER, buffer); gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW); var arrBuffer = new ArrayBuffer(vertices.length * Float32Array.BYTES_PER_ELEMENT); gl.getBufferSubData(gl.ARRAY_BUFFER, 0, arrBuffer);
Specifications
Specification | Status | Comment |
---|---|---|
WebGL 2.0 The definition of 'getBufferSubData' in that specification. |
Editor's Draft | Initial definition. |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
getBufferSubData | Chrome Full support 56 | Edge Full support 79 | Firefox Full support 51 | IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support 58 | Chrome Android Full support 58 | Firefox Android Full support 51 | Opera Android Full support Yes | Safari iOS No support No | Samsung Internet Android Full support 7.0 |
SharedArrayBuffer as a parameter | Chrome Full support 60 | Edge Full support 79 | Firefox Full support 79 | IE No support No | Opera Full support 47 | Safari No support No | WebView Android Full support 60 | Chrome Android Full support 60 | Firefox Android ? | Opera Android Full support 44 | Safari iOS No support No | Samsung Internet Android Full support 8.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown