WebGLRenderingContext: bufferSubData() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Note: This feature is available in Web Workers.
The WebGLRenderingContext.bufferSubData() method of the
WebGL API updates a subset of a buffer
object's data store.
Syntax
bufferSubData(target, offset)
bufferSubData(target, offset, srcData)
Parameters
target-
A
GLenumspecifying 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
GLintptrspecifying an offset in bytes where the data replacement will start. srcDataOptional-
A
TypedArrayor aDataViewthat views anArrayBufferorSharedArrayBufferthat will be copied into the data store. srcOffset-
A
GLuintspecifying the element index offset where to start reading the buffer. lengthOptional-
A
GLuintdefaulting to 0.
Return value
None (undefined).
Exceptions
- A
gl.INVALID_VALUEerror is thrown if the data would be written past the end of the buffer or ifdataisnull. - A
gl.INVALID_ENUMerror is thrown iftargetis not one of the allowed enums.
Examples
Using bufferSubData
const canvas = document.getElementById("canvas");
const gl = canvas.getContext("webgl");
const buffer = gl.createBuffer();
const data = new Float32Array([1, 2, 3, 4]);
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
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