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
, aDataView
, or aTypedArray
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 ifdata
isnull
. -
A
gl.INVALID_ENUM
error is thrown iftarget
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
Specification |
---|
WebGL Specification # 5.14.5 |
Browser compatibility
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