WebGLRenderingContext.bufferData()
The WebGLRenderingContext.bufferData()
method of the WebGL API initializes and creates the
buffer object's data store.
Syntax
// WebGL1:
void gl.bufferData(target, size, usage);
void gl.bufferData(target, ArrayBuffer? srcData, usage);
void gl.bufferData(target, ArrayBufferView srcData, usage);
// WebGL2:
void gl.bufferData(target, ArrayBufferView srcData, usage, 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.
-
-
size
-
A
GLsizeiptr
setting the size in bytes of the buffer object's data store. srcData
Optional-
An
ArrayBuffer
,SharedArrayBuffer
or one of theArrayBufferView
typed array types that will be copied into the data store. Ifnull
, a data store is still created, but the content is uninitialized and undefined. usage
-
A
GLenum
specifying the intended usage pattern of the data store for optimization purposes. Possible values:-
gl.STATIC_DRAW
: The contents are intended to be specified once by the application, and used many times as the source for WebGL drawing and image specification commands. -
gl.DYNAMIC_DRAW
: The contents are intended to be respecified repeatedly by the application, and used many times as the source for WebGL drawing and image specification commands. -
gl.STREAM_DRAW
: The contents are intended to be specified once by the application, and used at most a few times as the source for WebGL drawing and image specification commands. - When using a WebGL 2 context, the following values are available additionally:
-
gl.STATIC_READ
: The contents are intended to be specified once by reading data from WebGL, and queried many times by the application. -
gl.DYNAMIC_READ
: The contents are intended to be respecified repeatedly by reading data from WebGL, and queried many times by the application. -
gl.STREAM_READ
: The contents are intended to be specified once by reading data from WebGL, and queried at most a few times by the application -
gl.STATIC_COPY
: The contents are intended to be specified once by reading data from WebGL, and used many times as the source for WebGL drawing and image specification commands. -
gl.DYNAMIC_COPY
: The contents are intended to be respecified repeatedly by reading data from WebGL, and used many times as the source for WebGL drawing and image specification commands. -
gl.STREAM_COPY
: The contents are intended to be specified once by reading data from WebGL, and used at most a few times as the source for WebGL drawing and image specification commands.
-
-
srcOffset
-
A
GLuint
specifying the element index offset where to start reading the buffer. length
Optional-
A
GLuint
defaulting to 0.
Return value
None.
Exceptions
-
A
gl.OUT_OF_MEMORY
error is thrown if the context is unable to create a data store with the givensize
. - A
gl.INVALID_VALUE
error is thrown ifsize
is negative. -
A
gl.INVALID_ENUM
error is thrown iftarget
orusage
are not one of the allowed enums.
Examples
Using bufferData
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);
Getting buffer information
To check the current buffer usage and buffer size, use the
WebGLRenderingContext.getBufferParameter()
method.
gl.getBufferParameter(gl.ARRAY_BUFFER, gl.BUFFER_SIZE);
gl.getBufferParameter(gl.ARRAY_BUFFER, gl.BUFFER_USAGE);
Getting size of a typed array
To calculate size parameter for a typed array.
var dataArray = new Float32Array([1, 2, 3, 4]);
var sizeInBytes = dataArray.length * dataArray.BYTES_PER_ELEMENT;
Specifications
Specification |
---|
WebGL Specification # 5.14.5 |
Browser compatibility
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