WebGLRenderingContext: bufferSubData() method

{{APIRef("WebGL")}}{{AvailableInWorkers}}

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 {{domxref("WebGL_API/Types", "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.

• offset

  • : A {{domxref("WebGL_API/Types", "GLintptr")}} specifying an offset in bytes where the data replacement will start.

• srcData {{optional_inline}}

  • : A {{jsxref("TypedArray")}} or a {{jsxref("DataView")}} that views an {{jsxref("ArrayBuffer")}} or {{jsxref("SharedArrayBuffer")}} that will be copied into the data store.

Return value

None ({{jsxref("undefined")}}).

Exceptions

• A gl.INVALID_VALUE error is thrown if the data would be written past the end of the buffer or if data is null.
• A gl.INVALID_ENUM error is thrown if target is 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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("WebGL2RenderingContext.bufferSubData()")}}
• {{domxref("WebGLRenderingContext.createBuffer()")}}
• {{domxref("WebGLRenderingContext.bufferData()")}}
• Other buffers: {{domxref("WebGLFramebuffer")}}, {{domxref("WebGLRenderbuffer")}}