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.
bufferSubData(target, offset)
bufferSubData(target, offset, srcData)targetA GLenum specifying the binding point (target). Possible values:
gl.ARRAY_BUFFERBuffer containing vertex attributes, such as vertex coordinates, texture coordinate data, or vertex color data.
gl.ELEMENT_ARRAY_BUFFERBuffer used for element indices.
offsetA GLintptr specifying an offset in bytes where the data replacement will start.
srcData OptionalA TypedArray or a DataView that views an ArrayBuffer or SharedArrayBuffer that will be copied into the data store.
None (undefined).
gl.INVALID_VALUE error is thrown if the data would be written past the end of the buffer or if data is null.gl.INVALID_ENUM error is thrown if target is not one of the allowed enums.bufferSubDataconst 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);