Note: This feature is available in Web Workers.
The WebGL2RenderingContext.copyBufferSubData() method of the WebGL 2 API copies part of the data of a buffer to another buffer.
copyBufferSubData(readTarget, writeTarget, readOffset, writeOffset, size)readTarget, writeTargetA GLenum specifying the binding point (target) from whose data store should be read or written. 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.gl.COPY_READ_BUFFER: Buffer for copying from one buffer object to another (provided specifically for copy operations).gl.COPY_WRITE_BUFFER: Buffer for copying from one buffer object to another (provided specifically for copy operations).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.readOffset, writeOffsetA GLintptr specifying the byte offset from which to start reading from or writing to the buffer.
sizeA GLsizei in bytes specifying the size of the data to be copied from readTarget to writeTarget.
None (undefined).
const srcBuffer = gl.createBuffer();
const dstBuffer = gl.createBuffer();
const data = new Float32Array(vertices);
const length = vertices.length * 4;
gl.bindBuffer(gl.ARRAY_BUFFER, srcBuffer);
gl.bufferData(gl.ARRAY_BUFFER, data, gl.STATIC_DRAW);
gl.bindBuffer(gl.COPY_READ_BUFFER, srcBuffer);
gl.bindBuffer(gl.ARRAY_BUFFER, dstBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(length), gl.STATIC_DRAW);
gl.copyBufferSubData(gl.COPY_READ_BUFFER, gl.ARRAY_BUFFER, 0, 0, length);