     // // Read the pixels asynchronously
            // gl.readPixels( 0, 0, gl.canvas.width, gl.canvas.height, gl.RGBA, gl.UNSIGNED_BYTE, 0 );
            //
            // // Wait for the read operation to complete
            // gl.finish();
            //
            // // Get the pixel data from the buffer
            // gl.bindBuffer( gl.PIXEL_PACK_BUFFER, this.pbo );
            // gl.getBufferSubData( gl.PIXEL_PACK_BUFFER, 0, this.rgba );
            //
            // // Unbind the buffer and delet