blur_grey_horiz(prev_smokebuf, cur_smokebuf, fb_width, fb_height, BLUR_RAD, 240);
blur_grey_horiz(prev_smokebuf, cur_smokebuf, fb_width, fb_height, BLUR_RAD, 240);
blur_grey_vert(cur_smokebuf, prev_smokebuf, fb_width, fb_height, BLUR_RAD, 240);
swap_smoke_buffers();
blur_grey_vert(cur_smokebuf, prev_smokebuf, fb_width, fb_height, BLUR_RAD, 240);
swap_smoke_buffers();