VBO_FLAG_BITMAP_OUT
VBO_RESET_DIRTY | VBO_FLAG_BITMAP_OUT, bitmap);
CTASSERT(VNO_FLAG_BITMAP_OUT == VBO_FLAG_BITMAP_OUT);
const bool bit_output = (oper & VBO_FLAG_BITMAP_OUT) != 0;
oper & ~(VBO_FLAG_BITMAP_IN | VBO_FLAG_BITMAP_OUT);