开始

初始化

计算写入的层数numLevels

是否还有

未处理的层?

写入skipData

记录当前层的skipData信息

u8_seg0 u8_seg1
u9_seg0 u9_seg1
u10_seg0 u10_seg1
u11_seg0 u11_seg1

当前层是否为第0层?

u13_seg0 u13_seg1
u14_seg0 u14_seg1

写入指向下一层的信息childPointer

u16_seg0 u16_seg1
u17_seg0 u17_seg1 u17_seg2 u17_seg3
u18_seg0 u18_seg1 u18_seg2 u18_seg3