precision of VertexData::height

[pasu]

if the type of height is unsigned short, we should use [0, 65,535] instead of [0, 32767]. I guess we choose 32767 due to compatibility issues. Thank you for the explanation.

[pasu]

I think I find the reason, the value before zigzag is short because it is possible to be negative, after the zigzag, it is unsigned short, so, the maxShort is 32767.