Unity 2018 Shaders and Effects Cookbook - Third Edition

Output semantics

When binding, semantics are used in vertOutput; they do not automatically guarantee that fields will be initialized. Quite the opposite; it's our responsibility to do so. The compiler will do its best to ensure that the fields are initialized with the right data:

Binding semantics	Description
POSITION, SV_POSITION, HPOS	The position of a vertex in camera coordinates (clip space, from zero to one for each dimension)
COLOR, COLOR0, COL0, COL, SV_TARGET	The front primary color
COLOR1, COL1	The front secondary color
TEXCOORD0, TEXCOORD1, …, TEXCOORDi, TEXi	The i-th UV data stored in the vertex
WPOS	The position, in pixels, in the window (origin in the lower left corner)

If, for any reason, ...