A primitive's tpage attribute.
This is a common building block piece used in primitives. The binary representation is meant to be the same as the 16-bits tpage argument for GPU commands. See the TPage struct for actual usage, or the various triangle and quad primitives.
When dealing with tpage attributes, it can be more efficient to create a new TPageAttr object on the stack, setting its properties, and then assigning it to the primitive's attribute, instead of directly manipulating the existing one, as the compiler will better optimize the former sequence of operations.
