This vertex shader output register contains a per-vertex fog color.
A register consists of properties that determine how each register behaves.
|Count||One vector, of which only one component can be used and must be specified by the component mask|
The output fog value registers. The value is the fog factor to be interpolated and then routed to the fog table. Only the scalar x-component of the fog is used.
Build date: 11/16/2013