Indices for which thread group a compute shader is executing in. The indices are to the whole group and not an individual thread. Possible values vary across the range passed as parameters to Dispatch. For example calling Dispatch(2,1,1) results in possible values of 0,0,0 and 1,0,0.
Defines the group offset within a Dispatch call, per dimension of the dispatch call.
This system value is optional.
The following illustration shows the relationship between the parameters passed to Dispatch, Dispatch(5,3,2), the values specified in the numthreads attribute, numthreads(10,8,3), and values that will passed to the compute shader for the thread-related system values (SV_GroupIndex,SV_DispatchThreadID,SV_GroupThreadID,SV_GroupID).
This function is supported in the following types of shaders: