SPIR-V Built-In

SubgroupId

Subgroup ID
SubgroupId

Decorating a variable with the SubgroupId built-in decoration will make that variable contain the index of the subgroup within the local workgroup. This variable is in range [0, NumSubgroups-1].

Valid Usage

VUID-SubgroupId-SubgroupId-04367

The SubgroupId decoration must be used only within the GLCompute, MeshEXT, TaskEXT, MeshNV, or TaskNV

Execution Model

VUID-SubgroupId-SubgroupId-04368

The variable decorated with SubgroupId must be declared using the Input Storage Class

VUID-SubgroupId-SubgroupId-04369

The variable decorated with SubgroupId must be declared as a scalar 32-bit integer value