Indirect args buffer (5×u32 per instance). This pass writes only the instanceCount field; the caller fills the rest and resets instanceCount to its visible value each frame before this pass runs.
OptionalhizOptional Hi-Z pyramid (from HiZPass) for occlusion culling. Omit for frustum-only culling.
Per-instance world bounding spheres (vec4 center.xyz + radius), storage-read. A negative radius means "never cull" (kept regardless of frustum / Hi-Z).