struct DrawIndirectArgs {
  vertexCount : atomic<u32>;
}

@group(0) @binding(5) var<storage, read_write> drawOut : DrawIndirectArgs;

var<private> cubeVerts : u32 = 0u;

@stage(compute) @workgroup_size(1)
fn computeMain(@builtin(global_invocation_id) global_id : vec3<u32>) {
  let firstVertex : u32 = atomicAdd(&(drawOut.vertexCount), cubeVerts);
}