blob: 9a71baba737977e3af60ab96a6f22729d89cbdbf [file] [log] [blame]
layout(metal, binding = 0) buffer ssbo {
atomicUint globalCounter;
};
workgroup atomicUint localCounter;
void main() {
// Initialize the local counter.
if (sk_LocalInvocationID.x == 0) {
atomicStore(localCounter, 0);
}
// Synchronize the threads in the workgroup so they all see the initial value.
workgroupBarrier();
// All threads increment the counter.
atomicAdd(localCounter, 1);
// Synchronize the threads again to ensure they have all executed the increment
// and the following load reads the same value across all threads in the
// workgroup.
workgroupBarrier();
// Add the workgroup-only tally to the global counter.
if (sk_LocalInvocationID.x == 0) {
atomicAdd(globalCounter, atomicLoad(localCounter));
}
}