resolveCounterHeap(_:range:buffer:fenceToWait:fenceToUpdate:)

Declaration

func resolveCounterHeap(_ counterHeap: any MTL4CounterHeap, range: Range<Int>, buffer: MTL4BufferRange, fenceToWait: (any MTLFence)? = nil, fenceToUpdate: (any MTLFence)? = nil)

Parameters

• counterHeap:

  A counter heap the command resolves.

• range:

  A range of index values within the heap to resolve.

• buffer:

  A buffer where the command stores the resolved data.

• fenceToWait:

  An optional fence the GPU waits for before starting; otherwise nil.

• fenceToUpdate:

  An optional fence the system updates after the command finishes resolving the data; otherwise nil.

Discussion

The command converts the data within a counter heap into a common format and stores it in buffer.

The command places each entry in the counter heap within range sequentially. Each entry has a fixed size that you can query by calling the size(ofCounterHeapEntry:) method.

This command runs during the blit stage of the GPU timeline. Barrier against this stage to ensure the data is present in the buffer before you access it.

Similarly, your app needs to synchronize any GPU accesses to buffer after the command completes with a barrier.

If your app needs to access buffer from the CPU, signal an MTLSharedEvent to notify the CPU when it’s ready. Alternatively, you can resolve the heap’s data from the CPU by calling the heap’s resolveCounterRange: method.