Contents

updateFence(_:)

Encodes a command that instructs the GPU to update a fence after the acceleration structure pass completes.

Declaration

func updateFence(_ fence: any MTLFence)

Parameters

  • fence:

    A fence the pass updates after it completes.

Discussion

You can synchronize memory operations of an acceleration structure pass that access resources with an MTLFence. This method instructs the pass to update fence after it runs all its memory store operations to the resources it accesses. The fence indicates when other passes can access those resources without a race condition.

For more information about synchronization with fences, see:

Reuse a fence by waiting first and updating second

When encoding an acceleration structure pass that reuses a fence, wait for other passes to update the fence before repurposing that fence to notify subsequent passes with an update:

  1. Call the waitForFence(_:) method before encoding commands that need to wait for other passes.

  2. Call the updateFence(_:) method after encoding commands that later passes depend on.

The GPU driver evaluates the fences that apply to the pass and the commands that depend on those fences when your app commits the enclosing MTLCommandBuffer.

See Also

Preventing resource access conflicts