Enum wgpu_hal::vulkan::Fence

pub enum Fence {
    TimelineSemaphore(Semaphore),
    FencePool {
        last_completed: FenceValue,
        active: Vec<(FenceValue, Fence)>,
        free: Vec<Fence>,
    },
}

The Api::Fence type for vulkan::Api.

This is an enum because there are two possible implementations of wgpu-hal fences on Vulkan: Vulkan fences, which work on any version of Vulkan, and Vulkan timeline semaphores, which are easier and cheaper but require non-1.0 features.

Device::create_fence returns a TimelineSemaphore if VK_KHR_timeline_semaphore is available and enabled, and a FencePool otherwise.

Variants

TimelineSemaphore(Semaphore)

A Vulkan timeline semaphore.

These are simpler to use than Vulkan fences, since timeline semaphores work exactly the way wpgu_hal::Api::Fence is specified to work.

FencePool

A collection of Vulkan fences, each associated with a FenceValue.

The effective FenceValue of this variant is the greater of last_completed and the maximum value associated with a signalled fence in active.

Fences are available in all versions of Vulkan, but since they only have two states, “signaled” and “unsignaled”, we need to use a separate fence for each queue submission we might want to wait for, and remember which FenceValue each one represents.

Fields

last_completed: FenceValue

active: Vec<(FenceValue, Fence)>

The pending fence values have to be ascending.

free: Vec<Fence>

Trait Implementations

impl Debug for Fence

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.