impeller::SwapchainImplVK Class Reference

An instance of a swapchain that does NOT adapt to going out of date with the underlying surface. Errors will be indicated when the next drawable is acquired from this implementation of the swapchain. If the error is due the swapchain going out of date, the caller must recreate another instance by optionally stealing this implementations guts. More...

#include <swapchain_impl_vk.h>

Inheritance diagram for impeller::SwapchainImplVK:

Classes
struct	AcquireResult

Public Member Functions
	~SwapchainImplVK ()
bool	IsValid () const
AcquireResult	AcquireNextDrawable ()
vk::Format	GetSurfaceFormat () const
vk::SurfaceTransformFlagBitsKHR	GetLastTransform () const
std::shared_ptr< Context >	GetContext () const
std::pair< vk::UniqueSurfaceKHR, vk::UniqueSwapchainKHR >	DestroySwapchain ()

Static Public Member Functions
static std::shared_ptr< SwapchainImplVK >	Create (const std::shared_ptr< Context > &context, vk::UniqueSurfaceKHR surface, vk::SwapchainKHR old_swapchain=VK_NULL_HANDLE, vk::SurfaceTransformFlagBitsKHR last_transform=vk::SurfaceTransformFlagBitsKHR::eIdentity)

Detailed Description

An instance of a swapchain that does NOT adapt to going out of date with the underlying surface. Errors will be indicated when the next drawable is acquired from this implementation of the swapchain. If the error is due the swapchain going out of date, the caller must recreate another instance by optionally stealing this implementations guts.

Definition at line 31 of file swapchain_impl_vk.h.

Constructor & Destructor Documentation

~SwapchainImplVK()

impeller::SwapchainImplVK::~SwapchainImplVK

(

)

Definition at line 302 of file swapchain_impl_vk.cc.

                                  {
  DestroySwapchain();
}

References DestroySwapchain().

Member Function Documentation

AcquireNextDrawable()

SwapchainImplVK::AcquireResult impeller::SwapchainImplVK::AcquireNextDrawable

(

)

Wait on the host for the synchronizer fence.

Poll to see if the orientation has changed.

https://developer.android.com/games/optimize/vulkan-prerotation#using_polling

Get the next image index.

Record all subsequent cmd buffers as part of the current frame.

Definition at line 339 of file swapchain_impl_vk.cc.

                                                                  {
  auto context_strong = context_.lock();
  if (!context_strong) {
    return SwapchainImplVK::AcquireResult{};
  }
 
  const auto& context = ContextVK::Cast(*context_strong);
 
  current_frame_ = (current_frame_ + 1u) % synchronizers_.size();
 
  const auto& sync = synchronizers_[current_frame_];
 
  //----------------------------------------------------------------------------
  /// Wait on the host for the synchronizer fence.
  ///
  if (!sync->WaitForFence(context.GetDevice())) {
    VALIDATION_LOG << "Could not wait for fence.";
    return SwapchainImplVK::AcquireResult{};
  }
 
  //----------------------------------------------------------------------------
  /// Poll to see if the orientation has changed.
  ///
  /// https://developer.android.com/games/optimize/vulkan-prerotation#using_polling
  current_transform_poll_count_++;
  if (current_transform_poll_count_ >= kPollFramesForOrientation) {
    current_transform_poll_count_ = 0u;
    auto [caps_result, caps] =
        context.GetPhysicalDevice().getSurfaceCapabilitiesKHR(*surface_);
    if (caps_result != vk::Result::eSuccess) {
      VALIDATION_LOG << "Could not get surface capabilities: "
                     << vk::to_string(caps_result);
      return SwapchainImplVK::AcquireResult{};
    }
    if (caps.currentTransform != transform_if_changed_discard_swapchain_) {
      transform_if_changed_discard_swapchain_ = caps.currentTransform;
      return AcquireResult{true /* out of date */};
    }
  }
 
  //----------------------------------------------------------------------------
  /// Get the next image index.
  ///
  auto [acq_result, index] = context.GetDevice().acquireNextImageKHR(
      *swapchain_,          // swapchain
      1'000'000'000,        // timeout (ns) 1000ms
      *sync->render_ready,  // signal semaphore
      nullptr               // fence
  );
 
  switch (acq_result) {
    case vk::Result::eSuccess:
      // Keep going.
      break;
    case vk::Result::eSuboptimalKHR:
    case vk::Result::eErrorOutOfDateKHR:
      // A recoverable error. Just say we are out of date.
      return AcquireResult{true /* out of date */};
      break;
    default:
      // An unrecoverable error.
      VALIDATION_LOG << "Could not acquire next swapchain image: "
                     << vk::to_string(acq_result);
      return AcquireResult{false /* out of date */};
  }
 
  if (index >= images_.size()) {
    VALIDATION_LOG << "Swapchain returned an invalid image index.";
    return SwapchainImplVK::AcquireResult{};
  }
 
  /// Record all subsequent cmd buffers as part of the current frame.
  context.GetGPUTracer()->MarkFrameStart();
 
  auto image = images_[index % images_.size()];
  uint32_t image_index = index;
  return AcquireResult{SurfaceVK::WrapSwapchainImage(
      context_strong,  // context
      image,           // swapchain image
      [weak_swapchain = weak_from_this(), image, image_index]() -> bool {
        auto swapchain = weak_swapchain.lock();
        if (!swapchain) {
          return false;
        }
        return swapchain->Present(image, image_index);
      }  // swap callback
      )};
}

References impeller::BackendCast< ContextVK, Context >::Cast(), impeller::kPollFramesForOrientation, and VALIDATION_LOG.

Create()

std::shared_ptr< SwapchainImplVK > impeller::SwapchainImplVK::Create ( const std::shared_ptr< Context > &  context, vk::UniqueSurfaceKHR  surface, vk::SwapchainKHR  old_swapchain = VK_NULL_HANDLE, vk::SurfaceTransformFlagBitsKHR  last_transform = vk::SurfaceTransformFlagBitsKHR::eIdentity  )

static

Definition at line 140 of file swapchain_impl_vk.cc.

                                                  {
  return std::shared_ptr<SwapchainImplVK>(new SwapchainImplVK(
      context, std::move(surface), old_swapchain, last_transform));
}

Referenced by impeller::SwapchainVK::AcquireNextDrawable(), and impeller::SwapchainVK::Create().

DestroySwapchain()

std::pair< vk::UniqueSurfaceKHR, vk::UniqueSwapchainKHR > impeller::SwapchainImplVK::DestroySwapchain

(

)

Definition at line 318 of file swapchain_impl_vk.cc.

                                  {
  WaitIdle();
  is_valid_ = false;
  synchronizers_.clear();
  images_.clear();
  context_.reset();
  return {std::move(surface_), std::move(swapchain_)};
}

Referenced by ~SwapchainImplVK().

GetContext()

std::shared_ptr< Context > impeller::SwapchainImplVK::GetContext

(

)

const

Definition at line 335 of file swapchain_impl_vk.cc.

                                                         {
  return context_.lock();
}

GetLastTransform()

vk::SurfaceTransformFlagBitsKHR impeller::SwapchainImplVK::GetLastTransform

(

)

const

Definition at line 331 of file swapchain_impl_vk.cc.

                                                                      {
  return transform_if_changed_discard_swapchain_;
}

GetSurfaceFormat()

vk::Format impeller::SwapchainImplVK::GetSurfaceFormat

(

)

const

Definition at line 327 of file swapchain_impl_vk.cc.

                                                 {
  return surface_format_;
}

IsValid()

bool impeller::SwapchainImplVK::IsValid

(

)

const

Definition at line 306 of file swapchain_impl_vk.cc.

                                    {
  return is_valid_;
}

---

The documentation for this class was generated from the following files:

• impeller/renderer/backend/vulkan/swapchain_impl_vk.h
• impeller/renderer/backend/vulkan/swapchain_impl_vk.cc