[Impeller] Treat SubOptimalKHR as rotated.

impeller/renderer/backend/vulkan/swapchain_impl_vk.cc

@@ -124,13 +124,15 @@ static std::optional<vk::Queue> ChoosePresentQueue(
 std::shared_ptr<SwapchainImplVK> SwapchainImplVK::Create(
     const std::shared_ptr<Context>& context,
     vk::UniqueSurfaceKHR surface,
+    bool was_rotated,
     vk::SwapchainKHR old_swapchain) {
-  return std::shared_ptr<SwapchainImplVK>(
-      new SwapchainImplVK(context, std::move(surface), old_swapchain));
+  return std::shared_ptr<SwapchainImplVK>(new SwapchainImplVK(
+      context, std::move(surface), was_rotated, old_swapchain));
 }
 
 SwapchainImplVK::SwapchainImplVK(const std::shared_ptr<Context>& context,
                                  vk::UniqueSurfaceKHR surface,
+                                 bool was_rotated,
                                  vk::SwapchainKHR old_swapchain) {
   if (!context) {
     return;
@@ -197,7 +199,7 @@ SwapchainImplVK::SwapchainImplVK(const std::shared_ptr<Context>& context,
   );
   swapchain_info.imageArrayLayers = 1u;
   swapchain_info.imageUsage = vk::ImageUsageFlagBits::eColorAttachment;
-  swapchain_info.preTransform = caps.currentTransform;
+  swapchain_info.preTransform = vk::SurfaceTransformFlagBitsKHR::eIdentity;
   swapchain_info.compositeAlpha = composite.value();
   // If we set the clipped value to true, Vulkan expects we will never read back
   // from the buffer. This is analogous to [CAMetalLayer framebufferOnly] in
@@ -273,6 +275,8 @@ SwapchainImplVK::SwapchainImplVK(const std::shared_ptr<Context>& context,
   synchronizers_ = std::move(synchronizers);
   current_frame_ = synchronizers_.size() - 1u;
   is_valid_ = true;
+  was_rotated_ = was_rotated;
+  is_rotated_ = was_rotated;
 }
 
 SwapchainImplVK::~SwapchainImplVK() {
@@ -314,6 +318,10 @@ SwapchainImplVK::AcquireResult SwapchainImplVK::AcquireNextDrawable() {
     return {};
   }
 
+  if (was_rotated_ != is_rotated_) {
+    return AcquireResult{true /* out of date */};
+  }
+
   const auto& context = ContextVK::Cast(*context_strong);
 
   current_frame_ = (current_frame_ + 1u) % synchronizers_.size();
@@ -448,6 +456,10 @@ bool SwapchainImplVK::Present(const std::shared_ptr<SwapchainImageVK>& image,
       // successfully.
       [[fallthrough]];
     case vk::Result::eSuccess:
+      is_rotated_ = false;
+      return true;
+    case vk::Result::eSuboptimalKHR:
+      is_rotated_ = true;
       return true;
     default:
       VALIDATION_LOG << "Could not present queue: " << vk::to_string(result);

impeller/renderer/backend/vulkan/swapchain_impl_vk.h

@@ -31,6 +31,7 @@ class SwapchainImplVK final
   static std::shared_ptr<SwapchainImplVK> Create(
       const std::shared_ptr<Context>& context,
       vk::UniqueSurfaceKHR surface,
+      bool was_rotated,
       vk::SwapchainKHR old_swapchain = VK_NULL_HANDLE);
 
   ~SwapchainImplVK();
@@ -47,6 +48,8 @@ class SwapchainImplVK final
         : surface(std::move(p_surface)) {}
   };
 
+  bool GetIsRotated() const { return is_rotated_; }
+
   AcquireResult AcquireNextDrawable();
 
   vk::Format GetSurfaceFormat() const;
@@ -66,8 +69,12 @@ class SwapchainImplVK final
   size_t current_frame_ = 0u;
   bool is_valid_ = false;
 
+  bool was_rotated_ = false;
+  bool is_rotated_ = false;
+
   SwapchainImplVK(const std::shared_ptr<Context>& context,
                   vk::UniqueSurfaceKHR surface,
+                  bool was_rotated,
                   vk::SwapchainKHR old_swapchain);
 
   bool Present(const std::shared_ptr<SwapchainImageVK>& image, uint32_t index);

impeller/renderer/backend/vulkan/swapchain_vk.cc

@@ -12,7 +12,8 @@ namespace impeller {
 std::shared_ptr<SwapchainVK> SwapchainVK::Create(
     const std::shared_ptr<Context>& context,
     vk::UniqueSurfaceKHR surface) {
-  auto impl = SwapchainImplVK::Create(context, std::move(surface));
+  auto impl = SwapchainImplVK::Create(context, std::move(surface),
+                                      /*was_rotated=*/false);
   if (!impl || !impl->IsValid()) {
     return nullptr;
   }
@@ -45,10 +46,12 @@ std::unique_ptr<Surface> SwapchainVK::AcquireNextDrawable() {
   // This swapchain implementation indicates that it is out of date. Tear it
   // down and make a new one.
   auto context = impl_->GetContext();
+  auto was_rotated = impl_->GetIsRotated();
   auto [surface, old_swapchain] = impl_->DestroySwapchain();
 
   auto new_impl = SwapchainImplVK::Create(context,             //
                                           std::move(surface),  //
+                                          was_rotated,         //
                                           *old_swapchain       //
   );
   if (!new_impl || !new_impl->IsValid()) {