diff --git a/render/GpuRender/GpuRender.upp b/render/GpuRender/GpuRender.upp
index 5f48979..168ee66 100644
--- a/render/GpuRender/GpuRender.upp
+++ b/render/GpuRender/GpuRender.upp
@@ -19,8 +19,6 @@ file
 	GpuWindow.h,
 	GpuWindow.cpp,
 	RenderPresentation.h,
-	RenderPresentationBackend.h,
 	RenderPresentation.cpp,
-	RenderPresentationVulkan.cpp,
 	RenderCtrlBridge.h,
 	RenderCtrlBridge.cpp;
diff --git a/render/GpuRender/RenderPresentation.cpp b/render/GpuRender/RenderPresentation.cpp
index 800ffcc..35cd417 100644
--- a/render/GpuRender/RenderPresentation.cpp
+++ b/render/GpuRender/RenderPresentation.cpp
@@ -1,53 +1,26 @@
 #include "RenderPresentation.h"
-#include "RenderPresentationBackend.h"
+
+#include <RenderGpu2D/RenderGpu2D.h>
+#include <RenderRhi/RenderRhiBackend.h>
+#include <memory>
 
 namespace Upp {
 
 namespace {
 
-struct BackendRegistration : Moveable<BackendRegistration> {
-	GpuBackendKind kind = GpuBackendKind::Unknown;
-	GpuPresentationBackend *backend = nullptr;
-};
-
-static Vector<BackendRegistration>& BackendRegistry()
+static GpuClearColor ToClearColor(Rgba8 color)
 {
-	static Vector<BackendRegistration> registry;
-	return registry;
-}
-
-static int FindBackendIndex(GpuBackendKind kind)
-{
-	const Vector<BackendRegistration>& registry = BackendRegistry();
-	for(int i = 0; i < registry.GetCount(); ++i)
-		if(registry[i].kind == kind)
-			return i;
-	return -1;
+	const float scale = 1.0f / 255.0f;
+	GpuClearColor out;
+	out.red = color.r * scale;
+	out.green = color.g * scale;
+	out.blue = color.b * scale;
+	out.alpha = color.a * scale;
+	return out;
 }
 
 } // namespace
 
-bool RegisterGpuPresentationBackend(GpuBackendKind kind, GpuPresentationBackend& backend)
-{
-	if(kind == GpuBackendKind::Unknown || FindBackendIndex(kind) >= 0)
-		return false;
-	BackendRegistration& registration = BackendRegistry().Add();
-	registration.kind = kind;
-	registration.backend = &backend;
-	return true;
-}
-
-GpuPresentationBackend *FindGpuPresentationBackend(GpuBackendKind kind)
-{
-	int index = FindBackendIndex(kind);
-	return index >= 0 ? BackendRegistry()[index].backend : nullptr;
-}
-
-bool IsGpuPresentationBackendRegistered(GpuBackendKind kind)
-{
-	return FindGpuPresentationBackend(kind) != nullptr;
-}
-
 struct GpuContext::Impl {
 	struct ContextEntry : Moveable<ContextEntry> {
 		GpuBackendKind kind = GpuBackendKind::Unknown;
@@ -99,9 +72,131 @@ GpuContext& GpuContext::Default()
 
 struct GpuDisplayPresenter::Impl {
 	One<GpuPresentationBackendSession> session;
+	std::unique_ptr<UiRenderer2D> renderer;
 	GpuContext *context = nullptr;
 	GpuBackendKind backend = GpuBackendKind::Unknown;
+	GpuNativeWindowDesc native_window;
+	GpuSurfaceId surface;
+	GpuSwapchainId swapchain;
+	Size swapchain_request_size = Size(0, 0);
 	String error;
+
+	GpuDevice *GetDevice() const
+	{
+		return session ? session->GetDevice() : nullptr;
+	}
+
+	void DestroyPresentationObjects()
+	{
+		renderer.reset();
+		GpuDevice *device = GetDevice();
+		if(device) {
+			if(swapchain.IsValid())
+				device->DestroySwapchain(swapchain);
+			if(surface.IsValid())
+				device->DestroySurface(surface);
+		}
+		swapchain = GpuSwapchainId();
+		surface = GpuSurfaceId();
+		swapchain_request_size = Size(0, 0);
+		native_window = GpuNativeWindowDesc();
+	}
+
+	bool EnsureSwapchain(Size requested_size, String& out_error)
+	{
+		GpuDevice *device = GetDevice();
+		if(!device) {
+			error = "GPU presentation backend exposes no device";
+			out_error = error;
+			return false;
+		}
+
+		if(!surface.IsValid()) {
+			GpuSurfaceDesc desc;
+			desc.label = "GPU presentation surface";
+			desc.size = requested_size;
+			desc.native_window = native_window;
+			GpuResult result = device->CreateSurface(desc, surface);
+			if(result != GpuResult::Ok) {
+				error = device->GetLastError();
+				if(error.IsEmpty())
+					error = "logical GPU surface creation failed";
+				out_error = error;
+				return false;
+			}
+		}
+
+		if(!swapchain.IsValid()) {
+			GpuSwapchainDesc desc;
+			desc.label = "GPU presentation swapchain";
+			desc.surface = surface;
+			desc.size = requested_size;
+			desc.color_format = GpuFormat::RGBA8;
+			desc.image_count = 2;
+			GpuResult result = device->CreateSwapchain(desc, swapchain);
+			if(result != GpuResult::Ok) {
+				error = device->GetLastError();
+				if(error.IsEmpty())
+					error = "logical GPU swapchain creation failed";
+				out_error = error;
+				return false;
+			}
+			swapchain_request_size = requested_size;
+		}
+		else if(requested_size != swapchain_request_size) {
+			GpuResult result = device->ResizeSwapchain(swapchain, requested_size);
+			if(result != GpuResult::Ok) {
+				error = device->GetLastError();
+				if(error.IsEmpty())
+					error = "logical GPU swapchain resize failed";
+				out_error = error;
+				return false;
+			}
+			swapchain_request_size = requested_size;
+		}
+		return true;
+	}
+
+	GpuResult PresentOnce(const UiDisplayList& list, Rgba8 background, String& out_error)
+	{
+		GpuDevice *device = GetDevice();
+		if(!device || !renderer) {
+			error = "GPU presentation session is not ready";
+			out_error = error;
+			return GpuResult::InvalidState;
+		}
+
+		GpuFrameInfo frame;
+		GpuResult result = device->BeginFrame(swapchain, frame);
+		if(result != GpuResult::Ok) {
+			error = device->GetLastError();
+			if(error.IsEmpty())
+				error = "GPU BeginFrame failed";
+			out_error = error;
+			return result;
+		}
+
+		if(!renderer->RenderFrame(list, frame, ToClearColor(background))) {
+			String render_error = renderer->GetError();
+			device->Present(frame.frame); // Release the acquired frame on the failure path.
+			error = render_error.IsEmpty() ? String("UiRenderer2D frame render failed") : render_error;
+			out_error = error;
+			return GpuResult::InvalidState;
+		}
+
+		result = device->Present(frame.frame);
+		if(result != GpuResult::Ok) {
+			error = device->GetLastError();
+			if(error.IsEmpty())
+				error = "GPU Present failed";
+			out_error = error;
+			return result;
+		}
+
+		error.Clear();
+		out_error.Clear();
+		return GpuResult::Ok;
+	}
 };
 
 GpuDisplayPresenter::GpuDisplayPresenter()
@@ -130,6 +225,7 @@ bool GpuDisplayPresenter::Open(GpuContext& context, GpuBackendKind backend,
 	out_error.Clear();
 	impl->context = &context;
 	impl->backend = backend;
+	impl->native_window = native_window;
 
 	GpuPresentationBackend *provider = FindGpuPresentationBackend(backend);
 	if(!provider) {
@@ -171,6 +267,27 @@ bool GpuDisplayPresenter::Open(GpuContext& context, GpuBackendKind backend,
 		impl->session.Clear();
 		return false;
 	}
+
+	GpuDevice *device = impl->GetDevice();
+	if(!device || device->GetBackendKind() != backend) {
+		impl->error = "GPU presentation backend returned an incompatible device";
+		out_error = impl->error;
+		impl->session->Close();
+		impl->session.Clear();
+		return false;
+	}
+
+	impl->renderer.reset(new UiRenderer2D(*device));
+	if(!impl->renderer->IsReady()) {
+		String failure = impl->renderer->GetError();
+		impl->renderer.reset();
+		impl->session->Close();
+		impl->session.Clear();
+		impl->error = failure.IsEmpty() ? String("UiRenderer2D initialization failed") : failure;
+		out_error = impl->error;
+		return false;
+	}
+
 	impl->error.Clear();
 	out_error.Clear();
 	return true;
@@ -180,6 +297,7 @@ void GpuDisplayPresenter::Close()
 {
 	if(!impl)
 		return;
+	impl->DestroyPresentationObjects();
 	if(impl->session)
 		impl->session->Close();
 	impl->session.Clear();
@@ -190,7 +308,8 @@ void GpuDisplayPresenter::Close()
 
 bool GpuDisplayPresenter::IsReady() const
 {
-	return impl && impl->session && impl->session->IsReady();
+	return impl && impl->session && impl->session->IsReady() && impl->GetDevice() &&
+	       impl->renderer && impl->renderer->IsReady();
 }
 
 GpuBackendKind GpuDisplayPresenter::GetBackend() const
@@ -211,6 +330,8 @@ bool GpuDisplayPresenter::Present(Size requested_size, const UiDisplayList& list
                                   Rgba8 background, String& out_error)
 {
 	out_error.Clear();
+	if(requested_size.cx <= 0 || requested_size.cy <= 0)
+		return true;
 	if(!IsReady()) {
 		impl->error = GetError();
 		if(impl->error.IsEmpty())
@@ -218,14 +339,25 @@ bool GpuDisplayPresenter::Present(Size requested_size, const UiDisplayList& list
 		out_error = impl->error;
 		return false;
 	}
-	if(!impl->session->Present(requested_size, list, background, out_error)) {
-		impl->error = out_error.IsEmpty() ? impl->session->GetError() : out_error;
+	if(!impl->EnsureSwapchain(requested_size, out_error))
+		return false;
+
+	GpuResult result = impl->PresentOnce(list, background, out_error);
+	if(result == GpuResult::Ok)
+		return true;
+	if(result != GpuResult::OutOfDate)
+		return false;
+
+	GpuDevice *device = impl->GetDevice();
+	if(!device || device->ResizeSwapchain(impl->swapchain, requested_size) != GpuResult::Ok) {
+		impl->error = device ? device->GetLastError() : String();
+		if(impl->error.IsEmpty())
+			impl->error = "GPU swapchain recreation after out-of-date presentation failed";
 		out_error = impl->error;
 		return false;
 	}
-	impl->error.Clear();
-	out_error.Clear();
-	return true;
+	impl->swapchain_request_size = requested_size;
+	return impl->PresentOnce(list, background, out_error) == GpuResult::Ok;
 }
 
 }
diff --git a/render/GpuRender/RenderPresentationVulkan.cpp b/render/GpuRender/RenderPresentationVulkan.cpp
deleted file mode 100644
index 36ce193..0000000
--- a/render/GpuRender/RenderPresentationVulkan.cpp
+++ /dev/null
@@ -1,253 +0,0 @@
-#include "RenderPresentationBackend.h"
-
-#include <RenderGpu2D/RenderGpu2D.h>
-#include <RenderVulkan/RenderVulkanRhi.h>
-
-#include <memory>
-
-namespace Upp {
-
-namespace {
-
-static GpuClearColor ToClearColor(Rgba8 color)
-{
-	const float scale = 1.0f / 255.0f;
-	GpuClearColor out;
-	out.red = color.r * scale;
-	out.green = color.g * scale;
-	out.blue = color.b * scale;
-	out.alpha = color.a * scale;
-	return out;
-}
-
-class VulkanPresentationContext : public GpuPresentationBackendContext {
-public:
-	VulkanSurfaceSessionGroup group;
-};
-
-class VulkanPresentationSession : public GpuPresentationBackendSession {
-public:
-	explicit VulkanPresentationSession(VulkanPresentationContext& context)
-		: session(context.group)
-	{
-	}
-
-	~VulkanPresentationSession() override
-	{
-		Close();
-	}
-
-	bool Open(bool request_validation, const GpuNativeWindowDesc& window,
-	          String& out_error) override
-	{
-		Close();
-		error.Clear();
-		native_window = window;
-		if(!session.Open(request_validation, native_window)) {
-			error = session.GetError();
-			out_error = error;
-			return false;
-		}
-
-		device.reset(new VulkanGpuDevice(session));
-		if(!device->IsReady()) {
-			String failure = device->GetError();
-			Close();
-			error = failure.IsEmpty() ? String("VulkanGpuDevice initialization failed") : failure;
-			out_error = error;
-			return false;
-		}
-
-		renderer.reset(new UiRenderer2D(*device));
-		if(!renderer->IsReady()) {
-			String failure = renderer->GetError();
-			Close();
-			error = failure.IsEmpty() ? String("UiRenderer2D initialization failed") : failure;
-			out_error = error;
-			return false;
-		}
-
-		out_error.Clear();
-		return true;
-	}
-
-	void Close() override
-	{
-		renderer.reset();
-		if(device) {
-			if(swapchain.IsValid())
-				device->DestroySwapchain(swapchain);
-			swapchain = GpuSwapchainId();
-			if(surface.IsValid())
-				device->DestroySurface(surface);
-			surface = GpuSurfaceId();
-		}
-		device.reset();
-		session.Close();
-		native_window = GpuNativeWindowDesc();
-		swapchain_request_size = Size(0, 0);
-		error.Clear();
-	}
-
-	bool IsReady() const override
-	{
-		return session.IsReady() && device && device->IsReady() &&
-		       renderer && renderer->IsReady();
-	}
-
-	String GetError() const override
-	{
-		return error;
-	}
-
-	bool Present(Size requested_size, const UiDisplayList& list,
-	             Rgba8 background, String& out_error) override
-	{
-		out_error.Clear();
-		if(requested_size.cx <= 0 || requested_size.cy <= 0)
-			return true;
-		if(!IsReady()) {
-			error = !device ? session.GetError() : device->GetError();
-			if(error.IsEmpty())
-				error = "GPU presentation session is not ready";
-			out_error = error;
-			return false;
-		}
-		if(!EnsureSwapchain(requested_size, out_error))
-			return false;
-		if(PresentOnce(list, background, out_error))
-			return true;
-
-		if(!session.GetFrameReport().out_of_date)
-			return false;
-		if(device->ResizeSwapchain(swapchain, requested_size) != GpuResult::Ok) {
-			error = device->GetError();
-			if(error.IsEmpty())
-				error = "GPU swapchain recreation after out-of-date presentation failed";
-			out_error = error;
-			return false;
-		}
-		swapchain_request_size = requested_size;
-		if(PresentOnce(list, background, out_error)) {
-			out_error.Clear();
-			return true;
-		}
-		return false;
-	}
-
-private:
-	bool EnsureSwapchain(Size requested_size, String& out_error)
-	{
-		if(!surface.IsValid()) {
-			GpuSurfaceDesc desc;
-			desc.label = "GPU presentation surface";
-			desc.size = requested_size;
-			desc.native_window = native_window;
-			GpuResult result = device->CreateSurface(desc, surface);
-			if(result != GpuResult::Ok) {
-				error = device->GetError();
-				if(error.IsEmpty())
-					error = "logical GPU surface creation failed";
-				out_error = error;
-				return false;
-			}
-		}
-
-		if(!swapchain.IsValid()) {
-			GpuSwapchainDesc desc;
-			desc.label = "GPU presentation swapchain";
-			desc.surface = surface;
-			desc.size = requested_size;
-			desc.color_format = GpuFormat::RGBA8;
-			desc.image_count = 2;
-			GpuResult result = device->CreateSwapchain(desc, swapchain);
-			if(result != GpuResult::Ok) {
-				error = device->GetError();
-				if(error.IsEmpty())
-					error = "logical GPU swapchain creation failed";
-				out_error = error;
-				return false;
-			}
-			swapchain_request_size = requested_size;
-		}
-		else if(requested_size != swapchain_request_size) {
-			GpuResult result = device->ResizeSwapchain(swapchain, requested_size);
-			if(result != GpuResult::Ok) {
-				error = device->GetError();
-				if(error.IsEmpty())
-					error = "logical GPU swapchain resize failed";
-				out_error = error;
-				return false;
-			}
-			swapchain_request_size = requested_size;
-		}
-		return true;
-	}
-
-	bool PresentOnce(const UiDisplayList& list, Rgba8 background, String& out_error)
-	{
-		GpuFrameInfo frame;
-		GpuResult result = device->BeginFrame(swapchain, frame);
-		if(result != GpuResult::Ok) {
-			error = device->GetError();
-			if(error.IsEmpty())
-				error = "GPU BeginFrame failed";
-			out_error = error;
-			return false;
-		}
-
-		if(!renderer->RenderFrame(list, frame, ToClearColor(background))) {
-			String render_error = renderer->GetError();
-			device->Present(frame.frame);
-			error = render_error.IsEmpty() ? String("UiRenderer2D frame render failed") : render_error;
-			out_error = error;
-			return false;
-		}
-
-		result = device->Present(frame.frame);
-		if(result != GpuResult::Ok) {
-			error = device->GetError();
-			if(error.IsEmpty())
-				error = "GPU Present failed";
-			out_error = error;
-			return false;
-		}
-
-		error.Clear();
-		out_error.Clear();
-		return true;
-	}
-
-	VulkanSurfaceSession session;
-	std::unique_ptr<VulkanGpuDevice> device;
-	std::unique_ptr<UiRenderer2D> renderer;
-	GpuNativeWindowDesc native_window;
-	GpuSurfaceId surface;
-	GpuSwapchainId swapchain;
-	Size swapchain_request_size = Size(0, 0);
-	String error;
-};
-
-class VulkanPresentationBackend : public GpuPresentationBackend {
-public:
-	One<GpuPresentationBackendContext> CreateContext(String& error) override
-	{
-		error.Clear();
-		return new VulkanPresentationContext;
-	}
-
-	One<GpuPresentationBackendSession> CreateSession(GpuPresentationBackendContext& context,
-	                                                  String& error) override
-	{
-		error.Clear();
-		return new VulkanPresentationSession(static_cast<VulkanPresentationContext&>(context));
-	}
-};
-
-static VulkanPresentationBackend s_vulkan_backend;
-static bool s_vulkan_backend_registered =
-	RegisterGpuPresentationBackend(GpuBackendKind::Vulkan, s_vulkan_backend);
-
-} // namespace
-
-}
diff --git a/render/RenderRhi/RenderRhi.cpp b/render/RenderRhi/RenderRhi.cpp
index b97a198..8be9518 100644
--- a/render/RenderRhi/RenderRhi.cpp
+++ b/render/RenderRhi/RenderRhi.cpp
@@ -196,6 +196,7 @@ String DumpGpuResult(GpuResult result)
 	case GpuResult::InvalidArgument: return "InvalidArgument";
 	case GpuResult::InvalidHandle: return "InvalidHandle";
 	case GpuResult::InvalidState: return "InvalidState";
+	case GpuResult::OutOfDate: return "OutOfDate";
 	case GpuResult::NotFound: return "NotFound";
 	case GpuResult::Unsupported: return "Unsupported";
 	}
diff --git a/render/RenderRhi/RenderRhi.h b/render/RenderRhi/RenderRhi.h
index b0d4e1b..6a32baf 100644
--- a/render/RenderRhi/RenderRhi.h
+++ b/render/RenderRhi/RenderRhi.h
@@ -108,6 +108,7 @@ enum class GpuResult {
 	InvalidArgument,
 	InvalidHandle,
 	InvalidState,
+	OutOfDate,
 	NotFound,
 	Unsupported,
 };
@@ -253,6 +254,7 @@ class GpuDevice {
 	virtual GpuDeviceId GetDeviceId() const = 0;
 	virtual GpuBackendKind GetBackendKind() const = 0;
 	virtual GpuAdapterInfo GetAdapterInfo() const = 0;
+	virtual String GetLastError() const { return String(); }
 
 	virtual GpuResult CreateBuffer(const GpuBufferDesc& desc, GpuBufferId& out) = 0;
 	virtual GpuResult WriteBuffer(GpuBufferId id, int64 offset, const void *data, int64 size) = 0;
diff --git a/render/RenderRhi/RenderRhi.upp b/render/RenderRhi/RenderRhi.upp
index 129e72a..0d80806 100644
--- a/render/RenderRhi/RenderRhi.upp
+++ b/render/RenderRhi/RenderRhi.upp
@@ -3,4 +3,6 @@ uses
 
 file
 	RenderRhi.h,
-	RenderRhi.cpp;
+	RenderRhiBackend.h,
+	RenderRhi.cpp,
+	RenderRhiBackend.cpp;
diff --git a/render/RenderRhi/RenderRhiBackend.cpp b/render/RenderRhi/RenderRhiBackend.cpp
new file mode 100644
index 0000000..8dcceae
--- /dev/null
+++ b/render/RenderRhi/RenderRhiBackend.cpp
@@ -0,0 +1,50 @@
+#include "RenderRhiBackend.h"
+
+namespace Upp {
+
+namespace {
+
+struct BackendRegistration : Moveable<BackendRegistration> {
+	GpuBackendKind kind = GpuBackendKind::Unknown;
+	GpuPresentationBackend *backend = nullptr;
+};
+
+static Vector<BackendRegistration>& BackendRegistry()
+{
+	static Vector<BackendRegistration> registry;
+	return registry;
+}
+
+static int FindBackendIndex(GpuBackendKind kind)
+{
+	const Vector<BackendRegistration>& registry = BackendRegistry();
+	for(int i = 0; i < registry.GetCount(); ++i)
+		if(registry[i].kind == kind)
+			return i;
+	return -1;
+}
+
+} // namespace
+
+bool RegisterGpuPresentationBackend(GpuBackendKind kind, GpuPresentationBackend& backend)
+{
+	if(kind == GpuBackendKind::Unknown || FindBackendIndex(kind) >= 0)
+		return false;
+	BackendRegistration& registration = BackendRegistry().Add();
+	registration.kind = kind;
+	registration.backend = &backend;
+	return true;
+}
+
+GpuPresentationBackend *FindGpuPresentationBackend(GpuBackendKind kind)
+{
+	int index = FindBackendIndex(kind);
+	return index >= 0 ? BackendRegistry()[index].backend : nullptr;
+}
+
+bool IsGpuPresentationBackendRegistered(GpuBackendKind kind)
+{
+	return FindGpuPresentationBackend(kind) != nullptr;
+}
+
+}
diff --git a/render/GpuRender/RenderPresentationBackend.h b/render/RenderRhi/RenderRhiBackend.h
similarity index 66%
rename from render/GpuRender/RenderPresentationBackend.h
rename to render/RenderRhi/RenderRhiBackend.h
index 2c0804f..2fd8839 100644
--- a/render/GpuRender/RenderPresentationBackend.h
+++ b/render/RenderRhi/RenderRhiBackend.h
@@ -1,12 +1,11 @@
 #pragma once
 
-#include "RenderPresentation.h"
+#include <RenderRhi/RenderRhi.h>
 
 namespace Upp {
 
-// Internal backend plug-in seam for GpuRender presentation.
-// Application-facing GpuCtrl/GpuWindow/GpuTopWindow code never depends on this
-// interface and never sees backend-native types.
+// Internal provider seam between application presentation and a compiled GPU backend.
+// It contains no backend-native types and deliberately stops at the neutral GpuDevice.
 class GpuPresentationBackendContext {
 public:
 	virtual ~GpuPresentationBackendContext() {}
@@ -21,8 +20,7 @@ class GpuPresentationBackendSession {
 	virtual void Close() = 0;
 	virtual bool IsReady() const = 0;
 	virtual String GetError() const = 0;
-	virtual bool Present(Size requested_size, const UiDisplayList& list,
-	                     Rgba8 background, String& error) = 0;
+	virtual GpuDevice *GetDevice() const = 0;
 };
 
 class GpuPresentationBackend {
@@ -34,8 +32,8 @@ class GpuPresentationBackend {
 	                                                          String& error) = 0;
 };
 
-// Registration is intended for compiled backend packages during process start.
-// One provider owns each backend kind; duplicate registration is rejected.
+// Compiled backend packages register during process start. One provider owns each
+// backend kind; duplicate registration and Unknown are rejected.
 bool RegisterGpuPresentationBackend(GpuBackendKind kind, GpuPresentationBackend& backend);
 GpuPresentationBackend *FindGpuPresentationBackend(GpuBackendKind kind);
 bool IsGpuPresentationBackendRegistered(GpuBackendKind kind);
diff --git a/render/RenderVulkan/RenderVulkan.upp b/render/RenderVulkan/RenderVulkan.upp
index 6b96963..df0d33e 100644
--- a/render/RenderVulkan/RenderVulkan.upp
+++ b/render/RenderVulkan/RenderVulkan.upp
@@ -11,4 +11,5 @@ file
 	RenderVulkanFrame.cpp,
 	RenderVulkanClearFrame.cpp,
 	RenderVulkanRhiBase.inc,
-	RenderVulkanRhi.cpp;
+	RenderVulkanRhi.cpp,
+	RenderVulkanPresentation.cpp;
diff --git a/render/RenderVulkan/RenderVulkanPresentation.cpp b/render/RenderVulkan/RenderVulkanPresentation.cpp
new file mode 100644
index 0000000..0222c7a
--- /dev/null
+++ b/render/RenderVulkan/RenderVulkanPresentation.cpp
@@ -0,0 +1,106 @@
+#include "RenderVulkanRhi.h"
+
+#include <RenderRhi/RenderRhiBackend.h>
+#include <memory>
+
+namespace Upp {
+
+namespace {
+
+class VulkanPresentationContext : public GpuPresentationBackendContext {
+public:
+	VulkanSurfaceSessionGroup group;
+};
+
+class VulkanPresentationSession : public GpuPresentationBackendSession {
+public:
+	explicit VulkanPresentationSession(VulkanPresentationContext& context)
+		: session(context.group)
+	{
+	}
+
+	~VulkanPresentationSession() override
+	{
+		Close();
+	}
+
+	bool Open(bool request_validation, const GpuNativeWindowDesc& native_window,
+	          String& out_error) override
+	{
+		Close();
+		error.Clear();
+		out_error.Clear();
+		if(!session.Open(request_validation, native_window)) {
+			error = session.GetError();
+			out_error = error;
+			return false;
+		}
+
+		device.reset(new VulkanGpuDevice(session));
+		if(!device->IsReady()) {
+			String failure = device->GetError();
+			device.reset();
+			session.Close();
+			error = failure.IsEmpty() ? String("VulkanGpuDevice initialization failed") : failure;
+			out_error = error;
+			return false;
+		}
+
+		return true;
+	}
+
+	void Close() override
+	{
+		device.reset();
+		session.Close();
+		error.Clear();
+	}
+
+	bool IsReady() const override
+	{
+		return session.IsReady() && device && device->IsReady();
+	}
+
+	String GetError() const override
+	{
+		if(!error.IsEmpty())
+			return error;
+		if(device && !device->GetError().IsEmpty())
+			return device->GetError();
+		return session.GetError();
+	}
+
+	GpuDevice *GetDevice() const override
+	{
+		return IsReady() ? device.get() : nullptr;
+	}
+
+private:
+	VulkanSurfaceSession session;
+	std::unique_ptr<VulkanGpuDevice> device;
+	String error;
+};
+
+class VulkanPresentationBackend : public GpuPresentationBackend {
+public:
+	One<GpuPresentationBackendContext> CreateContext(String& error) override
+	{
+		error.Clear();
+		return new VulkanPresentationContext;
+	}
+
+	One<GpuPresentationBackendSession> CreateSession(GpuPresentationBackendContext& context,
+	                                                  String& error) override
+	{
+		error.Clear();
+		return new VulkanPresentationSession(static_cast<VulkanPresentationContext&>(context));
+	}
+};
+
+static VulkanPresentationBackend s_vulkan_backend;
+static bool s_vulkan_backend_registered =
+	RegisterGpuPresentationBackend(GpuBackendKind::Vulkan, s_vulkan_backend);
+
+} // namespace
+
+}
diff --git a/render/RenderVulkan/RenderVulkanRhi.h b/render/RenderVulkan/RenderVulkanRhi.h
index 014d668..e0ea213 100644
--- a/render/RenderVulkan/RenderVulkanRhi.h
+++ b/render/RenderVulkan/RenderVulkanRhi.h
@@ -31,6 +31,7 @@ class VulkanGpuDevice final : public GpuDevice {
 	GpuDeviceId GetDeviceId() const override;
 	GpuBackendKind GetBackendKind() const override;
 	GpuAdapterInfo GetAdapterInfo() const override;
+	String GetLastError() const override;
 
 	GpuResult CreateBuffer(const GpuBufferDesc& desc, GpuBufferId& out) override;
 	GpuResult WriteBuffer(GpuBufferId id, int64 offset, const void *data, int64 size) override;
diff --git a/render/RenderVulkan/RenderVulkanRhiBase.inc b/render/RenderVulkan/RenderVulkanRhiBase.inc
index ad6b1b9..b770273 100644
--- a/render/RenderVulkan/RenderVulkanRhiBase.inc
+++ b/render/RenderVulkan/RenderVulkanRhiBase.inc
@@ -893,6 +893,7 @@ int VulkanGpuDevice::GetLiveFrameCount() const
 GpuDeviceId VulkanGpuDevice::GetDeviceId() const { return impl->device_id; }
 GpuBackendKind VulkanGpuDevice::GetBackendKind() const { return GpuBackendKind::Vulkan; }
 GpuAdapterInfo VulkanGpuDevice::GetAdapterInfo() const { return impl->adapter_info; }
+String VulkanGpuDevice::GetLastError() const { return impl ? impl->error : String(); }
 
 GpuResult VulkanGpuDevice::CreateBuffer(const GpuBufferDesc& desc, GpuBufferId& out)
 {
@@ -1150,7 +1151,7 @@ GpuResult VulkanGpuDevice::BeginFrame(GpuSwapchainId swapchain, GpuFrameInfo& ou
 	if(!impl->session->AcquireFrame()) {
 		impl->error = impl->session->GetFrameReport().error;
 		if(impl->error.IsEmpty()) impl->error = "VulkanSurfaceSession frame acquisition failed";
-		return GpuResult::InvalidState;
+		return impl->session->GetFrameReport().out_of_date ? GpuResult::OutOfDate : GpuResult::InvalidState;
 	}
 	VulkanSurfaceSession::FrameInterop interop;
 	uint32_t image_index = UINT32_MAX;
@@ -1205,7 +1206,7 @@ GpuResult VulkanGpuDevice::Present(GpuFrameId frame)
 			state->active = false;
 			swapchain->active_frame = GpuFrameId();
 		}
-		return GpuResult::InvalidState;
+		return impl->session->GetFrameReport().out_of_date ? GpuResult::OutOfDate : GpuResult::InvalidState;
 	}
 	Impl::TextureState *texture = impl->FindTexture(state->color_target);
 	if(texture) impl->ClearBorrowedTexture(*texture);
diff --git a/tests/GpuBackendRegistryTest/main.cpp b/tests/GpuBackendRegistryTest/main.cpp
index bdb0d9c..e122a33 100644
--- a/tests/GpuBackendRegistryTest/main.cpp
+++ b/tests/GpuBackendRegistryTest/main.cpp
@@ -1,4 +1,4 @@
-#include <GpuRender/RenderPresentationBackend.h>
+#include <RenderRhi/RenderRhiBackend.h>
 
 using namespace Upp;