M2(Vulkan): too-late detection + red relaunch banner on the mirror window

The hook reports vk_too_late when vulkan-1.dll is loaded and the GPA hook has
been in for >4s but it never caught the app creating its device -- i.e. the app
resolved its Vulkan functions before we hooked (injected too late). Surfaced
through a new HookStatus.vk_too_late field (protocol 15->16) and shown by the
host as a red banner on the mirror window: "Detected a Vulkan game, but the
mirror hook attached too late... enable Auto re-attach (and Set up Vulkan layer
if it persists) and relaunch." WGC keeps mirroring meanwhile.

mock_game_test gains a too-late detection check (late-inject a Vulkan game ->
vk_too_late trips). Verified live: the banner shows over the running tool when a
Vulkan game is injected late with the video subsystem on (added a debug-harness
`video on/off` command to drive it). 15/15 ctest.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

common/include/coop/protocol.hpp

@@ -12,7 +12,7 @@ namespace coop
 
 // Bump whenever the layout of SharedBlock or CoopPadState changes. The hook
 // refuses to attach to a host with a mismatched version.
-inline constexpr std::uint32_t kProtocolVersion = 15;
+inline constexpr std::uint32_t kProtocolVersion = 16;
 
 // 'COOP' little-endian, used to sanity-check the mapping before trusting it.
 inline constexpr std::uint32_t kProtocolMagic = 0x504F4F43u;
@@ -132,6 +132,11 @@ struct HookStatus
 	std::uint32_t raw_input_gamepad_sink; // ... and that usage has RIDEV_INPUTSINK (bg delivery)
 	std::uint32_t dinput_loaded;          // dinput8.dll is present in the process
 
+	// Video: set when vulkan-1.dll is loaded but the Vulkan capture hook attached too late to
+	// catch the game's present (it resolved its present pointer before us). Drives the host's
+	// "relaunch with Auto-attach / Vulkan layer" red banner.
+	std::uint32_t vk_too_late;
+
 	// Audio render-hook diagnostics. Stream counting runs whenever the DLL is
 	// injected, independent of whether audio mirroring is enabled, so a
 	// multi-stream game is visible before/without turning the mirror on.

hook/src/dllmain.cpp

@@ -227,6 +227,7 @@ DWORD WINAPI worker_thread(LPVOID)
 		coop::hook::update_input_diagnostics(g_ipc); // refreshes each tick; registrations can change
 		coop::hook::release_cursor_tick();           // free the operator's mouse if requested (no-op otherwise)
 		coop::hook::hook_publish(g_ipc);             // installed-hooks list + call counts
+		g_ipc.set_vk_too_late(coop::hook::vk_injected_too_late()); // Vulkan attached-too-late banner
 		g_ipc.heartbeat();
 
 		// Reconcile ~4x/s, but drain MKB events far more often (input must be

hook/src/ipc_client.hpp

@@ -147,6 +147,14 @@ public:
 		}
 	}
 
+	void set_vk_too_late(bool too_late)
+	{
+		if (block_ != nullptr)
+		{
+			block_->status.vk_too_late = too_late ? 1u : 0u;
+		}
+	}
+
 	// Record the rumble the game requested for a slot (so the host can forward it to
 	// the guest's controller). Plain stores; the hook is the sole writer.
 	void note_rumble(std::uint32_t slot, std::uint16_t left, std::uint16_t right)

hook/src/vk_hook.cpp

@@ -36,6 +36,7 @@ std::atomic<std::uint64_t> g_presents{0};
 std::atomic<std::uint64_t> g_frames_shared{0};
 std::atomic<bool> g_present_captured{false}; // set once we successfully read a present back
 bool g_unsupported_logged = false;
+ULONGLONG g_install_tick = 0; // GetTickCount64 when the GPA hook went in (for the too-late grace)
 
 // Real entry points. g_real_gdpa and below are unhooked exports/results, so they're plain PFNs;
 // the real vkGetInstanceProcAddr is reached through the inline hook's trampoline (real_gipa()).
@@ -638,6 +639,7 @@ bool install_vk_hooks(IpcClient& ipc)
 	}
 	g_unsupported_logged = false;
 	g_hk_gipa = safetyhook::create_inline(gipa, reinterpret_cast<void*>(&hk_vkGetInstanceProcAddr));
+	g_install_tick = GetTickCount64();
 	hook_set_installed(g_id_present, static_cast<bool>(g_hk_gipa));
 	logf("install_vk_hooks: vkGetInstanceProcAddr=%p hooked=%d", gipa, static_cast<bool>(g_hk_gipa) ? 1 : 0);
 	return static_cast<bool>(g_hk_gipa);
@@ -685,6 +687,7 @@ void remove_vk_hooks()
 	g_device = VK_NULL_HANDLE;
 	g_instance = VK_NULL_HANDLE;
 	g_real_gdpa = nullptr;
+	g_install_tick = 0;
 	g_present_captured.store(false, std::memory_order_relaxed);
 	g_presents.store(0, std::memory_order_relaxed);
 	g_frames_shared.store(0, std::memory_order_relaxed);
@@ -703,10 +706,16 @@ std::uint64_t vk_frames_shared()
 
 bool vk_injected_too_late()
 {
-	// vulkan-1.dll is loaded but we never captured a present -> the app resolved its present
+	// Too late = vulkan-1.dll is loaded and our GPA hook has been in for a few seconds, but we
-	// pointer before we hooked (or doesn't go through our chain). The host shows the banner.
+	// never even saw the app create its device -> it resolved its Vulkan functions before our
-	return GetModuleHandleW(L"vulkan-1.dll") != nullptr && g_presents.load(std::memory_order_relaxed) == 0 &&
+	// hook (we're not in the chain). A game we hooked early always trips hk_vkCreateDevice
-	       !g_present_captured.load(std::memory_order_relaxed);
+	// (g_device != null) well within the grace window, even before it presents. The host shows
+	// the "relaunch with Auto-attach / Vulkan layer" banner on this.
+	if (GetModuleHandleW(L"vulkan-1.dll") == nullptr || g_device != VK_NULL_HANDLE || g_install_tick == 0)
+	{
+		return false;
+	}
+	return (GetTickCount64() - g_install_tick) > 4000;
 }
 
 } // namespace coop::hook

host/src/ipc/ipc_server.cpp

@@ -78,6 +78,7 @@ HookStatusView IpcServer::hook_status() const
 	view.raw_input_gamepad = s.raw_input_gamepad != 0;
 	view.raw_input_gamepad_sink = s.raw_input_gamepad_sink != 0;
 	view.dinput_loaded = s.dinput_loaded != 0;
+	view.vk_too_late = s.vk_too_late != 0;
 	view.audio_streams_seen = s.audio_streams_seen;
 	for (std::uint32_t i = 0; i < kMaxAudioStreams; ++i)
 	{

host/src/ipc/ipc_server.hpp

@@ -29,6 +29,7 @@ struct HookStatusView
 	bool raw_input_gamepad = false;
 	bool raw_input_gamepad_sink = false;
 	bool dinput_loaded = false;
+	bool vk_too_late = false; // Vulkan game, but the capture hook attached too late (relaunch banner)
 
 	// Audio render-hook diagnostics (for the Audio panel's stream-count view).
 	std::uint32_t audio_streams_seen = 0;

host/src/main.cpp

@@ -139,6 +139,12 @@ std::string apply_test_command(const std::string& cmd, coop::UiState& ui, coop::
 		audio.dev_set_enabled(on);
 		return "ok";
 	}
+	if (v == "video")
+	{
+		// Install/remove the hooked video subsystem (Present/GL/D3D9/Vulkan capture hooks).
+		injection.request_video(arg(1) == "on");
+		return "ok";
+	}
 	if (v == "debug")
 	{
 		ui.debug_details = (arg(1) == "on");
@@ -219,6 +225,38 @@ std::string steam_manifest_path()
 }
 #endif
 
+// Red banner on the mirror window when a Vulkan game was injected too late for the hooked
+// capture (Vulkan caches its present pointer at startup, so the hook must be present before
+// vkCreateInstance). WGC still mirrors the window; this prompts the operator to relaunch with
+// Auto-attach so the hook arms before the game initializes Vulkan. Shown regardless of overlay
+// visibility, since it's an actionable alert about the mirror itself.
+void draw_vk_too_late_banner()
+{
+	const ImGuiViewport* vp = ImGui::GetMainViewport();
+	float w = vp->WorkSize.x - 40.0f;
+	if (w > 760.0f)
+	{
+		w = 760.0f;
+	}
+	ImGui::SetNextWindowPos(ImVec2(vp->WorkPos.x + vp->WorkSize.x * 0.5f, vp->WorkPos.y + 16.0f),
+	                        ImGuiCond_Always, ImVec2(0.5f, 0.0f));
+	ImGui::SetNextWindowSize(ImVec2(w, 0.0f));
+	const ImGuiWindowFlags flags = ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoInputs |
+	                               ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoFocusOnAppearing |
+	                               ImGuiWindowFlags_NoNav | ImGuiWindowFlags_AlwaysAutoResize;
+	ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(0.28f, 0.03f, 0.03f, 0.92f));
+	ImGui::Begin("##vk_too_late", nullptr, flags);
+	ImGui::PushStyleColor(ImGuiCol_Text, ImVec4(1.0f, 0.5f, 0.45f, 1.0f));
+	ImGui::TextWrapped("Detected a Vulkan game, but the mirror hook attached too late to capture it "
+	                   "with low latency (Vulkan resolves its present function at startup). The window "
+	                   "is mirroring via WGC meanwhile. For the hooked path, enable \"Auto re-attach "
+	                   "this game on relaunch\" (and \"Set up Vulkan layer\" if it persists) in the "
+	                   "Injection panel, then relaunch the game.");
+	ImGui::PopStyleColor();
+	ImGui::End();
+	ImGui::PopStyleColor();
+}
+
 // When the overlay is hidden, briefly show a fading hint so the operator can find
 // the way back. The window is borderless and non-interactive so it never steals a
 // click or a frame from the mirror underneath.
@@ -431,6 +469,10 @@ int run()
 		{
 			draw_overlay_hidden_hint(ImGui::GetTime() - overlay_hidden_at);
 		}
+		if (injection.hook_status().vk_too_late) // Vulkan game injected too late -> relaunch prompt
+		{
+			draw_vk_too_late_banner();
+		}
 		coop::apply_layout_end_frame(); // clear the one-shot "Reset layout" force
 
 		if (ui.request_quit) // File -> Exit

tests/mock_game_test.cpp

@@ -403,6 +403,57 @@ void test_vk_capture(ID3D11Device* device)
 	cleanup();
 }
 
+// Vulkan too-late detection: launch the vk mock normally (it inits Vulkan immediately), inject
+// *late* (the realistic case), and assert the hook reports vk_too_late -- it sees vulkan-1.dll
+// loaded but never caught the device, because the app resolved its present pointer first. This is
+// what drives the host's relaunch banner.
+void test_vk_too_late()
+{
+	std::printf("== vk too-late detection (late inject) ==\n");
+	MockGame game = MockGame::launch(L"vk 30");
+	if (!game.ok)
+	{
+		check(false, "launch vk mock (too-late)");
+		return;
+	}
+	Sleep(1200); // let it create its instance/device and start presenting
+	if (!game.alive() && game.exit_code() == 2)
+	{
+		std::printf("   Vulkan unavailable on this machine -- skipping\n");
+		game.kill();
+		return;
+	}
+	SharedMemory shm;
+	const std::uint32_t disabled = (1u << HookSubsys_Input) | (1u << HookSubsys_Focus) |
+	                               (1u << HookSubsys_Audio) | (1u << HookSubsys_Mkb);
+	SharedBlock* block = make_ipc(shm, game.pid(), disabled);
+	if (block == nullptr || !inject_retry(game.pid()))
+	{
+		if (!game.alive() && game.exit_code() == 2)
+		{
+			std::printf("   Vulkan unavailable -- skipping\n");
+		}
+		else
+		{
+			check(false, "inject vk mock (too-late)");
+		}
+		game.kill();
+		return;
+	}
+	bool too_late = false;
+	for (int i = 0; i < 160 && game.alive(); ++i) // ~8 s (past the hook's 4 s grace)
+	{
+		Sleep(50);
+		if (block->status.vk_too_late != 0)
+		{
+			too_late = true;
+			break;
+		}
+	}
+	check(too_late, "hook reports vk_too_late after a late inject into a Vulkan game");
+	game.kill();
+}
+
 // Launch the mock game rendering audio at `rate`/`channels`/`bits`/`fmt`, inject the audio
 // hook (late, so it's the guessed path), and verify the hook MEASURES the right sample rate
 // for this variant and captures non-silent audio. (Channels/bit-depth aren't recoverable for
@@ -628,6 +679,7 @@ int main()
 	// Vulkan: present pointer cached at init -> can't be late-hooked, so we capture via the
 	// early-load path (suspended launch + inject + resume; the mock loads Vulkan and waits).
 	test_vk_capture(device);
+	test_vk_too_late();
 	test_video_capture("gl", device);
 	test_video_capture("dx9ex", device);
 	test_video_capture("dx9", device);