1 files changed, 76 insertions, 0 deletions
diff --git a/NorthstarDLL/latencyflex.cpp b/NorthstarDLL/latencyflex.cpp
new file mode 100644
index 00000000..3e2cecd7
--- /dev/null
+++ b/NorthstarDLL/latencyflex.cpp
@@ -0,0 +1,76 @@
+#include "pch.h"
+#include "latencyflex.h"
+#include "hookutils.h"
+#include "convar.h"
+
+typedef void (*OnRenderStartType)();
+OnRenderStartType OnRenderStart;
+
+ConVar* Cvar_r_latencyflex;
+
+HMODULE m_lfxModule {};
+typedef void (*PFN_lfx_WaitAndBeginFrame)();
+PFN_lfx_WaitAndBeginFrame m_lfx_WaitAndBeginFrame {};
+
+void OnRenderStartHook()
+{
+	// Sleep before next frame as needed to reduce latency.
+	if (Cvar_r_latencyflex->GetInt())
+	{
+		if (m_lfx_WaitAndBeginFrame)
+		{
+			m_lfx_WaitAndBeginFrame();
+		}
+	}
+
+	OnRenderStart();
+}
+
+void InitialiseLatencyFleX(HMODULE baseAddress)
+{
+	// Connect to the LatencyFleX service
+	// LatencyFleX is an open source vendor agnostic replacement for Nvidia Reflex input latency reduction technology.
+	// https://ishitatsuyuki.github.io/post/latencyflex/
+	const auto lfxModuleName = "latencyflex_layer.dll";
+	const auto lfxModuleNameFallback = "latencyflex_wine.dll";
+	auto useFallbackEntrypoints = false;
+
+	// Load LatencyFleX library.
+	m_lfxModule = ::LoadLibraryA(lfxModuleName);
+	if (m_lfxModule == nullptr && ::GetLastError() == ERROR_MOD_NOT_FOUND)
+	{
+		spdlog::info("LFX: Primary LatencyFleX library not found, trying fallback.");
+
+		m_lfxModule = ::LoadLibraryA(lfxModuleNameFallback);
+		if (m_lfxModule == nullptr)
+		{
+			if (::GetLastError() == ERROR_MOD_NOT_FOUND)
+			{
+				spdlog::info("LFX: Fallback LatencyFleX library not found.");
+			}
+			else
+			{
+				spdlog::info("LFX: Error loading fallback LatencyFleX library - Code: {}", ::GetLastError());
+			}
+
+			return;
+		}
+
+		useFallbackEntrypoints = true;
+	}
+	else if (m_lfxModule == nullptr)
+	{
+		spdlog::info("LFX: Error loading primary LatencyFleX library - Code: {}", ::GetLastError());
+		return;
+	}
+
+	m_lfx_WaitAndBeginFrame = reinterpret_cast<PFN_lfx_WaitAndBeginFrame>(reinterpret_cast<void*>(
+		GetProcAddress(m_lfxModule, !useFallbackEntrypoints ? "lfx_WaitAndBeginFrame" : "winelfx_WaitAndBeginFrame")));
+
+	spdlog::info("LFX: Initialized.");
+
+	Cvar_r_latencyflex = new ConVar("r_latencyflex", "1", FCVAR_ARCHIVE, "Whether or not to use LatencyFleX input latency reduction.");
+
+	HookEnabler hook;
+	ENABLER_CREATEHOOK(hook, (char*)baseAddress + 0x1952C0, &OnRenderStartHook, reinterpret_cast<LPVOID*>(&OnRenderStart));
+}
+\ No newline at end of file