From 23012a8e4658a8e3993cbd1e030081ff130b4638 Mon Sep 17 00:00:00 2001
From: crosire <crosiredev@gmail.com>
Date: Sun, 28 Apr 2024 15:32:35 +0200
Subject: [PATCH] Change "IDXGISwapChain::GetFullscreenState" to return forced
 fullscreen state when set by an add-on or config

Needed in Fallout 4, since otherwise it continues trying to change the fullscreen state
---
 source/dxgi/dxgi_swapchain.cpp | 32 ++++++++++++++++++++++++++++++++
 source/dxgi/dxgi_swapchain.hpp |  4 ++++
 2 files changed, 36 insertions(+)

diff --git a/source/dxgi/dxgi_swapchain.cpp b/source/dxgi/dxgi_swapchain.cpp
index 4b31be277..8949ce543 100644
--- a/source/dxgi/dxgi_swapchain.cpp
+++ b/source/dxgi/dxgi_swapchain.cpp
@@ -261,6 +261,9 @@ HRESULT STDMETHODCALLTYPE DXGISwapChain::SetFullscreenState(BOOL Fullscreen, IDX
 	LOG(INFO) << "Redirecting " << "IDXGISwapChain::SetFullscreenState" << '(' << "this = " << this << ", Fullscreen = " << (Fullscreen ? "TRUE" : "FALSE") << ", pTarget = " << pTarget << ')' << " ...";
 
 #if RESHADE_ADDON
+	_force_windowed_addon = false;
+	_force_fullscreen_addon = false;
+
 	HMONITOR hmonitor = nullptr;
 	if (pTarget != nullptr)
 	{
@@ -270,7 +273,11 @@ HRESULT STDMETHODCALLTYPE DXGISwapChain::SetFullscreenState(BOOL Fullscreen, IDX
 	}
 
 	if (reshade::invoke_addon_event<reshade::addon_event::set_fullscreen_state>(_impl, Fullscreen != FALSE, hmonitor))
+	{
+		_force_windowed_addon = Fullscreen == FALSE;
+		_force_fullscreen_addon = Fullscreen != FALSE;
 		return S_OK;
+	}
 #endif
 
 	if (_force_windowed)
@@ -286,6 +293,31 @@ HRESULT STDMETHODCALLTYPE DXGISwapChain::SetFullscreenState(BOOL Fullscreen, IDX
 }
 HRESULT STDMETHODCALLTYPE DXGISwapChain::GetFullscreenState(BOOL *pFullscreen, IDXGIOutput **ppTarget)
 {
+	if (_force_windowed
+#if RESHADE_ADDON
+		|| _force_windowed_addon
+#endif
+		)
+	{
+		if (pFullscreen != nullptr)
+			*pFullscreen = FALSE;
+		if (ppTarget != nullptr)
+			*ppTarget = nullptr;
+		return S_OK;
+	}
+	if (_force_fullscreen
+#if RESHADE_ADDON
+		|| _force_fullscreen_addon
+#endif
+		)
+	{
+		if (pFullscreen != nullptr)
+			*pFullscreen = TRUE;
+		if (ppTarget != nullptr)
+			_orig->GetContainingOutput(ppTarget);
+		return S_OK;
+	}
+
 	const bool was_in_dxgi_runtime = g_in_dxgi_runtime;
 	g_in_dxgi_runtime = true;
 	const HRESULT hr = _orig->GetFullscreenState(pFullscreen, ppTarget);
diff --git a/source/dxgi/dxgi_swapchain.hpp b/source/dxgi/dxgi_swapchain.hpp
index de0665330..cae12127c 100644
--- a/source/dxgi/dxgi_swapchain.hpp
+++ b/source/dxgi/dxgi_swapchain.hpp
@@ -105,4 +105,8 @@ struct DECLSPEC_UUID("1F445F9F-9887-4C4C-9055-4E3BADAFCCA8") DXGISwapChain final
 	bool _force_vsync = false;
 	bool _force_windowed = false;
 	bool _force_fullscreen = false;
+#if RESHADE_ADDON
+	bool _force_windowed_addon = false;
+	bool _force_fullscreen_addon = false;
+#endif
 };