From bc90faebf70b996c31a01b9210056fa6b5c7c92c Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 29 Feb 2020 22:48:32 -0800
Subject: [PATCH] D3D9: Allow vsync change at runtime.

---
 Windows/GPU/D3D9Context.cpp | 11 +++++++----
 Windows/GPU/D3D9Context.h   |  1 +
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/Windows/GPU/D3D9Context.cpp b/Windows/GPU/D3D9Context.cpp
index 4317fd13285e..2ea38836e024 100644
--- a/Windows/GPU/D3D9Context.cpp
+++ b/Windows/GPU/D3D9Context.cpp
@@ -56,7 +56,7 @@ static void GetRes(HWND hWnd, int &xres, int &yres) {
 }
 
 void D3D9Context::SwapInterval(int interval) {
-	// Dummy
+	swapInterval_ = interval;
 }
 
 bool D3D9Context::Init(HINSTANCE hInst, HWND wnd, std::string *error_message) {
@@ -159,7 +159,7 @@ bool D3D9Context::Init(HINSTANCE hInst, HWND wnd, std::string *error_message) {
 	presentParams_.hDeviceWindow = wnd;
 	presentParams_.EnableAutoDepthStencil = true;
 	presentParams_.AutoDepthStencilFormat = D3DFMT_D24S8;
-	presentParams_.PresentationInterval = (g_Config.bVSync) ? D3DPRESENT_INTERVAL_ONE : D3DPRESENT_INTERVAL_IMMEDIATE;
+	presentParams_.PresentationInterval = swapInterval_ == 1 ? D3DPRESENT_INTERVAL_ONE : D3DPRESENT_INTERVAL_IMMEDIATE;
 
 	if (has9Ex_) {
 		if (windowed && IsWin7OrLater()) {
@@ -205,16 +205,19 @@ void D3D9Context::Resize() {
 	// This should only be called from the emu thread.
 	int xres, yres;
 	GetRes(hWnd_, xres, yres);
+	uint32_t newInterval = swapInterval_ == 1 ? D3DPRESENT_INTERVAL_ONE : D3DPRESENT_INTERVAL_IMMEDIATE;;
 	bool w_changed = presentParams_.BackBufferWidth != xres;
 	bool h_changed = presentParams_.BackBufferHeight != yres;
+	bool i_changed = presentParams_.PresentationInterval != newInterval;
 
-	if (device_ && (w_changed || h_changed)) {
+	if (device_ && (w_changed || h_changed || i_changed)) {
 		draw_->HandleEvent(Draw::Event::LOST_BACKBUFFER, 0, 0, nullptr);
 		presentParams_.BackBufferWidth = xres;
 		presentParams_.BackBufferHeight = yres;
+		presentParams_.PresentationInterval = newInterval;
 		HRESULT hr = device_->Reset(&presentParams_);
 		if (FAILED(hr)) {
-      // Had to remove DXGetErrorStringA calls here because dxerr.lib is deprecated and will not link with VS 2015.
+			// Had to remove DXGetErrorStringA calls here because dxerr.lib is deprecated and will not link with VS 2015.
 			PanicAlert("Unable to reset D3D9 device");
 		}
 		draw_->HandleEvent(Draw::Event::GOT_BACKBUFFER, 0, 0, nullptr);
diff --git a/Windows/GPU/D3D9Context.h b/Windows/GPU/D3D9Context.h
index 474137bb7dbc..9ad836d338d3 100644
--- a/Windows/GPU/D3D9Context.h
+++ b/Windows/GPU/D3D9Context.h
@@ -53,5 +53,6 @@ class D3D9Context : public WindowsGraphicsContext {
 	HWND hWnd_;   // Holds Our Window Handle
 	HMODULE hD3D9_;
 	D3DPRESENT_PARAMETERS presentParams_;
+	int swapInterval_ = 0;
 };