From bfa5ef7990f7213a4877d400c5f3f86a4483ba10 Mon Sep 17 00:00:00 2001
From: Alexander Wilms <f.alexander.wilms@gmail.com>
Date: Tue, 26 Sep 2023 17:28:44 +0200
Subject: [PATCH] Don't sleep in FramerateManager::framerateDelay() if VSync is
 enabled

---
 client/gui/FramerateManager.cpp | 16 +++++++++++-----
 client/gui/FramerateManager.h   |  2 ++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/client/gui/FramerateManager.cpp b/client/gui/FramerateManager.cpp
index 59aa653e7..0e81ea8c8 100644
--- a/client/gui/FramerateManager.cpp
+++ b/client/gui/FramerateManager.cpp
@@ -11,22 +11,28 @@
 #include "StdInc.h"
 #include "FramerateManager.h"
 
+#include "../../lib/CConfigHandler.h"
+
 FramerateManager::FramerateManager(int targetFrameRate)
 	: targetFrameTime(Duration(boost::chrono::seconds(1)) / targetFrameRate)
 	, lastFrameIndex(0)
 	, lastFrameTimes({})
-	, lastTimePoint (Clock::now())
+	, lastTimePoint(Clock::now())
+	, vsyncEnabled(settings["video"]["vsync"].Bool())
 {
 	boost::range::fill(lastFrameTimes, targetFrameTime);
 }
 
 void FramerateManager::framerateDelay()
 {
-	Duration timeSpentBusy = Clock::now() - lastTimePoint;
+	if(!vsyncEnabled)
+	{
+		Duration timeSpentBusy = Clock::now() - lastTimePoint;
 
-	// FPS is higher than it should be, then wait some time
-	if(timeSpentBusy < targetFrameTime)
-		boost::this_thread::sleep_for(targetFrameTime - timeSpentBusy);
+		// FPS is higher than it should be, then wait some time
+		if(timeSpentBusy < targetFrameTime)
+			boost::this_thread::sleep_for(targetFrameTime - timeSpentBusy);
+	}
 
 	// compute actual timeElapsed taking into account actual sleep interval
 	// limit it to 100 ms to avoid breaking animation in case of huge lag (e.g. triggered breakpoint)
diff --git a/client/gui/FramerateManager.h b/client/gui/FramerateManager.h
index 818e55f94..d653bd667 100644
--- a/client/gui/FramerateManager.h
+++ b/client/gui/FramerateManager.h
@@ -25,6 +25,8 @@ class FramerateManager
 	/// index of last measured frome in lastFrameTimes array
 	ui32 lastFrameIndex;
 
+	bool vsyncEnabled;
+
 public:
 	FramerateManager(int targetFramerate);