From 5d20018faea982495f8b78b6cbbc0a0512a0f5d4 Mon Sep 17 00:00:00 2001
From: JackCarterSmith <jackcartersmith@jcsmith.fr>
Date: Sun, 1 Dec 2024 12:59:36 +0100
Subject: [PATCH] Fixed unstable FPS and profiler inaccuracy

---
 Game.cpp | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/Game.cpp b/Game.cpp
index e78205c..329086d 100644
--- a/Game.cpp
+++ b/Game.cpp
@@ -52,19 +52,24 @@ Game::Game(std::shared_ptr<sf::RenderWindow> mainWnd, bool dbgFlag) : mbDbgModeE
 
 GAME_STATUS Game::Tick() {
     static std::vector<double> msTicksMonitoring;
-    static double mPrevdelta = 0;
     static double mLastCycleSleepDelta = 0;
     static unsigned int mFrameCnt = 0;
-    double mDelta = mSysTimer.GetDeltaTimeUs();
 
     // Debug performance computations
     if (mDbgUI != nullptr && mPerfsTimer != nullptr) {
         msTicksMonitoring.push_back(((1000000.f / TARGET_FPS) - mLastCycleSleepDelta) * TARGET_FPS / 1000000.f);
         if (mPerfsTimer->GetDeltaTime() >= 1000) {  // Every 1s
             // This average CPU/cycle_time method can monitor when CPU is in overload state (>0%) or in underload one (<0%)
-            double cpuUsage = 200 * std::accumulate(msTicksMonitoring.begin(), msTicksMonitoring.end(), static_cast<double>(0)) / msTicksMonitoring.size() - 100;
+            double cpuUsage = 100 * std::accumulate(msTicksMonitoring.begin(), msTicksMonitoring.end(), static_cast<double>(0)) / msTicksMonitoring.size();
 
-            mDbgUI->UpdateDebugData(cpuUsage, (((1000000.f / TARGET_FPS) - mLastCycleSleepDelta) / 1000), ((-mPrevdelta + mSysTimer.GetDeltaTimeUs()) / 1000), mFrameCnt, (PerfsGetVirtMem() / 1000), (PerfsGetPhysMem() / 1000));
+            mDbgUI->UpdateDebugData(
+                cpuUsage,
+                ((1000000.f / TARGET_FPS) - mLastCycleSleepDelta) / 1000,
+                1000.f / TARGET_FPS,
+                mFrameCnt,
+                PerfsGetVirtMem() / 1000,
+                PerfsGetPhysMem() / 1000
+            );
 
             mFrameCnt = 0;
             msTicksMonitoring.clear();
@@ -75,22 +80,20 @@ GAME_STATUS Game::Tick() {
     // Update game stats and internal stuff
     Update();
 
-    // Ugly way to wait for next frame... Maybe create a separate thread for rendering?
-    //while(time.GetDeltaTime() < (1000/TARGET_FPS)) {}   
-
-    // Process to the final rendering if the window have the focus
-    if (mSysTimer.GetDeltaTime() >= (1000/TARGET_FPS) && mMainWindow->hasFocus()) {
-        Render();
-        mFrameCnt++;
+    // Loop the timer when reached the target FPS
+    if ((mSysTimer.GetDeltaTime() >= (1000/TARGET_FPS))) {
         mSysTimer.Reset();
-        mDelta = -mDelta;
+        mFrameCnt++;
+
+        // Process to the final rendering if the window have the focus
+        if (mMainWindow->hasFocus())
+            Render();
     }
-    mPrevdelta = mDelta;
 
     // Sleep for remaining time to avoid useless CPU usage
-    mLastCycleSleepDelta = (1000000.f / TARGET_FPS) - (-mPrevdelta + mSysTimer.GetDeltaTimeUs());
+    mLastCycleSleepDelta = (1000000.f / TARGET_FPS) - mSysTimer.GetDeltaTimeUs();
     if (mLastCycleSleepDelta > 0)
-        sf::sleep(sf::microseconds(mLastCycleSleepDelta));
+        sf::sleep(sf::microseconds(mLastCycleSleepDelta + (1000000.f / TARGET_FPS * 0.02f)));
     else
         mLastCycleSleepDelta = 0;