ATOM-15842 Update the fps calculation for editor (#1500)

Gems/AtomLyIntegration/AtomViewportDisplayInfo/Code/Source/AtomViewportDisplayInfoSystemComponent.cpp

@@ -248,68 +248,50 @@ namespace AZ::Render
 
     void AtomViewportDisplayInfoSystemComponent::UpdateFramerate()
     {
-        if (!m_tickRequests)
-        {
-            m_tickRequests = AZ::TickRequestBus::FindFirstHandler();
-            if (!m_tickRequests)
-            {
-                return;
-            }
-        }
-
-        AZ::ScriptTimePoint currentTime = m_tickRequests->GetTimeAtCurrentTick();
-        // Only keep as much sampling data as is required by our FPS history.
-        while (!m_fpsHistory.empty() && (currentTime.Get() - m_fpsHistory.front().Get()) > m_fpsInterval)
+        auto currentTime = AZStd::chrono::system_clock::now();
+        while (!m_fpsHistory.empty() && (currentTime - m_fpsHistory.front()) > m_fpsInterval)
         {
             m_fpsHistory.pop_front();
         }
-
-        // Discard entries with a zero time-delta (can happen when we don't have window focus).
-        if (m_fpsHistory.empty() || (currentTime.Get() - m_fpsHistory.back().Get()) != AZStd::chrono::seconds(0))
-        {
-            m_fpsHistory.push_back(currentTime);
-        }
+        m_fpsHistory.push_back(currentTime);
     }
 
     void AtomViewportDisplayInfoSystemComponent::DrawFramerate()
     {
-        AZStd::chrono::duration<double> actualInterval = AZStd::chrono::seconds(0);
-        AZStd::optional<AZ::ScriptTimePoint> lastTime;
-        AZStd::optional<double> minFPS;
-        AZStd::optional<double> maxFPS;
-        for (const AZ::ScriptTimePoint& time : m_fpsHistory)
+        AZStd::optional<AZStd::chrono::system_clock::time_point> lastTime;
+        double minFPS = DBL_MAX;
+        double maxFPS = 0;
+        AZStd::chrono::duration<double> deltaTime;
+        for (const auto& time : m_fpsHistory)
         {
             if (lastTime.has_value())
             {
-                AZStd::chrono::duration<double> deltaTime = time.Get() - lastTime.value().Get();
+                deltaTime = time - lastTime.value();
                 double fps = AZStd::chrono::seconds(1) / deltaTime;
-                if (!minFPS.has_value())
-                {
-                    minFPS = fps;
-                    maxFPS = fps;
-                }
-                else
-                {
-                    minFPS = AZStd::min(minFPS.value(), fps);
-                    maxFPS = AZStd::max(maxFPS.value(), fps);
-                }
-                actualInterval += deltaTime;
+                minFPS = AZStd::min(minFPS, fps);
+                maxFPS = AZStd::max(maxFPS, fps);
             }
             lastTime = time;
         }
 
-        const double averageFPS = (actualInterval.count() != 0.0)
-            ? aznumeric_cast<double>(m_fpsHistory.size()) / actualInterval.count()
-            : 0.0;
+        double averageFPS = 0;
+        double averageFrameMs = 0;
+        if (m_fpsHistory.size() > 1)
+        {
+            deltaTime = m_fpsHistory.back() - m_fpsHistory.front();
+            averageFPS = AZStd::chrono::seconds(m_fpsHistory.size()) / deltaTime;
+            averageFrameMs = 1000.0f/averageFPS;
+        }
 
         const double frameIntervalSeconds = m_fpsInterval.count();
 
         DrawLine(
             AZStd::string::format(
-                "FPS %.1f [%.0f..%.0f], frame avg over %.1fs",
+                "FPS %.1f [%.0f..%.0f], %.1fms/frame, avg over %.1fs",
                 averageFPS,
-                minFPS.value_or(0.0),
-                maxFPS.value_or(0.0),
+                minFPS,
+                maxFPS,
+                averageFrameMs,
                 frameIntervalSeconds),
             AZ::Colors::Yellow);
     }

Gems/AtomLyIntegration/AtomViewportDisplayInfo/Code/Source/AtomViewportDisplayInfoSystemComponent.h

@@ -65,9 +65,8 @@ namespace AZ
             AzFramework::FontDrawInterface* m_fontDrawInterface = nullptr;
             float m_lineSpacing;
             AZStd::chrono::duration<double> m_fpsInterval = AZStd::chrono::seconds(1);
-            AZStd::deque<AZ::ScriptTimePoint> m_fpsHistory;
+            AZStd::deque<AZStd::chrono::system_clock::time_point> m_fpsHistory;
             AZStd::optional<AZStd::chrono::system_clock::time_point> m_lastMemoryUpdate;
-            AZ::TickRequests* m_tickRequests = nullptr;
             bool m_updateRootPassQuery = true;
         };
     } // namespace Render