From 31f361d49ca445ce84ca7c0a3ca8875554f42a7a Mon Sep 17 00:00:00 2001
From: "Anthony J. Thibault" <tony@highfidelity.io>
Date: Tue, 3 Nov 2015 15:51:18 -0800
Subject: [PATCH] Moved fps timing to beginning of paintGL

This should improve accuracy.

However the fps displayed can still sometimes be slightly greater then the
vsync, this is either due to timer accuracy problems or QTimer delay within
OpenGLDisplayPlugin.
---
 interface/src/Application.cpp | 40 +++++++++++++++++------------------
 interface/src/Application.h   |  2 +-
 2 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 1f04338f99..d31d9de4a0 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -1041,8 +1041,25 @@ void Application::initializeUi() {
 }
 
 void Application::paintGL() {
+    _frameCount++;
 
-    idle();
+    // update fps moving average
+    uint64_t now = usecTimestampNow();
+    static uint64_t lastPaintBegin{ now };
+    uint64_t diff = now - lastPaintBegin;
+    if (diff != 0) {
+        _framesPerSecond.updateAverage((float)USECS_PER_SECOND / (float)diff);
+    }
+
+    lastPaintBegin = now;
+
+    // update fps once a second
+    if (now - _lastFramesPerSecondUpdate > USECS_PER_SECOND) {
+        _fps = _framesPerSecond.getAverage();
+        _lastFramesPerSecondUpdate = now;
+    }
+
+    idle(now);
 
     PROFILE_RANGE(__FUNCTION__);
     PerformanceTimer perfTimer("paintGL");
@@ -1318,24 +1335,6 @@ void Application::paintGL() {
             batch.resetStages();
         });
     }
-
-    // update fps moving average
-    {
-        uint64_t now = usecTimestampNow();
-        static uint64_t lastPaintEnd{ now };
-        uint64_t diff = now - lastPaintEnd;
-        if (diff != 0) {
-            _framesPerSecond.updateAverage((float)USECS_PER_SECOND / (float)diff);
-        }
-        lastPaintEnd = now;
-
-        // update fps once a second
-        if (now - _lastFramesPerSecondUpdate > USECS_PER_SECOND) {
-            _fps = _framesPerSecond.getAverage();
-            _lastFramesPerSecondUpdate = now;
-        }
-        _frameCount++;
-    }
 }
 
 void Application::runTests() {
@@ -2107,7 +2106,7 @@ void Application::ping() {
     }
 }
 
-void Application::idle() {
+void Application::idle(uint64_t now) {
     if (_aboutToQuit) {
         return; // bail early, nothing to do here.
     }
@@ -2130,7 +2129,6 @@ void Application::idle() {
 
     {
         PROFILE_RANGE(__FUNCTION__);
-        uint64_t now = usecTimestampNow();
         static uint64_t lastIdleStart{ now };
         uint64_t idleStartToStartDuration = now - lastIdleStart;
         if (idleStartToStartDuration != 0) {
diff --git a/interface/src/Application.h b/interface/src/Application.h
index 0fd8c74494..212687c11e 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -307,7 +307,7 @@ public slots:
 private slots:
     void clearDomainOctreeDetails();
     void ping();
-    void idle();
+    void idle(uint64_t now);
     void aboutToQuit();
 
     void handleScriptEngineLoaded(const QString& scriptFilename);