From 90f55f0cd5d68060b5e81d19dc996b8a7b0442fc Mon Sep 17 00:00:00 2001
From: Brad Davis <bdavis@saintandreas.org>
Date: Tue, 8 Nov 2016 09:13:53 -0800
Subject: [PATCH] Add stutter tracking

---
 interface/resources/qml/Stats.qml             |  4 ++++
 interface/src/ui/Stats.cpp                    |  3 ++-
 interface/src/ui/Stats.h                      |  5 ++++-
 libraries/plugins/src/plugins/DisplayPlugin.h |  2 ++
 plugins/openvr/src/OpenVrDisplayPlugin.cpp    | 10 ++++++++++
 plugins/openvr/src/OpenVrDisplayPlugin.h      |  3 +++
 6 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/interface/resources/qml/Stats.qml b/interface/resources/qml/Stats.qml
index 9c55b1ce2d..cb7186456f 100644
--- a/interface/resources/qml/Stats.qml
+++ b/interface/resources/qml/Stats.qml
@@ -69,6 +69,10 @@ Item {
                     StatText {
                         text: "Present Drop Rate: " + root.presentdroprate.toFixed(2);
                     }
+                    StatText {
+                        text: "Stutter Rate: " + root.stutterrate.toFixed(3);
+                        visible: root.stutterrate != -1;
+                    }
                     StatText {
                         text: "Simrate: " + root.simrate
                     }
diff --git a/interface/src/ui/Stats.cpp b/interface/src/ui/Stats.cpp
index edf72d9758..bad2c3c056 100644
--- a/interface/src/ui/Stats.cpp
+++ b/interface/src/ui/Stats.cpp
@@ -128,7 +128,8 @@ void Stats::updateStats(bool force) {
         STAT_UPDATE(renderrate, displayPlugin->renderRate());
         STAT_UPDATE(presentrate, displayPlugin->presentRate());
         STAT_UPDATE(presentnewrate, displayPlugin->newFramePresentRate());
-        STAT_UPDATE(presentdroprate, qApp->getActiveDisplayPlugin()->droppedFrameRate());
+        STAT_UPDATE(presentdroprate, displayPlugin->droppedFrameRate());
+        STAT_UPDATE(stutterrate, displayPlugin->stutterRate());
     } else {
         STAT_UPDATE(presentrate, -1);
         STAT_UPDATE(presentnewrate, -1);
diff --git a/interface/src/ui/Stats.h b/interface/src/ui/Stats.h
index ffa5c08bc6..5d1aac4287 100644
--- a/interface/src/ui/Stats.h
+++ b/interface/src/ui/Stats.h
@@ -36,7 +36,9 @@ class Stats : public QQuickItem {
     STATS_PROPERTY(float, renderrate, 0)
     // How often the display plugin is presenting to the device
     STATS_PROPERTY(float, presentrate, 0)
-    
+    // How often the display device reprojecting old frames
+    STATS_PROPERTY(float, stutterrate, 0)
+
     STATS_PROPERTY(float, presentnewrate, 0)
     STATS_PROPERTY(float, presentdroprate, 0)
     STATS_PROPERTY(int, simrate, 0)
@@ -140,6 +142,7 @@ signals:
     void presentrateChanged();
     void presentnewrateChanged();
     void presentdroprateChanged();
+    void stutterrateChanged();
     void simrateChanged();
     void avatarSimrateChanged();
     void avatarCountChanged();
diff --git a/libraries/plugins/src/plugins/DisplayPlugin.h b/libraries/plugins/src/plugins/DisplayPlugin.h
index 3a9107390a..c87669c99a 100644
--- a/libraries/plugins/src/plugins/DisplayPlugin.h
+++ b/libraries/plugins/src/plugins/DisplayPlugin.h
@@ -188,6 +188,8 @@ public:
     virtual float renderRate() const { return -1.0f; }
     // Rate at which we present to the display device
     virtual float presentRate() const { return -1.0f; }
+    // Rate at which old frames are presented to the device display
+    virtual float stutterRate() const { return -1.0f; }
     // Rate at which new frames are being presented to the display device
     virtual float newFramePresentRate() const { return -1.0f; }
     // Rate at which rendered frames are being skipped
diff --git a/plugins/openvr/src/OpenVrDisplayPlugin.cpp b/plugins/openvr/src/OpenVrDisplayPlugin.cpp
index 1a4067a847..e300ad3ece 100644
--- a/plugins/openvr/src/OpenVrDisplayPlugin.cpp
+++ b/plugins/openvr/src/OpenVrDisplayPlugin.cpp
@@ -641,6 +641,12 @@ void OpenVrDisplayPlugin::hmdPresent() {
         vr::VRCompositor()->PostPresentHandoff();
         _presentRate.increment();
     }
+
+    vr::Compositor_FrameTiming frameTiming;
+    memset(&frameTiming, 0, sizeof(vr::Compositor_FrameTiming));
+    frameTiming.m_nSize = sizeof(vr::Compositor_FrameTiming);
+    vr::VRCompositor()->GetFrameTiming(&frameTiming);
+    _stutterRate.increment(frameTiming.m_nNumDroppedFrames);
 }
 
 void OpenVrDisplayPlugin::postPreview() {
@@ -702,3 +708,7 @@ bool OpenVrDisplayPlugin::isKeyboardVisible() {
 int OpenVrDisplayPlugin::getRequiredThreadCount() const { 
     return Parent::getRequiredThreadCount() + (_threadedSubmit ? 1 : 0);
 }
+
+float OpenVrDisplayPlugin::stutterRate() const {
+    return _stutterRate.rate();
+}
diff --git a/plugins/openvr/src/OpenVrDisplayPlugin.h b/plugins/openvr/src/OpenVrDisplayPlugin.h
index 3403bae27c..0f4c5a6320 100644
--- a/plugins/openvr/src/OpenVrDisplayPlugin.h
+++ b/plugins/openvr/src/OpenVrDisplayPlugin.h
@@ -58,6 +58,8 @@ public:
     // Possibly needs an additional thread for VR submission
     int getRequiredThreadCount() const override; 
 
+    float stutterRate() const override;
+
 protected:
     bool internalActivate() override;
     void internalDeactivate() override;
@@ -77,6 +79,7 @@ private:
     vr::HmdMatrix34_t _lastGoodHMDPose;
     mat4 _sensorResetMat;
     bool _threadedSubmit { true };
+    RateCounter<> _stutterRate;
 
     CompositeInfo::Array _compositeInfos;
     size_t _renderingIndex { 0 };