From ea03067a02515ab967ff6db502caae0b96f4e461 Mon Sep 17 00:00:00 2001
From: David Rowe <david@ctrlaltstudio.com>
Date: Fri, 7 Aug 2015 12:23:43 -0700
Subject: [PATCH] When eye tracking data is lot for > N seconds handle as "not
 tracking"

Revert to default look-at behaviour and saccades until tracking resumes.
---
 interface/src/Application.cpp        | 2 +-
 interface/src/devices/EyeTracker.cpp | 9 +++++++++
 interface/src/devices/EyeTracker.h   | 5 ++++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index c9047e527f..56a33695bc 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2050,7 +2050,7 @@ void Application::setActiveEyeTracker() {
     bool isEyeTracking = Menu::getInstance()->isOptionChecked(MenuOption::SMIEyeTracking);
     bool isSimulating = Menu::getInstance()->isOptionChecked(MenuOption::SimulateEyeTracking);
     eyeTracker->setEnabled(isEyeTracking, isSimulating);
-    if (isEyeTracking && !eyeTracker->isTracking()) {
+    if (isEyeTracking && !eyeTracker->isEnabled()) {
         Menu::getInstance()->setIsOptionChecked(MenuOption::SMIEyeTracking, false);
         isEyeTracking = false;
     }
diff --git a/interface/src/devices/EyeTracker.cpp b/interface/src/devices/EyeTracker.cpp
index c8942a889b..9a35448bd0 100644
--- a/interface/src/devices/EyeTracker.cpp
+++ b/interface/src/devices/EyeTracker.cpp
@@ -13,6 +13,8 @@
 
 #include <QMessageBox>
 
+#include <SharedUtil.h>
+
 #include "InterfaceLogging.h"
 #include "OctreeConstants.h"
 
@@ -36,6 +38,8 @@ EyeTracker::~EyeTracker() {
 
 #ifdef HAVE_IVIEWHMD
 void EyeTracker::processData(smi_CallbackDataStruct* data) {
+    _lastProcessDataTimestamp = usecTimestampNow();
+
     if (!_isEnabled) {
         return;
     }
@@ -150,6 +154,11 @@ void EyeTracker::reset() {
     // Nothing to do.
 }
 
+bool EyeTracker::isTracking() const {
+    static const quint64 ACTIVE_TIMEOUT_USECS = 2000000;  // 2 secs
+    return (usecTimestampNow() - _lastProcessDataTimestamp < ACTIVE_TIMEOUT_USECS);
+}
+
 #ifdef HAVE_IVIEWHMD
 void EyeTracker::calibrate(int points) {
     smi_CalibrationHMDStruct* calibrationHMDStruct;
diff --git a/interface/src/devices/EyeTracker.h b/interface/src/devices/EyeTracker.h
index 8747076340..4976c14d08 100644
--- a/interface/src/devices/EyeTracker.h
+++ b/interface/src/devices/EyeTracker.h
@@ -34,7 +34,8 @@ public:
     void reset();
 
     bool isInitialized() const { return _isInitialized; }
-    bool isTracking() const { return _isEnabled; }
+    bool isEnabled() const { return _isEnabled; }
+    bool isTracking() const;
     bool isSimulating() const { return _isSimulating; }
 
     glm::vec3 getLookAtPosition() const { return _lookAtPosition; }  // From mid eye point in head frame.
@@ -52,6 +53,8 @@ private:
     bool _isEnabled = false;
     bool _isSimulating = false;
 
+    quint64 _lastProcessDataTimestamp;
+
     glm::vec3 _lookAtPosition;
 };