From e1ad9d3b4b1c730b8c39f3e1360f9d73f7381542 Mon Sep 17 00:00:00 2001
From: Philip Rosedale <philip@highfidelity.io>
Date: Thu, 20 Nov 2014 17:26:11 -0600
Subject: [PATCH] Fix eyes jittering when turning away/toward someone

---
 interface/src/avatar/Avatar.h     | 1 +
 interface/src/avatar/MyAvatar.cpp | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/interface/src/avatar/Avatar.h b/interface/src/avatar/Avatar.h
index 376e229d0c..2d1a44403f 100644
--- a/interface/src/avatar/Avatar.h
+++ b/interface/src/avatar/Avatar.h
@@ -87,6 +87,7 @@ public:
     void setDisplayingLookatVectors(bool displayingLookatVectors) { getHead()->setRenderLookatVectors(displayingLookatVectors); }
     void setMouseRay(const glm::vec3 &origin, const glm::vec3 &direction);
     void setIsLookAtTarget(const bool isLookAtTarget) { _isLookAtTarget = isLookAtTarget; }
+    bool getIsLookAtTarget() const { return _isLookAtTarget; }
     //getters
     bool isInitialized() const { return _initialized; }
     SkeletonModel& getSkeletonModel() { return _skeletonModel; }
diff --git a/interface/src/avatar/MyAvatar.cpp b/interface/src/avatar/MyAvatar.cpp
index 8b5fefc3be..39c88ef642 100644
--- a/interface/src/avatar/MyAvatar.cpp
+++ b/interface/src/avatar/MyAvatar.cpp
@@ -930,14 +930,16 @@ void MyAvatar::updateLookAtTargetAvatar() {
     glm::vec3 lookForward = faceRotation * IDENTITY_FRONT;
     glm::vec3 cameraPosition = Application::getInstance()->getCamera()->getPosition();
     float smallestAngleTo = glm::radians(Application::getInstance()->getCamera()->getFieldOfView()) / 2.f;
+    const float KEEP_LOOKING_AT_CURRENT_ANGLE_FACTOR = 1.3f;
     
     int howManyLookingAtMe = 0;
     foreach (const AvatarSharedPointer& avatarPointer, Application::getInstance()->getAvatarManager().getAvatarHash()) {
         Avatar* avatar = static_cast<Avatar*>(avatarPointer.data());
+        bool isCurrentTarget = avatar->getIsLookAtTarget();
         avatar->setIsLookAtTarget(false);
         if (!avatar->isMyAvatar() && avatar->isInitialized()) {
             float angleTo = glm::angle(lookForward, glm::normalize(avatar->getHead()->getEyePosition() - cameraPosition));
-            if (angleTo < smallestAngleTo) {
+            if (angleTo < (smallestAngleTo * (isCurrentTarget ? KEEP_LOOKING_AT_CURRENT_ANGLE_FACTOR : 1.0f))) {
                 _lookAtTargetAvatar = avatarPointer;
                 _targetAvatarPosition = avatarPointer->getPosition();
                 smallestAngleTo = angleTo;