From bed266dfe993469cb6252fccf90a6e48e00767a8 Mon Sep 17 00:00:00 2001
From: David Rowe <david@ctrlaltstudio.com>
Date: Tue, 21 Jul 2015 18:23:50 -0700
Subject: [PATCH] Fade looking-at-me eye spheres over half a second

---
 interface/src/avatar/Avatar.cpp | 31 ++++++++++++++++++-------------
 interface/src/avatar/Head.cpp   |  4 ++++
 interface/src/avatar/Head.h     |  2 ++
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/interface/src/avatar/Avatar.cpp b/interface/src/avatar/Avatar.cpp
index f9a1185e24..884540bf7c 100644
--- a/interface/src/avatar/Avatar.cpp
+++ b/interface/src/avatar/Avatar.cpp
@@ -464,19 +464,24 @@ void Avatar::render(RenderArgs* renderArgs, const glm::vec3& cameraPosition, boo
         // If the avatar is looking at me, indicate that they are
         if (getHead()->getIsLookingAtMe() && Menu::getInstance()->isOptionChecked(MenuOption::ShowWhosLookingAtMe)) {
             const glm::vec3 LOOKING_AT_ME_COLOR = { 1.0f, 1.0f, 1.0f };
-            float alpha = 1.0f;
-            float radius = 0.035f;
-            Transform transform;
-            glm::vec3 position = getHead()->getLeftEyePosition();
-            transform.setTranslation(position);
-            batch.setModelTransform(transform);
-            DependencyManager::get<DeferredLightingEffect>()->renderSolidSphere(batch, radius, 15, 15, 
-                glm::vec4(LOOKING_AT_ME_COLOR, alpha));
-            position = getHead()->getRightEyePosition();
-            transform.setTranslation(position);
-            batch.setModelTransform(transform);
-            DependencyManager::get<DeferredLightingEffect>()->renderSolidSphere(batch, radius, 15, 15,
-                glm::vec4(LOOKING_AT_ME_COLOR, alpha));
+            const float LOOKING_AT_ME_DURATION = 0.5f;  // seconds
+            quint64 now = usecTimestampNow();
+            float alpha = 1.0f - ((float)(usecTimestampNow() - getHead()->getIsLookingAtMeStarted())) 
+                / (LOOKING_AT_ME_DURATION * (float)USECS_PER_SECOND);
+            if (alpha > 0.0f) {
+                float radius = 0.035f;
+                Transform transform;
+                glm::vec3 position = getHead()->getLeftEyePosition();
+                transform.setTranslation(position);
+                batch.setModelTransform(transform);
+                DependencyManager::get<DeferredLightingEffect>()->renderSolidSphere(batch, radius, 15, 15,
+                    glm::vec4(LOOKING_AT_ME_COLOR, alpha));
+                position = getHead()->getRightEyePosition();
+                transform.setTranslation(position);
+                batch.setModelTransform(transform);
+                DependencyManager::get<DeferredLightingEffect>()->renderSolidSphere(batch, radius, 15, 15,
+                    glm::vec4(LOOKING_AT_ME_COLOR, alpha));
+            }
         }
 
         // quick check before falling into the code below:
diff --git a/interface/src/avatar/Head.cpp b/interface/src/avatar/Head.cpp
index 43e68557ce..94a163e508 100644
--- a/interface/src/avatar/Head.cpp
+++ b/interface/src/avatar/Head.cpp
@@ -55,6 +55,7 @@ Head::Head(Avatar* owningAvatar) :
     _deltaLeanForward(0.0f),
     _isCameraMoving(false),
     _isLookingAtMe(false),
+    _isLookingAtMeStarted(0),
     _faceModel(this),
     _leftEyeLookAtID(DependencyManager::get<GeometryCache>()->allocateID()),
     _rightEyeLookAtID(DependencyManager::get<GeometryCache>()->allocateID())
@@ -323,6 +324,9 @@ glm::vec3 Head::getCorrectedLookAtPosition() {
 }
 
 void Head::setCorrectedLookAtPosition(glm::vec3 correctedLookAtPosition) {
+    if (!_isLookingAtMe) {
+        _isLookingAtMeStarted = usecTimestampNow();
+    }
     _isLookingAtMe = true;
     _correctedLookAtPosition = correctedLookAtPosition;
 }
diff --git a/interface/src/avatar/Head.h b/interface/src/avatar/Head.h
index d7a8462693..58f6f14b0a 100644
--- a/interface/src/avatar/Head.h
+++ b/interface/src/avatar/Head.h
@@ -53,6 +53,7 @@ public:
     glm::vec3 getCorrectedLookAtPosition();
     void clearCorrectedLookAtPosition() { _isLookingAtMe = false; }
     bool getIsLookingAtMe() { return _isLookingAtMe; }
+    quint64 getIsLookingAtMeStarted() { return _isLookingAtMeStarted; }
     
     float getScale() const { return _scale; }
     glm::vec3 getPosition() const { return _position; }
@@ -139,6 +140,7 @@ private:
 
     bool _isCameraMoving;
     bool _isLookingAtMe;
+    quint64 _isLookingAtMeStarted;
     FaceModel _faceModel;
     
     glm::vec3 _correctedLookAtPosition;