From e55efb81a83142ab3299fa11aabfde93ae1fa625 Mon Sep 17 00:00:00 2001
From: Philip Rosedale <philip@coffeeandpower.com>
Date: Thu, 16 May 2013 19:12:48 -0600
Subject: [PATCH] Added acceleration decay of pitch (you look up/straight if
 you start moving)

---
 interface/src/Avatar.cpp | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/interface/src/Avatar.cpp b/interface/src/Avatar.cpp
index bb70f230a9..0e7cad3f05 100644
--- a/interface/src/Avatar.cpp
+++ b/interface/src/Avatar.cpp
@@ -18,6 +18,7 @@
 #include <AgentList.h>
 #include <AgentTypes.h>
 #include <PacketHeaders.h>
+#include <OculusManager.h>
 
 using namespace std;
 
@@ -29,8 +30,6 @@ const float THRUST_MAG                    = 1200.0;
 const float YAW_MAG                       = 500.0;
 const float BODY_SPIN_FRICTION            = 5.0;
 const float BODY_UPRIGHT_FORCE            = 10.0;
-const float BODY_PITCH_WHILE_WALKING      = 40.0;
-const float BODY_ROLL_WHILE_TURNING       = 0.1;
 const float VELOCITY_DECAY                = 5.0;
 const float MY_HAND_HOLDING_PULL          = 0.2;
 const float YOUR_HAND_HOLDING_PULL        = 1.0;
@@ -50,7 +49,6 @@ const float HEAD_MAX_YAW                  = 85;
 const float HEAD_MIN_YAW                  = -85;
 const float AVATAR_BRAKING_RANGE          = 1.6f;
 const float AVATAR_BRAKING_STRENGTH       = 30.0f;
-//const float MAX_JOINT_TOUCH_DOT           = 0.995f;
 const float JOINT_TOUCH_RANGE             = 0.0005f;
 
 float skinColor [] = {1.0, 0.84, 0.66};
@@ -188,15 +186,6 @@ Avatar::Avatar(const Avatar &otherAvatar) {
     
     initializeSkeleton();
 
-/*
-    if (iris_texture.size() == 0) {
-        switchToResourcesParentIfRequired();
-        unsigned error = lodepng::decode(iris_texture, iris_texture_width, iris_texture_height, iris_texture_file);
-        if (error != 0) {
-            printLog("error %u: %s\n", error, lodepng_error_text(error));
-        }
-    }
-*/
 }
 
 Avatar::~Avatar()  {
@@ -332,7 +321,10 @@ void  Avatar::updateFromMouse(int mouseX, int mouseY, int screenWidth, int scree
 
 void Avatar::simulate(float deltaTime) {
 
-    //figure out if the mouse cursor is over any body spheres... 
+    // copy velocity so we can use it later for acceleration
+    glm::vec3 oldVelocity = getVelocity();
+    
+    // figure out if the mouse cursor is over any body spheres...
     checkForMouseRayTouching();
     
     // update balls
@@ -403,10 +395,12 @@ void Avatar::simulate(float deltaTime) {
 	// add thrust to velocity
 	_velocity += _thrust * deltaTime;
     
-    // calculate speed                             
+    // calculate speed 
     _speed = glm::length(_velocity);
     
     //pitch and roll the body as a function of forward speed and turning delta
+    const float BODY_PITCH_WHILE_WALKING      = 20.0;
+    const float BODY_ROLL_WHILE_TURNING       = 0.2;
     float forwardComponentOfVelocity = glm::dot(_orientation.getFront(), _velocity);
     _bodyPitch += BODY_PITCH_WHILE_WALKING * deltaTime * forwardComponentOfVelocity;
     _bodyRoll  += BODY_ROLL_WHILE_TURNING  * deltaTime * _speed * _bodyYawDelta;
@@ -442,10 +436,15 @@ void Avatar::simulate(float deltaTime) {
         }
     }
     
+    //  Compute instantaneous acceleration 
+    float acceleration = glm::distance(getVelocity(), oldVelocity) / deltaTime;
+    const float ACCELERATION_PITCH_DECAY = 0.4f;
     
-    
-    
-
+    // Decay HeadPitch as a function of acceleration, so that you look straight ahead when
+    // you start moving, but don't do this with an HMD like the Oculus. 
+    if (!OculusManager::isConnected()) {
+        setHeadPitch(getHeadPitch() * (1.f - acceleration * ACCELERATION_PITCH_DECAY * deltaTime));
+    }
     // Get head position data from network for other people
     if (!_isMine) {
         _head.leanSideways = getHeadLeanSideways();