From 4b95f2bae518fe3be981b407731e8da91634edb1 Mon Sep 17 00:00:00 2001
From: Philip Rosedale <philip@coffeeandpower.com>
Date: Thu, 11 Jul 2013 19:10:34 -0700
Subject: [PATCH] Better thrust values and no jittering when standing

---
 interface/src/Avatar.cpp | 58 +++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 30 deletions(-)

diff --git a/interface/src/Avatar.cpp b/interface/src/Avatar.cpp
index a3ebc4db8e..7953194ad8 100755
--- a/interface/src/Avatar.cpp
+++ b/interface/src/Avatar.cpp
@@ -364,10 +364,10 @@ void Avatar::updateThrust(float deltaTime, Transmitter * transmitter) {
     glm::vec3 up = orientation * IDENTITY_UP;
 
     const float THRUST_MAG_UP = 800.0f;
-    const float THRUST_MAG_DOWN = 200.f;
-    const float THRUST_MAG_FWD = 300.f;
-    const float THRUST_MAG_BACK = 150.f;
-    const float THRUST_MAG_LATERAL = 200.f;
+    const float THRUST_MAG_DOWN = 300.f;
+    const float THRUST_MAG_FWD = 500.f;
+    const float THRUST_MAG_BACK = 300.f;
+    const float THRUST_MAG_LATERAL = 250.f;
     const float THRUST_JUMP = 120.f;
     
     //  Add Thrusts from keyboard
@@ -422,7 +422,7 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
     glm::quat orientation = getOrientation();
     glm::vec3 front = orientation * IDENTITY_FRONT;
     glm::vec3 right = orientation * IDENTITY_RIGHT;
-
+    
     // Update movement timers
     if (isMyAvatar()) {
         _elapsedTimeSinceCollision += deltaTime;
@@ -445,9 +445,6 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
     glm::vec3 oldVelocity = getVelocity();
     
     if (isMyAvatar()) {
-        // update position by velocity
-        _position += _velocity * deltaTime;
-        
         // calculate speed
         _speed = glm::length(_velocity);
     }
@@ -482,7 +479,7 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
         enableHandMovement &= (it->jointID != AVATAR_JOINT_RIGHT_WRIST);
     }
     
-     // update avatar skeleton
+    // update avatar skeleton
     _skeleton.update(deltaTime, getOrientation(), _position);
             
     //determine the lengths of the body springs now that we have updated the skeleton at least once
@@ -503,42 +500,41 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
         _ballSpringsInitialized = true;
     }
     
-    
     // if this is not my avatar, then hand position comes from transmitted data
     if (!isMyAvatar()) {
         _skeleton.joint[ AVATAR_JOINT_RIGHT_FINGERTIPS ].position = _handPosition;
     }
-    
-    //detect and respond to collisions with other avatars...
-    if (isMyAvatar()) {
-        updateAvatarCollisions(deltaTime);
-    }
-    
+        
     //update the movement of the hand and process handshaking with other avatars...
     updateHandMovementAndTouching(deltaTime, enableHandMovement);
     _avatarTouch.simulate(deltaTime);
     
-    // apply gravity and collision with the ground/floor
-    if (isMyAvatar() && USING_AVATAR_GRAVITY) {
-        _velocity += _gravity * (GRAVITY_EARTH * deltaTime);
-    }
     if (isMyAvatar()) {
+
+        // apply gravity
+        if (USING_AVATAR_GRAVITY) {
+            // For gravity, always move the avatar by the amount driven by gravity, so that the collision
+            // routines will detect it and collide every frame when pulled by gravity to a surface
+            // 
+            _velocity += _gravity * (GRAVITY_EARTH * deltaTime);
+            _position += _gravity * (GRAVITY_EARTH * deltaTime) * deltaTime;
+        }
+
         updateCollisionWithEnvironment();
+        updateCollisionWithVoxels();
+        updateAvatarCollisions(deltaTime);
     }
     
     // update body balls
     updateBodyBalls(deltaTime);
     
+
     // test for avatar collision response with the big sphere
     if (usingBigSphereCollisionTest) {
         updateCollisionWithSphere(_TEST_bigSpherePosition, _TEST_bigSphereRadius, deltaTime);
     }
     
-    // collision response with voxels
-    if (isMyAvatar()) {
-        updateCollisionWithVoxels();
-    }
-    
+        
     if (isMyAvatar()) {
     
         // add thrust to velocity
@@ -547,7 +543,6 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
         // update body yaw by body yaw delta
         orientation = orientation * glm::quat(glm::radians(
                                                            glm::vec3(_bodyPitchDelta, _bodyYawDelta, _bodyRollDelta) * deltaTime));
-        
         // decay body rotation momentum
         float bodySpinMomentum = 1.0 - BODY_SPIN_FRICTION * deltaTime;
         if  (bodySpinMomentum < 0.0f) { bodySpinMomentum = 0.0f; }
@@ -555,14 +550,14 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
         _bodyYawDelta   *= bodySpinMomentum;
         _bodyRollDelta  *= bodySpinMomentum;
         
-        const float MAX_STATIC_FRICTION_VELOCITY = 0.25f;
+        const float MAX_STATIC_FRICTION_VELOCITY = 0.5f;
         const float STATIC_FRICTION_STRENGTH = 20.f;
         applyStaticFriction(deltaTime, _velocity, MAX_STATIC_FRICTION_VELOCITY, STATIC_FRICTION_STRENGTH);
         
-        const float LINEAR_DAMPING_STRENGTH = 0.2f;
-        const float SQUARED_DAMPING_STRENGTH = 0.1f;
+        const float LINEAR_DAMPING_STRENGTH = 3.0f;
+        const float SQUARED_DAMPING_STRENGTH = 0.2f;
         applyDamping(deltaTime, _velocity, LINEAR_DAMPING_STRENGTH, SQUARED_DAMPING_STRENGTH);
-                
+        
         //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;
@@ -653,6 +648,9 @@ void Avatar::simulate(float deltaTime, Transmitter* transmitter) {
         _mode = AVATAR_MODE_INTERACTING;
     }
     
+    // update position by velocity, and subtract the change added earlier for gravity 
+    _position += _velocity * deltaTime;
+    
     // Zero thrust out now that we've added it to velocity in this frame
     _thrust = glm::vec3(0, 0, 0);