From 4392af3b3a8018ea7c5a89feaa2a1cb49e46e07c Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Fri, 16 Jan 2015 09:26:43 -0800
Subject: [PATCH] Remove pre-Bullet server-side EntityItem motion

---
 libraries/entities/src/EntityItem.cpp | 32 ++-------------------------
 1 file changed, 2 insertions(+), 30 deletions(-)

diff --git a/libraries/entities/src/EntityItem.cpp b/libraries/entities/src/EntityItem.cpp
index 9cfb0c6c11..69cd16469e 100644
--- a/libraries/entities/src/EntityItem.cpp
+++ b/libraries/entities/src/EntityItem.cpp
@@ -691,15 +691,7 @@ void EntityItem::simulate(const quint64& now) {
         }
     }
 
-#ifdef USE_BULLET_PHYSICS
-    // When Bullet is available we assume that "zero velocity" means "at rest"
-    // because of collision conditions this simulation does not know about
-    // so we don't fall in for the non-zero gravity case here.
     if (hasVelocity()) {
-#else // !USE_BULLET_PHYSICS
-    if (hasVelocity() || hasGravity()) {
-#endif // USE_BULLET_PHYSICS
-
         // linear damping
         glm::vec3 velocity = getVelocity();
         if (_damping > 0.0f) {
@@ -733,14 +725,6 @@ void EntityItem::simulate(const quint64& now) {
         // handle bounces off the ground... We bounce at the distance to the bottom of our entity
         if (position.y <= getDistanceToBottomOfEntity()) {
             velocity = velocity * glm::vec3(1,-1,1);
-
-#ifndef USE_BULLET_PHYSICS
-            // if we've slowed considerably, then just stop moving, but only if no BULLET
-            if (glm::length(velocity) <= ENTITY_ITEM_EPSILON_VELOCITY_LENGTH) {
-                velocity = ENTITY_ITEM_ZERO_VEC3;
-            }
-#endif // !USE_BULLET_PHYSICS
-            
             position.y = getDistanceToBottomOfEntity();
         }
 
@@ -756,14 +740,8 @@ void EntityItem::simulate(const quint64& now) {
             }
         }
         
-#ifdef USE_BULLET_PHYSICS
-        // When Bullet is available we assume that it will tell us when velocities go to zero...
-#else // !USE_BULLET_PHYSICS
-        // ... otherwise we help things come to rest by clamping small velocities.
-        if (glm::length(velocity) <= ENTITY_ITEM_EPSILON_VELOCITY_LENGTH) {
-            velocity = ENTITY_ITEM_ZERO_VEC3;
-        }
-#endif // USE_BULLET_PHYSICS
+        // NOTE: we don't zero out very small velocities --> we rely on a remote Bullet simulation 
+        // to tell us when the entity has stopped.
 
         // NOTE: the simulation should NOT set any DirtyFlags on this entity
         setPosition(position); // this will automatically recalculate our collision shape
@@ -781,13 +759,7 @@ void EntityItem::simulate(const quint64& now) {
 }
 
 bool EntityItem::isMoving() const {
-#ifdef USE_BULLET_PHYSICS
-    // When Bullet is available we assume that "zero velocity" means "at rest"
-    // because of collision conditions this simulation does not know about.
     return hasVelocity() || hasAngularVelocity();
-#else // !USE_BULLET_PHYSICS
-    return hasVelocity() || (hasGravity() && !isRestingOnSurface()) || hasAngularVelocity();
-#endif //USE_BULLET_PHYSICS
 }
 
 bool EntityItem::lifetimeHasExpired() const {