From bc119d6c850e62d2fc10f56d2c3440a6772fce5e Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Thu, 12 Sep 2019 17:02:19 -0700
Subject: [PATCH] don't expect final kinematic simulation update

---
 libraries/physics/src/EntityMotionState.cpp | 73 +++++++++++----------
 1 file changed, 38 insertions(+), 35 deletions(-)

diff --git a/libraries/physics/src/EntityMotionState.cpp b/libraries/physics/src/EntityMotionState.cpp
index 68c8266e9f..de82dd6ace 100644
--- a/libraries/physics/src/EntityMotionState.cpp
+++ b/libraries/physics/src/EntityMotionState.cpp
@@ -84,48 +84,51 @@ EntityMotionState::~EntityMotionState() {
 }
 
 void EntityMotionState::updateServerPhysicsVariables() {
-    if (_ownershipState != EntityMotionState::OwnershipState::LocallyOwned) {
-        // only slam these values if we are NOT the simulation owner
-        Transform localTransform;
-        _entity->getLocalTransformAndVelocities(localTransform, _serverVelocity, _serverAngularVelocity);
-        _serverPosition = localTransform.getTranslation();
-        _serverRotation = localTransform.getRotation();
-        _serverAcceleration = _entity->getAcceleration();
-        _serverActionData = _entity->getDynamicData();
-        _lastStep = ObjectMotionState::getWorldSimulationStep();
-    }
+    // only slam these values if we are NOT the simulation owner
+    Transform localTransform;
+    _entity->getLocalTransformAndVelocities(localTransform, _serverVelocity, _serverAngularVelocity);
+    _serverPosition = localTransform.getTranslation();
+    _serverRotation = localTransform.getRotation();
+    _serverAcceleration = _entity->getAcceleration();
+    _serverActionData = _entity->getDynamicData();
+    _lastStep = ObjectMotionState::getWorldSimulationStep();
 }
 
 void EntityMotionState::handleDeactivation() {
-   if (_entity->getDirtyFlags() & (Simulation::DIRTY_TRANSFORM | Simulation::DIRTY_VELOCITIES)) {
-       // Some non-physical event (script-call or network-packet) has modified the entity's transform and/or velocities
-       // at the last minute before deactivation --> the values stored in _server* and _body are stale.
-       // We assume the EntityMotionState is the last to know, so we copy from EntityItem and let things sort themselves out.
-       Transform localTransform;
-       _entity->getLocalTransformAndVelocities(localTransform, _serverVelocity, _serverAngularVelocity);
-       _serverPosition = localTransform.getTranslation();
-       _serverRotation = localTransform.getRotation();
-       _serverAcceleration = _entity->getAcceleration();
-       _serverActionData = _entity->getDynamicData();
-       _lastStep = ObjectMotionState::getWorldSimulationStep();
-   } else {
-       // copy _server data to entity
-       Transform localTransform = _entity->getLocalTransform();
-       localTransform.setTranslation(_serverPosition);
-       localTransform.setRotation(_serverRotation);
-       _entity->setLocalTransformAndVelocities(localTransform, ENTITY_ITEM_ZERO_VEC3, ENTITY_ITEM_ZERO_VEC3);
-       // and also to RigidBody
-       btTransform worldTrans;
-       worldTrans.setOrigin(glmToBullet(_entity->getWorldPosition()));
-       worldTrans.setRotation(glmToBullet(_entity->getWorldOrientation()));
-       _body->setWorldTransform(worldTrans);
-       // no need to update velocities... should already be zero
-   }
+    if (_entity->getDirtyFlags() & (Simulation::DIRTY_TRANSFORM | Simulation::DIRTY_VELOCITIES)) {
+        // Some non-physical event (script-call or network-packet) has modified the entity's transform and/or
+        // velocities at the last minute before deactivation --> the values stored in _server* and _body are stale.
+        // We assume the EntityMotionState is the last to know, so we copy from EntityItem to _server* variables
+        // here but don't clear the flags --> the will body be set straight before next simulation step.
+        updateServerPhysicsVariables();
+    } else if (_body->isStaticOrKinematicObject() && _ownershipState != EntityMotionState::OwnershipState::LocallyOwned) {
+            // To allow the ESS to move entities around in a kinematic way we had to remove the requirement that
+            // every moving+simulated entity has an authoritative simulation owner.  As a result, we cannot rely
+            // on a final authoritative update of kinmatic objects prior to deactivation in the local simulation.
+            // For this case (unowned kinematic objects) we update the _server* variables for good measure but
+            // leave the entity and body alone. They should have been updated correctly in the last call to
+            // EntityMotionState::getWorldTransform().
+            updateServerPhysicsVariables();
+    } else {
+        // copy _server data to entity
+        Transform localTransform = _entity->getLocalTransform();
+        localTransform.setTranslation(_serverPosition);
+        localTransform.setRotation(_serverRotation);
+        _entity->setLocalTransformAndVelocities(localTransform, ENTITY_ITEM_ZERO_VEC3, ENTITY_ITEM_ZERO_VEC3);
+        // and also to RigidBody
+        btTransform worldTrans;
+        worldTrans.setOrigin(glmToBullet(_entity->getWorldPosition()));
+        worldTrans.setRotation(glmToBullet(_entity->getWorldOrientation()));
+        _body->setWorldTransform(worldTrans);
+        // no need to update velocities... should already be zero
+    }
 }
 
 // virtual
 void EntityMotionState::handleEasyChanges(uint32_t& flags) {
-    updateServerPhysicsVariables();
+    if (_ownershipState != EntityMotionState::OwnershipState::LocallyOwned) {
+        updateServerPhysicsVariables();
+    }
     ObjectMotionState::handleEasyChanges(flags);
 
     if (flags & Simulation::DIRTY_SIMULATOR_ID) {