From d28c400cea46fc1b41d50450f48027ec967c3d77 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Thu, 14 May 2015 12:36:59 -0700
Subject: [PATCH] add restitution and friction Entity properties

---
 examples/html/entityProperties.html           | 23 +++++++-
 libraries/entities/src/EntityItem.cpp         | 53 ++++++++++++++-----
 libraries/entities/src/EntityItem.h           | 11 +++-
 .../entities/src/EntityItemProperties.cpp     | 14 +++++
 libraries/entities/src/EntityItemProperties.h |  4 ++
 .../src/EntityItemPropertiesDefaults.h        |  8 +++
 libraries/entities/src/EntityPropertyFlags.h  |  2 +
 libraries/networking/src/PacketHeaders.cpp    |  2 +-
 libraries/networking/src/PacketHeaders.h      |  1 +
 9 files changed, 101 insertions(+), 17 deletions(-)

diff --git a/examples/html/entityProperties.html b/examples/html/entityProperties.html
index 25467f7573..0e3494bff8 100644
--- a/examples/html/entityProperties.html
+++ b/examples/html/entityProperties.html
@@ -233,6 +233,9 @@
             var elAngularVelocityZ = document.getElementById("property-avel-z");
             var elAngularDamping = document.getElementById("property-adamping");
 
+            var elRestitution = document.getElementById("property-restitution");
+            var elFriction = document.getElementById("property-friction");
+
             var elGravityX = document.getElementById("property-grav-x");
             var elGravityY = document.getElementById("property-grav-y");
             var elGravityZ = document.getElementById("property-grav-z");
@@ -427,6 +430,9 @@
                             elAngularVelocityZ.value = (properties.angularVelocity.z * RADIANS_TO_DEGREES).toFixed(2);
                             elAngularDamping.value = properties.angularDamping.toFixed(2);
 
+                            elRestitution.value = properties.restitution.toFixed(2);
+                            elFriction.value = properties.friction.toFixed(2);
+
                             elGravityX.value = properties.gravity.x.toFixed(2);
                             elGravityY.value = properties.gravity.y.toFixed(2);
                             elGravityZ.value = properties.gravity.z.toFixed(2);
@@ -607,7 +613,10 @@
             elAngularVelocityX.addEventListener('change', angularVelocityChangeFunction);
             elAngularVelocityY.addEventListener('change', angularVelocityChangeFunction);
             elAngularVelocityZ.addEventListener('change', angularVelocityChangeFunction);
-            elAngularDamping.addEventListener('change', createEmitNumberPropertyUpdateFunction('angularDamping'))
+            elAngularDamping.addEventListener('change', createEmitNumberPropertyUpdateFunction('angularDamping'));
+
+            elRestitution.addEventListener('change', createEmitNumberPropertyUpdateFunction('restitution'));
+            elFriction.addEventListener('change', createEmitNumberPropertyUpdateFunction('friction'));
 
             var gravityChangeFunction = createEmitVec3PropertyUpdateFunction(
                 'gravity', elGravityX, elGravityY, elGravityZ);
@@ -963,6 +972,18 @@
                 <input class="coord" type='number' id="property-adamping"></input>
             </div>
         </div>
+        <div class="property">
+            <div class="label">Restitution</div>
+            <div class="value">
+                <input class="coord" type='number' id="property-restitution"></input>
+            </div>
+        </div>
+        <div class="property">
+            <div class="label">Friction</div>
+            <div class="value">
+                <input class="coord" type='number' id="property-friction"></input>
+            </div>
+        </div>
 
         <div class="property">
             <div class="label">Gravity</div>
diff --git a/libraries/entities/src/EntityItem.cpp b/libraries/entities/src/EntityItem.cpp
index 470426d55e..e5b620210f 100644
--- a/libraries/entities/src/EntityItem.cpp
+++ b/libraries/entities/src/EntityItem.cpp
@@ -51,6 +51,8 @@ EntityItem::EntityItem(const EntityItemID& entityItemID) :
     _gravity(ENTITY_ITEM_DEFAULT_GRAVITY),
     _acceleration(ENTITY_ITEM_DEFAULT_ACCELERATION),
     _damping(ENTITY_ITEM_DEFAULT_DAMPING),
+    _restitution(ENTITY_ITEM_DEFAULT_RESTITUTION),
+    _friction(ENTITY_ITEM_DEFAULT_FRICTION),
     _lifetime(ENTITY_ITEM_DEFAULT_LIFETIME),
     _script(ENTITY_ITEM_DEFAULT_SCRIPT),
     _collisionSoundURL(ENTITY_ITEM_DEFAULT_COLLISION_SOUND_URL),
@@ -100,6 +102,8 @@ EntityPropertyFlags EntityItem::getEntityProperties(EncodeBitstreamParams& param
     requestedProperties += PROP_GRAVITY;
     requestedProperties += PROP_ACCELERATION;
     requestedProperties += PROP_DAMPING;
+    requestedProperties += PROP_RESTITUTION;
+    requestedProperties += PROP_FRICTION;
     requestedProperties += PROP_LIFETIME;
     requestedProperties += PROP_SCRIPT;
     requestedProperties += PROP_COLLISION_SOUND_URL;
@@ -227,6 +231,8 @@ OctreeElement::AppendState EntityItem::appendEntityData(OctreePacketData* packet
         APPEND_ENTITY_PROPERTY(PROP_GRAVITY, getGravity());
         APPEND_ENTITY_PROPERTY(PROP_ACCELERATION, getAcceleration());
         APPEND_ENTITY_PROPERTY(PROP_DAMPING, getDamping());
+        APPEND_ENTITY_PROPERTY(PROP_RESTITUTION, getRestitution());
+        APPEND_ENTITY_PROPERTY(PROP_FRICTION, getFriction());
         APPEND_ENTITY_PROPERTY(PROP_LIFETIME, getLifetime());
         APPEND_ENTITY_PROPERTY(PROP_SCRIPT, getScript());
         APPEND_ENTITY_PROPERTY(PROP_REGISTRATION_POINT, getRegistrationPoint());
@@ -552,7 +558,9 @@ int EntityItem::readEntityDataFromBuffer(const unsigned char* data, int bytesLef
             READ_ENTITY_PROPERTY(PROP_ACCELERATION, glm::vec3, setAcceleration);
         }
 
-        READ_ENTITY_PROPERTY(PROP_DAMPING, float, setDamping);
+        READ_ENTITY_PROPERTY(PROP_DAMPING, float, updateDamping);
+        READ_ENTITY_PROPERTY(PROP_RESTITUTION, float, updateRestitution);
+        READ_ENTITY_PROPERTY(PROP_FRICTION, float, updateFriction);
         READ_ENTITY_PROPERTY(PROP_LIFETIME, float, updateLifetime);
         READ_ENTITY_PROPERTY(PROP_SCRIPT, QString, setScript);
         READ_ENTITY_PROPERTY(PROP_REGISTRATION_POINT, glm::vec3, setRegistrationPoint);
@@ -561,7 +569,7 @@ int EntityItem::readEntityDataFromBuffer(const unsigned char* data, int bytesLef
         } else {
             READ_ENTITY_PROPERTY(PROP_ANGULAR_VELOCITY, glm::vec3, updateAngularVelocityInDegrees);
         }
-        READ_ENTITY_PROPERTY(PROP_ANGULAR_DAMPING, float, setAngularDamping);
+        READ_ENTITY_PROPERTY(PROP_ANGULAR_DAMPING, float, updateAngularDamping);
         READ_ENTITY_PROPERTY(PROP_VISIBLE, bool, setVisible);
         READ_ENTITY_PROPERTY(PROP_IGNORE_FOR_COLLISIONS, bool, updateIgnoreForCollisions);
         READ_ENTITY_PROPERTY(PROP_COLLISIONS_WILL_MOVE, bool, updateCollisionsWillMove);
@@ -697,17 +705,6 @@ void EntityItem::setMass(float mass) {
     }
 }
 
-const float DEFAULT_ENTITY_RESTITUTION = 0.5f;
-const float DEFAULT_ENTITY_FRICTION = 0.5f;                                                                                
-
-float EntityItem::getRestitution() const { 
-    return DEFAULT_ENTITY_RESTITUTION; 
-}
-
-float EntityItem::getFriction() const { 
-    return DEFAULT_ENTITY_FRICTION;
-}
-
 void EntityItem::simulate(const quint64& now) {
     if (_lastSimulated == 0) {
         _lastSimulated = now;
@@ -900,6 +897,8 @@ EntityItemProperties EntityItem::getProperties() const {
     COPY_ENTITY_PROPERTY_TO_PROPERTIES(gravity, getGravity);
     COPY_ENTITY_PROPERTY_TO_PROPERTIES(acceleration, getAcceleration);
     COPY_ENTITY_PROPERTY_TO_PROPERTIES(damping, getDamping);
+    COPY_ENTITY_PROPERTY_TO_PROPERTIES(restitution, getRestitution);
+    COPY_ENTITY_PROPERTY_TO_PROPERTIES(friction, getFriction);
     COPY_ENTITY_PROPERTY_TO_PROPERTIES(lifetime, getLifetime);
     COPY_ENTITY_PROPERTY_TO_PROPERTIES(script, getScript);
     COPY_ENTITY_PROPERTY_TO_PROPERTIES(collisionSoundURL, getCollisionSoundURL);
@@ -933,6 +932,8 @@ bool EntityItem::setProperties(const EntityItemProperties& properties) {
     SET_ENTITY_PROPERTY_FROM_PROPERTIES(gravity, updateGravity);
     SET_ENTITY_PROPERTY_FROM_PROPERTIES(acceleration, setAcceleration);
     SET_ENTITY_PROPERTY_FROM_PROPERTIES(damping, updateDamping);
+    SET_ENTITY_PROPERTY_FROM_PROPERTIES(restitution, updateRestitution);
+    SET_ENTITY_PROPERTY_FROM_PROPERTIES(friction, updateFriction);
     SET_ENTITY_PROPERTY_FROM_PROPERTIES(lifetime, updateLifetime);
     SET_ENTITY_PROPERTY_FROM_PROPERTIES(script, setScript);
     SET_ENTITY_PROPERTY_FROM_PROPERTIES(collisionSoundURL, setCollisionSoundURL);
@@ -1267,6 +1268,32 @@ void EntityItem::updateCollisionsWillMove(bool value) {
     }
 }
 
+void EntityItem::updateRestitution(float value) {
+    float clampedValue = glm::max(glm::min(ENTITY_ITEM_MAX_RESTITUTION, value), ENTITY_ITEM_MIN_RESTITUTION);
+    if (_restitution != clampedValue) {
+        _restitution = clampedValue;
+        _dirtyFlags |= EntityItem::DIRTY_MATERIAL;
+    }
+}
+
+void EntityItem::updateFriction(float value) {
+    float clampedValue = glm::max(glm::min(ENTITY_ITEM_MAX_FRICTION, value), ENTITY_ITEM_MIN_FRICTION);
+    if (_friction != clampedValue) {
+        _friction = clampedValue;
+        _dirtyFlags |= EntityItem::DIRTY_MATERIAL;
+    }
+}
+
+void EntityItem::setRestitution(float value) {
+    float clampedValue = glm::max(glm::min(ENTITY_ITEM_MAX_RESTITUTION, value), ENTITY_ITEM_MIN_RESTITUTION);
+    _restitution = clampedValue;
+}
+
+void EntityItem::setFriction(float value) {
+    float clampedValue = glm::max(glm::min(ENTITY_ITEM_MAX_FRICTION, value), ENTITY_ITEM_MIN_FRICTION);
+    _friction = clampedValue;
+}
+
 void EntityItem::updateLifetime(float value) {
     if (_lifetime != value) {
         _lifetime = value;
diff --git a/libraries/entities/src/EntityItem.h b/libraries/entities/src/EntityItem.h
index b9dc14251c..4f51e8896c 100644
--- a/libraries/entities/src/EntityItem.h
+++ b/libraries/entities/src/EntityItem.h
@@ -221,8 +221,11 @@ public:
     float getDamping() const { return _damping; }
     void setDamping(float value) { _damping = value; }
 
-    float getRestitution() const;
-    float getFriction() const;
+    float getRestitution() const { return _restitution; }
+    void setRestitution(float value);
+
+    float getFriction() const { return _friction; }
+    void setFriction(float value);
 
     // lifetime related properties.
     float getLifetime() const { return _lifetime; } /// get the lifetime in seconds for the entity
@@ -314,6 +317,8 @@ public:
     void updateVelocityInDomainUnits(const glm::vec3& value);
     void updateVelocity(const glm::vec3& value);
     void updateDamping(float value);
+    void updateRestitution(float value);
+    void updateFriction(float value);
     void updateGravityInDomainUnits(const glm::vec3& value);
     void updateGravity(const glm::vec3& value);
     void updateAngularVelocity(const glm::vec3& value);
@@ -375,6 +380,8 @@ protected:
     glm::vec3 _gravity;
     glm::vec3 _acceleration;
     float _damping;
+    float _restitution;
+    float _friction;
     float _lifetime;
     QString _script;
     QString _collisionSoundURL;
diff --git a/libraries/entities/src/EntityItemProperties.cpp b/libraries/entities/src/EntityItemProperties.cpp
index 2d68a20022..85f5a5511e 100644
--- a/libraries/entities/src/EntityItemProperties.cpp
+++ b/libraries/entities/src/EntityItemProperties.cpp
@@ -44,6 +44,8 @@ EntityItemProperties::EntityItemProperties() :
     CONSTRUCT_PROPERTY(gravity, ENTITY_ITEM_DEFAULT_GRAVITY),
     CONSTRUCT_PROPERTY(acceleration, ENTITY_ITEM_DEFAULT_ACCELERATION),
     CONSTRUCT_PROPERTY(damping, ENTITY_ITEM_DEFAULT_DAMPING),
+    CONSTRUCT_PROPERTY(restitution, ENTITY_ITEM_DEFAULT_RESTITUTION),
+    CONSTRUCT_PROPERTY(friction, ENTITY_ITEM_DEFAULT_FRICTION),
     CONSTRUCT_PROPERTY(lifetime, ENTITY_ITEM_DEFAULT_LIFETIME),
     CONSTRUCT_PROPERTY(script, ENTITY_ITEM_DEFAULT_SCRIPT),
     CONSTRUCT_PROPERTY(collisionSoundURL, ENTITY_ITEM_DEFAULT_COLLISION_SOUND_URL),
@@ -287,6 +289,8 @@ EntityPropertyFlags EntityItemProperties::getChangedProperties() const {
     CHECK_PROPERTY_CHANGE(PROP_GRAVITY, gravity);
     CHECK_PROPERTY_CHANGE(PROP_ACCELERATION, acceleration);
     CHECK_PROPERTY_CHANGE(PROP_DAMPING, damping);
+    CHECK_PROPERTY_CHANGE(PROP_RESTITUTION, restitution);
+    CHECK_PROPERTY_CHANGE(PROP_FRICTION, friction);
     CHECK_PROPERTY_CHANGE(PROP_LIFETIME, lifetime);
     CHECK_PROPERTY_CHANGE(PROP_SCRIPT, script);
     CHECK_PROPERTY_CHANGE(PROP_COLLISION_SOUND_URL, collisionSoundURL);
@@ -362,6 +366,8 @@ QScriptValue EntityItemProperties::copyToScriptValue(QScriptEngine* engine, bool
     COPY_PROPERTY_TO_QSCRIPTVALUE(gravity);
     COPY_PROPERTY_TO_QSCRIPTVALUE(acceleration);
     COPY_PROPERTY_TO_QSCRIPTVALUE(damping);
+    COPY_PROPERTY_TO_QSCRIPTVALUE(restitution);
+    COPY_PROPERTY_TO_QSCRIPTVALUE(friction);
     COPY_PROPERTY_TO_QSCRIPTVALUE(density);
     COPY_PROPERTY_TO_QSCRIPTVALUE(lifetime);
     if (!skipDefaults) {
@@ -470,6 +476,8 @@ void EntityItemProperties::copyFromScriptValue(const QScriptValue& object) {
     COPY_PROPERTY_FROM_QSCRIPTVALUE(gravity, glmVec3, setGravity);
     COPY_PROPERTY_FROM_QSCRIPTVALUE(acceleration, glmVec3, setAcceleration);
     COPY_PROPERTY_FROM_QSCRIPTVALUE(damping, float, setDamping);
+    COPY_PROPERTY_FROM_QSCRIPTVALUE(restitution, float, setRestitution);
+    COPY_PROPERTY_FROM_QSCRIPTVALUE(friction, float, setFriction);
     COPY_PROPERTY_FROM_QSCRIPTVALUE(lifetime, float, setLifetime);
     COPY_PROPERTY_FROM_QSCRIPTVALUE(script, QString, setScript);
     COPY_PROPERTY_FROM_QSCRIPTVALUE(registrationPoint, glmVec3, setRegistrationPoint);
@@ -662,6 +670,8 @@ bool EntityItemProperties::encodeEntityEditPacket(PacketType command, EntityItem
             APPEND_ENTITY_PROPERTY(PROP_GRAVITY, properties.getGravity());
             APPEND_ENTITY_PROPERTY(PROP_ACCELERATION, properties.getAcceleration());
             APPEND_ENTITY_PROPERTY(PROP_DAMPING, properties.getDamping());
+            APPEND_ENTITY_PROPERTY(PROP_RESTITUTION, properties.getRestitution());
+            APPEND_ENTITY_PROPERTY(PROP_FRICTION, properties.getFriction());
             APPEND_ENTITY_PROPERTY(PROP_LIFETIME, properties.getLifetime());
             APPEND_ENTITY_PROPERTY(PROP_SCRIPT, properties.getScript());
             APPEND_ENTITY_PROPERTY(PROP_COLOR, properties.getColor());
@@ -922,6 +932,8 @@ bool EntityItemProperties::decodeEntityEditPacket(const unsigned char* data, int
     READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_GRAVITY, glm::vec3, setGravity);
     READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_ACCELERATION, glm::vec3, setAcceleration);
     READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_DAMPING, float, setDamping);
+    READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_RESTITUTION, float, setRestitution);
+    READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_FRICTION, float, setFriction);
     READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_LIFETIME, float, setLifetime);
     READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_SCRIPT,QString, setScript);
     READ_ENTITY_PROPERTY_TO_PROPERTIES(PROP_COLOR, xColor, setColor);
@@ -1036,6 +1048,8 @@ void EntityItemProperties::markAllChanged() {
     _gravityChanged = true;
     _accelerationChanged = true;
     _dampingChanged = true;
+    _restitutionChanged = true;
+    _frictionChanged = true;
     _lifetimeChanged = true;
     _userDataChanged = true;
     _simulatorIDChanged = true;
diff --git a/libraries/entities/src/EntityItemProperties.h b/libraries/entities/src/EntityItemProperties.h
index 7d8cbfe9b1..530013bbb6 100644
--- a/libraries/entities/src/EntityItemProperties.h
+++ b/libraries/entities/src/EntityItemProperties.h
@@ -95,6 +95,8 @@ public:
     DEFINE_PROPERTY_REF(PROP_GRAVITY, Gravity, gravity, glm::vec3);
     DEFINE_PROPERTY_REF(PROP_ACCELERATION, Acceleration, acceleration, glm::vec3);
     DEFINE_PROPERTY(PROP_DAMPING, Damping, damping, float);
+    DEFINE_PROPERTY(PROP_RESTITUTION, Restitution, restitution, float);
+    DEFINE_PROPERTY(PROP_FRICTION, Friction, friction, float);
     DEFINE_PROPERTY(PROP_LIFETIME, Lifetime, lifetime, float);
     DEFINE_PROPERTY_REF(PROP_SCRIPT, Script, script, QString);
     DEFINE_PROPERTY_REF(PROP_COLLISION_SOUND_URL, CollisionSoundURL, collisionSoundURL, QString);
@@ -243,6 +245,8 @@ inline QDebug operator<<(QDebug debug, const EntityItemProperties& properties) {
     DEBUG_PROPERTY_IF_CHANGED(debug, properties, Gravity, gravity, "");
     DEBUG_PROPERTY_IF_CHANGED(debug, properties, Acceleration, acceleration, "in meters per second");
     DEBUG_PROPERTY_IF_CHANGED(debug, properties, Damping, damping, "");
+    DEBUG_PROPERTY_IF_CHANGED(debug, properties, Restitution, restitution, "");
+    DEBUG_PROPERTY_IF_CHANGED(debug, properties, Friction, friction, "");
     DEBUG_PROPERTY_IF_CHANGED(debug, properties, Lifetime, lifetime, "");
     DEBUG_PROPERTY_IF_CHANGED(debug, properties, Script, script, "");
     DEBUG_PROPERTY_IF_CHANGED(debug, properties, CollisionSoundURL, collisionSoundURL, "");
diff --git a/libraries/entities/src/EntityItemPropertiesDefaults.h b/libraries/entities/src/EntityItemPropertiesDefaults.h
index ae44322377..b33e6de1ac 100644
--- a/libraries/entities/src/EntityItemPropertiesDefaults.h
+++ b/libraries/entities/src/EntityItemPropertiesDefaults.h
@@ -53,6 +53,14 @@ const glm::vec3 ENTITY_ITEM_DEFAULT_ACCELERATION = ENTITY_ITEM_ZERO_VEC3;
 const float ENTITY_ITEM_DEFAULT_DAMPING = 0.39347f;  // approx timescale = 2.0 sec (see damping timescale formula in header)
 const float ENTITY_ITEM_DEFAULT_ANGULAR_DAMPING = 0.39347f;  // approx timescale = 2.0 sec (see damping timescale formula in header)
 
+const float ENTITY_ITEM_MIN_RESTITUTION = 0.0f;
+const float ENTITY_ITEM_MAX_RESTITUTION = 0.99f;
+const float ENTITY_ITEM_DEFAULT_RESTITUTION = 0.5f;
+
+const float ENTITY_ITEM_MIN_FRICTION = 0.0f;
+const float ENTITY_ITEM_MAX_FRICTION = 0.99f;
+const float ENTITY_ITEM_DEFAULT_FRICTION = 0.5f;
+
 const bool ENTITY_ITEM_DEFAULT_IGNORE_FOR_COLLISIONS = false;
 const bool ENTITY_ITEM_DEFAULT_COLLISIONS_WILL_MOVE = false;
 
diff --git a/libraries/entities/src/EntityPropertyFlags.h b/libraries/entities/src/EntityPropertyFlags.h
index 66ec70ae60..8a5d96e8d2 100644
--- a/libraries/entities/src/EntityPropertyFlags.h
+++ b/libraries/entities/src/EntityPropertyFlags.h
@@ -107,6 +107,8 @@ enum EntityPropertyList {
     PROP_SIMULATOR_ID, // all entities
     PROP_NAME, // all entities
     PROP_COLLISION_SOUND_URL,
+    PROP_RESTITUTION,
+    PROP_FRICTION,
 
     ////////////////////////////////////////////////////////////////////////////////////////////////////
     // ATTENTION: add new properties ABOVE this line
diff --git a/libraries/networking/src/PacketHeaders.cpp b/libraries/networking/src/PacketHeaders.cpp
index 0dcd30a55c..689c958cbb 100644
--- a/libraries/networking/src/PacketHeaders.cpp
+++ b/libraries/networking/src/PacketHeaders.cpp
@@ -72,7 +72,7 @@ PacketVersion versionForPacketType(PacketType packetType) {
             return 1;
         case PacketTypeEntityAddOrEdit:
         case PacketTypeEntityData:
-            return VERSION_ENTITIES_HAVE_COLLISION_SOUND_URL;
+            return VERSION_ENTITIES_HAVE_FRICTION;
         case PacketTypeEntityErase:
             return 2;
         case PacketTypeAudioStreamStats:
diff --git a/libraries/networking/src/PacketHeaders.h b/libraries/networking/src/PacketHeaders.h
index 01eb488c14..b4e630c677 100644
--- a/libraries/networking/src/PacketHeaders.h
+++ b/libraries/networking/src/PacketHeaders.h
@@ -177,5 +177,6 @@ const PacketVersion VERSION_ENTITIES_ZONE_ENTITIES_STAGE_HAS_AUTOMATIC_HOURDAY =
 const PacketVersion VERSION_ENTITIES_PARTICLE_ENTITIES_HAVE_TEXTURES = 23;
 const PacketVersion VERSION_ENTITIES_HAVE_LINE_TYPE = 24;
 const PacketVersion VERSION_ENTITIES_HAVE_COLLISION_SOUND_URL = 25;
+const PacketVersion VERSION_ENTITIES_HAVE_FRICTION = 26;
 
 #endif // hifi_PacketHeaders_h