From fbede0a23f56749d2fa7abd07fa1179c3dcc0c3d Mon Sep 17 00:00:00 2001
From: Seth Alves <seth.alves@gmail.com>
Date: Mon, 29 Jun 2015 15:54:24 -0700
Subject: [PATCH] guard against feeding bullet a NaN

---
 interface/src/avatar/AvatarActionHold.cpp    | 20 +++++++++++++++++
 libraries/physics/src/ObjectActionSpring.cpp | 23 ++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/interface/src/avatar/AvatarActionHold.cpp b/interface/src/avatar/AvatarActionHold.cpp
index c1e2080521..dbeb5c5358 100644
--- a/interface/src/avatar/AvatarActionHold.cpp
+++ b/interface/src/avatar/AvatarActionHold.cpp
@@ -54,6 +54,22 @@ void AvatarActionHold::updateActionWorker(float deltaTimeStep) {
     if (!tryLockForWrite()) {
         return;
     }
+
+    // check for NaNs
+    if (position.x != position.x ||
+        position.y != position.y ||
+        position.z != position.z) {
+        qDebug() << "AvatarActionHold::updateActionWorker -- target position includes NaN";
+        return;
+    }
+    if (rotation.x != rotation.x ||
+        rotation.y != rotation.y ||
+        rotation.z != rotation.z ||
+        rotation.w != rotation.w) {
+        qDebug() << "AvatarActionHold::updateActionWorker -- target rotation includes NaN";
+        return;
+    }
+
     _positionalTarget = position;
     _rotationalTarget = rotation;
     unlock();
@@ -145,6 +161,7 @@ QByteArray AvatarActionHold::serialize() {
     dataStream << _relativePosition;
     dataStream << _relativeRotation;
     dataStream << _hand;
+    dataStream << _linearTimeScale;
 
     return ba;
 }
@@ -168,6 +185,9 @@ void AvatarActionHold::deserialize(QByteArray serializedArguments) {
     dataStream >> _relativePosition;
     dataStream >> _relativeRotation;
     dataStream >> _hand;
+    dataStream >> _linearTimeScale;
+    _angularTimeScale = _linearTimeScale;
+
     _parametersSet = true;
 
     _active = true;
diff --git a/libraries/physics/src/ObjectActionSpring.cpp b/libraries/physics/src/ObjectActionSpring.cpp
index b3b8536b06..715c0bc4e4 100644
--- a/libraries/physics/src/ObjectActionSpring.cpp
+++ b/libraries/physics/src/ObjectActionSpring.cpp
@@ -55,6 +55,17 @@ void ObjectActionSpring::updateActionWorker(btScalar deltaTimeStep) {
 
     // handle the linear part
     if (_positionalTargetSet) {
+        // check for NaN
+        if (_positionalTarget.x != _positionalTarget.x ||
+            _positionalTarget.y != _positionalTarget.y ||
+            _positionalTarget.z != _positionalTarget.z) {
+            qDebug() << "ObjectActionSpring::updateActionWorker -- target position includes NaN";
+            unlock();
+            lockForWrite();
+            _active = false;
+            unlock();
+            return;
+        }
         glm::vec3 offset = _positionalTarget - bulletToGLM(rigidBody->getCenterOfMassPosition());
         float offsetLength = glm::length(offset);
         float speed = offsetLength / _linearTimeScale;
@@ -70,6 +81,18 @@ void ObjectActionSpring::updateActionWorker(btScalar deltaTimeStep) {
 
     // handle rotation
     if (_rotationalTargetSet) {
+        if (_rotationalTarget.x != _rotationalTarget.x ||
+            _rotationalTarget.y != _rotationalTarget.y ||
+            _rotationalTarget.z != _rotationalTarget.z ||
+            _rotationalTarget.w != _rotationalTarget.w) {
+            qDebug() << "AvatarActionHold::updateActionWorker -- target rotation includes NaN";
+            unlock();
+            lockForWrite();
+            _active = false;
+            unlock();
+            return;
+        }
+
         glm::quat bodyRotation = bulletToGLM(rigidBody->getOrientation());
         // if qZero and qOne are too close to each other, we can get NaN for angle.
         auto alignmentDot = glm::dot(bodyRotation, _rotationalTarget);