From 66b6328687114ff429ac00b00f0103db316ac3ab Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Thu, 10 Apr 2014 16:58:52 -0700
Subject: [PATCH 1/2] protection against bad avatar-avatar collisions

Also with logging if we encounter incorrectly large penetration depths
---
 interface/src/avatar/MyAvatar.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/interface/src/avatar/MyAvatar.cpp b/interface/src/avatar/MyAvatar.cpp
index 7a05c593db..6c69fd3e3a 100644
--- a/interface/src/avatar/MyAvatar.cpp
+++ b/interface/src/avatar/MyAvatar.cpp
@@ -62,6 +62,7 @@ MyAvatar::MyAvatar() :
     _isThrustOn(false),
     _thrustMultiplier(1.0f),
     _moveTarget(0,0,0),
+    _lastBodyPenetration(0.0f),
     _moveTargetStepCounter(0),
     _lookAtTargetAvatar(),
     _shouldRender(true),
@@ -681,7 +682,7 @@ void MyAvatar::updateThrust(float deltaTime) {
     _thrust -= _driveKeys[DOWN] * _scale * THRUST_MAG_DOWN * _thrustMultiplier * deltaTime * up;
 
     // attenuate thrust when in penetration
-    if (glm::dot(_thrust, _lastBodyPenetration) > 0.0f) {
+    if (glm::dot(_thrust, _lastBodyPenetration) > EPSILON) {
         const float MAX_BODY_PENETRATION_DEPTH = 0.6f * _skeletonModel.getBoundingShapeRadius();
         float penetrationFactor = glm::min(1.0f, glm::length(_lastBodyPenetration) / MAX_BODY_PENETRATION_DEPTH);
         glm::vec3 penetrationDirection = glm::normalize(_lastBodyPenetration);
@@ -932,7 +933,11 @@ void MyAvatar::updateCollisionWithAvatars(float deltaTime) {
 
             CollisionInfo collision;
             if (ShapeCollider::collideShapesCoarse(myShapes, theirShapes, collision)) {
-                if (glm::length2(collision._penetration) > EPSILON) {
+                float penetrationDepth = glm::length(collision._penetration);
+                if (penetrationDepth > myBoundingRadius) {
+                    qDebug() << "WARNING: ignoring avatar-avatar penetration depth " << penetrationDepth;
+                }
+                else if (penetrationDepth > EPSILON) {
                     setPosition(getPosition() - BODY_COLLISION_RESOLUTION_FACTOR * collision._penetration);
                     _lastBodyPenetration += collision._penetration;
                     emit collisionWithAvatar(getSessionUUID(), avatar->getSessionUUID(), collision);

From f7862eb600056e6f9955af89137281c7aac95164 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Fri, 11 Apr 2014 08:58:26 -0700
Subject: [PATCH 2/2] check for bad deltaTime during avatar-avatar collisions

---
 interface/src/avatar/MyAvatar.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/interface/src/avatar/MyAvatar.cpp b/interface/src/avatar/MyAvatar.cpp
index 6c69fd3e3a..a716d6f49a 100644
--- a/interface/src/avatar/MyAvatar.cpp
+++ b/interface/src/avatar/MyAvatar.cpp
@@ -910,7 +910,7 @@ void MyAvatar::updateCollisionWithAvatars(float deltaTime) {
     updateShapePositions();
     float myBoundingRadius = getBoundingRadius();
 
-    const float BODY_COLLISION_RESOLUTION_FACTOR = deltaTime / BODY_COLLISION_RESOLUTION_TIMESCALE;
+    const float BODY_COLLISION_RESOLUTION_FACTOR = glm::max(1.0f, deltaTime / BODY_COLLISION_RESOLUTION_TIMESCALE);
 
     foreach (const AvatarSharedPointer& avatarPointer, avatars) {
         Avatar* avatar = static_cast<Avatar*>(avatarPointer.data());