From 2c8bf4aaa66a4cc9fc8fd9f89825e7cd1b43f3d6 Mon Sep 17 00:00:00 2001
From: Robert Adams <Robert.Adams@intel.com>
Date: Wed, 17 Jul 2013 10:19:44 -0700
Subject: [PATCH] BulletSim: fix small bug where everything looked like it was
 colliding before the first simulator step.

---
 .../Region/Physics/BulletSPlugin/BSPhysObject.cs    | 13 +++++++------
 OpenSim/Region/Physics/BulletSPlugin/BSScene.cs     |  3 +++
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
index a41eaf8617..fc4545f4e3 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
@@ -103,9 +103,10 @@ public abstract class BSPhysObject : PhysicsActor
         CollisionsLastTickStep = -1;
 
         SubscribedEventsMs = 0;
-        CollidingStep = 0;
-        CollidingGroundStep = 0;
-        CollisionAccumulation = 0;
+        // Crazy values that will never be true
+        CollidingStep = BSScene.NotASimulationStep;
+        CollidingGroundStep = BSScene.NotASimulationStep;
+        CollisionAccumulation = BSScene.NotASimulationStep;
         ColliderIsMoving = false;
         CollisionScore = 0;
 
@@ -349,7 +350,7 @@ public abstract class BSPhysObject : PhysicsActor
             if (value)
                 CollidingStep = PhysScene.SimulationStep;
             else
-                CollidingStep = 0;
+                CollidingStep = BSScene.NotASimulationStep;
             }
     }
     public override bool CollidingGround {
@@ -359,7 +360,7 @@ public abstract class BSPhysObject : PhysicsActor
             if (value)
                 CollidingGroundStep = PhysScene.SimulationStep;
             else
-                CollidingGroundStep = 0;
+                CollidingGroundStep = BSScene.NotASimulationStep;
         }
     }
     public override bool CollidingObj {
@@ -368,7 +369,7 @@ public abstract class BSPhysObject : PhysicsActor
             if (value)
                 CollidingObjectStep = PhysScene.SimulationStep;
             else
-                CollidingObjectStep = 0;
+                CollidingObjectStep = BSScene.NotASimulationStep;
         }
     }
 
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
index 214271b247..41aca3b2a7 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
@@ -97,6 +97,9 @@ public sealed class BSScene : PhysicsScene, IPhysicsParameters
 
     internal long m_simulationStep = 0; // The current simulation step.
     public long SimulationStep { get { return m_simulationStep; } }
+    // A number to use for SimulationStep that is probably not any step value
+    // Used by the collision code (which remembers the step when a collision happens) to remember not any simulation step.
+    public static long NotASimulationStep = -1234;
 
     internal float LastTimeStep { get; private set; }   // The simulation time from the last invocation of Simulate()