Rework PhysX collision flutter bug workaround

To better handle erroneous trigger events under the new timing method, use the number of times the simulation has actually advanced instead of the number of evals received.

Cleaned up a bit.

Sources/Plasma/PubUtilLib/plPhysX/plSimulationMgr.cpp

@@ -283,6 +283,7 @@ plSimulationMgr* plSimulationMgr::GetInstance()
 plSimulationMgr::plSimulationMgr()
     : fSuspended(true)
     , fAccumulator(0.0f)
+    , fStepCount(0)
     , fLOSDispatch(new plLOSDispatch())
     , fSoundMgr(new plPhysicsSoundMgr)
     , fLog(nil)
@@ -468,6 +469,8 @@ void plSimulationMgr::Advance(float delSecs)
         fAccumulator = kDefaultMaxDelta;
     }
 
+    ++fStepCount;
+
     // Perform as many whole substeps as possible saving the remainder in our accumulator.
     int numSubSteps = (int)(fAccumulator / kDefaultStepSize + 0.000001f);
     float delta = numSubSteps * kDefaultStepSize;

Sources/Plasma/PubUtilLib/plPhysX/plSimulationMgr.h

@@ -99,6 +99,8 @@ public:
 
     int GetMaterialIdx(NxScene* scene, float friction, float restitution);
 
+    uint32_t GetStepCount() const { return fStepCount; }
+
     //Fix to Move collision messages and their handling out of the simulation step
     void AddCollisionMsg(plKey hitee, plKey hitter, bool entering);
     void AddCollisionMsg(plCollideMsg* msg);
@@ -139,6 +141,7 @@ protected:
     bool fSuspended;
 
     float fAccumulator;
+    uint32_t fStepCount;
 
     // A utility class to keep track of a request for a physical synchronization.
     // These requests must pass a certain criteria (see the code for the latest)