BGE showstopper bug fix:

- Reset hit object pointer at end of frame of touch sensor to avoid returning invalid pointer to getHitObject().
- Clear all references in KX_TouchSensor::m_colliders when the sensor is disabled to avoid loose references. 
- Test GetSGNode() systematically for all KX_GameObject functions that can be called from python in case a python controller keeps a reference in GameLogic (bad practice anyway).

1 files changed, 23 insertions, 20 deletions

diff --git a/source/gameengine/Ketsji/KX_VehicleWrapper.cpp b/source/gameengine/Ketsji/KX_VehicleWrapper.cpp
index 342e71c5093..028f96f6c5b 100644
--- a/source/gameengine/Ketsji/KX_VehicleWrapper.cpp
+++ b/source/gameengine/Ketsji/KX_VehicleWrapper.cpp
@@ -49,26 +49,29 @@ PyObject* KX_VehicleWrapper::PyAddWheel(PyObject* self,
 	if (PyArg_ParseTuple(args,"OOOOffi",&wheelGameObject,&pylistPos,&pylistDir,&pylistAxleDir,&suspensionRestLength,&wheelRadius,&hasSteering))
 	{
 		KX_GameObject* gameOb = (KX_GameObject*) wheelGameObject;
-		
-		PHY_IMotionState* motionState = new KX_MotionState(gameOb->GetSGNode());
-
-		MT_Vector3 attachPos,attachDir,attachAxle;
-		PyVecTo(pylistPos,attachPos);
-		PyVecTo(pylistDir,attachDir);
-		PyVecTo(pylistAxleDir,attachAxle);
-		PHY__Vector3 aPos,aDir,aAxle;
-		aPos[0] = attachPos[0];
-		aPos[1] = attachPos[1];
-		aPos[2] = attachPos[2];
-		aDir[0] = attachDir[0];
-		aDir[1] = attachDir[1];
-		aDir[2] = attachDir[2];
-		aAxle[0] = -attachAxle[0];//someone reverse some conventions inside Bullet (axle winding)
-		aAxle[1] = -attachAxle[1];
-		aAxle[2] = -attachAxle[2];
-		
-		printf("attempt for addWheel: suspensionRestLength%f wheelRadius %f, hasSteering:%d\n",suspensionRestLength,wheelRadius,hasSteering);
-		m_vehicle->AddWheel(motionState,aPos,aDir,aAxle,suspensionRestLength,wheelRadius,hasSteering);
+
+		if (gameOb->GetSGNode())
+		{
+			PHY_IMotionState* motionState = new KX_MotionState(gameOb->GetSGNode());
+
+			MT_Vector3 attachPos,attachDir,attachAxle;
+			PyVecTo(pylistPos,attachPos);
+			PyVecTo(pylistDir,attachDir);
+			PyVecTo(pylistAxleDir,attachAxle);
+			PHY__Vector3 aPos,aDir,aAxle;
+			aPos[0] = attachPos[0];
+			aPos[1] = attachPos[1];
+			aPos[2] = attachPos[2];
+			aDir[0] = attachDir[0];
+			aDir[1] = attachDir[1];
+			aDir[2] = attachDir[2];
+			aAxle[0] = -attachAxle[0];//someone reverse some conventions inside Bullet (axle winding)
+			aAxle[1] = -attachAxle[1];
+			aAxle[2] = -attachAxle[2];
+			
+			printf("attempt for addWheel: suspensionRestLength%f wheelRadius %f, hasSteering:%d\n",suspensionRestLength,wheelRadius,hasSteering);
+			m_vehicle->AddWheel(motionState,aPos,aDir,aAxle,suspensionRestLength,wheelRadius,hasSteering);
+		}
 		
 	} else {
 		return NULL;