UPBGE: Fix lod update using always the scene active camera.

Previously lod update was always using the scene active camera, but this camera
don't have a meaning when the user use multiple viewports.

To fix this issue the function KX_Scene::UpdateObjectLod accept as argument the
current camera used for rendering.

source/gameengine/Ketsji/KX_KetsjiEngine.cpp

@@ -1034,7 +1034,7 @@ void KX_KetsjiEngine::RenderFrame(KX_Scene *scene, KX_Camera *cam, unsigned shor
 	scene->CalculateVisibleMeshes(m_rasterizer, cam);
 
 	// update levels of detail
-	scene->UpdateObjectLods();
+	scene->UpdateObjectLods(cam);
 
 	m_logger->StartLog(tc_animations, m_kxsystem->GetTimeInSeconds(), true);
 	SG_SetActiveStage(SG_STAGE_ANIMATION_UPDATE);

source/gameengine/Ketsji/KX_Scene.cpp

@@ -1715,13 +1715,10 @@ void KX_Scene::RenderCubeMaps(RAS_IRasterizer *rasty)
 	m_cubeMapManager->Render(rasty);
 }
 
-void KX_Scene::UpdateObjectLods()
+void KX_Scene::UpdateObjectLods(KX_Camera *cam)
 {
-	if (!m_active_camera)
-		return;
-
-	const MT_Vector3& cam_pos = m_active_camera->NodeGetWorldPosition();
-	const float lodfactor = m_active_camera->GetLodDistanceFactor();
+	const MT_Vector3& cam_pos = cam->NodeGetWorldPosition();
+	const float lodfactor = cam->GetLodDistanceFactor();
 
 	for (CListValue::iterator<KX_GameObject> it = m_objectlist->GetBegin(), end = m_objectlist->GetEnd(); it != end; ++it) {
 		KX_GameObject *gameobj = *it;

source/gameengine/Ketsji/KX_Scene.h

@@ -501,7 +501,7 @@ class KX_Scene : public CValue, public SCA_IScene
 	void Resume();
 
 	/// Update the mesh for objects based on level of detail settings
-	void UpdateObjectLods();
+	void UpdateObjectLods(KX_Camera *cam);
 
 	// LoD Hysteresis functions
 	void SetLodHysteresis(bool active);