void CollisionSystem::Update( double DeltaTime )
{
    static const auto enableCollision = Settings::Get().GetInt( "collisions.enable", 1 ) != 0;
    if( !enableCollision )
    {
        return;
    }
    mUpdateTimer.Log( "start collision" );
    mPerfTimer.Log( "pre build grid" );
    std::vector<std::pair<Opt<CollisionSubSystem>, Actor*>> collisionAndActors;
    for (auto actor : mScene.GetActorsFromMap( GetType_static() ))
    {
        Opt<ICollisionComponent> collisionC = actor->Get<ICollisionComponent>();
        if ( collisionC.IsValid() )
        {
            Opt<CollisionSubSystem> collisionSS = GetCollisionSubSystem( collisionC->GetId() );
            if ( collisionSS.IsValid() )
            {
                collisionAndActors.push_back( std::make_pair( collisionSS, actor ) );
                collisionSS->ClipScene( *actor );
            }
            mCollisionGrid.AddActor( actor, DeltaTime, collisionC );
        }
    }
    mPerfTimer.Log( "post build grid" );
    PossibleCollisions_t const& PossibleCollisions = mCollisionGrid.GetPossibleCollisions();
    for( PossibleCollisions_t::const_iterator i = PossibleCollisions.begin(), e = PossibleCollisions.end(); i != e; ++i )
    {
        Actor& A = *( i->A1 );
        Actor& B = *( i->A2 );
        Opt<ICollisionComponent> ACollisionC = A.Get<ICollisionComponent>();
        Opt<ICollisionComponent> BCollisionC = B.Get<ICollisionComponent>();
        BOOST_ASSERT( ACollisionC.IsValid() && BCollisionC.IsValid() ); //TODO: here this one should be true

        CollisionModel const& CollModel = mCollisionStore.GetCollisionModel( ACollisionC->GetCollisionClass(), BCollisionC->GetCollisionClass() );
        if( !CollModel.AreActorsColliding( A, B, DeltaTime ) )
        {
            continue;
        }
        //TODO: needs optimization, maybe a template parameter for SubSystemHolder to subsystem would do
        Opt<CollisionSubSystem> ACollisionSS = GetCollisionSubSystem( ACollisionC->GetId() );
        if ( ACollisionSS.IsValid() )
        {
            ACollisionSS->Collide( A, B );
        }
        Opt<CollisionSubSystem> BCollisionSS = GetCollisionSubSystem( BCollisionC->GetId() );
        if ( BCollisionSS.IsValid() )
        {
            BCollisionSS->Collide( B, A );
        }
    }
    mPerfTimer.Log( "post collide" );
    for (auto& collAndActor : collisionAndActors)
    {
        collAndActor.first->Update( *collAndActor.second, DeltaTime );
    }
    mPerfTimer.Log( "post collSS" );
    mUpdateTimer.Log( "end collision" );
}
void CollisionSystem::Update( double DeltaTime )
{
    mCollisionGrid.Clear();
    for( ActorList_t::iterator it = mScene.GetActors().begin(), e = mScene.GetActors().end(); it != e; ++it )
    {
        Actor& actor = **it;
        Opt<ICollisionComponent> collisionC = actor.Get<ICollisionComponent>();
        if ( collisionC.IsValid() )
        {
            mCollisionGrid.AddActor( &actor, DeltaTime );
            Opt<CollisionSubSystem> collisionSS = GetCollisionSubSystem( collisionC->GetId() );
            if ( collisionSS.IsValid() )
            {
                collisionSS->ClipScene( actor );
            }
        }
    }
    PossibleCollisions_t const& PossibleCollisions = mCollisionGrid.GetPossibleCollisions();
    for( PossibleCollisions_t::const_iterator i = PossibleCollisions.begin(), e = PossibleCollisions.end(); i != e; ++i )
    {
        Actor& A = *( i->A1 );
        Actor& B = *( i->A2 );
        Opt<ICollisionComponent> ACollisionC = A.Get<ICollisionComponent>();
        Opt<ICollisionComponent> BCollisionC = B.Get<ICollisionComponent>();
        BOOST_ASSERT( ACollisionC.IsValid() && BCollisionC.IsValid() ); //TODO: here this one should be true

        CollisionModel const& CollModel = mCollisionStore.GetCollisionModel( ACollisionC->GetCollisionClass(), BCollisionC->GetCollisionClass() );
        if( !CollModel.AreActorsColliding( A, B, DeltaTime ) )
        {
            continue;
        }
        //TODO: needs optimization, maybe a template parameter for SubSystemHolder to subsystem would do
        Opt<CollisionSubSystem> ACollisionSS = GetCollisionSubSystem( ACollisionC->GetId() );
        if ( ACollisionSS.IsValid() )
        {
            ACollisionSS->Collide( A, B );
        }
        Opt<CollisionSubSystem> BCollisionSS = GetCollisionSubSystem( BCollisionC->GetId() );
        if ( BCollisionSS.IsValid() )
        {
            BCollisionSS->Collide( B, A );
        }
    }
    for( ActorList_t::iterator it = mScene.GetActors().begin(), e = mScene.GetActors().end(); it != e; ++it )
    {
        Actor& actor = **it;
        Opt<ICollisionComponent> collisionC = actor.Get<ICollisionComponent>();
        if ( collisionC.IsValid() )
        {
            Opt<CollisionSubSystem> collisionSS = GetCollisionSubSystem( collisionC->GetId() );
            if ( collisionSS.IsValid() )
            {
                collisionSS->Update( actor, DeltaTime );
            }
        }
    }
}