public static int TransferExpressionToParameters(IList <VFXExpression> inputExpression, IEnumerable <VFXParameter> parameters, List <VFXExpression> backedUpExpressions = null)
        {
            int cptSlot = 0;

            foreach (var param in parameters)
            {
                VFXSlot outputSlot = param.outputSlots[0];

                param.subgraphMode = true;
                if (inputExpression.Count > cptSlot)
                {
                    if (backedUpExpressions != null)
                    {
                        backedUpExpressions.Add(outputSlot.GetExpression());
                    }
                    outputSlot.SetExpression(inputExpression[cptSlot]);
                }

                cptSlot += 1;
            }

            return(cptSlot);
        }