private static List <Action> FindSolution(IGoap igoap, List <Action> actions, Goal goal, DebugPlanning debug)
{
// Create the closed/ open list and add the goal state to the latter
List <Node> closedList = new List <Node>();
List <Node> openList = new List <Node>();
openList.Add(new Node(null, null, goal.succes));
DebugText(debug, DebugPlanning.Everything, "Starting state is {0}.", ConditionsToText(goal.succes));
// As long as there are nodes in the open list, we continue
while (true)
{
Node p = GetCheapestNode(openList);
if (p.action != null)
{
DebugText(debug, DebugPlanning.Everything, "Picked open node with action {0} from the open list.", p.action.GetType());
}
// Look for each action if it gives the desired effects
foreach (Action action in actions)
{
Action a = action.OnClone();
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Trying to add action {0} to the current state. Calling action {0}'s OnActionSetup.", a.GetType());
a.OnActionSetup(igoap, p.state);
// Make sure the effects add to the state
if (MatchesState(a.effects, p.state))
{
// Make sure the action is actually viable
if (!a.isViable)
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Action {0} could not be added because it's not viable.", a.GetType());
continue;
}
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Action {0} is viable, the state will now be altered with the effects and preconditions.", a.GetType());
// Add the actions preconditions
List <Condition> state = AddToState(p.state, a.preconditions);
DebugText(debug, DebugPlanning.Everything, "Current state after adding action {0}'s preconditions: {1}.", a.GetType(), ConditionsToText(state));
// Remove actions effects
state = RemoveFromState(state, a.effects);
DebugText(debug, DebugPlanning.Everything, "Current state after removing action {0}'s effects: {1}.", a.GetType(), ConditionsToText(state));
// Remove preconditions which our current state already fullfills
state = RemoveFromState(state, igoap.state);
DebugText(debug, DebugPlanning.Everything, "Current state after removing iGoap's state: {0}.", ConditionsToText(state));
// Create a new node
Node n = new Node(p, a, state);
// If the state hasn't changed, the action will be futile
if (MatchesState(n.state, p.state))
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Action {0} effects did not alter the state. Since this action is futile it will not be added.", a.GetType());
continue;
}
// See if we've reached the solution
if (n.state.Count == 0)
{
closedList.Add(n);
continue;
}
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Action {0} succesfully added to the open list. Current open list count: {1}.", a.GetType(), openList.Count);
// Otherwise we add it to the open list
openList.Add(n);
}
else
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Action {0} is not viable.", a.GetType());
}
}
// We're done with this node, so we remove it from the list
openList.Remove(p);
// Check to see if a solution has been found
if (openList.Count == 0 && closedList.Count != 0)
{
return(NodesToActions(GetCheapestNode(closedList)));
}
if (openList.Count == 0)
{
break;
}
}
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Ran out of viable path options for goal {0}.", goal.GetType());
return(null);
}
/// <summary>
/// Formulates a plan based on the given actions and goal
/// </summary>
/// <param name="actions">List of available actions</param>
/// <param name="goals">Available goal</param>
/// <param name="currentGoal">If a plan is found, this will be the current goal</param>
/// <returns>If a plan was found, a list of actions. Otherwise null</returns>
public static List <Action> FormulatePlan(IGoap igoap, List <Action> actions, Goal goal, out Goal currentGoal, DebugPlanning debug = DebugPlanning.None)
{
currentGoal = goal;
if (igoap == null || actions == null || actions.Count == 0 || goal == null)
{
if (igoap == null)
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Can't formulate a plan because no suitable iGoap was found.");
}
if (actions == null || actions.Count == 0)
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Can't formulate a plan because no suitable actions for iGoap were found.");
}
if (goal)
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Can't formulate a plan because no suitable goal for iGoap was found.");
}
}
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Formulating a plan for goal {0}.", goal.GetType());
goal.OnGoalSetup();
if (!goal.IsGoalRelevant())
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Goal {0} is not relevant.", goal.GetType());
return(null);
}
List <Action> plan = FindSolution(igoap, actions, goal, debug);
if (plan == null)
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Couldn't find a plan for goal {0}, returning null.", goal.GetType());
}
else
{
DebugText(debug, DebugPlanning.Basics | DebugPlanning.Everything, "Found a plan for goal {0} and returning it.", goal.GetType());
}
return(plan);
}