/// <summary>
/// Gets the possible action branches that arrive at the goals required state.
/// </summary>
/// <param name="goal"></param>
/// <returns></returns>
List <GoapNode> GetGoalTree(GoapGoal goal)
{
List <GoapNode> EndNodes = new List <GoapNode>();
GoapNode RootNode = new GoapNode(null, 0, goal.RequiredWorldState, null);
// check if the world state already matches this goal.
if (TestGoalStateAgainstWorldState(goal))
{
return(new List <GoapNode>());
}
List <GoapAction> ImmedeateActions = GetGoalActions(goal);
foreach (GoapAction action in ImmedeateActions)
{
// test each immediate action's pre-requisite states against the world states.
if (TestActionAgainstWorldState(action))
{
EndNodes.Add(new GoapNode(RootNode, RootNode.CumulativeCost + action.Cost, action.SatisfiesStates, action));
}
else
{
// recurse through this action's state requirements until it either matches the world state or has no prerequisites.
EndNodes.AddRange(GetActionTree(action, new GoapNode(RootNode, RootNode.CumulativeCost + action.Cost, action.SatisfiesStates, action)));
}
}
return(EndNodes);
}
// Returns a list of actions (from the available actions) that satisfy one or all of our goals required states.
List <GoapAction> GetGoalActions(GoapGoal goal)
{
List <GoapAction> ReturnActions = new List <GoapAction>();
foreach (GoapState state in goal.RequiredWorldState)
{
foreach (GoapAction action in AvailableActions)
{
if (action.CanActionRun())
{
for (int i = 0; i < action.SatisfiesStates.Count; ++i)
{
if (GoapState.Compare(state, action.SatisfiesStates[i]))
{
ReturnActions.Add(action);
}
}
}
}
}
return(ReturnActions);
}
// test to see if our current world state matches that of our goals required states.
bool TestGoalStateAgainstWorldState(GoapGoal goal)
{
bool GoalStatesMatch = true;
foreach (GoapState goalState in goal.RequiredWorldState)
{
bool currentStateCheck = false;
foreach (GoapState worldState in CurrentWorldState)
{
if (GoapState.Compare(worldState, goalState))
{
currentStateCheck = true;
}
}
if (!currentStateCheck)
{
GoalStatesMatch = false;
break;
}
}
return(GoalStatesMatch);
}
