//HTN forward plan builder
private void BuildPlan()
{
node cur;
tasks = new Queue <node>();
plan = new Queue <string>();
tasks.Enqueue(htn_tree.rootNode);
while (tasks.Count > 0)
{
bool preConditionsMet = false;
cur = tasks.Dequeue();
//rootnode is a compound task we need to evaluate regardless of wolrd state
if (cur.t == node.type.Root)
{
compound_task c_cur = (compound_task)cur;
LoadChildren(c_cur.children);
}
//normal compound nodes extraction and evaluation
else if (cur.t == node.type.Compound)
{
compound_task c_cur = (compound_task)cur;
preConditionsMet = EvalCompoundPreConditions(c_cur.behaviorName);
if (preConditionsMet == true)
{
//in a sequence all tasks are evaluated
if (c_cur.st == compound_task.subType.Sequence)
{
LoadChildren(c_cur.children);
}
//in the selector 1 random task is evaluated
else if (c_cur.st == compound_task.subType.Selector)
{
int index = Random.Range(0, c_cur.children.Count);
List <node> l = new List <node>();
l.Add(c_cur.children[index]);
LoadChildren(l);
}
}
}
//primitive tasks preconditions are evaluated one last time before being added to the execution plan. A failure triggers a replan.
else if (cur.t == node.type.Primitive)
{
primitive_task p_cur = (primitive_task)cur;
preConditionsMet = EvalPrimitivePreConditions(p_cur.taskName);
if (preConditionsMet == true)
{
plan.Enqueue(p_cur.taskName);
}
else
{
planIsValid = false;
break;
}
}
}
}
//default constructor builds the htn tree model in the implementation doc
public monster_htn()
{
monster = GameObject.Find("Monster");
m = monster.GetComponent <monster_controller>();
//define rootNode node
rootNode = new compound_task(node.type.Root, "beAMonster");
rootNode.children = new List <node>();
rootNode.children.Add(new compound_task(rootNode, node.type.Compound, compound_task.subType.Sequence, "wander"));
rootNode.children.Add(new compound_task(rootNode, node.type.Compound, compound_task.subType.Sequence, "attack"));
//build left handside of the htn: wandering behavior
compound_task wanderNode = (compound_task)rootNode.children[0];
wanderNode.children = new List <node>
{
new compound_task(wanderNode, node.type.Compound, compound_task.subType.Selector, "navSpeed"), //movement type
new primitive_task(wanderNode, node.type.Primitive, "setNavDest"), //choose dest
new primitive_task(wanderNode, node.type.Primitive, "idle") //rest
};
compound_task navSpeedNode = (compound_task)wanderNode.children[0];
navSpeedNode.children = new List <node>
{
new primitive_task(navSpeedNode, node.type.Primitive, "walk"),
new primitive_task(navSpeedNode, node.type.Primitive, "run")
};
//build the right handside of the tree: attack behavior
compound_task attackNode = (compound_task)rootNode.children[1];
attackNode.children = new List <node>
{
new primitive_task(attackNode, node.type.Primitive, "getAngry"), //change skin color
new compound_task(attackNode, node.type.Compound, compound_task.subType.Sequence, "findObjectToThrow"), //pick up object
new compound_task(attackNode, node.type.Compound, compound_task.subType.Selector, "throw"), //throw
new primitive_task(wanderNode, node.type.Primitive, "recover") //rest
};
compound_task findObjNode = (compound_task)attackNode.children[1];
findObjNode.children = new List <node>
{
new primitive_task(findObjNode, node.type.Primitive, "findObj"), //find closest obj
new primitive_task(findObjNode, node.type.Primitive, "navToObj"), //navigate to it
new primitive_task(findObjNode, node.type.Primitive, "pickUp") //pick it up
};
compound_task throwNode = (compound_task)attackNode.children[2];
throwNode.children = new List <node>
{
new compound_task(throwNode, node.type.Compound, compound_task.subType.Sequence, "superThrow"), //throw rock
new primitive_task(throwNode, node.type.Primitive, "objectThrow") //throw object
};
compound_task superThrowNode = (compound_task)throwNode.children[0];
superThrowNode.children = new List <node>
{
new primitive_task(superThrowNode, node.type.Primitive, "growl"), //growl
new primitive_task(superThrowNode, node.type.Primitive, "objectThrow") //throw object
};
}
