private N_CompositionNode RandomComp()
{
N_CompositionNode randomComp;
int randomComposition = UnityEngine.Random.Range(0, 3);
switch (randomComposition)
{
case 0:
randomComp = new N_Selection();
break;
case 1:
randomComp = new N_Sequence();
break;
case 2:
randomComp = new N_ProbabilitySelector();
break;
default:
randomComp = null;
Debug.LogError("No comp was chosen for generation of BT.");
break;
}
return(randomComp);
}
// Sequence for moving by patroling or kiting.
// If an enemy is spotted, there's a probability of the agent either patroling.
// or kiting. If no enemy, always patrol.
// Returns success if path found and started.
// Returns running if in process of walking towards destination.
public static Node Tree_PatrolOrKite(N_AgentNode.AgentType agent)
{
N_ProbabilitySelector kiteOrPatrol = new N_ProbabilitySelector();
kiteOrPatrol.AddLast(new N_Kite(agent));
kiteOrPatrol.AddLast(new N_Patrol(agent));
//N_DecSuccess kiteOrPatrolSuccess = new N_DecSuccess(kiteOrPatrol);
N_Sequence enemyThenKiteOrPatrol = new N_Sequence();
enemyThenKiteOrPatrol.AddLast(new N_IsEnemyVisible(agent));
enemyThenKiteOrPatrol.AddLast(kiteOrPatrol);
//N_DecSuccess patrolSuccess = new N_DecSuccess(new N_Patrol(agent));
N_Selection enemyOrPatrol = new N_Selection();
enemyOrPatrol.AddLast(enemyThenKiteOrPatrol);
enemyOrPatrol.AddLast(new N_Patrol(agent));
enemyOrPatrol.IsSubtree = true;
return(enemyOrPatrol);
}
// Assign random mutations to the given tree.
protected void Mutate(N_Root child)
{
// First, check if there'll be any mutation at all.
float random = UnityEngine.Random.Range(0.0f, 1.0f);
if (random < mutationRate)
{
List <Node> thresholds = TreeOperations.RetrieveNodesOfType(child, typeof(N_Threshold));
List <Node> probNodes = TreeOperations.RetrieveNodesOfType(child, typeof(N_ProbabilitySelector));
// Randomise between whether to change thresholds or probabilities
random = UnityEngine.Random.Range(0.0f, 1.0f);
// If no probnode exists, change condition if there are any instead
if ((random <= 0.25f && thresholds.Count > 0))
{
//Debug.Log("Changing threshold!");
// Get random index within range of list
int index = UnityEngine.Random.Range(0, thresholds.Count);
N_Threshold thresh = thresholds[index] as N_Threshold;
// Mutate threshold by random offset
int offset = UnityEngine.Random.Range(minThresholdOffset, maxTresholdOffset);
thresh.SetThreshold(thresh.Threshold + offset);
}
else if (random > 0.25f && random <= 0.5f && probNodes.Count > 0) // Adjust relative probabilities on a probability selector.
{
//Debug.Log("Changing prob!");
// Get random index within range of list
int index = UnityEngine.Random.Range(0, probNodes.Count);
N_ProbabilitySelector probSelect = probNodes[index] as N_ProbabilitySelector;
// Check so that the probablitySelector has any children.
if (probSelect.GetChildren().Count <= 0)
{
return;
}
// Calculate total probability and retrieve a relative offset based on it.
float totalProb = 0.0f;
foreach (Node n in probSelect.GetChildren())
{
totalProb += probSelect.GetProbabilityWeight(n);
}
float offset = totalProb * (relativeProbabilityMutation / 100.0f);
// Also, get a random sign to decide whether to substract or add offset
// and a random index for which child to be changed.
float randomSign = Mathf.Sign(UnityEngine.Random.Range(-1.0f, 1.0f));
int randomChildIndex = UnityEngine.Random.Range(0, probSelect.GetChildren().Count);
// Finally, offset the given childs probability by the random amount.
probSelect.OffsetProbabilityWeight(probSelect.GetChildren()[randomChildIndex]
, offset * randomSign);
}
else if (random > 0.5f && random <= 0.75f) // Change subtree
{
//Debug.Log("Changing subtree!");
List <Node> subtrees = TreeOperations.RetrieveSubtreeNodes(child);
int randomIndex = UnityEngine.Random.Range(0, subtrees.Count);
Node subtree = subtrees[randomIndex];
N_CompositionNode parentComp = subtree.Parent as N_CompositionNode;
// Get a random subtree index and replace its position in the tree with
// a new randomized subtree instead.
parentComp.ReplaceChild(subtree, RandomSubtree());
}
else if (random > 0.75f) // Change composition
{
//Debug.Log("Changing composition!");
List <Node> comps = TreeOperations.RetrieveNodesOfType(child, typeof(N_CompositionNode));
int randomIndex = UnityEngine.Random.Range(0, comps.Count);
N_CompositionNode replaceComp = comps[randomIndex] as N_CompositionNode;
// If parent is null, this comp is the initial comp.
if (replaceComp.Parent != null)
{
Node compParent = replaceComp.Parent;
List <Node> children = replaceComp.GetChildren();
// Attach old comps children to the new one.
N_CompositionNode newComp = RandomComp();
// Make sure to keep structure of subtrees
if (replaceComp.IsSubtree)
{
newComp.IsSubtree = true;
}
foreach (Node c in children)
{
c.Parent = newComp;
newComp.AddLast(c);
}
// Reattach parent to the new comp
if (compParent.GetType().IsSubclassOf(typeof(N_CompositionNode)))
{
N_CompositionNode compParent_comp = compParent as N_CompositionNode;
compParent_comp.ReplaceChild(replaceComp, newComp);
}
else if (compParent.GetType().IsSubclassOf(typeof(N_Decorator)))
{
N_Decorator compParent_dec = compParent as N_Decorator;
compParent_dec.Child = newComp;
}
}
}
}
}
