Unity-How to Create a Dialogue Tree? - unity3d

Question

So I have this program set up for a simple dialogue tree, where I want to display a question and two options in the unity editor, and if you click one option, you either go to another level of the tree or a leaf. I want to use the composite design pattern to make separate level instances, each with different parameters for one question and two options and add them together into a list. What I'm stuck on is how do I start at the first level and traverse down the tree depending on which button I press. It seems like no matter what I do, it only displays the last level parameters added to the list. The best I can think is maybe add some sort of shifting list function during the button click events. If anyone could shoot some ideas, I would appreciate it. Thank you.
public class Level : MonoBehaviour {
bool button1Pressed;
bool button2Pressed;
private void Start()
{
Level Level1 = new Level("Hello", "Hi", "Shut Up");
Level leaf1 = new Level("Don't be Rude");
Level Level2 = new Level("What you Doing?", "Not Much", "None of your Business");
Level leaf2 = new Level("Well Excuuuuse Me");
Level Level3 = new Level("Can I do that too?", "Sure", "Go Away");
Level leaf3 = new Level("Fine. Be a Jerk");
Level Level4 = new Level("This is boring, can we do something else?", "Why not?", "You're boring");
Level leaf4 = new Level("I'll go be boring somewhere else");
Level Level5 = new Level("You want ice cream?", "Sounds Good", "I'm allergic");
Level leaf5 = new Level("ok.......");
Level leaf = new Level("I Want Chocolate");
Level1.add(Level1);
Level1.add(leaf1);
Level2.add(Level3);
Level2.add(leaf2);
Level3.add(Level4);
Level3.add(leaf3);
Level4.add(Level5);
Level4.add(leaf4);
Level5.add(leaf5);
Level5.add(leaf);
}
public static Text Textbox;
public static Button Button1;
public static Button Button2;
public string OptionA;
public string OptionB;
public string Question;
public string Leaf;
private List<Level> levels;
public Level(string question, string optionA, string optionB)
{
this.Question = question;
this.OptionA = optionA;
this.OptionB = optionB;
GameObject.FindGameObjectWithTag("Level").GetComponentInChildren<Text>().text = Question;
GameObject.FindGameObjectWithTag("OptionA").GetComponentInChildren<Text>().text = OptionA;
GameObject.FindGameObjectWithTag("OptionB").GetComponentInChildren<Text>().text = OptionB;
levels = new List<Level>();
}
public Level(string leaf)
{
this.Leaf = leaf;
Textbox.text = leaf;
}
public void add(Level lvl)
{
levels.Add(lvl);
}
public List<Level> getLevels()
{
return levels;
}
public void Button1Pressed()
{
}
public void Button2Pressed()
{
}
}
public class Initializer : MonoBehaviour {
public Text Textbox;
public Button Button1;
public Button Button2;
void Awake()
{
Level.Textbox = this.Textbox;
Level.Button1 = this.Button1;
Level.Button2 = this.Button2;
}
}

Answer 1

The short answer: All nodes know their parent and children.
There are a few ways to approach this problem. I'll explain an approach using a tree structure with multiple node classes. First we can examine the interactions with the player as you've outlined:
Making a dialog choice (speaking)
Observing a dialog response (listening)
There's also some important conditions we need to consider:
User terminated conversations
AI terminated conversations
From this outline we can build our tree with some classes. I've scratched out some examples but I haven't tested them. Hopefully it conveys the idea and you can build your own solution. It may also be more useful for you to make a single Node class that just knows which type it is. Another improvement would be using an interface or some way to generalize the parent/child relationship which would allow for more complicated tree structures.
class ChoiceNode
{
public ChoiceNode(ResponseNode myParent)
{
parent = myParent;
}
ResponseNode parent = null;
List<ResponseNode> children = new List<ResponseNode>;
bool canSayGoodbye = true;
}
class ResponseNode
{
public ResponseNode(ChoiceNode myParent, string myMessage)
{
parent = myParent;
parent.children.Add(this);
response = myMessage;
}
ChoiceNode parent;
ChoiceNode child;
string response;
}
We should now be able to use a method to display dialog choice by simply enumerating the ResponseNode.children. Then whenever we make a dialog choice we want to display the ResponseNode.response and then move to the ResponseNode.child to find the next set of dialog choices. When parent == null we're at the root branch. When child == null we display some termination text.
I hope this is helpful and gives you some ideas.

Answer 2

Ok, I tried to understand the logic of your code but there are several things that I don't understand, maybe it's better if I try to explain my "Unity dialogue tree".
First:
We need to create a Tree object. If you just want a binary tree you just need tree variables:
public class BinaryTree{
private string root;
private BinaryTree left;
private BinaryTree right
getters/setters
}
this object don't even need to be a Unity component.
root is "dialog"
left is "optionA"
right is "optionB"
if you don't need multiple answer just make left=right.
If you need a way to identify multiple answer I suggest you to create an object like this:
public class Tree{
private Dictionary<string,string> root;
private List<Tree> next;
getters/setters
}
root is again your dialog. A key (that identify your answer) and a value that is the actual dialog.
next is a List of Tree (you identify your answer by making a loop in your next and by checking the key of the dictionary).
Now in the Start method you need to create a new Tree object and set your nexts.
Example
Start(){
BinaryTree bn = new BinaryTree();
bn.Root = "Is this a question?";
BinaryTree left = new BinaryTree();
left.Root = "Nope";
bn.Left = left;
BinaryTree right = new BinaryTree();
right.Root = "Yes it is...";
bn.Right = right;
}
Almost the same for the Tree version:
Start(){
Tree bn = new Tree();
bn.Root = new Dictionary<string, string>();
bn.Root.Add("key1", "Do you need something?");
bn.Next = new List<Tree>();
Tree answer1 = new Tree();
answer1.Root = new Dictionary<string, string>();
answer1.Root.Add("key2", "Yes");
bn.Next.Add();
... iterate...
}
Of course this is just a basic example. The best way to initialize that is to add your dialog to an array and iterate.
Anyway.
Now you can (for example) create a button. In the Start you can Initialize it's text value to your root. In the PointerDown/Clicked method you can make an array of the possible answer keys and, for example, you can decide to generate multiple buttons for multiple answers (or just use 2 static button answer with the BinaryTree) and change the text based on the answer root value (or left/right value). each of the answer button should, in the PointerDown/Clicked method, send the key value (or left/right object) of your user selection (in practice the next value that will display in the main question button).
Of course the "question button" once clicked again should display the next of your answer (and maybe you can decide to add a bool question variable to your object... or maybe you can just decide to use only the left side for a question... or maybe you can decide that if there is only 1 value in the next List that value is a question and it should just show it in the main button text value).
And if the next is null of course you can end the conversation.
There are multiple ways to do this.