Dialogue System

Create a Dialogue Folder in your content drawer and  open up the folder

Create a new Character Blueprint

Name it BP_NPC

Open it up

Apply the mesh settings

Add your NPC into your game

In your Dialogue Folder

Create a new BluePrint but this time you are going to create a Blueprint Interface

Name it BPI_Dialogue

Add a function

Name the fuction Speak

Compile and save

Open up the third person blueprint

Right Click 

Seach E Key

Pull out For Each Loop

From the Array in For Each Loop, pull out Get overlapping actors NOT Get Overlapping Actors (capsule component)

We are going to add a Collision Sphere to the NPC we created so we have something to set off the conversation

Name it trigger

Change the radius to 200

In your collision in the details panel, select OverlapAllDynamic in in the Collision Preset

Go back to your event graph and select the NPC you created as the class filter

Pull out the Array Element from For Each Loop and add Does Implement Interface

The interface is the BPI_Dialogue that we created

Pull out a branch from the return value of Does Implement Interface

Connect Loop Body to the Branch

So what is happening here is that if you can interact with the BPI_Dialogue, then it is true

Go back to your NPC Blueprint

Click on Class Settings

Find Interfaces and add Implrmrnted Interfaces

Select your BPI_Dialogue

Open the Third Person Blueprint Event Graph

From the Array Element Pull out and add Speak

Connect your True Branch into the Speak Node

Now your Third Person Player should interact

Open up the NPC Blueprint

Right-click on your Speak Interface and select Implement event

Pull out Print String

Compile, Save, Test

When you run into the collision and press E, you should get the hello on your screen

In your NPC Blueprint, add a new variable

Name it Dialogue and make it a string variable

In the Details panel, chance it to an Array (so we can have a few messages)

Drag in youe Dialogue Variable and select GET

Create a new Integer Variable and name it talkIndex

With your talkIndex Selected, go to your details panel and change the Integer Variable Type to Single

Delete your Print String

Drom your Dialogue Variable, add GET (a copy)

Bring in your talkIndex and select GET then connect to your Get Copy

Pull in another Talk Index (Get) then pull out Incredent by adding ++

Connect Event Speak

Pull out a new print screen and connect the ++

Compile and save so we can start with the integer

With the talkIndex Integer Selected, set the default value to -1

We are setting it to -1 because the array always starts a Zero (remember the different hit animations)

So it starts at -1 and when the 1 get added from the ++, it will fire off at 0

With your Dialogue Variable Selected, add three array elements and add some text

So we have created a bug because once we press E, it adds to the talk indext and we only have three arrays so we need to add some code to fix this.

Break the link between the ++ and Print String

Pull in a talkIndex (GET) 

Pull out a less equal node

Pull in a Dialogue Variable (GET)

Pull out Length (get the numbers in the array)

Connect the length to the <=

Make this the condidtion of your branch

In your UI Folder or your NPC Folder, create a new UI Widget Blueprint

Select User Widget

Name it UI_Dialogue

Open your widget

Add canvas panel

Drop in some text

Zize the text box

add your anchors

Change the text

Set it how you wish

In the details panel, make sure your Text is a variable

Go back to your NPC Blueprint

From Print String, pull out Create Widget and select the UI_Dialogue for the class

From the Owning Player, pull out Get Player Controller Node

In the return value of Create Widget, promote to variable (right click on the node)

Name the variable UI

From Set, pull out Add to Viewport

Compile, Save and Test

You can see that it only works with teh first message.

Go back to the NPC BP

Pull in your new UI Variable at GET UI

Right click on the UI Variable

Select Convert to Validated Get

Connect the Print Strint to the Input of Get Variable

Connect the Is Not Valid to the input of the Create UI Dialogue Widget

Now we want to get the different messages

Disconnect the UI from Add to Viewport

From UI, pull out Get TextBlock or whatever you named it

Pull out Set Text

Connect to Output of Add to Viewport

SUPER IMPORTANT

You must also connect the IS Valid output from GET to the input of SelfText

We don't want the text to run through the print string anymore, we want it showing up in the UI so disconect the output of GET and connect it to the SetText Input

Remove orint screen node and connect the true output from the brancg ti the GET input

Bring in a UI Variable (GET) and place it near the False Output of your branch node. 

From the UI Variable, pull out Remove From Parent