Visual Novel / Storyboard

TL;DR: Dialog nodes are an inspector-edited array of DialogNode structs (speaker, text, default next node, two choice strings + goto indexes). The script reveals text character-by-character, then shows either a continue button or a two-choice panel depending on whether the current node defines choices. Pure local, no networking.

Context: World. Purely scene-based; no storage or networking required.

Scene setup

• A world Canvas with:
  • speakerLabel (TMP) — who’s talking.
  • textLabel (TMP) — dialog text (revealed over time).
  • continuePanel — a button hosting Advance (onClick → OnAdvanceClicked).
  • choicePanel — two buttons with labels choiceALabel, choiceBLabel, wired to OnChoiceAClicked and OnChoiceBClicked.
• A VisualNovel component on the world root. In its nodes[] array, lay out the story:
  • Each entry has speaker, text, and either nextDefault (for linear continuation) or choiceA / choiceAGoto / choiceB / choiceBGoto (for a branch).

Shape

[Serializable]
public struct DialogNode
{
    public string speaker;
    public string text;
    public int    nextDefault;
    public string choiceA;
    public int    choiceAGoto;
    public string choiceB;
    public int    choiceBGoto;
}

Example nodes (you’d fill these out in the Unity inspector):

[0] speaker: "Narrator"  text: "You stand at a crossroads."  nextDefault: 1
[1] speaker: "Guide"     text: "Which way?"
    choiceA: "Left path"  choiceAGoto: 2
    choiceB: "Right path" choiceBGoto: 5
[2] speaker: "Narrator"  text: "You head left."  nextDefault: 3
...

Code highlights

void Update()
{
    if (revealed || nodes == null || nodes.Length == 0) return;
    string full = nodes[currentIndex].text ?? "";
    int chars = Mathf.Clamp(Mathf.FloorToInt((Time.time - revealStartTime) * charsPerSecond), 0, full.Length);
    textLabel.text = full.Substring(0, chars);
    if (chars >= full.Length) EndReveal();
}

OnAdvanceClicked snaps to the full text if mid-reveal, otherwise moves to nextDefault. OnChoiceAClicked / OnChoiceBClicked jump to the goto index.

Source: examples/world/VisualNovel.cs.

Dos

• Pre-load all dialog in the inspector as a single DialogNode[]. No runtime parsing, no file reads per node.
• Use Time.time deltas for the reveal animation — it’s cheap and the drift across a session doesn’t matter for text pacing.
• Store currentIndex as [WasmSerialized] so inspector edits carry through and replaying from test mode resumes.
• Validate nextDefault / choiceAGoto / choiceBGoto against nodes.Length before jumping. Invalid indexes silently do nothing.

Don’ts

• Don’t parse dialog from FileStorage at runtime. Keep it in-inspector. You’d pay a per-node FileStorage.ReadFile and the sandbox’s string marshaling — wasteful for what’s essentially a static asset.
• Don’t allocate new string(...) every frame. Substring allocates — that’s acceptable once per frame during a reveal. Don’t spam it beyond that.
• Don’t use Unity’s IEnumerator coroutines for reveal timing. Use Update + a stored revealStartTime. Coroutines aren’t fully bound and async patterns run single-threaded.
• Don’t branch on Player.GetUsername() — username isn’t persistent identity. If you want a named save, use Player.GetUserId() (+ AccessUserIdentity permission) and write to FileStorage.

Validator

Paste VisualNovel.cs into the validator. Expect:

• err 0, warn 0 under World context.
• info reporting Unity events detected: Start, Update.
• No game events (dialog is fully local).

Extensions

• Audio per line — add an AudioClip field to DialogNode and play in ShowNode.
• Portraits — a Sprite field + a dedicated UnityEngine.UI.Image swap.
• Save progress — combine with the Idle save pattern to remember the last-seen node across sessions.
• Flag-based branching — add a bool[] flags state and conditional goto logic in TakeChoice.
• Rich text — since TMP supports inline tags, embed <color> / <b> in node text to style individual words.

Full source

using System;
using UnityEngine;
using TMPro;
using WasmScripting;

public partial class VisualNovel : WasmBehaviour
{
    [Serializable]
    public struct DialogNode
    {
        public string speaker;
        public string text;
        public int    nextDefault;
        public string choiceA;
        public int    choiceAGoto;
        public string choiceB;
        public int    choiceBGoto;
    }

    public DialogNode[] nodes;
    public TextMeshProUGUI speakerLabel;
    public TextMeshProUGUI textLabel;
    public TextMeshProUGUI choiceALabel;
    public TextMeshProUGUI choiceBLabel;
    public GameObject choicePanel;
    public GameObject continuePanel;

    public float charsPerSecond = 40f;

    [WasmSerialized] private int currentIndex;
    [WasmSerialized] private float revealStartTime;
    [WasmSerialized] private bool revealed;

    void Start()
    {
        currentIndex = Mathf.Max(0, currentIndex);
        ShowNode(currentIndex);
    }

    void Update()
    {
        if (revealed || nodes == null || nodes.Length == 0 || textLabel == null) return;
        string full = nodes[currentIndex].text ?? "";
        float t = Time.time - revealStartTime;
        int chars = Mathf.Clamp(Mathf.FloorToInt(t * charsPerSecond), 0, full.Length);
        textLabel.text = full.Substring(0, chars);
        if (chars >= full.Length) EndReveal();
    }

    public void OnAdvanceClicked()
    {
        if (nodes == null || nodes.Length == 0) return;
        if (!revealed) { textLabel.text = nodes[currentIndex].text; EndReveal(); return; }
        int next = nodes[currentIndex].nextDefault;
        if (next < 0 || next >= nodes.Length) return;
        ShowNode(next);
    }

    public void OnChoiceAClicked() { TakeChoice(nodes[currentIndex].choiceAGoto); }
    public void OnChoiceBClicked() { TakeChoice(nodes[currentIndex].choiceBGoto); }

    private void TakeChoice(int goTo)
    {
        if (nodes == null || goTo < 0 || goTo >= nodes.Length) return;
        ShowNode(goTo);
    }

    private void ShowNode(int idx)
    {
        currentIndex = idx;
        revealed = false;
        revealStartTime = Time.time;

        DialogNode n = nodes[idx];
        if (speakerLabel != null) speakerLabel.text = n.speaker ?? "";
        if (textLabel != null) textLabel.text = "";

        bool hasChoices = !string.IsNullOrEmpty(n.choiceA) || !string.IsNullOrEmpty(n.choiceB);
        if (choicePanel != null) choicePanel.SetActive(false);
        if (continuePanel != null) continuePanel.SetActive(!hasChoices);

        if (choiceALabel != null) choiceALabel.text = n.choiceA ?? "";
        if (choiceBLabel != null) choiceBLabel.text = n.choiceB ?? "";
    }

    private void EndReveal()
    {
        revealed = true;
        DialogNode n = nodes[currentIndex];
        bool hasChoices = !string.IsNullOrEmpty(n.choiceA) || !string.IsNullOrEmpty(n.choiceB);
        if (choicePanel != null) choicePanel.SetActive(hasChoices);
        if (continuePanel != null) continuePanel.SetActive(!hasChoices);
    }
}

Related

• File Storage — for save progress extensions.
• Events — why Unity coroutines are discouraged here.