How can I make a menu item that splits animations based on a text file?

Question

I want to split all the animations inside a FBX by using a .txt file which contains start times and names for the animations in this FBX.

I found a script that does exactely that here.

However, this script uses the PostProcessor, and this means that I have little possiblity over when it's called.

Instead, I would like this to happen when I click a certain menu item. To do that, I have added a new menu item to the Unity toolbar like this:

public class NewBehaviourScript : MonoBehaviour
{
    [MenuItem("Tools/FBX/Split")]
    private static void SplitFBX()
    {

However, as soon as I add the line

 ModelImporter modelImporter = assetImporter as ModelImporter;

from the other script, the Editor says that

 "The name assetImporter isn't available in the current context".

Does anybody see why this compiler error occurs?

I have also tried

"public class NewBehaviourScript : AssetPostprocessor" 

but it gave me the error "An object reference is required for the non-static field, method or property "AssetPostprocessor.assetImporter".

This is the entire script:

using UnityEngine;
using UnityEditor;
using UnityEditor.VersionControl;
using System.IO;
using System.Collections;
using System.Text.RegularExpressions;
using System;

public class NewBehaviourScript : MonoBehaviour
{
    [MenuItem("Tools/FBX/Split")]
    private static void SplitFBX()
    {
        var selected = Selection.activeObject;
        string assetPath = AssetDatabase.GetAssetPath(selected);

        EditorUtility.DisplayDialog("", assetPath, "Ok");

        try
        {
            // Remove 6 chars because dataPath and assetPath both contain "assets" directory
            string fileAnim = Application.dataPath + Path.ChangeExtension(assetPath, ".txt").Substring(6);

            if (!File.Exists(fileAnim))
            {
                return;
            }

            StreamReader file = new StreamReader(fileAnim);

            string sAnimList = file.ReadToEnd();
            file.Close();

            if (EditorUtility.DisplayDialog("FBX Animation Import from file", fileAnim, "Import", "Cancel"))
            {
                System.Collections.ArrayList List = new ArrayList();
                pParseAnimFile(sAnimList, ref List);

                ModelImporter modelImporter = assetImporter as ModelImporter;
                modelImporter.clipAnimations = (ModelImporterClipAnimation[])List.ToArray(typeof(ModelImporterClipAnimation));

                EditorUtility.DisplayDialog("Imported animations", "Number of imported clips: " + modelImporter.clipAnimations.GetLength(0).ToString(), "OK");
            }
        }
        catch (Exception e)
        {
            // EditorUtility.DisplayDialog("Imported animations error: ", e.Message, "OK");
        }
    }

    void pParseAnimFile(string sAnimList, ref System.Collections.ArrayList List)
    {
        Regex regexString = new Regex(" *(?<firstFrame>[0-9]+) *- *(?<lastFrame>[0-9]+) *(?<loop>(loop|noloop| )) *(?<name>[^\r^\n]*[^\r^\n^ ])",
                                      RegexOptions.Compiled | RegexOptions.ExplicitCapture);

        Match match = regexString.Match(sAnimList, 0);
        while (match.Success)
        {
            ModelImporterClipAnimation clip = new ModelImporterClipAnimation();

            if (match.Groups["firstFrame"].Success)
            {
                clip.firstFrame = System.Convert.ToInt32(match.Groups["firstFrame"].Value, 10);
            }
            if (match.Groups["lastFrame"].Success)
            {
                clip.lastFrame = System.Convert.ToInt32(match.Groups["lastFrame"].Value, 10);
            }
            if (match.Groups["loop"].Success)
            {
                clip.loop = match.Groups["loop"].Value == "loop";
            }
            if (match.Groups["name"].Success)
            {
                clip.name = match.Groups["name"].Value;
            }

            List.Add(clip);

            match = regexString.Match(sAnimList, match.Index + match.Length);
        }
    }
}

Answer 1

I got the solution:

I have re-written the code because some variable names were not easy to understand.

And as DMGregory pointed out, now that the ModelImporter is called from a different location (and not from the PostProcessor), it doesn't know which FBX we're dealing with, so we need to get the ModelImporter from the Asset.

Here is what it looks like:

using UnityEngine;
using UnityEditor;
using UnityEditor.VersionControl;
using System.IO;
using System.Collections;
using System.Text.RegularExpressions;
using System;
using System.Collections.Generic;

public class NewBehaviourScript : AssetPostprocessor
{
    [MenuItem("Tools/FBX/Split")]
    private static void SplitFBX()
    {
        var nSelectedObject = Selection.activeObject;
        string sAssetPath = AssetDatabase.GetAssetPath(nSelectedObject);

        EditorUtility.DisplayDialog("", sAssetPath, "Ok");

        try
        {
            string sPathTextfile = Application.dataPath + Path.ChangeExtension(sAssetPath, ".txt").Substring(6);// Remove 6 chars because dataPath and assetPath both contain "assets" directory

            if (!File.Exists(sPathTextfile))
            {
                return;
            }

            var sLines = new List<string>();

            var lines = File.ReadAllLines(sPathTextfile);
            foreach (string line in lines)
            {
                sLines.Add(line);
            }

            System.Collections.ArrayList nList = new ArrayList();
            pParseAnimFile(sLines, ref nList);

            ModelImporter nModelImporter = (ModelImporter)AssetImporter.GetAtPath(sAssetPath);

            nModelImporter.clipAnimations = (ModelImporterClipAnimation[])nList.ToArray(typeof(ModelImporterClipAnimation));

            EditorUtility.DisplayDialog("Imported animations", "Number of imported clips: " + nModelImporter.clipAnimations.GetLength(0).ToString(), "OK");
        }
        catch (Exception e)
        {
            // EditorUtility.DisplayDialog("Imported animations error: ", e.Message, "OK");
        }
    }


    private static void pParseAnimFile(List<string> sAnimList, ref System.Collections.ArrayList uList)
    {
        // My text file has lines that look like this: animation name, 0, 76
        for (int i = 0; i < sAnimList.Count; i++)
        {
            string s = sAnimList[i];
            List<string> sItems = SplitReturnEmptyListIfInputIsEmptyEx(s, ",");

            string sName = sItems[0].Trim();
            string sFrom = sItems[1].Trim();
            string sTo = sItems[2].Trim();

            ModelImporterClipAnimation nClip = new ModelImporterClipAnimation();
            nClip.firstFrame = float.Parse(sFrom);
            nClip.lastFrame = float.Parse(sTo);
            nClip.loop = false;
            nClip.name = sName;
            uList.Add(nClip);
        }
    }
    public static List<string> SplitReturnEmptyListIfInputIsEmptyEx(string u, string uSplitBy)
    {
        var n = new List<string>();
        if (string.IsNullOrEmpty(u))
        {
        }
        // do nothing, else we get a "" string as the only item in our list
        else
        {
            var sDelimitersAsStringArray = new string[] { uSplitBy };
            var sLines = u.Split(sDelimitersAsStringArray, StringSplitOptions.None);
            foreach (string sLine in sLines)
                n.Add(sLine);
        }

        return n;
    }
}