CustomAnimatorWindow.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

#if UNITY_EDITOR
using UnityEditor;
using UnityEditor.Animations;
#endif

public class CustomAnimatorWindow : EditorWindow
{

    string savePath = "Assets/Animations/";
    RuntimeAnimatorController runtimeAnimCtrl = null;

    //WIndow設定
    [MenuItem("Window/CustomAnimatorWindow")]
    static void Open()
    {
        EditorWindow.GetWindow<CustomAnimatorWindow>("CustomAnimator");
    }

    void OnGUI()
    {
        printCustomLabel("Stateと同じ名前のAnimationClipを生成", Color.white, Color.black, 18);

        savePath = EditorGUILayout.TextField("保存するディレクトリ", savePath);
        runtimeAnimCtrl = (RuntimeAnimatorController)EditorGUILayout.ObjectField("Stateを取得する対象のAnimationController", runtimeAnimCtrl, typeof(RuntimeAnimatorController), false);

        if (GUILayout.Button("Clip生成"))
        {
            AnimatorController animCtrl = runtimeAnimCtrl as AnimatorController;
            AnimatorControllerLayer layer = animCtrl.layers[0]; //todo 複数レイヤー
            AnimatorStateMachine stateMachine = layer.stateMachine;

            //Stateを取得し、State名がついたClipファイルを生成+Stateにセットする
            foreach (var state in stateMachine.states)
            {
                AnimatorState animState = state.state;
                AnimationClip animclip = new AnimationClip();
                state.state.motion = (Motion)animclip; //空のClipをセット
                
                AssetDatabase.CreateAsset(animclip, AssetDatabase.GenerateUniqueAssetPath(savePath + animState.name + ".anim"));
            }
            AssetDatabase.SaveAssets();
            AssetDatabase.Refresh();
        }
    }

    //Label装飾用のラッパー
    void printCustomLabel(string text, Color textColor, Color backColor, int fontSize, FontStyle fontStyle = FontStyle.Bold)
    {
        Color beforeBackColor = GUI.backgroundColor;

        GUIStyle guiStyle = new GUIStyle();
        GUIStyleState styleState = new GUIStyleState();

        styleState.textColor = textColor;
        styleState.background = Texture2D.whiteTexture;
        GUI.backgroundColor = backColor;
        guiStyle.normal = styleState;
        guiStyle.fontSize = fontSize;

        GUILayout.Label(text, guiStyle); //labelFieldだとうまくいかない？

        GUI.backgroundColor = beforeBackColor;
    }
}