Sprite Sheet Generator for Unity

using System;
using UnityEditor;
using UnityEditor.Animations;
using UnityEngine;

public static class AutoSpriteClipBuilder
{
    [MenuItem("AutoSprite/Create Idle Clip")]
    public static void CreateIdleClip()
    {
        var path = "Assets/Sprites/hero_idle.png";
        var frames = AssetDatabase.LoadAllAssetRepresentationsAtPath(path);
        // Sort by trailing frame number so hero_idle_2 comes before hero_idle_10.
        Array.Sort(frames, (a, b) => FrameIndex(a.name).CompareTo(FrameIndex(b.name)));

        var clip = new AnimationClip { frameRate = 12 };
        var clipSettings = AnimationUtility.GetAnimationClipSettings(clip);
        clipSettings.loopTime = true;
        AnimationUtility.SetAnimationClipSettings(clip, clipSettings);
        var binding = new EditorCurveBinding
        {
            type = typeof(SpriteRenderer),
            path = "",
            propertyName = "m_Sprite"
        };

        var keys = new ObjectReferenceKeyframe[frames.Length];
        for (var i = 0; i < frames.Length; i++)
        {
            keys[i] = new ObjectReferenceKeyframe
            {
                time = i / clip.frameRate,
                value = frames[i]
            };
        }

        AnimationUtility.SetObjectReferenceCurve(clip, binding, keys);
        if (!AssetDatabase.IsValidFolder("Assets/Animations"))
            AssetDatabase.CreateFolder("Assets", "Animations");
        AssetDatabase.CreateAsset(clip, "Assets/Animations/hero_idle.anim");
        AnimatorController.CreateAnimatorControllerAtPathWithClip(
            "Assets/Animations/Hero.controller",
            clip
        );
    }

    private static int FrameIndex(string name)
    {
        var index = name.LastIndexOf('_');
        return int.TryParse(name.Substring(index + 1), out var n) ? n : 0;
    }
}