FadeAssistant.cs

using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System.Collections.Generic;
using Holoville.HOTween;

public class FadeAssistant {

    public static float duration = 0.3f;
    public static Dictionary<int, float> alphaDictionary;

    public static void Init()
    {
        if (alphaDictionary == null) alphaDictionary = new Dictionary<int, float>();
    }

    public static Sequence FadeInCascade(GameObject g, float modifier = 1f)
    {
        return FadeInCascade(g.transform, modifier);
    }

	public static Sequence FadeInCascade(Transform t, float modifier=1f)
    {
         
        var s = new Sequence();
        s.Append(FadeCascade(t, 1, false, modifier));
        return s;
    }

    public static Sequence FadeOutCascade(GameObject g, float modifier = 1f)
    {
        return FadeOutCascade(g.transform, modifier);
    }

    public static Sequence FadeOutCascade(Transform t, float modifier = 1f)
    {
        var s = new Sequence();
        s.Append(FadeCascade(t, 0, true, modifier));
        return s;
    }

    private static Sequence FadeCascade(Transform t, float alpha, bool disableButtons, float modifier = 1f)
    {
        var s = new Sequence();
        s.Insert(0,Fade(t, alpha, disableButtons, modifier));

        // Don't cascade if it's a canvas group plz!
        if (t.GetComponent<CanvasGroup>() != null) return s;

        foreach (Transform child in t)
        {
            s.Insert(0, FadeCascade(child, alpha, disableButtons, modifier));
        }

        return s;
    }

    public static Sequence FadeIn(Object obj, float modifier=1f)
    {
        var s = new Sequence();
        s.Append(Fade(obj, 1, false, modifier));
        return s;
    }

    public static Sequence FadeOut(Object obj, float modifier = 1f)
    {
        var s = new Sequence();
        s.Append(Fade(obj, 0, true, modifier));
        return s;
    }

    private static Sequence Fade(Object obj, float alpha, bool disableButtons, float modifier = 1f)
    {
        Init();

        float alphaMax = 1;
        bool found = alphaDictionary.TryGetValue(obj.GetHashCode(), out alphaMax);

        var s = new Sequence();


        if (obj is CanvasGroup)
        {
            var group = obj as CanvasGroup;

            if (!found) alphaDictionary.Add(obj.GetHashCode(), group.alpha);
            else alpha = Mathf.Clamp(alpha, 0, alphaMax);

            s.Insert(0,
                HOTween.To(group, duration * modifier, "alpha", alpha)
            );

            if (disableButtons)
            {
                group.interactable = false;
                group.blocksRaycasts = false;
            }
            else
            {
                group.interactable = true;
                group.blocksRaycasts = true;
            }

        }
        else if(obj is TMPro.TextMeshProUGUI)
        {
            var text = obj as TMPro.TextMeshProUGUI;

            if (!found) alphaDictionary.Add(obj.GetHashCode(), text.color.a);
            else alpha = Mathf.Clamp(alpha, 0, alphaMax);

            s.Insert(0,
                HOTween.To(text, duration * modifier, "color", text.color.SetA(alpha))
            );
        }
        else if (obj is Text)
        {
            var text = obj as Text;

            if (!found) alphaDictionary.Add(obj.GetHashCode(), text.color.a);
            else alpha = Mathf.Clamp(alpha, 0, alphaMax);

            s.Insert(0,
                HOTween.To(text, duration * modifier, "color", text.color.SetA(alpha))
            );
        }
        else if (obj is Image)
        {
            var img = obj as Image;

            if (!found) alphaDictionary.Add(obj.GetHashCode(), img.color.a);
            else alpha = Mathf.Clamp(alpha, 0, alphaMax);

            s.Insert(0,
                HOTween.To(img, duration * modifier, "color", img.color.SetA(alpha))
            );
        }
        else if (obj is Button)
        {
            var button = obj as Button;

            if(disableButtons)
            {
                button.interactable = false;
                var img = button.GetComponent<Image>();
                if (img != null) img.raycastTarget = false;
            }
            else
            {
                button.interactable = true;
                var img = button.GetComponent<Image>();
                if (img != null) img.raycastTarget = true;
            }
        }
        else if (obj is Toggle)
        {
            var button = obj as Toggle;

            if (disableButtons)
            {
                button.interactable = false;
                var img = button.GetComponent<Image>();
                if (img != null) img.raycastTarget = false;

            }
            else
            {
                button.interactable = true;
                var img = button.GetComponent<Image>();
                if (img != null) img.raycastTarget = true;
            }
        }
        else if (obj is Transform)
        {
            var t = obj as Transform;


            // fade if canvas group
            var group = t.GetComponent<CanvasGroup>();
            if (group != null)
            {
                s.Insert(0,
                    Fade(group, alpha, disableButtons, modifier)
                );
                return s; // we don't want to cascade when we meet a canvas group, since that's what it's fore
            }

            // buttons and toggles
            var button = t.GetComponent<Button>();
            if (button != null)
            {
                s.Insert(0,
                    Fade(button, alpha, disableButtons, modifier)
                );
            }
            var toggle = t.GetComponent<Toggle>();
            if (toggle != null)
            {
                s.Insert(0,
                    Fade(toggle, alpha, disableButtons, modifier)
                );
            }


            // fade if anythng else
            var tmtext = t.GetComponent<TMPro.TextMeshProUGUI>();
            if (tmtext != null)
            {
                s.Insert(0,
                    Fade(tmtext, alpha, disableButtons, modifier)
                );
            }
            var text = t.GetComponent<Text>();
            if (text != null)
            {
                s.Insert(0,
                    Fade(text, alpha, disableButtons, modifier)
                );
            }
            var img = t.GetComponent<Image>();
            if (img != null)
            {
                s.Insert(0,
                    Fade(img, alpha, disableButtons, modifier)
                );
            }
        }
        else if (obj is GameObject)
        {
            var g = obj as GameObject;
            s.Append(Fade(g.transform, alpha, disableButtons, modifier));
        }
        return s;
    }

}