ui/Runtime/TransitionController.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using Sirenix.OdinInspector;
using KairoEngine.Core;
using UniRx;

namespace KairoEngine.UI
{
    // Todo: Send events when fade starts and ends

    /// <summary>
    /// Controls a fade to black and fade from black curtain to use as transitions in the game.
    /// </summary>
    [HideMonoScript]
    public class TransitionController : MonoBehaviour
    {
        public static TransitionController instance;

        [InfoBox("The TransitionController is a full screen dissolve fader. It can transition the game to a black screen and back again.")]

        [Tooltip("An image component with no sprite and painted black. The object needs to cover the hole screen.")]
        public Image image;
        public CanvasGroup canvasGroup;
        private float timer;
        private float counter;
        private bool fadeIn = false;
        private bool fadeOut = false;
        private float alpha;

        private LTDescr _tweenObject = new LTDescr();

        void Awake()
        {
            if(instance == null) instance = this;
            else Destroy(this);
        }

        void OnEnable()
        {
            TransitionEvents.OnFadeIn += FadeIn;
            TransitionEvents.OnFadeOut += FadeOut;
        }

        void OnDisable()
        {
            TransitionEvents.OnFadeIn -= FadeIn;
            TransitionEvents.OnFadeOut -= FadeOut;
        }

        void Start()
        {
            image.gameObject.SetActive(false);
        }

        void Update()
        {
            // counter += Time.deltaTime;
            // if(fadeIn) alpha = Mathf.Lerp(0, 255, counter / timer);
            // if(fadeOut) alpha = Mathf.Lerp(255, 0, counter / timer);
            // image.color = new Color32(0, 0, 0, (byte)Mathf.FloorToInt(alpha));
            // if(counter > timer)
            // {
            //     counter = 0;
            //     if(fadeOut) image.gameObject.SetActive(false);
            //     fadeIn= false;
            //     fadeOut = false;
            //     TransitionEvents.TransitionFinish();
            // }
        }

        [Button("Fade In"), ButtonGroup, PropertyTooltip("Transition the game to a black screen. Only works during gameplay.")]
        public void StartFadeIn(float time = 0.7f)
        {
            fadeIn = true;
            fadeOut = false;
            timer = time;
            counter = 0;
            image.gameObject.SetActive(true);
            if(_tweenObject == null) _tweenObject = new LTDescr();
            canvasGroup.alpha = 0;
            _tweenObject = LeanTween.alphaCanvas(canvasGroup, 1, time).setIgnoreTimeScale( true );
            //Debug.Log("Fading In");
        }

        [Button("Fade Out"), ButtonGroup, PropertyTooltip("Transition from a black screen back to the game. Only works during gameplay.")]
        public void StartFadeOut(float time = 0.7f)
        {
            fadeOut = true;
            fadeIn= false;
            timer = time;
            counter = 0;
            image.gameObject.SetActive(true);
            //Debug.Log("Fading Out");
            if(_tweenObject == null) _tweenObject = new LTDescr();
            canvasGroup.alpha = 1;
            _tweenObject = LeanTween.alphaCanvas(canvasGroup, 0, time).setIgnoreTimeScale( true );
            Timer.Execute(time * 1000, () => {
                image.gameObject.SetActive(false);
            });
        }

        public static void FadeIn(float time = 0.7f)
        {
            if(instance != null) instance.StartFadeIn(time);
        }

        public static void FadeOut(float time = 0.7f)
        {
            if(instance != null) instance.StartFadeOut(time);
        }
    }
}