ichni_Official/Assets/Scripts/Game/Animations/Transform/LookAt.cs

using System;
using System.Collections;
using System.Collections.Generic;
using Ichni.RhythmGame.Beatmap;
using UnityEngine;

namespace Ichni.RhythmGame
{
    /// <summary>
    /// 将物体的z轴指向目标物体，注意，LookAt的启用期间，物体的旋转将被锁定
    /// </summary>
    public partial class LookAt : AnimationBase
    {
        public GameElement targetGameElement;
        public TransformSubmodule targetTransformSubmodule;
        public GameElement lookAtObject;
        public FlexibleBool enabling;

        public static LookAt GenerateElement(string elementName, Guid id,
            List<string> tags, bool isFirstGenerated, GameElement animatedObject,
            GameElement lookAtTarget, FlexibleBool enabling)
        {
            LookAt look = Instantiate(GameManager.instance.basePrefabs.emptyObject).AddComponent<LookAt>();

            look.Initialize(elementName, id, tags, isFirstGenerated, animatedObject);

            look.animatedObject = animatedObject;
            look.lookAtObject = lookAtTarget;
            look.enabling = enabling;
            look.animationReturnType = FlexibleReturnType.Before;

            look.targetGameElement = lookAtTarget;
            look.targetTransformSubmodule = (animatedObject as IHaveTransformSubmodule).transformSubmodule;
            

            //look.timeDurationSubmodule.SetDuration(-999f, 999f); //TODO: 换为(-delay, songLength)

            return look;
        }

        public override void SetDefaultSubmodules()
        {
            timeDurationSubmodule = new TimeDurationSubmodule(this);
        }

        protected override void UpdateAnimation(float songTime)
        {
            enabling.UpdateFlexibleBool(songTime);
            
            if (enabling.value)
            {
                animationReturnType = FlexibleReturnType.MiddleExecuting;
                Vector3 lookingDirection = (lookAtObject.transform.position - animatedObject.transform.position).normalized;

                Vector3 eulerAnglesOffset = Quaternion.LookRotation(lookingDirection).eulerAngles;

                targetTransformSubmodule.eulerAnglesOffsetLock = true;
                targetTransformSubmodule.currentEulerAngles = eulerAnglesOffset;
            }
            else
            {
                animationReturnType = FlexibleReturnType.MiddleInterval;
                targetTransformSubmodule.eulerAnglesOffsetLock = false;
            }
        }

        public override void SaveBM()
        {
            matchedBM = new LookAt_BM(elementName, elementGuid, tags, parentElement.matchedBM as GameElement_BM,
                enabling.ConvertToBM(), lookAtObject.elementGuid);
        }
        
        public override void ApplyTimeOffset(float offset)
        {
            base.ApplyTimeOffset(offset);
            enabling.animations.ForEach(anim => anim.ApplyTimeOffset(offset));
        }
    }
    
    namespace Beatmap
    {
        public class LookAt_BM : GameElement_BM
        {
            public FlexibleBool_BM enabling;
            public Guid lookAtObjectGuid;

            public LookAt_BM()
            {
            }

            public LookAt_BM(string elementName, Guid elementGuid, List<string> tags,
                GameElement_BM attachedElement, FlexibleBool_BM enabling, Guid lookAtObjectGuid)
                : base(elementName, elementGuid, tags, attachedElement)
            {
                this.enabling = enabling;
                this.lookAtObjectGuid = lookAtObjectGuid;
            }
            
            public override void ExecuteBM()
            {
                matchedElement = LookAt.GenerateElement(elementName, elementGuid, tags, false,
                    GetElement(attachedElementGuid), GetElement(lookAtObjectGuid), enabling.ConvertToGameType());
            }
            
            public override GameElement DuplicateBM(GameElement parent)
            {
                return LookAt.GenerateElement(elementName, Guid.NewGuid(), tags, false, parent, 
                    GetElement(lookAtObjectGuid), enabling.ConvertToGameType());
            }
        }
    }
}