控制一個(gè)GameObject隨著某一個(gè)路徑進(jìn)行移動(dòng)柏副，這是一個(gè)經(jīng)常需要用到的功能。一個(gè)比較常用的實(shí)現(xiàn)方式是利用DoTween這樣的插件來(lái)做到，其他的方式也都大同小異棵介，原理都是通過(guò)設(shè)置一條路徑摩骨，然后每一幀都利用這個(gè)路徑來(lái)計(jì)算當(dāng)前需要出現(xiàn)的位置擎椰，然后把目標(biāo)GameObject放到那個(gè)位置上秉沼。

那這里我就對(duì)這種方式進(jìn)行一個(gè)封裝州刽，寫(xiě)一個(gè)類(lèi)來(lái)專(zhuān)門(mén)做這件事呕寝，這樣以后每次需要用這個(gè)功能的時(shí)候就只要一行代碼就可以實(shí)現(xiàn)勋眯。原理很簡(jiǎn)單，代碼也不復(fù)雜下梢。

using UnityEngine;
using System.Collections.Generic;


namespace LDFW.Math
{

    [System.Serializable]
    public class LDFWPath
    {

        public AnimationCurve xValueCurve;
        public AnimationCurve yValueCurve;
        public AnimationCurve zValueCurve;

        public float totalDistance;
        public bool useSmoothCurve = true;

        public LDFWPath()
        {
            Init();
        }

        public void Init()
        {
            xValueCurve = new AnimationCurve();
            yValueCurve = new AnimationCurve();
            zValueCurve = new AnimationCurve();
            totalDistance = 0;
        }


        public void ConstructPath(Vector3[] pathPoints)
        {
            if (pathPoints == null || pathPoints.Length < 2)
            {
                return;
            }
            Init();

            float[] pathDistance = new float[pathPoints.Length];
            totalDistance = 0;
            pathDistance[0] = 0;
            for (int i = 1; i < pathPoints.Length; i++)
            {
                totalDistance += Vector3.Distance(pathPoints[i], pathPoints[i - 1]);
                pathDistance[i] = totalDistance;
            }


            float currentDistance = 0;
            float currentPercentage = 0;
            Vector3 inTangent = Vector3.zero;
            Vector3 outTangent = Vector3.zero;

            // Add first point
            if (useSmoothCurve)
                AddSmoothKeyFrame(pathPoints[0], 0);
            else
            {
                float deltaPercentage = pathDistance[1] / totalDistance;
                if (deltaPercentage == 0)
                    AddSmoothKeyFrame(pathPoints[0], 0);
                else
                    AddTangentKeyFrame(pathPoints[0], 0, Vector3.zero, (pathPoints[1] - pathPoints[0]) / (pathDistance[1] / totalDistance));
            }

            // Add rest points
            for (int i = 1; i < pathPoints.Length; i++)
            {
                currentDistance += Vector3.Distance(pathPoints[i], pathPoints[i - 1]);
                currentPercentage = currentDistance / totalDistance;

                if (useSmoothCurve)
                {
                    AddSmoothKeyFrame(pathPoints[i], currentPercentage);
                }
                else
                {
                    if (i == pathPoints.Length - 1)
                    {
                        inTangent = (pathPoints[i] - pathPoints[i - 1]) / ((pathDistance[i] - pathDistance[i - 1]) / totalDistance);
                        outTangent = Vector3.zero;
                    }
                    else
                    {
                        inTangent = (pathPoints[i] - pathPoints[i - 1]) / ((pathDistance[i] - pathDistance[i - 1]) / totalDistance);
                        outTangent = (pathPoints[i + 1] - pathPoints[i]) / ((pathDistance[i + 1] - pathDistance[i]) / totalDistance);
                    }
                    AddTangentKeyFrame(pathPoints[i], currentPercentage, inTangent, outTangent);
                }
            }
        }

        public void ConstructPath(List<Vector3> pointList)
        {
            for (int i = 1; i < pointList.Count; i++)
            {
                if (pointList[i] == pointList[i - 1])
                {
                    pointList.RemoveAt(i);
                    i--;
                }
            }

            ConstructPath(pointList.ToArray());
        }


        public void AddSmoothKeyFrame(Vector3 position, float percentage)
        {
            percentage = Mathf.Clamp(percentage, 0, 1);

            int x = xValueCurve.AddKey(percentage, position.x);
            int y = yValueCurve.AddKey(percentage, position.y);
            int z = zValueCurve.AddKey(percentage, position.z);
        }

        public void AddTangentKeyFrame(Vector3 position, float percentage, Vector3 inTangent, Vector3 outTangent)
        {
            percentage = Mathf.Clamp(percentage, 0, 1);

            int x = xValueCurve.AddKey(new Keyframe(percentage, position.x, inTangent.x, outTangent.x));
            int y = yValueCurve.AddKey(new Keyframe(percentage, position.y, inTangent.y, outTangent.y));
            int z = zValueCurve.AddKey(new Keyframe(percentage, position.z, inTangent.z, outTangent.z));
        }

        public Vector3 Evaluate(float percentage)
        {
            return new Vector3(xValueCurve.Evaluate(percentage), yValueCurve.Evaluate(percentage), zValueCurve.Evaluate(percentage));
        }

    }

}