这里介绍一个通过路径点，动态自定义生成Mesh，来做到画线效果的一种实现方式：

首先通过点来定义线的形状。然后用AnimationCurve来平滑这个曲线，然后根据精确度和一些其他的设置来生成Mesh，最后通过设置材质球来给Mesh挂上皮肤。

代码如下：

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

namespace LDFW.Math
{

    public class LDFWLineRenderer : MonoBehaviour
    {

        // Public variables
        public Transform[] pathPoints;
        public float lineWidth = 1f;
        public int lineSegmentCount = 10;
        public AnimationCurve xAnimationCurve;
        public AnimationCurve yAnimationCurve;
        public AnimationCurve zAnimationCurve;
        public Transform referenceCamera;

        // Private variables
        private MeshFilter meshFilter;
        private MeshRenderer meshRenderer;
        private Mesh mesh;
        private List<Vector3> vertices = new List<Vector3> ();
        private List<Vector2> uvs = new List<Vector2> ();
        private List<int> triangles = new List<int> ();

        void Awake()
        {

            meshFilter = GetComponent<MeshFilter>();
            meshRenderer = GetComponent<MeshRenderer>();

            if (meshFilter == null)
            {
                meshFilter = gameObject.AddComponent<MeshFilter>();
            }
            if (meshRenderer == null)
            {
                meshRenderer = gameObject.AddComponent<MeshRenderer>();
            }

            mesh = new Mesh();
            meshFilter.mesh = mesh;
        }

        // Constant Z
        [ContextMenu("InitWithRespectToXYPlane")]
        public void InitWithRespectToXYPlane()
        {
            transform.position = Vector3.zero;

            if (pathPoints == null)
            {
                Debug.LogError("path is null!");
                return;
            }

            if (pathPoints.Length < 2)
            {
                Debug.LogError("path needs at least two points");
                return;
            }
            
            // Get the camera position;
            Vector3 cameraPosition = Vector3.zero;
            if (referenceCamera == null)
            {
                cameraPosition = Camera.main.transform.position;
            }
            else
            {
                cameraPosition = referenceCamera.position;
            }

            // Calculate total segmented straight line lenth
            float totalLength = 0;
            for (int i = 1; i < pathPoints.Length; i++)
            {
                totalLength += (pathPoints[i].position - pathPoints[i - 1].position).magnitude;
            }
            //Debug.Log ("totalLength = " + totalLength);

            // Construct the X,Y,Z animation curves
            xAnimationCurve = new AnimationCurve();
            yAnimationCurve = new AnimationCurve();
            zAnimationCurve = new AnimationCurve();
            Vector3 currentPosition = Vector3.zero;
            float lineSegmentLength = 0f;
            for (int i = 0; i < pathPoints.Length; i++)
            {
                currentPosition = pathPoints[i].position;
                if (i == 0)
                {
                    xAnimationCurve.AddKey(0, currentPosition.x);
                    yAnimationCurve.AddKey(0, currentPosition.y);
                    zAnimationCurve.AddKey(0, currentPosition.z);
                }
                else
                {
                    lineSegmentLength += (currentPosition - pathPoints[i - 1].position).magnitude;
                    xAnimationCurve.AddKey(lineSegmentLength / totalLength, currentPosition.x);
                    yAnimationCurve.AddKey(lineSegmentLength / totalLength, currentPosition.y);
                    zAnimationCurve.AddKey(lineSegmentLength / totalLength, currentPosition.z);
                }
            }

            // Construct vertices and UVs
            vertices = new List<Vector3>();
            uvs = new List<Vector2>();
            triangles = new List<int>();

            float startSegmentTime;
            float endSegmentTime;
            float centerSegmentTime;
            Vector3 perpendicualrVectorLHS;
            Vector3 perpendicularVectorRHS;
            Vector3 perpendicularRelativePositionLHS;
            Vector3 perpendicularRelativePositionRHS;
            Vector3 currentLineSegmentStartPosition;
            Vector3 currentLineSegmentEndPosition;
            Vector3 currentLineSegmentCenterPosition;

            Vector3 cameraOffsetVector = Vector3.zero;
            if ((cameraPosition - transform.position).z > 0)
            {
                cameraOffsetVector.z = 1f;
            }
            else
            {
                cameraOffsetVector.z = -1f;
            }

            for (int i = 0; i <= lineSegmentCount; i++)
            {
                if (i == 0)
                {
                    startSegmentTime = (float)i / lineSegmentCount;
                    endSegmentTime = (float)(i + 1) / lineSegmentCount;

                }
                else if (i == lineSegmentCount)
                {
                    startSegmentTime = (float)(i - 1) / lineSegmentCount;
                    endSegmentTime = (float)i / lineSegmentCount;

                }
                else
                {
                    startSegmentTime = (float)(i - 1) / lineSegmentCount;
                    endSegmentTime = (float)(i + 1) / lineSegmentCount;

                }

                centerSegmentTime = (float)i / lineSegmentCount;


                currentLineSegmentStartPosition = new Vector3(xAnimationCurve.Evaluate(startSegmentTime), yAnimationCurve.Evaluate(startSegmentTime), zAnimationCurve.Evaluate(startSegmentTime));
                currentLineSegmentEndPosition = new Vector3(xAnimationCurve.Evaluate(endSegmentTime), yAnimationCurve.Evaluate(endSegmentTime), zAnimationCurve.Evaluate(endSegmentTime));
                currentLineSegmentCenterPosition = new Vector3(xAnimationCurve.Evaluate(centerSegmentTime), yAnimationCurve.Evaluate(centerSegmentTime), zAnimationCurve.Evaluate(centerSegmentTime));

                perpendicualrVectorLHS = Vector3.Cross(currentLineSegmentEndPosition - currentLineSegmentStartPosition, cameraOffsetVector);
                perpendicularVectorRHS = Vector3.Cross(cameraOffsetVector, currentLineSegmentEndPosition - currentLineSegmentStartPosition);

                perpendicularRelativePositionLHS = currentLineSegmentCenterPosition + perpendicualrVectorLHS.normalized * lineWidth / 2f;
                perpendicularRelativePositionRHS = currentLineSegmentCenterPosition + perpendicularVectorRHS.normalized * lineWidth / 2f;


                vertices.Add(perpendicularRelativePositionLHS);
                vertices.Add(perpendicularRelativePositionRHS);

                // calculate UV
                if (i == 0)
                {
                    uvs.Add(new Vector2(0, 0));
                    uvs.Add(new Vector2(0, 1));
                }
                else if (i == lineSegmentCount)
                {
                    uvs.Add(new Vector2(1, 0));
                    uvs.Add(new Vector2(1, 1));
                }
                else
                {
                    uvs.Add(new Vector2((float)i / lineSegmentCount, 0));
                    uvs.Add(new Vector2((float)i / lineSegmentCount, 1));
                }

                // calculate triangle
                if (i < lineSegmentCount)
                {
                    triangles.Add(i * 2);
                    triangles.Add(i * 2 + 2);
                    triangles.Add(i * 2 + 1);
                    triangles.Add(i * 2 + 1);
                    triangles.Add(i * 2 + 2);
                    triangles.Add(i * 2 + 3);
                }
            }

            mesh.vertices = vertices.ToArray();
            mesh.uv = uvs.ToArray();
        }

        public void DisplayLine(float percentage)
        {
            int arrayLength = (int)(percentage * triangles.Count);
            while (arrayLength % 3 != 0)
            {
                arrayLength++;
            }

            arrayLength = Mathf.Min(arrayLength, triangles.Count);
            List<int> newTriangles = new List<int>();
            for (int i = 0; i < arrayLength; i++)
            {
                newTriangles.Add(triangles[i]);
            }
            mesh.triangles = newTriangles.ToArray();
        }

        [ContextMenu("PlayTest")]
        public void Test()
        {
            StartCoroutine(TestCoroutine());
        }
        private IEnumerator TestCoroutine()
        {
            for (int i = 0; i < 200; i++)
            {
                DisplayLine(i * 0.01f);
                yield return null;
            }
        }
    }

}