unity LineRenderer之美

这个例子实现鼠标在屏幕上画线，通过LineRenderer来实现，这个效果也可以通过GL来实现，这个后面在写。

首先来看看效果图：

下面是实现代码：

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

public class Paint : MonoBehaviour
{
    //画笔颜色
    private Color paintColor = Color.red;
    //画笔材质（材质为Sprite/Default这个shader）
    public Material materialLine;
    //保存LineRenderer
    private LineRenderer currentLine;
    //点集合
    private List pointList = new List();
    //鼠标是否按下
    private bool isMouseDown;
 
    private void Update()
    {
         //开始画
        if(Input.GetMouseButtonDown(0))
        {
            GameObject go = new GameObject();
            go.transform.SetParent(this.transform);
            currentLine = go.AddComponent();
            //下面是设置LineRenderer组件材质、颜色、宽度等。
            currentLine.material = materialLine;
            currentLine.startColor = paintColor;
            currentLine.endColor = paintColor;
            currentLine.startWidth = 0.1f;
            currentLine.endWidth = 0.1f;
            currentLine.numCornerVertices = 5;
            currentLine.numCapVertices = 5;
            //添加点
            AddPosition();
            isMouseDown = true;
        }
        //画的过程
        if(isMouseDown)
        {
            AddPosition();
        }
         //画完
        if(Input.GetMouseButtonUp(0))
        {
            currentLine = null;
            pointList.Clear();
            isMouseDown = false;
        }
    }
     //得到点
    Vector3 GetMousePoint()
    {
        Ray ray= Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        if(Physics.Raycast(ray,out hit))
        {
            //返回射线和物体碰撞的点
            return hit.point;
        }
        return Vector3.zero;
    }
    //添加点
    void AddPosition()
    {
        Vector3 position = GetMousePoint();
        position.z -= 0.01f;
        pointList.Add(position);
        currentLine.positionCount = pointList.Count;
        currentLine.SetPositions(pointList.ToArray());
    }

    //下面3个函数主要是设置画笔颜色，这个通过Toogle实现
    public void RedChange(bool isOn)
    {
        if (isOn)
        {
            paintColor = Color.red;
        }
    }
    public void GreenChange(bool isOn)
    {
        if (isOn)
        {
            paintColor = Color.green;
        }
    }
    public void BlueChange(bool isOn)
    {
        if (isOn)
        {
            paintColor = Color.blue;
        }
    }
}