[游戏开发]Unity 多人签名

unity触摸屏多人写字

前言

在多媒体行业的项目中，有一种互动方式是在触摸屏上手写文字（应用于签名、互动写字、涂鸦等），之前尝试性的写了一个多人书写的互动脚本，因为制作过程都是比较基础的，只要对unity引擎有一定的使用经验都能复制出来，这里就不多加赘述了，现在将主要步骤、主要脚本分享给大家。

正文

（1）新建工程，在layer选项新建一个line层，再创建一个相机目标层级line，在LineCam相机下创建子物体Empty，具体如下图：

（2）在Empty下新建物体GameObject，给物体添加组件Line Render，并添加Shader脚本Painting，如下图所示：

Painting.shader的脚本如下：

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
 
Shader "Painting"  
{  
    Properties  
    {  
        _MainTex ("MainTex (RGB) Trans (A)", 2D) = "white" {}  
        _Color ("Color", Color) = (1,1,1,1)  
    }  
  
    SubShader  
    {  
        Tags  
        {   
            "Queue"="Transparent"   
            "IgnoreProjector"="True"   
            "RenderType"="Transparent"   
            "PreviewType"="Plane"  
            "CanUseSpriteAtlas"="True"  
        }  
  
        Cull Off  
        Lighting Off  
        ZWrite Off  
        Fog { Mode Off }  
        Blend One OneMinusSrcAlpha  
  
        Pass  
        {  
            CGPROGRAM  
            #pragma vertex vert  
            #pragma fragment frag  
            #include "UnityCG.cginc"  
  
            struct v2f  
            {  
                float4 vertex : SV_POSITION;  
                half2 texcoord : TEXCOORD0;  
            };  
  
            fixed4 _Color;  
  
            v2f vert(appdata_base IN)  
            {  
                v2f OUT;  
                OUT.vertex = UnityObjectToClipPos(IN.vertex);  
                OUT.texcoord = IN.texcoord;  
                return OUT;  
            }  
  
            sampler2D _MainTex;  
  
            fixed4 frag(v2f IN) : SV_Target{ 
                float4 texColor = tex2D(_MainTex, IN.texcoord); 
                float value = step(_Color.r + _Color.g + _Color.b, 0.1f); 
                float4 col = (1 - texColor) * (1 - value) * _Color + texColor * value; 
                col.a = texColor.a; col.rgb *= col.a; 
                return col; 
            }
            ENDCG  
        }  
    }  
} 

将相应的图片赋值给Painting这一步就OK了。

3）将myLine.cs脚本挂载，MyLine的内容如下：

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEditor;
using UnityEngine;
using UnityEngine.UI;

[System.Serializable]
public class Paints
{
    public Material mat;
    public float minWidth;
    public float maxWidth;
}

public class MyLine : MonoBehaviour
{

    public static MyLine instance;
    public Camera LineCam; //渲染笔划相机
    public Texture2D tex;
    public Paints[] paints; 
    public int penValue = 0; //选择笔划（毛笔、钢笔等）
    public Color penColor; //笔划的颜色
    public GameObject empty; //笔划实例化的父物体
    public float penWidth; //笔划大小
    public bool isWrite = false;
    public GameObject lineObj; //实例化的笔划
    public Transform par;

    private void Awake()
    {
        instance = this;
    }

    void Start()
    {
        isWrite = false;
        penWidth = 0.22f;
    }

    void Update()
    {
        if (Input.touchCount > 0)
        {
            for (int i = 0; i < Input.touchCount; i++)
            {
                switch (Input.touches[i].phase)
                {
                    case TouchPhase.Began:
                        BeginDraw(Input.touches[i]);
                        break;
                    case TouchPhase.Stationary:
                    case TouchPhase.Moved:
                        MovedDraw(Input.touches[i]);
                        break;
                    case TouchPhase.Canceled:
                    case TouchPhase.Ended:
                        EndedDraw(Input.touches[i]);
                        break;
                    default: break;
                }
            }
        }
    }


    Dictionary<int, (int, LineRenderer)> DrawingLineMaps = new Dictionary<int, (int, LineRenderer)>();
    List<LineRenderer> DrawedLines = new List<LineRenderer>();
    /// <summary>
    /// 手指抬起书写结束
    /// </summary>
    /// <param name="touch"></param>
    private void EndedDraw(Touch touch)
    {
        if (DrawingLineMaps.ContainsKey(touch.fingerId))
        {
            var (index, Line) = DrawingLineMaps[touch.fingerId];
            index++;
            Line.positionCount = index+1;
            var pos = LineCam.ScreenToWorldPoint(new Vector3(touch.position.x, touch.position.y, 0));
            pos.z = 0;
            Line.SetPosition(index, pos);
            DrawingLineMaps.Remove(touch.fingerId);
            DrawedLines.Add(Line);
        }
    }

    /// <summary>
    /// 手指滑动书写
    /// </summary>
    /// <param name="touch"></param>
    private void MovedDraw(Touch touch)
    {
        if (DrawingLineMaps.ContainsKey(touch.fingerId))
        {
            var (index, Line) = DrawingLineMaps[touch.fingerId];
            index++;
            Line.positionCount = index+1;
            var pos = LineCam.ScreenToWorldPoint(new Vector3(touch.position.x, touch.position.y, 0));
            pos.z = 0;
            Line.SetPosition(index, pos);
            DrawingLineMaps[touch.fingerId] = (index, Line);
        }
    }

    /// <summary>
    /// 开始书写
    /// </summary>
    /// <param name="touch"></param>
    void BeginDraw(Touch touch)
    {
        if (!DrawingLineMaps.ContainsKey(touch.fingerId))
        {
            GameObject clone = Instantiate(lineObj, lineObj.transform.position, Quaternion.identity, par);
            var line = clone.GetComponent<LineRenderer>();
            line.material = paints[penValue].mat;
            line.material.SetColor("_Color", penColor);
            line.startWidth = penWidth;
            line.endWidth = penWidth;
            int index = 0;
            line.positionCount = index+1;
            var pos= LineCam.ScreenToWorldPoint(new Vector3(touch.position.x, touch.position.y, 0));
            pos.z = 0;
            line.SetPosition(index,pos);
            DrawingLineMaps.Add(touch.fingerId, (index, line));
        }
    }

    /// <summary>
    /// 清除书写痕迹
    /// </summary>
    public void ClearSavePens()
    {
        if (empty.transform.childCount > 0)
        {
            for (int i = 0; i < empty.transform.childCount; i++)
            {
                Destroy(empty.transform.GetChild(i).gameObject);
            }
        }
    }
}

（4）效果演示