unity制作刮刮乐效果

网上看过了很多刮刮乐的文章，自己参考了一些，也改良了一些方法，比如说改良了画的每个点不连续的情况。具体效果如下:   做出这种效果，其实挺简单，主要就是利用unity的render texture加上自己写的遮罩shader。 我们首先设置两个摄像机，一个是专门渲染render texture用的，让它只能看到笔刷图层，命名为brushCamera，并且要设为dont clear模式：     然后我们要创建一个笔刷预设体，这个笔刷预设体主要实现笔刷效果：   下面的实现思路就是：当按下鼠标时，我们就克隆一个笔刷，这样就形成了涂画的效果。 然后我们写一个遮罩shader，shader中需要两张图，一张是遮罩的图片（就是图中的蓝色图片），另一张是用于剔除遮罩的图片，我们将渲染出的rendertexture作为剔除遮罩的图片。这样就完成了刮刮乐效果。 其中，我们要注意几个问题： 1、由于当鼠标快速滑动时，可能会产生每个点不连续的情况，这里我们用了贝塞尔平滑方法进行处理。 2、大量克隆笔刷，会非常消耗性能，这里我们采用创建对象池方法的方法解决这个问题。 下面是主要的代码: c#代码: [C#] 纯文本查看 复制代码 ?   001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 using System; using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;   public class DrawMask : MonoBehaviour {     public float radius = 0.5f;//半径     public GameObject brush;     bool startDraw = false;     bool twoPoints = false;     Vector2 lastPos;//最后一个点     Vector2 penultPos;//倒数第二个点     List<GameObject> brushesPool = new List<GameObject>(),activeBrushes = new List<GameObject>();//笔刷对象池       public delegate void DrawHandler(Vector2 pos);     public event DrawHandler onStartDraw;     public event DrawHandler onEndDraw;     public event DrawHandler drawing;     // Use this for initialization     void Start () {     }           // Update is called once per frame     void Update () {          GetInput();       }       void GetInput()     {         if (Input.GetMouseButtonDown(0))         {             startDraw = true;             if (onStartDraw != null)             {                 onStartDraw(VectorTransfer(Input.mousePosition));             }             penultPos = Input.mousePosition;         }         else if (Input.GetMouseButton(0))         {             if (twoPoints && Vector2.Distance(Input.mousePosition,lastPos) > 0.5f)//如果两次记录的鼠标坐标距离大于一定的距离，开始记录鼠标的点             {                 Vector2 pos = Input.mousePosition;                 float dis = Vector2.Distance(lastPos, pos);                 int segments = (int)(dis / radius);//计算出平滑的段数                 segments = segments < 1 ? 1 : segments;                 Vector2[] points = Beizier(penultPos, lastPos, pos, segments);//进行贝塞尔平滑                 for (int i = 0; i < points.Length; i++)                 {                     InstanceBrush(VectorTransfer(points[i]));                 }                 if (drawing != null)                 {                     drawing(VectorTransfer(Input.mousePosition));                 }                 lastPos = pos;                 penultPos = points[points.Length - 2];             }             else             {                 twoPoints = true;                 lastPos = Input.mousePosition;             }         }         else if (Input.GetMouseButtonUp(0))         {             if (onEndDraw != null)             {                 onEndDraw(VectorTransfer(Input.mousePosition));             }             startDraw = false;             twoPoints = false;         }     }       private void OnPostRender()     {         InitBrushes();     }       void InitBrushes()     {         for (int i = 0; i < activeBrushes.Count; i++)         {             activeBrushes[i].SetActive(false);             brushesPool.Add(activeBrushes[i]);         }         activeBrushes.Clear();     }       void InstanceBrush(Vector2 pos)     {         GameObject brushClone;         if (brushesPool.Count > 0)         {             brushClone = brushesPool[brushesPool.Count - 1];             brushesPool.RemoveAt(brushesPool.Count - 1);         }         else         {             brushClone = Instantiate(brush, pos, Quaternion.identity);         }         brushClone.transform.position = pos;           brushClone.transform.localScale = Vector3.one * radius;         brushClone.SetActive(true);         activeBrushes.Add(brushClone);     }       /// <summary>     /// 贝塞尔平滑     /// </summary>     /// <param name="start">起点</param>     /// <param name="mid">中点</param>     /// <param name="end">终点</param>     /// <param name="segments">段数</param>     /// <returns></returns>     public Vector2[] Beizier(Vector2 start,Vector2 mid, Vector2 end,int segments)     {         float d = 1f / segments;         Vector2[] points = new Vector2[segments - 1];         for (int i = 0; i < points.Length; i++)         {             float t = d * (i + 1);             points[i] = (1 - t) * (1 - t) * mid + 2 * t * (1 - t) * start + t * t * end;         }         List<Vector2> rps = new List<Vector2>();         rps.Add(mid);         rps.AddRange(points);         rps.Add(end);         return rps.ToArray();     }       Vector2 VectorTransfer(Vector2 point)     {         return Camera.main.ScreenToWorldPoint(new Vector3(point.x, point.y, 0));     } } 遮罩shader： [C] 纯文本查看 复制代码 ?   01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 // Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'   Shader "Custom/MaskShader" {     Properties {         _Color ("Color", Color) = (1,1,1,1)         //_MainTex ("Albedo (RGB)", 2D) = "white" {}         _MaskTex("Mask Texture",2D) = "white"{}         _Mask("Mask",2D) = "white"{}       }     SubShader {         Tags{"RenderType" = "Transparent" "Queue" = "Transparent"}         pass         {             Blend SrcAlpha OneMinusSrcAlpha             CGPROGRAM             #pragma vertex vert             #pragma fragment frag             #include "unitycg.cginc"               struct v2f             {                 float4 pos:POSITION;                 float2 uv:TEXCOORD1;             };               //sampler2D _MainTex;             sampler2D _MaskTex;             sampler2D _Mask;               v2f vert(appdata_base v)             {                 v2f o;                 o.pos = UnityObjectToClipPos(v.vertex);                 o.uv = v.texcoord;                 return o;             }               float4 frag(v2f i):COLOR             {                 //float4 mainColor = tex2D(_MainTex,i.uv);                 float4 maskTexColor = tex2D(_MaskTex,i.uv);                 float4 maskColor = tex2D(_Mask,i.uv);                 maskTexColor.a = 1 - maskColor.a;                 return maskTexColor;             }             ENDCG         }     }     FallBack "Diffuse" }