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 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 brushesPool = new List(),activeBrushes = new List(); //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); } /// /// 贝塞尔平滑 /// /// 起点 /// 中点 /// 终点 /// 段数 /// 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 rps = new List(); 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 // 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" }