Mask裁切UI粒子特效或者3D模型

Mask裁切UI粒子特效或者3D模型

刚好前几天有人问我这个问题，再加上新项目也可能用，所以这两天就研究了一下。其实如果粒子特效 和3D模型 都用RenderTexture来做的话就不会有裁切的问题，但是粒子特效用RenderTexture来做会有显示的问题，所以还是得用摄像机。废话不多说了，进入正题。 原理就是把Mask的裁切区域传给粒子特效Shader，当超出这个区域那么直接让它完全透明即可。粒子特效的源生shader大家可以去unity官网下载，我在这里把需要修改的地方标注给大家。 //add 注释中的内容就是我做修改的地方。 [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 Shader "Particles/Additive" { Properties {     _TintColor ("Tint Color", Color) = (0.5,0.5,0.5,0.5)     _MainTex ("Particle Texture", 2D) = "white" {}     _InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0           //-------------------add----------------------       _MinX ("Min X", Float) = -10       _MaxX ("Max X", Float) = 10       _MinY ("Min Y", Float) = -10       _MaxY ("Max Y", Float) = 10       //-------------------add----------------------       }    Category {     Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }     Blend SrcAlpha One     AlphaTest Greater .01     ColorMask RGB     Cull Off Lighting Off ZWrite Off Fog { Color (0,0,0,0) }           SubShader {         Pass {                       CGPROGRAM             #pragma vertex vert             #pragma fragment frag             #pragma multi_compile_particles                #include "UnityCG.cginc"                sampler2D _MainTex;             fixed4 _TintColor;             //-------------------add----------------------             float _MinX;             float _MaxX;             float _MinY;             float _MaxY;             //-------------------add----------------------                           struct appdata_t {                 float4 vertex : POSITION;                 fixed4 color : COLOR;                 float2 texcoord : TEXCOORD0;             };                struct v2f {                 float4 vertex : SV_POSITION;                 fixed4 color : COLOR;                 float2 texcoord : TEXCOORD0;                 #ifdef SOFTPARTICLES_ON                 float4 projPos : TEXCOORD1;                 #endif                 //-------------------add----------------------                 float3 vpos : TEXCOORD2;                 //-------------------add----------------------             };                           float4 _MainTex_ST;                v2f vert (appdata_t v)             {                 v2f o;                 //-------------------add----------------------                 o.vpos = v.vertex.xyz;                 //-------------------add----------------------                 o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);                 #ifdef SOFTPARTICLES_ON                 o.projPos = ComputeScreenPos (o.vertex);                 COMPUTE_EYEDEPTH(o.projPos.z);                 #endif                 o.color = v.color;                 o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);                 return o;             }                sampler2D_float _CameraDepthTexture;             float _InvFade;                           fixed4 frag (v2f i) : SV_Target             {                 #ifdef SOFTPARTICLES_ON                 float sceneZ = LinearEyeDepth (SAMPLE_DEPTH_TEXTURE_PROJ(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos)));                 float partZ = i.projPos.z;                 float fade = saturate (_InvFade * (sceneZ-partZ));                 i.color.a *= fade;                 #endif                                   //-------------------add----------------------                  fixed4 c =2.0f * i.color * _TintColor * tex2D(_MainTex, i.texcoord);                  c.a *= (i.vpos.x >= _MinX );                  c.a *= (i.vpos.x <= _MaxX);                  c.a *= (i.vpos.y >= _MinY);                  c.a *= (i.vpos.y <= _MaxY);                  c.rgb *= c.a;                 return c;                 //-------------------add----------------------             }             ENDCG         }     }   } } 然后是自己写了个类继承Mask。把Mask的区域传给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 using UnityEngine; using System.Collections; using UnityEngine.UI;    public class MyMask :Mask {     protected override void Start ()     {         base.Start ();            int width = Screen.width;         int height = Screen.height;         int designWidth = 960;//开发时分辨率宽         int designHeight = 640;//开发时分辨率高         float s1 = (float)designWidth / (float)designHeight;         float s2 = (float)width / (float)height;            //目标分辨率小于 960X640的 需要计算缩放比例         float contentScale =1f;          if(s1 > s2) {             contentScale = s1/s2;         }         Canvas  canvas = GameObject.Find("Canvas").GetComponent<Canvas>();         Vector2 pos;         if(RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas.transform as RectTransform, transform.position, canvas.camera, out pos)){             ParticleSystem  [] particlesSystems  = transform.GetComponentsInChildren<ParticleSystem>();             RectTransform rectTransform = transform as RectTransform;             float minX,minY,maxX,maxY;             minX = rectTransform.rect.x  + pos.x;             minY = rectTransform.rect.y+ pos.y;             maxX = minX + rectTransform.rect.width ;             maxY = minY + rectTransform.rect.height;                   //这里 100  是因为ugui默认的缩放比例是100  你也可以去改这个值，但是我觉得最好别改。             foreach(ParticleSystem particleSystem in particlesSystems)             {                 particleSystem.renderer.sharedMaterial.SetFloat("_MinX",minX/100/contentScale);                 particleSystem.renderer.sharedMaterial.SetFloat("_MinY",minY/100/contentScale);                 particleSystem.renderer.sharedMaterial.SetFloat("_MaxX",maxX/100/contentScale);                 particleSystem.renderer.sharedMaterial.SetFloat("_MaxY",maxY/100/contentScale);             }         }     } } OK，如下图所示，把粒子特效直接挂在Mask下面， 就可以进行裁切了。。 1.png (181.88 KB, 下载次数: 0) 下载附件  保存到相册 2015-7-8 17:50 上传