本文寫於2017-6-2，原創，轉載請註明。

以下為正文

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半年前看的一篇講溶解特效的文章，然而只講思路，沒有原始檔，最近挺流行這種特效的，決定嘗試一下。

面板可輸入各類數值，注意給一個噪聲貼圖（這裡是用Photoshop分層雲彩濾鏡生成）：

以下是Shader原始碼：

Shader "Custom/MyDissolveSurface" {
Properties {
//英文版
//_Color ("Color", Color) = (1,1,1,1)
//_MainTex ("Albedo (RGB)", 2D) = "white" {}
//_Glossiness ("Smoothness", Range(0,1)) = 0.5
//_Metallic ("Metallic", Range(0,1)) = 0.0
//
// _NoiseTex ("NoiseTex (R)",2D) = "white"{}  
//        _EdgeWidth("EdgeWidth",Range(0,0.5)) = 0.1  
//        _EdgeColor("EdgeColor",Color) =  (1,1,1,1)  
//  _EdgeThresholdValue ("EdgeThresholdValue(Zero for not use)",Range(0,1)) = 0.5  
//        _DissolvePercentage ("DissolvePercentage",Range(0,1)) = 0  
//中文版
_Color ("顏色", Color) = (1,1,1,1)
_MainTex ("主貼圖 (RGB)", 2D) = "white" {}
_Glossiness ("平滑度", Range(0,1)) = 0.5
_Metallic ("金屬性", Range(0,1)) = 0.0
_NoiseTex ("噪聲貼圖 (R)",2D) = "white"{}  
_EdgeWidth("邊緣寬度",Range(0,0.5)) = 0.1  
_EdgeColor("邊緣顏色",Color) =  (1,1,1,1)  
_EdgeThresholdValue ("硬邊緣閾值(0為不使用)",Range(0,1)) = 0.5  
_DissolvePercentage ("溶解百分比",Range(0,1)) = 0  
}

SubShader {
Tags { "RenderType"="Opaque" }
LOD 200
CGPROGRAM
// Physically based Standard lighting model, and enable shadows on all light types
//原編譯指令
//#pragma surface surf Standard fullforwardshadows
//增加addshadow以獲得正確的陰影
#pragma surface surf Standard fullforwardshadows addshadow
// Use shader model 3.0 target, to get nicer looking lighting
#pragma target 3.0
sampler2D _MainTex;
sampler2D _NoiseTex;  
float _EdgeWidth;  
float4 _EdgeColor;  
float _EdgeThresholdValue;  
float _DissolvePercentage;
struct Input {
float2 uv_MainTex;
float3 worldPos;
};
half _Glossiness;
half _Metallic;
fixed4 _Color;
void surf (Input IN, inout SurfaceOutputStandard o) {

// Albedo comes from a texture tinted by color
fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
o.Albedo = c.rgb;
// Metallic and smoothness come from slider variables
o.Metallic = _Metallic;
o.Smoothness = _Glossiness;
o.Alpha = c.a;
float DissolveFactor = saturate(_DissolvePercentage);  
//使用固定座標
           // float noiseValue = tex2D(_NoiseTex,IN.uv_MainTex).r;   
            //使用世界座標
             float noiseValue = tex2D(_NoiseTex,IN.worldPos.rg).r;

              //如果該值對應噪聲圖的值更大，則拋棄

            if(noiseValue <= DissolveFactor)  
            {  
                discard;  
            }   
            float4 texColor = tex2D(_MainTex,IN.uv_MainTex);  
            float EdgeFactor = saturate((noiseValue - DissolveFactor)/(_EdgeWidth*DissolveFactor));  
            float4 BlendColor = texColor * _EdgeColor;  

           if(_EdgeThresholdValue>0){
           //不使用漸變（硬邊緣）
          float HardEdgeFactor=EdgeFactor;
          if(HardEdgeFactor>_EdgeThresholdValue){
          HardEdgeFactor=1;
          o.Emission =0;  
          }else{ 
          HardEdgeFactor=0;
          o.Emission =_EdgeColor; 
          }
          o.Albedo = lerp(texColor,BlendColor,1-EdgeFactor);  
           }else{
           o.Emission =0; 
           //使用漸變（軟邊緣）
           if(_EdgeThresholdValue>=1){
             o.Albedo = BlendColor; 
             o.Alpha=0;
           }else{
            o.Albedo = lerp(texColor,BlendColor,1 - EdgeFactor);  
           }
           }

}
ENDCG
}
FallBack "Diffuse"
}
 

參考文章：
 《Trifox》中的遮擋處理和溶解著色器技術（上）
http://gad.qq.com/article/detail/7190982
《Trifox》中的遮擋處理和溶解著色器技術（下）
http://gad.qq.com/article/detail/7190975
 Shader溶解特效
http://blog.csdn.net/xiaoge132/article/details/51657246