OcclusionDissolve.shader

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "OcclusionDissolve"  
{  
    Properties{  
        _Diffuse("Diffuse", Color) = (1,1,1,1)  
        _DissolveColorA("Dissolve Color A", Color) = (0,1,1,0)  
        _DissolveColorB("Dissolve Color B", Color) = (0.3,0.3,0.3,1)  
        _MainTex("Base 2D", 2D) = "white"{}  
        _DissolveMap("DissolveMap", 2D) = "white"{}  
        _DissolveThreshold("DissolveThreshold", Range(0,2)) = 2  
        _ColorFactorA("ColorFactorA", Range(0,1)) = 0.7  
        _ColorFactorB("ColorFactorB", Range(0,1)) = 0.8  
        _DissolveDistance("DissolveDistance", Range(0, 20)) = 14  
        _DissolveDistanceFactor("DissolveDistanceFactor", Range(0,3)) = 3  
    }  
      
    CGINCLUDE  
    #include "Lighting.cginc"  
    uniform fixed4 _Diffuse;  
    uniform fixed4 _DissolveColorA;  
    uniform fixed4 _DissolveColorB;  
    uniform sampler2D _MainTex;  
    uniform float4 _MainTex_ST;  
    uniform sampler2D _DissolveMap;  
    uniform float _DissolveThreshold;  
    uniform float _ColorFactorA;  
    uniform float _ColorFactorB;  
    uniform float _DissolveDistance;  
    uniform float _DissolveDistanceFactor;  
      
    struct v2f  
    {  
        float4 pos : SV_POSITION;  
        float3 worldNormal : TEXCOORD0;  
        float2 uv : TEXCOORD1;  
        float4 screenPos : TEXCOORD2;  
        float3 viewDir : TEXCOORD3;  
    };  
      
    v2f vert(appdata_base v)  
    {  
        v2f o;  
        o.pos = UnityObjectToClipPos(v.vertex);  
        o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);  
        o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);  
        o.pos = UnityObjectToClipPos(v.vertex);  
        o.viewDir = ObjSpaceViewDir(v.vertex);  
        //计算屏幕坐标  
        o.screenPos = ComputeGrabScreenPos(o.pos);  
        return o;  
    }  
      
    fixed4 frag(v2f i) : SV_Target  
    {  
        float2 screenPos = i.screenPos.xy / i.screenPos.w;  
        //计算距离中心点距离作为一个控制系数  
        float2 dir = float2(0.5, 0.5) - screenPos;  
        float screenSpaceDistance = 0.5 - sqrt(dir.x * dir.x + dir.y * dir.y);  
        //计算一下像素点到相机距离作为另一个控制系数  
        float viewDistance =  max(0,(_DissolveDistance - length(i.viewDir)) / _DissolveDistance) * _DissolveDistanceFactor;  
        //用两个控制系数作为最终溶解的系数  
        float disolveFactor = viewDistance * screenSpaceDistance * _DissolveThreshold;  
        //采样Dissolve Map  
        fixed4 dissolveValue = tex2D(_DissolveMap, i.uv);  
        //小于阈值的部分直接discard  
        if (dissolveValue.r < disolveFactor)  
        {  
            discard;  
        }  
        //Diffuse + Ambient光照计算  
        fixed3 worldNormal = normalize(i.worldNormal);  
        fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);  
        fixed3 lambert = saturate(dot(worldNormal, worldLightDir));  
        fixed3 albedo = lambert * _Diffuse.xyz * _LightColor0.xyz + UNITY_LIGHTMODEL_AMBIENT.xyz;  
        fixed3 color = tex2D(_MainTex, i.uv).rgb * albedo;  
        //这里为了比较方便，直接用color和最终的边缘lerp了  
        float lerpValue = disolveFactor / dissolveValue.r;  
        if (lerpValue > _ColorFactorA)  
        {  
            if (lerpValue > _ColorFactorB)  
                return _DissolveColorB;  
            return _DissolveColorA;  
        }  
        return fixed4(color, 1);  
    }  
    ENDCG  
      
    SubShader  
    {  
        Tags{ "RenderType" = "Opaque" }  
        Pass  
        {  
            CGPROGRAM  
            #pragma vertex vert  
            #pragma fragment frag     
            ENDCG  
        }  
    }  
    FallBack "Diffuse"  
}