为什么Hidden / Fastblur着色器不再适用于Unity 2018的iOS？

Question

上下文：如果你google for Hidden / Fatblur，你会发现这个着色器可用的多个网址，我不会在这里发布任何链接，因为我不知道原始位置。它基本上是模糊的着色器，应针对移动设备进行优化。

问题：如果您过去使用过此着色器并且只是将Unity版本更新为2018+，则着色器将停止工作。

我尝试了什么：我在编辑中弄乱了着色器......听到神的消息，能够得到相同的症状。所以我知道问题在于我的iOS设备上编译着色器的方式。在统一期间没有着色器错误 - > x代码项目编译。

问题：如何修复着色器以使其再次起作用？

以下是不起作用的着色器代码：

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


Shader "Hidden/FastBlur" {
Properties {
    _MainTex ("Base (RGB)", 2D) = "white" {}
    _Bloom ("Bloom (RGB)", 2D) = "black" {}
}

CGINCLUDE

    #include "UnityCG.cginc"

    sampler2D _MainTex;
    sampler2D _Bloom;

    uniform half4 _MainTex_TexelSize;
    half4 _MainTex_ST;

    half4 _Bloom_ST;

    uniform half4 _Parameter;

    struct v2f_tap
    {
        float4 pos : SV_POSITION;
        half2 uv20 : TEXCOORD0;
        half2 uv21 : TEXCOORD1;
        half2 uv22 : TEXCOORD2;
        half2 uv23 : TEXCOORD3;
    };          

    v2f_tap vert4Tap ( appdata_img v )
    {
        v2f_tap o;

        o.pos = UnityObjectToClipPos (v.vertex);
        o.uv20 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy, _MainTex_ST);
        o.uv21 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy * half2(-0.5h,-0.5h), _MainTex_ST);
        o.uv22 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy * half2(0.5h,-0.5h), _MainTex_ST);
        o.uv23 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy * half2(-0.5h,0.5h), _MainTex_ST);

        return o; 
    }                   

    fixed4 fragDownsample ( v2f_tap i ) : SV_Target
    {               
        fixed4 color = tex2D (_MainTex, i.uv20);
        color += tex2D (_MainTex, i.uv21);
        color += tex2D (_MainTex, i.uv22);
        color += tex2D (_MainTex, i.uv23);
        return color / 4;
    }

    // weight curves

    static const half curve[7] = { 0.0205, 0.0855, 0.232, 0.324, 0.232, 0.0855, 0.0205 };  // gauss'ish blur weights

    static const half4 curve4[7] = { half4(0.0205,0.0205,0.0205,0), half4(0.0855,0.0855,0.0855,0), half4(0.232,0.232,0.232,0),
        half4(0.324,0.324,0.324,1), half4(0.232,0.232,0.232,0), half4(0.0855,0.0855,0.0855,0), half4(0.0205,0.0205,0.0205,0) };

    struct v2f_withBlurCoords8 
    {
        float4 pos : SV_POSITION;
        half4 uv : TEXCOORD0;
        half2 offs : TEXCOORD1;
    };  

    struct v2f_withBlurCoordsSGX 
    {
        float4 pos : SV_POSITION;
        half2 uv : TEXCOORD0;
        half4 offs[3] : TEXCOORD1;
    };

    v2f_withBlurCoords8 vertBlurHorizontal (appdata_img v)
    {
        v2f_withBlurCoords8 o;
        o.pos = UnityObjectToClipPos (v.vertex);

        o.uv = half4(v.texcoord.xy,1,1);
        o.offs = _MainTex_TexelSize.xy * half2(1.0, 0.0) * _Parameter.x;

        return o; 
    }

    v2f_withBlurCoords8 vertBlurVertical (appdata_img v)
    {
        v2f_withBlurCoords8 o;
        o.pos = UnityObjectToClipPos (v.vertex);

        o.uv = half4(v.texcoord.xy,1,1);
        o.offs = _MainTex_TexelSize.xy * half2(0.0, 1.0) * _Parameter.x;

        return o; 
    }   

    half4 fragBlur8 ( v2f_withBlurCoords8 i ) : SV_Target
    {
        half2 uv = i.uv.xy; 
        half2 netFilterWidth = i.offs;  
        half2 coords = uv - netFilterWidth * 3.0;  

        half4 color = 0;
        for( int l = 0; l < 7; l++ )  
        {   
            half4 tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[l];
            coords += netFilterWidth;
        }
        return color;
    }


    v2f_withBlurCoordsSGX vertBlurHorizontalSGX (appdata_img v)
    {
        v2f_withBlurCoordsSGX o;
        o.pos = UnityObjectToClipPos (v.vertex);

        o.uv = UnityStereoScreenSpaceUVAdjust(v.texcoord.xy, _MainTex_ST);

        half offsetMagnitude = _MainTex_TexelSize.x * _Parameter.x;
        o.offs[0] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(-3.0h, 0.0h, 3.0h, 0.0h), _MainTex_ST);
        o.offs[1] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(-2.0h, 0.0h, 2.0h, 0.0h), _MainTex_ST);
        o.offs[2] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(-1.0h, 0.0h, 1.0h, 0.0h), _MainTex_ST);

        return o; 
    }

    v2f_withBlurCoordsSGX vertBlurVerticalSGX (appdata_img v)
    {
        v2f_withBlurCoordsSGX o;
        o.pos = UnityObjectToClipPos (v.vertex);

        o.uv = half4(UnityStereoScreenSpaceUVAdjust(v.texcoord.xy, _MainTex_ST),1,1);

        half offsetMagnitude = _MainTex_TexelSize.y * _Parameter.x;
        o.offs[0] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(0.0h, -3.0h, 0.0h, 3.0h), _MainTex_ST);
        o.offs[1] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(0.0h, -2.0h, 0.0h, 2.0h), _MainTex_ST);
        o.offs[2] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(0.0h, -1.0h, 0.0h, 1.0h), _MainTex_ST);

        return o; 
    }

    half4 fragBlurSGX ( v2f_withBlurCoordsSGX i ) : SV_Target
    {
        half2 uv = i.uv.xy;

        half4 color = tex2D(_MainTex, i.uv) * curve4[3];

        for( int l = 0; l < 3; l++ )  
        {   
            half4 tapA = tex2D(_MainTex, i.offs[l].xy);
            half4 tapB = tex2D(_MainTex, i.offs[l].zw); 
            color += (tapA + tapB) * curve4[l];
        }

        return color;

    }   

ENDCG

SubShader {
  ZTest Off Cull Off ZWrite Off Blend Off

// 0
Pass { 

    CGPROGRAM

    #pragma vertex vert4Tap
    #pragma fragment fragDownsample

    ENDCG

    }

// 1
Pass {
    ZTest Always
    Cull Off

    CGPROGRAM 

    #pragma vertex vertBlurVertical
    #pragma fragment fragBlur8

    ENDCG 
    }   

// 2
Pass {      
    ZTest Always
    Cull Off

    CGPROGRAM

    #pragma vertex vertBlurHorizontal
    #pragma fragment fragBlur8

    ENDCG
    }   

// alternate blur
// 3
Pass {
    ZTest Always
    Cull Off

    CGPROGRAM 

    #pragma vertex vertBlurVerticalSGX
    #pragma fragment fragBlurSGX

    ENDCG
    }   

// 4
Pass {      
    ZTest Always
    Cull Off

    CGPROGRAM

    #pragma vertex vertBlurHorizontalSGX
    #pragma fragment fragBlurSGX

    ENDCG
    }   
}   

FallBack Off
}

Answer 1

答案是展开for循环：有2个循环（一个大小3，一个大小7）只需手动展开它们，用[l]替换[0]等。

着色器现在可以正确编译，您可以在iOS设备上再次获得所需的结果！

以下是修改后的着色器代码，以便它可以工作：

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


Shader "Hidden/FastBlur" 
{
    Properties 
    {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _Bloom ("Bloom (RGB)", 2D) = "black" {}
    }

    CGINCLUDE

        #include "UnityCG.cginc"

        sampler2D _MainTex;
        sampler2D _Bloom;

        uniform half4 _MainTex_TexelSize;
        half4 _MainTex_ST;

        half4 _Bloom_ST;

        uniform half4 _Parameter;

        struct v2f_tap
        {
            float4 pos : SV_POSITION;
            half2 uv20 : TEXCOORD0;
            half2 uv21 : TEXCOORD1;
            half2 uv22 : TEXCOORD2;
            half2 uv23 : TEXCOORD3;
        };          

        v2f_tap vert4Tap ( appdata_img v )
        {
            v2f_tap o;

            o.pos = UnityObjectToClipPos (v.vertex);
            o.uv20 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy, _MainTex_ST);
            o.uv21 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy * half2(-0.5h,-0.5h), _MainTex_ST);
            o.uv22 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy * half2(0.5h,-0.5h), _MainTex_ST);
            o.uv23 = UnityStereoScreenSpaceUVAdjust(v.texcoord + _MainTex_TexelSize.xy * half2(-0.5h,0.5h), _MainTex_ST);

            return o; 
        }                   

        fixed4 fragDownsample ( v2f_tap i ) : SV_Target
        {               
            fixed4 color = tex2D (_MainTex, i.uv20);
            color += tex2D (_MainTex, i.uv21);
            color += tex2D (_MainTex, i.uv22);
            color += tex2D (_MainTex, i.uv23);
            return color / 4;
        }

        // weight curves

        static const half curve[7] = { 0.0205, 0.0855, 0.232, 0.324, 0.232, 0.0855, 0.0205 };  // gauss'ish blur weights

        static const half4 curve4[7] = { half4(0.0205,0.0205,0.0205,0), half4(0.0855,0.0855,0.0855,0), half4(0.232,0.232,0.232,0),
            half4(0.324,0.324,0.324,1), half4(0.232,0.232,0.232,0), half4(0.0855,0.0855,0.0855,0), half4(0.0205,0.0205,0.0205,0) };

        struct v2f_withBlurCoords8 
        {
            float4 pos : SV_POSITION;
            half4 uv : TEXCOORD0;
            half2 offs : TEXCOORD1;
        };  

        struct v2f_withBlurCoordsSGX 
        {
            float4 pos : SV_POSITION;
            half2 uv : TEXCOORD0;
            half4 offs[3] : TEXCOORD1;
        };

        v2f_withBlurCoords8 vertBlurHorizontal (appdata_img v)
        {
            v2f_withBlurCoords8 o;
            o.pos = UnityObjectToClipPos (v.vertex);

            o.uv = half4(v.texcoord.xy,1,1);
            o.offs = _MainTex_TexelSize.xy * half2(1.0, 0.0) * _Parameter.x;

            return o; 
        }

        v2f_withBlurCoords8 vertBlurVertical (appdata_img v)
        {
            v2f_withBlurCoords8 o;
            o.pos = UnityObjectToClipPos (v.vertex);

            o.uv = half4(v.texcoord.xy,1,1);
            o.offs = _MainTex_TexelSize.xy * half2(0.0, 1.0) * _Parameter.x;

            return o; 
        }   

        half4 fragBlur8 ( v2f_withBlurCoords8 i ) : SV_Target
        {
            half2 uv = i.uv.xy; 
            half2 netFilterWidth = i.offs;  
            half2 coords = uv - netFilterWidth * 3.0;  

            half4 color = 0;

            //for( int l = 0; l < 7; l++ )
            half4 tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[0];
            coords += netFilterWidth;

            tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[1];
            coords += netFilterWidth;

            tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[2];
            coords += netFilterWidth;

            tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[3];
            coords += netFilterWidth;

            tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[4];
            coords += netFilterWidth;

            tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[5];
            coords += netFilterWidth;

            tap = tex2D(_MainTex, UnityStereoScreenSpaceUVAdjust(coords, _MainTex_ST));
            color += tap * curve4[6];
            coords += netFilterWidth;

            return color;
        }


        v2f_withBlurCoordsSGX vertBlurHorizontalSGX (appdata_img v)
        {
            v2f_withBlurCoordsSGX o;
            o.pos = UnityObjectToClipPos (v.vertex);

            o.uv = UnityStereoScreenSpaceUVAdjust(v.texcoord.xy, _MainTex_ST);

            half offsetMagnitude = _MainTex_TexelSize.x * _Parameter.x;
            o.offs[0] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(-3.0h, 0.0h, 3.0h, 0.0h), _MainTex_ST);
            o.offs[1] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(-2.0h, 0.0h, 2.0h, 0.0h), _MainTex_ST);
            o.offs[2] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(-1.0h, 0.0h, 1.0h, 0.0h), _MainTex_ST);

            return o; 
        }

        v2f_withBlurCoordsSGX vertBlurVerticalSGX (appdata_img v)
        {
            v2f_withBlurCoordsSGX o;
            o.pos = UnityObjectToClipPos (v.vertex);

            o.uv = half4(UnityStereoScreenSpaceUVAdjust(v.texcoord.xy, _MainTex_ST),1,1);

            half offsetMagnitude = _MainTex_TexelSize.y * _Parameter.x;
            o.offs[0] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(0.0h, -3.0h, 0.0h, 3.0h), _MainTex_ST);
            o.offs[1] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(0.0h, -2.0h, 0.0h, 2.0h), _MainTex_ST);
            o.offs[2] = UnityStereoScreenSpaceUVAdjust(v.texcoord.xyxy + offsetMagnitude * half4(0.0h, -1.0h, 0.0h, 1.0h), _MainTex_ST);

            return o; 
        }

        half4 fragBlurSGX ( v2f_withBlurCoordsSGX i ) : SV_Target
        {
            half2 uv = i.uv.xy;

            half4 color = tex2D(_MainTex, i.uv) * curve4[3];

            //for( int l = 0; l < 3; l++ )
            half4 tapA = tex2D(_MainTex, i.offs[0].xy);
            half4 tapB = tex2D(_MainTex, i.offs[0].zw); 
            color += (tapA + tapB) * curve4[0];

            tapA = tex2D(_MainTex, i.offs[1].xy);
            tapB = tex2D(_MainTex, i.offs[1].zw); 
            color += (tapA + tapB) * curve4[1];

            tapA = tex2D(_MainTex, i.offs[2].xy);
            tapB = tex2D(_MainTex, i.offs[2].zw); 
            color += (tapA + tapB) * curve4[2];

            return color;

        }   

    ENDCG

    SubShader 
    {
        ZTest Off Cull Off ZWrite Off Blend Off

        // 0
        Pass 
        { 

            CGPROGRAM

            #pragma vertex vert4Tap
            #pragma fragment fragDownsample

            ENDCG

            }

        // 1
        Pass 
        {
            ZTest Always
            Cull Off

            CGPROGRAM 

            #pragma vertex vertBlurVertical
            #pragma fragment fragBlur8

            ENDCG 
            }   

        // 2
        Pass 
        {      
            ZTest Always
            Cull Off

            CGPROGRAM

            #pragma vertex vertBlurHorizontal
            #pragma fragment fragBlur8

            ENDCG
            }   

        // alternate blur
        // 3
        Pass 
        {
            ZTest Always
            Cull Off

            CGPROGRAM 

            #pragma vertex vertBlurVerticalSGX
            #pragma fragment fragBlurSGX

            ENDCG
            }   

        // 4
        Pass 
        {      
            ZTest Always
            Cull Off

            CGPROGRAM

            #pragma vertex vertBlurHorizontalSGX
            #pragma fragment fragBlurSGX

            ENDCG
        } 
    }   

    FallBack Off
}