Windows Phone and Shader Blend Factors issue

Unity Engine
1

Seems like using separate blend factors for color and alpha channels in shaders is not supported on Windows Phone platform.
The shader below will be marked as unsupported because of this line:

Shader "Custom/SimpleShader"
{
    Properties
    {
        [HideInInspector] _MainTex ("", 2D) = "" {}
    }
   
    SubShader
    {
        Pass
        {
            Lighting Off
            Fog { Mode off }
            ZWrite Off
            ZTest Always
            Cull Off
           
            Blend SrcAlpha OneMinusSrcAlpha, Zero One
           
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
           
            #include "UnityCG.cginc"
           
            struct v2f
            {
                float4 pos : POSITION;
                half2 uv : TEXCOORD0;
            };
           
            uniform sampler2D _MainTex;
           
            v2f vert(appdata_img v)
            {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.uv = v.texcoord.xy;
                return o;
            }
           
            fixed4 frag(v2f i) : COLOR
            {
                return tex2D(_MainTex, i.uv);
            }
            ENDCG
        }
    }
    FallBack Off
}

But I’ve found a workaround for this issue and that’s the reason of why I’m positng it here. This will work:

Shader "Custom/SimpleShader"
{
    Properties
    {
        [HideInInspector] _MainTex ("", 2D) = "" {}
       
        [HideInInspector] _SrcFactor ("", Float) = 5    // SrcAlpha
        [HideInInspector] _DstFactor ("", Float) = 10    // OneMinusSrcAlpha
        [HideInInspector] _SrcFactorA ("", Float) = 0    // Zero
        [HideInInspector] _DstFactorA ("", Float) = 1    // One
    }
   
    SubShader
    {
        Pass
        {
            Lighting Off
            Fog { Mode off }
            ZWrite Off
            ZTest Always
            Cull Off
           
            Blend [_SrcFactor] [_DstFactor], [_SrcFactorA] [_DstFactorA]
           
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
           
            #include "UnityCG.cginc"
           
            struct v2f
            {
                float4 pos : POSITION;
                half2 uv : TEXCOORD0;
            };
           
            uniform sampler2D _MainTex;
           
            v2f vert(appdata_img v)
            {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.uv = v.texcoord.xy;
                return o;
            }
           
            fixed4 frag(v2f i) : COLOR
            {
                return tex2D(_MainTex, i.uv);
            }
            ENDCG
        }
    }
    FallBack Off
}

So it seems like shader compilation bug, @Aras
I’m on Unity 4.6.1f1, btw.

2

Can you file a bug? My memory’s really bad and I will forget about this thread in about 5 seconds :wink: