色度着色器在IOS上无法正常工作

Question

更新：这已在Unity 5.3中修复

我为精灵写了一个色度着色器。它基于Unity的buildin着色器 Sprites-Diffuse 着色器，您可以下载here

我添加了一个纹理来映射第二种颜色和颜色属性。

着色器在Windows / Android设备上运行良好。但在IOS上，色度图似乎有一个偏移量。

我很欣赏每一个提示。

MainTexture（实际上是透明度上的白色圆圈;））

ChromaMap

结果

_Color  = Black

_ChromaColor = Orange

的Android IOS

着色器

Shader "Sprites/Chroma"
{
    Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _ChromaTex ("Chroma Map", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)
        _ChromaColor ("ChromaColor", Color) = (1,1,1,1)
        [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
    }

    SubShader
    {
        Tags
        { 
            "Queue"="Transparent" 
            "IgnoreProjector"="True" 
            "RenderType"="Transparent" 
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }

        Cull Off
        Lighting Off
        ZWrite Off
        Blend One OneMinusSrcAlpha

        Pass
        {
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile _ PIXELSNAP_ON
            #include "UnityCG.cginc"

            struct appdata_t
            {
                float4 vertex   : POSITION;
                float4 color    : COLOR;
                float2 texcoord : TEXCOORD0;
            };

            struct v2f
            {
                float4 vertex   : SV_POSITION;
                fixed4 color    : COLOR;
                half2 texcoord  : TEXCOORD0;
            };

            fixed4 _Color;
            fixed4 _ChromaColor;

            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.vertex = mul(UNITY_MATRIX_MVP, IN.vertex);
                OUT.texcoord = IN.texcoord;
                OUT.color = IN.color * _Color;
                #ifdef PIXELSNAP_ON
                OUT.vertex = UnityPixelSnap (OUT.vertex);
                #endif

                return OUT;
            }

            sampler2D _MainTex;
            sampler2D _ChromaTex;
            sampler2D _AlphaTex;
            float _AlphaSplitEnabled;

            fixed4 SampleSpriteTexture (float2 uv)
            {
                fixed4 color = tex2D (_MainTex, uv);
                if (_AlphaSplitEnabled)
                    color.a = tex2D (_AlphaTex, uv).r;

                return color;
            }

            fixed4 frag(v2f IN) : SV_Target
            {
                fixed4 c = SampleSpriteTexture (IN.texcoord) * IN.color;
                fixed chroma = tex2D (_ChromaTex, (IN.texcoord)).a;
                c.rgb = lerp(c.rgb,_ChromaColor.rgb,chroma);
                c.rgb *= c.a;
                return c;
            }
        ENDCG
        }
    }
}