Shader "Custom/SpriteGradient" {
    Properties{
        [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
        _Color("Left Color", Color) = (1,1,1,1)
        _Color2("Right Color", Color) = (1,1,1,1)
        _Scale("Scale", Float) = 1

            // these six unused properties are required when a shader
            // is used in the UI system, or you get a warning.
            // look to UI-Default.shader to see these.
            _StencilComp("Stencil Comparison", Float) = 8
            _Stencil("Stencil ID", Float) = 0
            _StencilOp("Stencil Operation", Float) = 0
            _StencilWriteMask("Stencil Write Mask", Float) = 255
            _StencilReadMask("Stencil Read Mask", Float) = 255
            _ColorMask("Color Mask", Float) = 15
            // see for example
            // http://answers.unity3d.com/questions/980924/ui-mask-with-shader.html

    }

        SubShader{
            Tags {"Queue" = "Background"  "IgnoreProjector" = "True"}
            LOD 100

            ZWrite On

         Stencil
         {
             Ref [_Stencil]
             Comp [_StencilComp]
             Pass [_StencilOp] 
             ReadMask [_StencilReadMask]
             WriteMask [_StencilWriteMask]
         }
         ColorMask [_ColorMask]

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

                fixed4 _Color;
                fixed4 _Color2;
                fixed  _Scale;

                struct v2f {
                    float4 pos : SV_POSITION;
                    fixed4 col : COLOR;
                };

                v2f vert(appdata_full v)
                {
                    v2f o;
                    o.pos = UnityObjectToClipPos(v.vertex);
                    o.col = lerp(_Color,_Color2, v.texcoord.x);
                    //            o.col = half4( v.vertex.y, 0, 0, 1);
                                return o;
                            }

                            float4 frag(v2f i) : COLOR {
                                float4 c = i.col;
                                c.a = 1;
                                return c;
                            }
                                ENDCG
                            }
        }
}