Shader "Custom/ImageEffect" {
    Properties {
        _MainTex("Base (RGB)",2D) = "white"{}
        _LuminosityAmount("GrayScale Amount",Range(0,1)) = 1.0
    }
    SubShader{
        Pass{
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            #pragma fragmentoption ARB_precision_hint_fastest
            #include "UnityCG.cginc"
            uniform sampler2D _MainTex;
            fixed _LuminosityAmount;

            fixed4 frag(v2f_img i) : COLOR{
                fixed4 renderTex = tex2D(_MainTex,i.uv);
                float luminosity = 0.299 * renderTex.r + 0.587 * renderTex.g + 0.114 * renderTex.b;
                fixed4 finalColor = lerp(renderTex,luminosity,_LuminosityAmount);
                return finalColor;
            }
            ENDCG
        }
    }

    FallBack "Diffuse"
}