Shader preto e branco

preto_e_branco.shader

Shader "Custom/preto_e_branco_shader"
{
    Properties
    {

        _MainTex ("Texture", 2D) = "black" {}

    }
    SubShader
    {   
    Pass
    {
        CGPROGRAM
        #pragma vertex vert
        #pragma fragment frag
        uniform sampler2D _MainTex;

        struct VertexInput
        {
            float4 vertex : POSITION;
            float4 texCoord : TEXCOORD0;
        };

        struct VertexOutput
        {
            float4 pos : SV_POSITION;
            float4 texCoord : TEXCOORD0;    
        };


        VertexOutput vert(VertexInput input)
        {
            VertexOutput output;
            output.pos = UnityObjectToClipPos(input.vertex);
            output.texCoord = input.texCoord;
            return output;
        }


        float4 frag(VertexInput input) : Color
        {
            float4 color = tex2D(_MainTex, input.texCoord.xy);

            float colorm = color.w *0.3 + 0.59 *color.x + 0.11* color.y;

            return float4(colorm,colorm,colorm, color.z );
        }

        ENDCG
    }    
    }
}