Contrast/Brightness Unity Shader

Shader "Custom/ContrastBrightness" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _Contrast ("Contrast", Float) = 0.8
        _Brightness ("Brightness", Float) = 0.1
    }
    SubShader {
        Pass {
            CGPROGRAM

            #pragma vertex vMain
            #pragma fragment fMain

            uniform sampler2D _MainTex;
            uniform float _Contrast;
            uniform float _Brightness;

            struct INPUT
            {
                float4 position : POSITION;
                float2 coord : TEXCOORD0;
            };

            struct OUTPUT
            {
                float4 position : SV_POSITION;
                float2 coord : TEXCOORD0;
            };

            OUTPUT vMain( INPUT input )
            {
                OUTPUT output;
                output.position = mul( UNITY_MATRIX_MVP, input.position );
                output.coord = input.coord;
                return output;
            }

            float4 fMain( OUTPUT input ) : COLOR
            {
                float4 col = tex2D( _MainTex, input.coord );
                col.xyz = ( ( col.xyz - 0.5.xxx ) * _Contrast.xxx ) + 0.5.xxx;
                col.xyz += _Brightness.xxx;
                return col;
            }

            ENDCG
        }
    }
    FallBack "Diffuse"
}