dot vs. add

DotVSAdd.shader

Shader "Unlit/MadVsDot"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _TestVector("_TestVector", Vector) = (0,1,2,3)
        [Toggle(DOT_VARIANT)] _DOT_VARIANT("DOT_VARIANT", Int) = 0
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog
            #pragma enable_d3d11_debug_symbols
            #pragma multi_compile _ DOT_VARIANT 

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
                return o;
            }
            half4 _TestVector;
            fixed4 frag (v2f i) : SV_Target
            {
                half val = 0;
                half4 smp = tex2D(_MainTex, i.uv);
                
                for(int i = 0; i < 1000; i++){
                    smp += i;
                    #ifdef DOT_VARIANT
                        val += dot(smp, 0.33);
                    #else
                        val += (smp.x + smp.y + smp.z) * 0.33;
                    #endif
                    
                }
                return val;
            }
            ENDCG
        }
    }
}