basic unity shader

Shader "Tutorial/01_Basic"{
    SubShader{
        Tags{
                "RenderType"="Opaque"
                "Queue"="Geometry"
            }
        Pass{


            CGPROGRAM
            #include "UnityCG.cginc"

            #pragma vertex vert
            #pragma fragment frag

            struct appdata{
                float4 vertex : POSITION;
            };

            struct v2f{
                float4 vertex : SV_POSITION;
            };

            v2f vert(appdata v){
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                return o;
            }

            fixed4 frag(v2f i) : SV_TARGET{
                return fixed4(0.5, 0, 0, 1);
            }

            ENDCG
        }
    }
}