Unity shader learning (II) the first shader

As in the previous section , Create a shader, In this section, we will try to output a color to the material , The code is as follows ：

Shader "Unlit/shader2"
{
    
    // Parameter variable 
    Properties
    {
    
        
    }
    SubShader
    {
    
        Tags {
     "RenderType"="Opaque" }
        LOD 100

        Pass
        {
    
            // Rendering starts 
            CGPROGRAM
            // Define vertex shaders 
            #pragma vertex vert_img
            // Define the slice shader 
            #pragma fragment frag
            // introduce unity Defined content 
            #include "UnityCG.cginc"

            // Slice shader functions 
            // Enter information about a vertex 
            //v2f_img by unity A pre written structure , You can use it directly 
            //SV_TARGET：SV_ by system value It means ,SV_Target yes DX10+ be used for fragment The semantics of the function shader's color output . Use it to finish it 
            // Return to one fixed4 Quaternion vector , It's actually a color parameter, that is RGBA, The range of values is -1——1
            fixed4 frag (v2f_img i) : SV_Target
            {
    
          
                return fixed4(1,0,0,1);
            }
            // End of rendering 
            ENDCG
        }
    }
}

v2f_img Source code

The effect is a red material , No lighting information

Change it return Value , To blue