3.纹理的采样

Shader "WSP/CharacterUnlitTest"
{
    Properties
    {
        _Tex("Tex",2D) = "White"{}   
    }
    SubShader
    {
        pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"
            sampler2D _Tex;
            struct appdata
            {
                float4 vertex :POSITION;
                float4 uv     :TEXCOORD;
            };
            struct v2f
            {
                float4 pos :SV_POSITION;
                float4 uv  :TEXCOORD; 
            };
            v2f vert(appdata v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }
            fixed4 frag(v2f i) :SV_TARGET
            {
                fixed4 tex = tex2D(_Tex,i.uv);
                return tex;
            }
            ENDCG 
        }
    }
}