Shader "NLD/NLD_Test"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { 
            "RenderType" = "Opaque"
            "RenderPipeline" = "UniversalPipeline"
        }
        LOD 100

        Pass
        {
            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            // 阴影相关定义
            #pragma multi_compile _ _ADDITIONAL_LIGHTS_VERTEX _ADDITIONAL_LIGHTS //开启额外光源
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS //主光源阴影
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS_CASCADE //主光源层级阴影是否开启
            #pragma multi_compile _ _ADDITIONAL_LIGHT_SHADOWS //额外光源阴影
            #pragma multi_compile _ _SHADOWS_SOFT //软阴影

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

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

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 posSV : SV_POSITION;
                float3 posWS : TEXCOORD1;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                o.posSV = TransformObjectToHClip(v.vertex);
                o.posWS = TransformObjectToWorld(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            half4 frag (v2f i) : SV_Target
            {
                // sample the texture
                half4 col = tex2D(_MainTex, i.uv);

                // 计算阴影uv
                float4 shadowCoord = TransformWorldToShadowCoord(i.posWS);
                float shadow = MainLightRealtimeShadow(shadowCoord);
                return half4(shadow, shadow, shadow, 1.0);
                
                return col;
            }
            ENDHLSL
        }
    }
}