Shader "Custom/URP/RoofSlopeProjection_Shadowed_URP2021"
{
    Properties
    {
        _BaseMap   ("Texture", 2D) = "white" {}
        _TileScale ("Density", Float) = 1
        _ShadowMin ("Shadow Min", Range(0,1)) = 0.35
    }

    SubShader
    {
        Tags
        {
            "RenderPipeline"="UniversalPipeline"
            "RenderType"="Opaque"
            "Queue"="Geometry"
        }

        // =========================================================
        // ForwardOnly (works even when the URP Renderer is Deferred)
        // Receives Main Light shadows (including screen-space in Deferred)
        // =========================================================
        Pass
        {
            Name "UniversalForwardOnly"
            Tags { "LightMode"="UniversalForwardOnly" }

            HLSLPROGRAM
            #pragma vertex   vert
            #pragma fragment frag

            #pragma multi_compile_instancing

            // IMPORTANT for Deferred: include screen-space main light shadows
            #pragma multi_compile_fragment _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
            #pragma multi_compile_fragment _ _SHADOWS_SOFT

		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Texture.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/TextureStack.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderGraphFunctions.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DBuffer.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/Editor/ShaderGraph/Includes/ShaderPass.hlsl"

            TEXTURE2D(_BaseMap);
            SAMPLER(sampler_BaseMap);

            CBUFFER_START(UnityPerMaterial)
                float _TileScale;
                float _ShadowMin;
            CBUFFER_END

            struct Attributes
            {
                float4 positionOS : POSITION;
                float3 normalOS   : NORMAL;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct Varyings
            {
                float4 positionHCS : SV_POSITION;
                float3 positionWS  : TEXCOORD0;
                float3 normalWS    : TEXCOORD1;
                float4 shadowCoord : TEXCOORD2;
                UNITY_VERTEX_INPUT_INSTANCE_ID
                UNITY_VERTEX_OUTPUT_STEREO
            };

            Varyings vert (Attributes v)
            {
                Varyings o;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_TRANSFER_INSTANCE_ID(v, o);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);

                VertexPositionInputs posInputs = GetVertexPositionInputs(v.positionOS.xyz);

                o.positionHCS = posInputs.positionCS;
                o.positionWS  = posInputs.positionWS;
                o.normalWS    = normalize(TransformObjectToWorldNormal(v.normalOS));

                // Works for both shadowmap and screen-space shadows
                o.shadowCoord = GetShadowCoord(posInputs);

                return o;
            }

            half4 frag (Varyings i) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(i);

                float3 n = normalize(i.normalWS);

                // Roof slope projection (your logic)
                float3 worldDown = float3(0, -1, 0);
                float3 slopeDir  = normalize(worldDown - n * dot(worldDown, n));
                float3 sideDir   = normalize(cross(slopeDir, n));

                float2 uv;
                uv.x = dot(i.positionWS, sideDir);
                uv.y = -dot(i.positionWS, slopeDir);
                uv *= _TileScale;

                half3 albedo = SAMPLE_TEXTURE2D(_BaseMap, sampler_BaseMap, uv).rgb;

                // Reliable main-light shadow attenuation (forward + deferred screen-space)
                float shadowAtten = MainLightRealtimeShadow(i.shadowCoord);

                // Prevent pitch-black shadows
                shadowAtten = lerp(_ShadowMin, 1.0, shadowAtten);
                albedo *= shadowAtten;

                return half4(albedo, 1.0);
            }
            ENDHLSL
        }

        // =========================================================
        // DepthNormalsOnly (for SSAO / effects needing normals in Deferred)
        // =========================================================
        Pass
        {
            Name "DepthNormalsOnly"
            Tags { "LightMode"="DepthNormalsOnly" }

            ZWrite On
            ZTest LEqual

            HLSLPROGRAM
            #pragma vertex   vertDN
            #pragma fragment fragDN
            #pragma multi_compile_instancing

		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Texture.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/TextureStack.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderGraphFunctions.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DBuffer.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/Editor/ShaderGraph/Includes/ShaderPass.hlsl"

            struct Attributes
            {
                float4 positionOS : POSITION;
                float3 normalOS   : NORMAL;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct Varyings
            {
                float4 positionHCS : SV_POSITION;
                float3 normalWS    : TEXCOORD0;
                UNITY_VERTEX_INPUT_INSTANCE_ID
                UNITY_VERTEX_OUTPUT_STEREO
            };

            Varyings vertDN (Attributes v)
            {
                Varyings o;
                UNITY_SETUP_INSTANCE_ID(v);
                UNITY_TRANSFER_INSTANCE_ID(v, o);
                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);

                VertexPositionInputs pos = GetVertexPositionInputs(v.positionOS.xyz);
                o.positionHCS = pos.positionCS;
                o.normalWS = normalize(TransformObjectToWorldNormal(v.normalOS));
                return o;
            }

            half4 fragDN (Varyings i) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(i);
                return half4(PackNormalOctRectEncode(normalize(i.normalWS)).rg, 0, 0);
            }
            ENDHLSL
        }

        // =========================================================
        // ShadowCaster (casts shadows)
        // =========================================================
        Pass
        {
            Name "ShadowCaster"
            Tags { "LightMode"="ShadowCaster" }

            ZWrite On
            ZTest LEqual
            ColorMask 0

            HLSLPROGRAM
            #pragma vertex   vertShadow
            #pragma fragment fragShadow
            #pragma multi_compile_instancing

		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Texture.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
		#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/TextureStack.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderGraphFunctions.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DBuffer.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
		#include "Packages/com.unity.render-pipelines.universal/Editor/ShaderGraph/Includes/ShaderPass.hlsl"

            struct Attributes
            {
                float4 positionOS : POSITION;
            };

            struct Varyings
            {
                float4 positionHCS : SV_POSITION;
				float4 shadowCoords : TEXCOORD3;
            };

            Varyings vertShadow (Attributes IN)
            {
				Varyings OUT;

				OUT.positionHCS = TransformObjectToHClip(IN.positionOS.xyz);

				// Get the VertexPositionInputs for the vertex position  
				VertexPositionInputs positions = GetVertexPositionInputs(IN.positionOS.xyz);

				// Convert the vertex position to a position on the shadow map
				float4 shadowCoordinates = GetShadowCoord(positions);

				// Pass the shadow coordinates to the fragment shader
				OUT.shadowCoords = shadowCoordinates;

				return OUT;
            }

            half4 fragShadow (Varyings IN) : SV_Target 
			{ 
				// Get the value from the shadow map at the shadow coordinates
				half shadowAmount = MainLightRealtimeShadow(IN.shadowCoords);

				// Set the fragment color to the shadow value
				return shadowAmount;
			}
            ENDHLSL
        }
    }

    FallBack Off
}