Shader "Unlit/SoftShadowMask"
{
    SubShader
    {
        Pass
        {
            ZTest Always
            ZWrite Off
            Cull Off

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #pragma enable_d3d11_debug_symbols
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/CommonMaterial.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl"

            #pragma multi_compile _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE

            #pragma multi_compile_fragment _ _Use16Samples

            struct Varyings
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            Varyings vert(uint vertexID: SV_VertexID)
            {
                Varyings o;
                o.vertex = GetFullScreenTriangleVertexPosition(vertexID);
                o.uv = GetFullScreenTriangleTexCoord(vertexID);
                return o;
            }

            #ifdef _Use16Samples
				float4 _Offset16[8];
            #else
            float4 _Offset5[2];
            #endif

            half GetDepth(float2 uv)
            {
                #if UNITY_REVERSED_Z
                float deviceDepth = SAMPLE_TEXTURE2D_X(_CameraDepthTexture, sampler_PointClamp, uv).r;
                #else
					float deviceDepth = SAMPLE_TEXTURE2D_X(_CameraDepthTexture, sampler_PointClamp, uv).r;
					deviceDepth = deviceDepth * 2.0 - 1.0;
                #endif
                return deviceDepth;
            }

            half frag(Varyings input) : SV_Target
            {
                float2 uv = input.uv;

                //Fetch shadow coordinates for cascade.
                float3 wpos = ComputeWorldSpacePosition(uv, GetDepth(uv), unity_MatrixInvVP);
                float4 coords = TransformWorldToShadowCoord(wpos);

            	if(BEYOND_SHADOW_FAR(coords))
				{
					return  1;
				}
            	
                half shadow = SAMPLE_TEXTURE2D_SHADOW(_MainLightShadowmapTexture, sampler_LinearClampCompare,
                                      coords.xyz);
                #ifdef _Use16Samples
					for (int i = 0; i < 8; ++i)
		            {
						uv =  input.uv+ _Offset16[i].xy;
		            	wpos = ComputeWorldSpacePosition(uv, GetDepth(uv), unity_MatrixInvVP);
		            	coords = TransformWorldToShadowCoord(wpos);
			            shadow += BEYOND_SHADOW_FAR(coords) ? 1 : SAMPLE_TEXTURE2D_SHADOW(_MainLightShadowmapTexture, sampler_LinearClampCompare,coords.xyz);
	    
		            	uv =  input.uv+ _Offset16[i].zw;
		            	wpos = ComputeWorldSpacePosition(uv, GetDepth(uv), unity_MatrixInvVP);
		            	coords = TransformWorldToShadowCoord(wpos);
			            shadow += BEYOND_SHADOW_FAR(coords) ? 1 : SAMPLE_TEXTURE2D_SHADOW(_MainLightShadowmapTexture, sampler_LinearClampCompare, coords.xyz );
		            }
                #else
                for (int i = 0; i < 2; ++i)
                {
                    uv = input.uv + _Offset5[i].xy;
                    wpos = ComputeWorldSpacePosition(uv, GetDepth(uv), unity_MatrixInvVP);
                    coords = TransformWorldToShadowCoord(wpos);
    
                	shadow += BEYOND_SHADOW_FAR(coords) ? 1 : SAMPLE_TEXTURE2D_SHADOW(_MainLightShadowmapTexture, sampler_LinearClampCompare,
                                         coords.xyz);
                    uv = input.uv + _Offset5[i].zw;
                    wpos = ComputeWorldSpacePosition(uv, GetDepth(uv), unity_MatrixInvVP);
                    coords = TransformWorldToShadowCoord(wpos);

                	shadow += BEYOND_SHADOW_FAR(coords) ? 1 : SAMPLE_TEXTURE2D_SHADOW(_MainLightShadowmapTexture, sampler_LinearClampCompare,
                                                      coords.xyz);
                }
     
                shadow *= 0.2f;
                #endif

                return shadow;
            }
            ENDHLSL
        }
    }
}