Shader "Unheimlich/Portal Meadow"
{
    Properties
    {
        _RootColor("Grass roots", Color) = (0.055, 0.12, 0.025, 1)
        _TipColor("Grass tips", Color) = (0.35, 0.48, 0.12, 1)
        _GroundColor("Ground", Color) = (0.08, 0.12, 0.035, 1)
        _Curvature("Curvature", Float) = 0.006
        _BendAngle("Bend angle (0 down, 180 up)", Range(0,360)) = 0
        _StartDistance("Bend start distance", Float) = 6
        _HorizontalInfluence("Horizontal influence", Range(0,1)) = 0.12
        _WindStrength("Wind strength", Range(0,1)) = 0.22
        _WindSpeed("Wind speed", Float) = 1.8
        _WindDirection("Wind direction XZ", Vector) = (1,0.4,0,0)
        [Enum(Default,0,Outside,1,Inside,2)] _MaskID("Portal mask", Float) = 0
        [HideInInspector] _MeadowRegion("Circular region", Vector) = (0,0,0,0)
        [HideInInspector] _MeadowEdgeFade("Edge fade", Float) = 4
        [HideInInspector] _MeadowEdgeColor("Edge haze", Color) = (0.36,0.43,0.46,1)
    }
    SubShader
    {
        Tags { "RenderPipeline"="UniversalPipeline" "RenderType"="Opaque" "Queue"="Geometry" }
        Cull Off
        HLSLINCLUDE
        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
        #include "Include/CurvedWorld.hlsl"
        #include "EnkiBilal/Include/Mask.hlsl"
        CBUFFER_START(UnityPerMaterial)
        float4 _RootColor, _TipColor, _GroundColor, _WindDirection;
        float _Curvature, _StartDistance, _HorizontalInfluence, _BendAngle;
        float _WindStrength, _WindSpeed, _MaskID;
        float4 _MeadowRegion, _MeadowEdgeColor;
        float _MeadowEdgeFade;
        float4x4 _MeadowWorldToLocal;
        CBUFFER_END
        #include "Include/PortalMeadowRegion.hlsl"
        float4x4 _Mask0, _Mask1, _Mask2;
        struct Attributes { float4 positionOS : POSITION; float3 normalOS : NORMAL; float2 uv : TEXCOORD0; float4 color : COLOR; };
        struct Varyings { float4 positionCS : SV_POSITION; float3 positionWS : TEXCOORD0; float3 normalWS : TEXCOORD1; float2 uv : TEXCOORD2; float4 color : COLOR; float fog : TEXCOORD3; float3 originalWS : TEXCOORD4; };
        Varyings Vert(Attributes input)
        {
            Varyings output;
            float3 p = input.positionOS.xyz;
            float3 ws = TransformObjectToWorld(p);
            float2 wind = _WindDirection.xy / max(length(_WindDirection.xy), 0.001);
            // UV.y is zero at the roots. Color.a is zero for ground vertices.
            float wave = sin(dot(ws.xz, float2(0.43,0.31)) - _Time.y * _WindSpeed);
            wave += 0.35 * sin(dot(ws.xz, float2(1.7,-0.9)) - _Time.y * _WindSpeed * 2.1 + input.color.g * 6.28);
            ws.xz += wind * (0.45 + wave * 0.55) * _WindStrength * input.uv.y * input.uv.y * input.color.a;
            p = TransformWorldToObject(ws);
            output.originalWS = ws;
            float3 positionVS = CurvedWorldToFrame(ws);
            float3 normalVS = CurvedWorldDirToFrame(TransformObjectToWorldNormal(input.normalOS));
            normalVS = CurvedWorldNormalVS(positionVS, normalVS, _Curvature, _StartDistance, _HorizontalInfluence, _BendAngle);
            CurvedWorld_float(p, _Curvature, _StartDistance, _HorizontalInfluence, _BendAngle, p);
            output.positionWS = TransformObjectToWorld(p);
            output.positionCS = TransformWorldToHClip(output.positionWS);
            output.normalWS = normalize(CurvedFrameDirToWorld(normalVS));
            output.uv = input.uv;
            output.color = input.color;
            output.fog = ComputeFogFactor(output.positionCS.z);
            return output;
        }
        void ApplyMask(float3 positionWS)
        {
            float alpha;
            Mask_float(positionWS, _MaskID, _Mask0, _Mask1, _Mask2, alpha);
            clip(alpha - 0.5);
        }
        half4 Frag(Varyings input) : SV_Target
        {
            float edgeFade = ClipMeadowRegion(input.originalWS, input.positionCS.xy);
            ApplyMask(input.positionWS);
            half3 grass = lerp(_RootColor.rgb, _TipColor.rgb, saturate(input.uv.y));
            half3 albedo = lerp(_GroundColor.rgb, grass, input.color.a) * lerp(0.75, 1.25, input.color.r);
            half3 n = normalize(input.normalWS);
            // Light layers keep the lights of the other world (e.g. the cave spot) out of PortalB.
            uint meshRenderingLayers = GetMeshRenderingLayer();
            Light sun = GetMainLight();
            half3 illumination = max(SampleSH(half3(0,1,0)), half3(0.32,0.32,0.32));
            if (IsMatchingLightLayer(sun.layerMask, meshRenderingLayers))
                illumination += sun.color * (0.3 + 0.7 * abs(dot(n, sun.direction))) * sun.distanceAttenuation;
            #if defined(_ADDITIONAL_LIGHTS)
            uint count = GetAdditionalLightsCount();
            for (uint i = 0u; i < count; ++i)
            {
                Light light = GetAdditionalLight(i, input.positionWS);
                if (IsMatchingLightLayer(light.layerMask, meshRenderingLayers))
                    illumination += light.color * saturate(abs(dot(n, light.direction))) * light.distanceAttenuation;
            }
            #endif
            return half4(lerp(_MeadowEdgeColor.rgb, MixFog(albedo * illumination, input.fog), edgeFade), 1);
        }
        half4 DepthFrag(Varyings input) : SV_Target { ClipMeadowRegion(input.originalWS, input.positionCS.xy); ApplyMask(input.positionWS); return 0; }
        half4 NormalsFrag(Varyings input) : SV_Target
        {
            ClipMeadowRegion(input.originalWS, input.positionCS.xy);
            ApplyMask(input.positionWS);
            float3 normalWS = normalize(input.normalWS);
            #if defined(_GBUFFER_NORMALS_OCT)
            float2 oct = PackNormalOctQuadEncode(normalWS);
            return half4(PackFloat2To888(saturate(oct * 0.5 + 0.5)), 0);
            #else
            return half4(normalWS, 0);
            #endif
        }
        ENDHLSL
        Pass
        {
            Name "Forward"
            Tags { "LightMode"="UniversalForwardOnly" }
            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment Frag
            #pragma target 3.5
            #pragma multi_compile_fog
            #pragma multi_compile _ _ADDITIONAL_LIGHTS
            #pragma multi_compile _ _LIGHT_LAYERS
            ENDHLSL
        }
        Pass
        {
            Name "DepthOnly"
            Tags { "LightMode"="DepthOnly" }
            ColorMask 0
            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment DepthFrag
            #pragma target 3.5
            ENDHLSL
        }
        Pass
        {
            Name "DepthNormals"
            Tags { "LightMode"="DepthNormalsOnly" }
            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment NormalsFrag
            #pragma target 3.5
            #pragma multi_compile_fragment _ _GBUFFER_NORMALS_OCT
            ENDHLSL
        }
    }
}