Shader "Custom/VolumetricFog_Full"
{
    Properties
    {
        _Density("Fog Density", Range(0,1)) = 0.1
        _LightContribution("Light Contribution", Color) = (1,1,1,1)
        _LightScattering("Scattering", Range(-1,1)) = 0.0
    }

    SubShader
    {
        Tags { "RenderPipeline"="UniversalPipeline" }
        Pass
        {
            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment Frag

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

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv : TEXCOORD0;
            };

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

            Varyings Vert(Attributes IN)
            {
                Varyings OUT;
                OUT.positionCS = TransformObjectToHClip(IN.positionOS.xyz);
                OUT.uv = IN.uv;
                return OUT;
            }

            float _Density;
            float4 _LightContribution;
            float _LightScattering;

            // Henyey-Greenstein phase function
            float henyey_greenstein(float cosTheta, float g)
            {
                float g2 = g * g;
                return (1.0 - g2) / pow(1.0 + g2 - 2.0 * g * cosTheta, 1.5);
            }

            half4 Frag(Varyings IN) : SV_Target
            {
                // Raymarching setup (tu wstawiasz swój kod raymarchingu)
                float3 rayPosWS = float3(0,0,0); // przykładowa pozycja w świecie
                float3 rayDir   = float3(0,0,1); // przykładowy kierunek

                float3 fogCol = 0;

                // === Main Light ===
                Light mainLight = GetMainLight();
                float phaseMain = henyey_greenstein(dot(rayDir, mainLight.direction), _LightScattering);
                fogCol += mainLight.color.rgb * _LightContribution.rgb * phaseMain;

                // === Additional Lights ===
                int addCount = GetAdditionalLightsCount();
                for (int li = 0; li < addCount; li++)
                {
                    Light addLight = GetAdditionalLight(li, rayPosWS);
                    float3 dir = normalize(addLight.direction);
                    float atten = addLight.distanceAttenuation * addLight.shadowAttenuation;
                    float phase = henyey_greenstein(dot(rayDir, dir), _LightScattering);

                    fogCol += addLight.color.rgb * _LightContribution.rgb * phase * atten;
                }

                // Final fog color
                return float4(fogCol * _Density, 1);
            }
            ENDHLSL
        }
    }
}