Shader "Synaptic/SkySphere"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _Tint ("Tint Color", Color) = (1,1,1,1)
    }

    // URP SubShader
    SubShader
    {
        PackageRequirements { "com.unity.render-pipelines.universal" }
        Tags { "RenderType"="Background" "Queue"="Background" "RenderPipeline"="UniversalPipeline" }

        Pass
        {
            Name "SkySphereURP"
            Cull Front
            ZWrite Off

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

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

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

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

            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);

            CBUFFER_START(UnityPerMaterial)
                float4 _MainTex_ST;
                float4 _Tint;
            CBUFFER_END

            Varyings vert(Attributes IN)
            {
                Varyings OUT;
                OUT.positionCS = TransformObjectToHClip(IN.positionOS.xyz);
                OUT.uv = TRANSFORM_TEX(IN.uv, _MainTex);
                return OUT;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                half4 col = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, IN.uv) * _Tint;
                return col;
            }
            ENDHLSL
        }
    }

    // HDRP SubShader
    SubShader
    {
        PackageRequirements { "com.unity.render-pipelines.high-definition" }
        Tags { "RenderType"="Background" "Queue"="Background" "RenderPipeline"="HDRenderPipeline" }

        Pass
        {
            Name "SkySphereHDRP"
            Cull Front
            ZWrite Off

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"

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

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

            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);
            float4 _MainTex_ST;
            float4 _Tint;

            Varyings vert(Attributes IN)
            {
                Varyings OUT;
                OUT.positionCS = TransformObjectToHClip(IN.positionOS.xyz);
                OUT.uv = IN.uv * _MainTex_ST.xy + _MainTex_ST.zw;
                return OUT;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                half4 col = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, IN.uv) * _Tint;
                return col;
            }
            ENDHLSL
        }
    }

    // Built-in Render Pipeline fallback
    SubShader
    {
        Tags { "RenderType"="Background" "Queue"="Background" }

        Pass
        {
            Name "SkySphereBuiltIn"
            Cull Front
            ZWrite Off

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

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

            struct v2f
            {
                float4 vertex : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            float4 _Tint;

            v2f vert(appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            fixed4 frag(v2f i) : SV_Target
            {
                fixed4 col = tex2D(_MainTex, i.uv) * _Tint;
                return col;
            }
            ENDCG
        }
    }

    FallBack Off
}