Shader "Hidden/MOITComposite"
{
    Properties
    {
        [Toggle] _CATCHBIASERRORS ("Catch Bias Errors", Float) = 0 // set this on if you see bloom fireflies and are not able to fix it with the other controls / are scared to see it again in build
    }

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

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

    v2f vert(uint vertexID: SV_VertexID)
    {
        v2f o;
        float2 uv = float2((vertexID << 1) & 2, vertexID & 2);
        float4 pos = float4(uv * 2.0 - 1.0, UNITY_NEAR_CLIP_VALUE, 1.0);
        #ifdef UNITY_PRETRANSFORM_TO_DISPLAY_ORIENTATION
        pos = ApplyPretransformRotation(pos);
        #endif

        #if UNITY_UV_STARTS_AT_TOP
        uv = float2((vertexID << 1) & 2, 1.0 - (vertexID & 2));
        #endif

        o.vertex = pos;
        o.uv = uv;
        return o;
    }


    #ifdef _MOMENT_SINGLE_PRECISION
    TEXTURE2D_FLOAT (_B0);
    #else
    TEXTURE2D_HALF(_B0);
    #endif

    // TEXTURE2D(_MOIT_Texture);
    SAMPLER(sampler_LinearClamp);

    TEXTURE2D_HALF(_MOIT);
    SAMPLER(sampler_MOIT);
    
    half4 MOITComposite(v2f input) : SV_Target
    {
        half4 moit = SAMPLE_TEXTURE2D(_MOIT, sampler_MOIT, input.uv);
        #ifdef _MOMENT_SINGLE_PRECISION
        float b0 = SAMPLE_TEXTURE2D(_B0, singleSampler, input.uv).r;
        #else
        half b0 = SAMPLE_TEXTURE2D(_B0, sampler_LinearClamp, input.uv).r;
        #endif
        moit.rgb /= moit.a;

        #if _CATCHBIASERRORS_ON
        // catch negative color values when alpha is very close to 1 (>0.99)
        // TODO: explore why the non shader graph tmpro shader writes negatives values in moit texture (in game view only)
        return half4(max(moit.rgb, 0.0), exp(-b0));
        #else
        return half4(max(0,moit.rgb), exp(-b0));
        #endif
    }
    ENDHLSL

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

        ZWrite Off Cull Off
        Pass
        {
            Name "Composite"

            ZTest Always
            Blend OneMinusSrcAlpha SrcAlpha

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment MOITComposite

            #pragma enable_d3d11_debug_symbols
            
            #pragma multi_compile_fragment _MOMENT_HALF_PRECISION __MOMENT_SINGLE_PRECISION
            #pragma shader_feature _CATCHBIASERRORS_ON
            ENDHLSL
        }

        //        Pass
        //        {
        //            Name "CompositeFrameBuffer"
        //
        //            ZTest Always
        //            Blend OneMinusSrcAlpha SrcAlpha
        //
        //            HLSLPROGRAM
        //
        //            #pragma vertex Vert
        //            #pragma fragment MOITCompositeFB
        //
        //            #pragma shader_feature _CATCHBIASERRORS_ON
        //
        //            FRAMEBUFFER_INPUT_X_FLOAT(0);
        //
        //            half4 MOITCompositeFB(Varyings input) : SV_Target
        //            {
        //                UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
        //
        //                //float4 moit = SAMPLE_TEXTURE2D(_BlitTexture, singleSampler, input.texcoord);
        //                //float4 moit = LOAD_FRAMEBUFFER_X_INPUT(0, input.positionCS.xy);
        //                half4 moit = LOAD_FRAMEBUFFER_X_INPUT(0, input.positionCS.xy);
        //                #ifdef _MOMENT_SINGLE_PRECISION
        //                float b0 = SAMPLE_TEXTURE2D(_B0, singleSampler, input.texcoord).r;
        //                #else
        //                half b0 = SAMPLE_TEXTURE2D(_B0, singleSampler, input.texcoord).r;
        //                #endif
        //                moit.rgb /= moit.a;
        //
        //                #if _CATCHBIASERRORS_ON
        //                // catch negative color values when alpha is very close to 1 (>0.99)
        //                // TODO: explore why the non shader graph tmpro shader writes negatives values in moit texture (in game view only)
        //                return half4(max(moit.rgb, 0.0), exp(-b0));
        //                #else
        //                return half4(moit.rgb, exp(-b0));
        //                #endif
        //            }
        //
        //            ENDHLSL
        //        }
    }
}