Texture2D<float4> ColorTexture : register(t0, space2);
SamplerState Sampler0 : register(s0, space2);

Texture2D<float4> EmissiveTexture : register(t1, space2);
SamplerState Sampler1 : register(s1, space2);

Texture2D<float4> SsaoTexture : register(t2, space2);
SamplerState Sampler2 : register(s2, space2);

float3 reinhard2(float3 x) {
  const float L_white = 10.0;

  const float3 a = 1.0 + x / (L_white * L_white);
  const float3 x2 = x * a;
  const float3 x3 = 1.0 + x;
  return x2 / x3;
}

float3 blurSSAO(float2 uv)
{
    const float offset[5] = {0.0, 1.0, 2.0, 3.0, 4.0};
    const float weight[5] = {0.2270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162};

    float3 c = float3(0,0,0); // SsaoTexture.Sample(Sampler2, uv).xyz * weight[0] / 25;

    for(int j = 0; j < 5; j++ )
    {
        for(int i = 0; i < 5; i++ )
        {
            {
                float2 uv2 = uv + float2(j - 2.5, i) / 1024;
                float3 s = SsaoTexture.Sample(Sampler2, uv2).xyz / 50;
                c += s;
            }

            {
                float2 uv2 = uv - float2(j - 2.5, i) / 1024;
                float3 s = SsaoTexture.Sample(Sampler2, uv2).xyz / 50;
                c += s;
            }
        }
    }

    return c;
}

float3 blur(float2 uv) 
{
    const float offset[5] = {0.0, 1.0, 2.0, 3.0, 4.0};
    const float weight[5] = {0.2270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162};

    float3 c = EmissiveTexture.Sample(Sampler1, uv).xyz * weight[0];

    for(int j = 0; j < 5; j++ )
    {
        for(int i = 0; i < 5; i++ )
        {
            {
                float2 uv2 = uv + float2(j - 2.5, i) / 512;
                float3 s = EmissiveTexture.Sample(Sampler1, uv2).xyz / 25;
                c += s;
            }

            {
                float2 uv2 = uv - float2(j - 2.5, i) / 512;
                float3 s = EmissiveTexture.Sample(Sampler1, uv2).xyz / 25;
                c += s;
            }
#if 0
            {
                float2 uv2 = uv + float2(0.0, offset[i]) / 1024;
                float3 s = EmissiveTexture.Sample(Sampler1, uv2).xyz * weight[i];
                c += s;
            }

            {
                float2 uv2 = uv - float2(0.0, offset[i]) / 1024;
                float3 s = EmissiveTexture.Sample(Sampler1, uv2).xyz * weight[i];
                c += s;
            }
#endif
        }
    }

    return c;

}

float4 main(float2 UV : TEXCOORD0) : SV_Target0
{
    float2 uv = UV;
    uv.y *= -1;
    uv.y += 1.0;

    float3 c; 

#if 0
    {
        c = ColorTexture.Sample(Sampler0, uv).xyz;
        c = reinhard2(c);
        c = pow(c, 1.0/2.2);
    }
#endif

    c = ColorTexture.Sample(Sampler0, uv).xyz;
    c = reinhard2(c);

    float3 b = float3(0.0, 0.0, 0.0);

    if(length(c) < 1.0)
    {
        b = blur(uv) * 0.3; 
    }

    c = pow(c, 1.0/2.2);

    float3 e = EmissiveTexture.Sample(Sampler1, uv).xyz;

    c = c + blur(uv) * 0.05;

    float exposure = 1.0;
    c *= exposure; //= exposure(c, 1.0, 0.3);

    // c = blur(uv) * 0.01;

    // c = float3(1.0, 1.0, 1.0) - (step(0.91, length(float3(1.0, 1.0, 1.0) - (e - c))));
    // c = c * c ;
    // c = e;

    // c = float3(uv.x, uv.y, 0.0);

    // c = SsaoTexture.Sample(Sampler2, uv).x;

#if 0
    float4 ssao = SsaoTexture.Sample(Sampler2, uv);
    //c.x += (1.0 - ssao.x) * 0.7;
    c = ssao;
#else

    float3 ssao = blurSSAO(uv);
    c =  c * ssao;
#endif
    
    //float4 x = SsaoTexture.Sample(Sampler2, uv);
    //c = x;

    c.x *= 1.0 + 0.000001 * EmissiveTexture.Sample(Sampler1, uv).x;
    c.x *= 1.0 + 0.000001 * ColorTexture.Sample(Sampler0, uv).x;
    c.x *= 1.0 + 0.000001 * SsaoTexture.Sample(Sampler2, uv).x;


    return float4(c, 1.0);
}