#ifndef AA_FROM_GREEN_CHANNEL_INCLUDED
#define AA_FROM_GREEN_CHANNEL_INCLUDED

// Shader Graph Custom Function
// UnityTexture2D와 UnitySamplerState를 받아서 G 채널에 안티에일리어싱 적용

void AAFromGreenChannel_float(
    float2 UV,
    UnityTexture2D Tex,
    UnitySamplerState Samp,
    float Strength,
    float2 Resolution,
    out float New)
{
    // Texel Size 계산
    float2 texelSize = 1.0 / Resolution;

    // 중앙값
    float center = SAMPLE_TEXTURE2D(Tex, Samp, UV).g;

    if (Strength > 0.0)
    {
        // 주변 8방향 샘플링
        float left   = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, 0)).g;
        float right  = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, 0)).g;
        float top    = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(0, texelSize.y)).g;
        float bottom = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(0, -texelSize.y)).g;

        float topLeft     = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, texelSize.y)).g;
        float topRight    = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, texelSize.y)).g;
        float bottomLeft  = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, -texelSize.y)).g;
        float bottomRight = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, -texelSize.y)).g;

        // 9탭 박스 필터 평균
        float average = (center + left + right + top + bottom +
                        topLeft + topRight + bottomLeft + bottomRight) / 9.0;

        // Strength에 따라 블렌딩
        New = lerp(center, average, saturate(Strength));
    }
    else
    {
        New = center;
    }
}

// Simple 버전 - 5탭 크로스 필터
void AAFromGreenChannelSimple_float(
    float2 UV,
    UnityTexture2D Tex,
    UnitySamplerState Samp,
    float Strength,
    float2 Resolution,
    out float New)
{
    float2 texelSize = 1.0 / Resolution;

    float center = SAMPLE_TEXTURE2D(Tex, Samp, UV).g;

    if (Strength > 0.0)
    {
        float left   = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, 0)).g;
        float right  = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, 0)).g;
        float top    = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(0, texelSize.y)).g;
        float bottom = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(0, -texelSize.y)).g;

        float average = (center + left + right + top + bottom) / 5.0;

        New = lerp(center, average, saturate(Strength));
    }
    else
    {
        New = center;
    }
}

// Weighted 버전 - 가우시안 가중치
void AAFromGreenChannelWeighted_float(
    float2 UV,
    UnityTexture2D Tex,
    UnitySamplerState Samp,
    float Strength,
    float2 Resolution,
    out float New)
{
    float2 texelSize = 1.0 / Resolution;

    float center = SAMPLE_TEXTURE2D(Tex, Samp, UV).g;

    if (Strength > 0.0)
    {
        float left   = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, 0)).g;
        float right  = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, 0)).g;
        float top    = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(0, texelSize.y)).g;
        float bottom = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(0, -texelSize.y)).g;

        float topLeft     = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, texelSize.y)).g;
        float topRight    = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, texelSize.y)).g;
        float bottomLeft  = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(-texelSize.x, -texelSize.y)).g;
        float bottomRight = SAMPLE_TEXTURE2D(Tex, Samp, UV + float2(texelSize.x, -texelSize.y)).g;

        // 가우시안 가중치
        float weighted = center * 0.25;
        weighted += (left + right + top + bottom) * 0.125;
        weighted += (topLeft + topRight + bottomLeft + bottomRight) * 0.0625;

        New = lerp(center, weighted, saturate(Strength));
    }
    else
    {
        New = center;
    }
}

#endif // AA_FROM_GREEN_CHANNEL_INCLUDED