uniform sampler2D SCREEN_TEXTURE;

const highp float[3] weights = float[](0.2, 0.0625, 0.0375);

// Function to adjust alpha
highp float adjustAlpha(highp vec4 background) {
    highp float avgColor = dot(background.rgb, vec3(0.3333));
    highp float boost = (1.0 - (1.0 - avgColor) / 1.25);
    highp float transition = clamp((avgColor - 0.035) / 0.125, 0.0, 2.0);
    return boost * (1.0 - transition) + transition;
}

// Function to warm up the color
highp vec3 warmColor(highp vec3 color) {
    highp vec3 warmTint = vec3(1.0, 0.8, 0.6);
    return color * warmTint;
}

// Function to adjust saturation
highp vec3 adjustSaturation(highp vec3 color, highp float saturation) {
    highp float luminance = dot(color, vec3(0.299, 0.587, 0.114));
    return mix(vec3(luminance), color, saturation);
}

// Function to add haze effect
highp vec4 addHaze(highp vec4 color, highp float intensity) {
    highp vec3 haze = vec3(0.9, 0.85, 0.8);
    return vec4(mix(color.rgb, haze, intensity), color.a);
}

// Function to perform enhanced blur calculation
highp vec4 enhancedBlur(highp vec2 offset, highp vec2 uv, highp vec2 frag, lowp int step) {
    highp vec4 bsample = texture2D(TEXTURE, uv + offset * TEXTURE_PIXEL_SIZE) * weights[step];
    bsample.rgb = warmColor(bsample.rgb);
    bsample.rgb = adjustSaturation(bsample.rgb, 1.2);
    bsample = addHaze(bsample, 0.1);
    bsample.a *= adjustAlpha(zTextureSpec(SCREEN_TEXTURE, (frag + offset) * SCREEN_PIXEL_SIZE));
    return bsample;
}

// Function to calculate offset based on index
highp vec2 calculateOffset(highp int index, highp float step) {
    highp vec3 offsetBase = vec3(1.0, 0.0, -1.0);
    highp vec2 offsets[8];
    offsets[0] = offsetBase.xy;
    offsets[1] = -offsetBase.xy;
    offsets[2] = offsetBase.yx;
    offsets[3] = -offsetBase.yx;
    offsets[4] = offsetBase.xx;
    offsets[5] = offsetBase.xz;
    offsets[6] = offsetBase.zx;
    offsets[7] = offsetBase.zz;

    return offsets[index % 8] * step;
}

void fragment() {
    highp vec4 sprite = zTexture(UV);

    if (sprite.a == 0.0) {
        discard;
    }

    highp vec3 offsetBase = vec3(1.0, 0.0, -1.0);
    highp vec4 sum = enhancedBlur(vec2(0), UV.xy, FRAGCOORD.xy, 0);

    highp vec4 bsample;
    highp float floatstep = 0.0;

    for (lowp int i = 0; i < 2; i++) {
        floatstep += 1.0;

        for (lowp int j = 0; j < 8; j++) {
            highp vec2 offset = calculateOffset(j, floatstep);
            bsample = enhancedBlur(offset, UV.xy, FRAGCOORD.xy, i + 1);
            sum += bsample;
        }
    }

    sum.rgb = warmColor(sum.rgb);
    sum.rgb = adjustSaturation(sum.rgb, 1.1);
    sum = addHaze(sum, 0.05);

    COLOR = sum;
}