Ipseity-Demo/Assets/_Content/Shaders/EnkiBilal/Include/Stripes.hlsl

#ifndef STRIPES_INCLUDED
#define STRIPES_INCLUDED

/*
    STRIPES - AGGRESSIVE / HEAVY HATCH VERSION

    Goal:
    Make the hatch pattern much stronger, darker and more visible.

    Changes from the Medium version:
    - Stronger width multiplier.
    - Stronger final mask shaping.
    - Weak strokes are boosted aggressively.
    - Output saturates faster, producing a harsher graphic look.
*/

float VanDerCorput(uint index)
{
    return (float)reversebits(index) * 2.3283064365386963e-10;
}

int WrapIndex(int x, int count)
{
    int r = x % count;
    return r < 0 ? r + count : r;
}

float EvalStripeCandidate(
    uint index,
    uint stripeCount,
    float wrappedXA,
    float wrappedXB,
    float stripDistanceY,
    float density,
    float thicknessInput
)
{
    float vdc = VanDerCorput(index);

    /*
        Stronger reveal than the Medium version.
        This makes stripes appear earlier and more densely.
    */
    float localProgress = saturate((density - vdc) * stripeCount * 1.35);

    if (localProgress <= 0.0001)
        return 0.0;

    float wrappedX = vdc >= 0.5 ? wrappedXB : wrappedXA;

    /*
        Original random thickness variation, but heavily boosted.
    */
    float thickness = vdc < 0.3 ? 1.0 : (vdc < 0.6 ? 1.8 : 2.6);

    /*
        Aggressive thickness boost.
        Raise this if you want even fatter strokes.
    */
    const float HATCH_WIDTH_BOOST = 2.4;

    thickness *= saturate(thicknessInput) * HATCH_WIDTH_BOOST;

    float stripeCenterX = ((float)index + 0.5) / (float)stripeCount;

    float stripDistanceX = abs(wrappedX - stripeCenterX);
    stripDistanceX = min(stripDistanceX, 1.0 - stripDistanceX);

    /*
        Wider X footprint = thicker hatch lines.
    */
    float stepX = (1.0 / (float)stripeCount) * localProgress * thickness * 0.5;

    /*
        Taller Y footprint = hatch bands cover more vertical space.
    */
    float stepY = localProgress * 0.65;

    /*
        Softer but larger edge zone.
        This makes strokes bleed more into nearby pixels.
    */
    float softEdgeX = 0.025;
    float softEdgeY = 0.085;

    float widthMask = 1.0 - smoothstep(stepX - softEdgeX, stepX, stripDistanceX);
    float heightMask = 1.0 - smoothstep(stepY - softEdgeY, stepY, stripDistanceY);

    return widthMask * heightMask;
}

void Stripes_float(
    float2 UV,
    float Density,
    float Count,
    float Thickness,
    float Offset,
    float DistortionAmplitude,
    float DistortionFrequency,
    out float Stripes
)
{
    /*
        Aggressive density boost.
        Even if the material density is moderate, the shader pushes it harder.
    */
    float density = saturate(Density * 1.45);

    float offset = frac(Offset);

    /*
        Keep the optimized candidate-based approach.
        Count is clamped to avoid bringing back the old expensive behavior.
    */
    uint stripeCount = max((uint)round(Count), 1u);
    stripeCount = min(stripeCount, 32u);

    /*
        Stronger distortion for a more nervous hand-drawn look.
    */
    float distortionAmplitude = DistortionAmplitude * 0.16;

    float2 uv = UV;
    uv.x = frac(uv.x + offset);

    float wrappedXA = frac(
        uv.x + cos((uv.y + offset) * sin(uv.x) * DistortionFrequency + offset * 7.8)
        * distortionAmplitude
    );

    float wrappedXB = frac(
        uv.x + sin((uv.y + offset) * cos(uv.x) * DistortionFrequency + offset * 5.3)
        * distortionAmplitude
    );

    float stripDistanceY = abs(saturate(uv.y) - 0.5);

    int sc = (int)stripeCount;

    int baseA = (int)floor(wrappedXA * sc);
    int baseB = (int)floor(wrappedXB * sc);

    float stripeMax = 0.0;

    /*
        Still only 6 candidates total:
        - 3 around distortion A
        - 3 around distortion B

        So this remains much cheaper than the original full Count loop.
    */
    [unroll]
    for (int k = -1; k <= 1; k++)
    {
        uint idxA = (uint)WrapIndex(baseA + k, sc);
        uint idxB = (uint)WrapIndex(baseB + k, sc);

        stripeMax = max(
            stripeMax,
            EvalStripeCandidate(
                idxA,
                stripeCount,
                wrappedXA,
                wrappedXB,
                stripDistanceY,
                density,
                Thickness
            )
        );

        stripeMax = max(
            stripeMax,
            EvalStripeCandidate(
                idxB,
                stripeCount,
                wrappedXA,
                wrappedXB,
                stripDistanceY,
                density,
                Thickness
            )
        );
    }

    /*
        Brutal final shaping.

        - smoothstep makes weak strokes become visible sooner.
        - pow with low exponent pulls mid/low values upward.
        - final multiplier forces a strong black graphic result downstream.
    */
    stripeMax = smoothstep(0.02, 0.28, stripeMax);

    const float HATCH_POWER = 0.38;
    const float HATCH_FINAL_BOOST = 2.8;

    Stripes = saturate(pow(stripeMax, HATCH_POWER) * HATCH_FINAL_BOOST);
}

#endif