noise.cpp

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#include "llviewerprecompiledheaders.h"

#include "noise.h"

#include "llrand.h"

// static
#define B 0x100
S32 p[B + B + 2];
F32 g3[B + B + 2][3];
F32 g2[B + B + 2][2];
F32 g1[B + B + 2];
S32 gNoiseStart = 1;


F32 noise2(F32 *vec)
{
        U8 bx0, bx1, by0, by1;
        U32 b00, b10, b01, b11;
        F32 rx0, rx1, ry0, ry1, *q, sx, sy, a, b, u, v;
        S32 i, j;

        if (gNoiseStart) {
                gNoiseStart = 0;
                init();
        }


        fast_setup(*vec, bx0, bx1, rx0, rx1);
        fast_setup(*(vec + 1), by0, by1, ry0, ry1);

        i = *(p + bx0);
        j = *(p + bx1);

        b00 = *(p + i + by0);
        b10 = *(p + j + by0);
        b01 = *(p + i + by1);
        b11 = *(p + j + by1);

        sx = s_curve(rx0);
        sy = s_curve(ry0);


        q = *(g2 + b00);
        u = fast_at2(rx0, ry0, q);
        q = *(g2 + b10); 
        v = fast_at2(rx1, ry0, q);
        a = lerp_m(sx, u, v);

        q = *(g2 + b01); 
        u = fast_at2(rx0,ry1,q);
        q = *(g2 + b11); 
        v = fast_at2(rx1,ry1,q);
        b = lerp_m(sx, u, v);

        return lerp_m(sy, a, b);
}

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