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#include "rsnoise.h"

#include "rsgame.h"

#ifdef RS_USE_C_LIBS

    #include 

    #include 

#else

    #include "rs/rsplatform.h"

#endif

rs_perlin_conf_t rs_perlin_conf;

void rs_perlin_configure(float freq, int octaves, float persistence, float seed, int tex_size) {

    rs_perlin_conf.freq = freq;

    rs_perlin_conf.octaves = octaves;

    rs_perlin_conf.persistence = persistence;

    rs_perlin_conf.seed = seed;

    rs_perlin_conf.tex_size = tex_size;

    rs_perlin_conf.period = (int) (0.1 + roundf(freq) ); // *tex_size

};

float rs_noise(int x, int y) {

    // from here, http://www.cplusplus.com/forum/general/85758/

    // koef. changed

    int n = x + y * 57 * 5; // no *2

    n = (n << 13) ^ n;

    int t = (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff;

    return 1.0 - ((float)t) * 0.931322574615478515625e-9;/// 1073741824.0);

}

float rs_noise_for_perlin(int x, int y) {

    x %= rs_perlin_conf.period;

    y %= rs_perlin_conf.period;

    // from here, http://www.cplusplus.com/forum/general/85758/

    // koef. changed

    int n = x + y * 57 * 5; // no *2

    n = (n << 13) ^ n;

    int t = (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff;

    return 1.0 - ((float)t) * 0.931322574615478515625e-9;/// 1073741824.0);

}

//float rs_noise_periodical(int x, int y, int period) {

//

//    x %= period;

//    y %= period;

//

//    // from here, http://www.cplusplus.com/forum/general/85758/

//    // koef. changed

//    int n = x + y * 57 * 5; // no *2

//    n = (n << 13) ^ n;

//    int t = (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff;

//    return 1.0 - ((float)t) * 0.931322574615478515625e-9;/// 1073741824.0);

//}

float rs_interpolate(float x, float y, float a) {

    float negA = 1.0 - a;

  float negASqr = negA * negA;

    float fac1 = 3.0 * (negASqr) - 2.0 * (negASqr * negA);

  float aSqr = a * a;

    float fac2 = 3.0 * aSqr - 2.0 * (aSqr * a);

    return x * fac1 + y * fac2; //add the weighted factors

}

float rs_perlin_noise(float x, float y) {

//    while (x > rs_perlin_conf.tile_period) {

//        x -= rs_perlin_conf.tile_period;

//    };

//

//    while (y > rs_perlin_conf.tile_period) {

//        y -= rs_perlin_conf.tile_period;

//    };

    int Xint = (int)x;

    int Yint = (int)y;

    float Xfrac = x - Xint;

    float Yfrac = y - Yint;

  //noise values

  float n01= rs_noise_for_perlin(Xint-1, Yint-1);

  float n02= rs_noise_for_perlin(Xint+1, Yint-1);

  float n03= rs_noise_for_perlin(Xint-1, Yint+1);

  float n04= rs_noise_for_perlin(Xint+1, Yint+1);

  float n05= rs_noise_for_perlin(Xint-1, Yint);

  float n06= rs_noise_for_perlin(Xint+1, Yint);

  float n07= rs_noise_for_perlin(Xint, Yint-1);

  float n08= rs_noise_for_perlin(Xint, Yint+1);

  float n09= rs_noise_for_perlin(Xint, Yint);

  float n12= rs_noise_for_perlin(Xint+2, Yint-1);

  float n14= rs_noise_for_perlin(Xint+2, Yint+1);

  float n16= rs_noise_for_perlin(Xint+2, Yint);

  float n23= rs_noise_for_perlin(Xint-1, Yint+2);

  float n24= rs_noise_for_perlin(Xint+1, Yint+2);

  float n28= rs_noise_for_perlin(Xint, Yint+2);

  float n34= rs_noise_for_perlin(Xint+2, Yint+2);

    //find the noise values of the four corners

    float x0y0 = 0.0625*(n01+n02+n03+n04) + 0.125*(n05+n06+n07+n08) + 0.25*(n09);

    float x1y0 = 0.0625*(n07+n12+n08+n14) + 0.125*(n09+n16+n02+n04) + 0.25*(n06);

    float x0y1 = 0.0625*(n05+n06+n23+n24) + 0.125*(n03+n04+n09+n28) + 0.25*(n08);

    float x1y1 = 0.0625*(n09+n16+n28+n34) + 0.125*(n08+n14+n06+n24) + 0.25*(n04);

    //interpolate between those values according to the x and y fractions

    float v1 = rs_interpolate(x0y0, x1y0, Xfrac); //interpolate in x direction (y)

    float v2 = rs_interpolate(x0y1, x1y1, Xfrac); //interpolate in x direction (y+1)

    float fin = rs_interpolate(v1, v2, Yfrac);  //interpolate in y direction

    return fin;

}

float rs_perlin(float i, float j) {

    float t = 0.0f;

    float _amplitude = 1.0;

    int k;

    float amplitude_divider = 0.0;

    for (k = 0; k < rs_perlin_conf.octaves; k++) {

        amplitude_divider += _amplitude;

        _amplitude *= rs_perlin_conf.persistence;

    };

    _amplitude = 1.0;

    float freq = rs_perlin_conf.freq;

    for(k = 0; k < rs_perlin_conf.octaves; k++)

    {

        t += rs_perlin_noise(j * freq / rs_perlin_conf.tex_size + rs_perlin_conf.seed, i * freq / rs_perlin_conf.tex_size + rs_perlin_conf.seed) * _amplitude;

        _amplitude *= rs_perlin_conf.persistence;

        freq *= 2;

    }

    return t / amplitude_divider;

};

float rs_quad_noise(float i, float j) {

    float t = 0.0f;

    float _amplitude = 1.0;

    int k;

    float amplitude_divider = 0.0;

    for (k = 0; k < rs_perlin_conf.octaves; k++) {

        amplitude_divider += _amplitude;

        _amplitude *= rs_perlin_conf.persistence;

    };

    _amplitude = 1.0;

    float freq = rs_perlin_conf.freq;

    for(k = 0; k < rs_perlin_conf.octaves; k++)

    {

        t += rs_noise(j * freq / rs_perlin_conf.tex_size + rs_perlin_conf.seed, i * freq / rs_perlin_conf.tex_size + rs_perlin_conf.seed) * _amplitude;

        _amplitude *= rs_perlin_conf.persistence;

        freq *= 2;

    }

    return t / amplitude_divider;

};