mmc_rand_common.h

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#ifndef _MMC_RNG_COMMON_H
#define _MMC_RNG_COMMON_H

#define TWO_PI     (M_PI*2.0)
#define EPS        1e-6f
#define EPS2       0.1*EPS

inlinefun float rand_next_scatlen(RandType t[RAND_BUF_LEN]) {
    return -logf(rand_uniform01(t) + EPS);
}
inlinefun float rand_next_aangle(RandType t[RAND_BUF_LEN]) {
    return rand_uniform01(t);
}
inlinefun float rand_next_zangle(RandType t[RAND_BUF_LEN]) {
    return rand_uniform01(t);
}
inlinefun float rand_next_reflect(RandType t[RAND_BUF_LEN]) {
    return rand_uniform01(t);
}
inlinefun float rand_do_roulette(RandType t[RAND_BUF_LEN]) {
    return rand_uniform01(t);
}
#ifdef MMC_USE_SSE_MATH      

#define MATH_BLOCK 8

inlinefun void rand_next_aangle_sincos(RandType t[RAND_BUF_LEN], float* si, float* co) {
    static __thread V4SF sine[MATH_BLOCK], cosine[MATH_BLOCK];
    static __thread int pos = (MATH_BLOCK << 2);

    if (pos >= (MATH_BLOCK << 2)) {
        V4SF ran[MATH_BLOCK];
        int i, j;

        for (i = 0; i < MATH_BLOCK; i++)
            for (j = 0; j < 4; j++) {
                ran[i].f[j] = TWO_PI * rand_uniform01(t);
            }

        for (i = 0; i < MATH_BLOCK; i++) {
            sincos_ps(ran[i].v, &(sine[i].v), &(cosine[i].v));
        }

        pos = 0;
    }

    *si = sine[0].f[pos];
    *co = cosine[0].f[pos++];
}

inlinefun float rand_next_scatlen_ps(RandType t[RAND_BUF_LEN]) {
    static __thread V4SF logval[MATH_BLOCK];
    static __thread int pos = (MATH_BLOCK << 2);
    float res;

    if (pos >= (MATH_BLOCK << 2)) {
        V4SF ran[MATH_BLOCK];
        int i, j;

        for (i = 0; i < MATH_BLOCK; i++)
            for (j = 0; j < 4; j++) {
                ran[i].f[j] = rand_uniform01(t);
            }

        for (i = 0; i < MATH_BLOCK; i++) {
            logval[i].v = log_ps(ran[i].v);
        }

        pos = 0;
    }

    res = ((logval[0].f[pos] != logval[0].f[pos]) ? LOG_RNG_MAX : (-logval[0].f[pos]));
    pos++;
    return res;
}
#endif

#endif