diff options
Diffstat (limited to 'generator/ppmforge.c')
| -rw-r--r-- | generator/ppmforge.c | 167 |
1 files changed, 102 insertions, 65 deletions
diff --git a/generator/ppmforge.c b/generator/ppmforge.c index 114f7f18..c7cfdb84 100644 --- a/generator/ppmforge.c +++ b/generator/ppmforge.c @@ -37,9 +37,10 @@ #include <assert.h> #include "pm_c_util.h" -#include "ppm.h" #include "mallocvar.h" +#include "rand.h" #include "shhopt.h" +#include "ppm.h" static double const hugeVal = 1e50; @@ -59,12 +60,8 @@ typedef struct { /* Definition for obtaining random numbers. */ -#define nrand 4 /* Gauss() sample count */ -#define Cast(low, high) ((low)+(((high)-(low)) * ((rand() & 0x7FFF) / arand))) - /* Local variables */ -static double arand, gaussadd, gaussfac; /* Gaussian random parameters */ static double fracdim; /* Fractal dimension */ static double powscale; /* Power law scaling exponent */ static int meshsize = 256; /* FFT mesh size */ @@ -335,45 +332,73 @@ fourn(float * const data, #undef SWAP +struct Gauss { + struct pm_randSt randSt; + unsigned int nrand; /* Gauss() sample count */ + double arand; + double gaussadd; + double gaussfac; +}; + + static void -initgauss(unsigned int const seed) { +initgauss(struct Gauss * const gaussP, + unsigned int const seed) { /*---------------------------------------------------------------------------- Initialize random number generators. As given in Peitgen & Saupe, page 77. -----------------------------------------------------------------------------*/ + gaussP->nrand = 4; + /* Range of random generator */ - arand = pow(2.0, 15.0) - 1.0; - gaussadd = sqrt(3.0 * nrand); - gaussfac = 2 * gaussadd / (nrand * arand); - srand(seed); + gaussP->arand = pow(2.0, 15.0) - 1.0; + gaussP->gaussadd = sqrt(3.0 * gaussP->nrand); + gaussP->gaussfac = 2 * gaussP->gaussadd / (gaussP->nrand * gaussP->arand); + + pm_randinit(&gaussP->randSt); + pm_srand(&gaussP->randSt, seed); } static double -gauss() { +gauss(struct Gauss * const gaussP) { /*---------------------------------------------------------------------------- A Gaussian random number. As given in Peitgen & Saupe, page 77. -----------------------------------------------------------------------------*/ - int i; + unsigned int i; double sum; - for (i = 1, sum = 0.0; i <= nrand; ++i) { - sum += (rand() & 0x7FFF); + for (i = 1, sum = 0.0; i <= gaussP->nrand; ++i) { + sum += (pm_rand(&gaussP->randSt) & 0x7FFF); } - return gaussfac * sum - gaussadd; + return gaussP->gaussfac * sum - gaussP->gaussadd; +} + + + +static double +cast(double const low, + double const high, + struct Gauss * const gaussP) { + + return + low + + ((high-low) * ((pm_rand(&gaussP->randSt) & 0x7FFF) / gaussP->arand)); + } static void -spectralsynth(float ** const x, - unsigned int const n, - double const h) { +spectralsynth(float ** const x, + unsigned int const n, + double const h, + struct Gauss * const gaussP) { /*---------------------------------------------------------------------------- Spectrally synthesized fractal motion in two dimensions. @@ -395,9 +420,10 @@ spectralsynth(float ** const x, for (i = 0; i <= n / 2; i++) { for (j = 0; j <= n / 2; j++) { - phase = 2 * M_PI * ((rand() & 0x7FFF) / arand); + phase = 2 * M_PI * ((pm_rand(&gaussP->randSt) & 0x7FFF) / + gaussP->arand); if (i != 0 || j != 0) { - rad = pow((double) (i * i + j * j), -(h + 1) / 2) * gauss(); + rad = pow((double) (i*i + j*j), -(h + 1) / 2) * gauss(gaussP); } else { rad = 0; } @@ -416,8 +442,9 @@ spectralsynth(float ** const x, Imag(a, n / 2, n / 2) = 0; for (i = 1; i <= n / 2 - 1; i++) { for (j = 1; j <= n / 2 - 1; j++) { - phase = 2 * M_PI * ((rand() & 0x7FFF) / arand); - rad = pow((double) (i * i + j * j), -(h + 1) / 2) * gauss(); + phase = 2 * M_PI * ((pm_rand(&gaussP->randSt) & 0x7FFF) / + gaussP->arand); + rad = pow((double) (i * i + j * j), -(h + 1) / 2) * gauss(gaussP); rcos = rad * cos(phase); rsin = rad * sin(phase); Real(a, i, n - j) = rcos; @@ -469,22 +496,22 @@ temprgb(double const temp, static void -etoile(pixel * const pix) { +etoile(pixel * const pix, + struct Gauss * const gaussP) { /*---------------------------------------------------------------------------- Set a pixel in the starry sky. -----------------------------------------------------------------------------*/ - if ((rand() % 1000) < starfraction) { -#define StarQuality 0.5 /* Brightness distribution exponent */ -#define StarIntensity 8 /* Brightness scale factor */ -#define StarTintExp 0.5 /* Tint distribution exponent */ - double v = StarIntensity * pow(1 / (1 - Cast(0, 0.9999)), - (double) StarQuality), - temp, - r, g, b; - - if (v > 255) { - v = 255; - } + if ((pm_rand(&gaussP->randSt) % 1000) < starfraction) { + double const starQuality = 0.5; + /* Brightness distribution exponent */ + double const starIntensity = 8; + /* Brightness scale factor */ + double const starTintExp = 0.5; + /* Tint distribution exponent */ + double const v = + MIN(255.0, + starIntensity * pow(1 / (1 - cast(0, 0.9999, gaussP)), + (double) starQuality)); /* We make a special case for star color of zero in order to prevent floating point roundoff which would otherwise @@ -493,13 +520,17 @@ etoile(pixel * const pix) { 256 shades in the image. */ if (starcolor == 0) { - int vi = v; + pixval const vi = v; PPM_ASSIGN(*pix, vi, vi, vi); } else { + double temp; + double r, g, b; + temp = 5500 + starcolor * - pow(1 / (1 - Cast(0, 0.9999)), StarTintExp) * - ((rand() & 7) ? -1 : 1); + pow(1 / (1 - cast(0, 0.9999, gaussP)), starTintExp) * + ((pm_rand(&gaussP->randSt) & 7) ? -1 : 1); + /* Constrain temperature to a reasonable value: >= 2600K (S Cephei/R Andromedae), <= 28,000 (Spica). */ temp = MAX(2600, MIN(28000, temp)); @@ -575,7 +606,8 @@ createPlanetStuff(bool const clouds, unsigned char ** const cpP, Vector * const sunvecP, unsigned int const cols, - pixval const maxval) { + pixval const maxval, + struct Gauss * const gaussP) { double *u, *u1; unsigned int *bxf, *bxc; @@ -585,8 +617,8 @@ createPlanetStuff(bool const clouds, /* Compute incident light direction vector. */ - shang = hourspec ? hourangle : Cast(0, 2 * M_PI); - siang = inclspec ? inclangle : Cast(-M_PI * 0.12, M_PI * 0.12); + shang = hourspec ? hourangle : cast(0, 2 * M_PI, gaussP); + siang = inclspec ? inclangle : cast(-M_PI * 0.12, M_PI * 0.12, gaussP); sunvecP->x = sin(shang) * cos(siang); sunvecP->y = sin(siang); @@ -594,7 +626,7 @@ createPlanetStuff(bool const clouds, /* Allow only 25% of random pictures to be crescents */ - if (!hourspec && ((rand() % 100) < 75)) { + if (!hourspec && ((pm_rand(&gaussP->randSt) % 100) < 75)) { flipped = (sunvecP->z < 0); sunvecP->z = fabs(sunvecP->z); } else @@ -634,7 +666,7 @@ createPlanetStuff(bool const clouds, pm_error("Cannot allocate %u element interpolation tables.", cols); { unsigned int j; - for (j = 0; j < cols; j++) { + for (j = 0; j < cols; ++j) { double const bx = (n - 1) * uprj(j, cols); bxf[j] = floor(bx); @@ -651,8 +683,9 @@ createPlanetStuff(bool const clouds, static void -generateStarrySkyRow(pixel * const pixels, - unsigned int const cols) { +generateStarrySkyRow(pixel * const pixels, + unsigned int const cols, + struct Gauss * const gaussP) { /*---------------------------------------------------------------------------- Generate a starry sky. Note that no FFT is performed; the output is generated directly from a power law @@ -660,8 +693,8 @@ generateStarrySkyRow(pixel * const pixels, -----------------------------------------------------------------------------*/ unsigned int j; - for (j = 0; j < cols; j++) - etoile(pixels + j); + for (j = 0; j < cols; ++j) + etoile(pixels + j, gaussP); } @@ -881,7 +914,8 @@ generatePlanetRow(pixel * const pixelrow, int const byc, int const byf, Vector const sunvec, - pixval const maxval) { + pixval const maxval, + struct Gauss * const gaussP) { unsigned int const StarClose = 2; @@ -924,24 +958,25 @@ generatePlanetRow(pixel * const pixelrow, /* Left stars */ for (col = 0; (int)col < (int)(cols/2 - (lcos + StarClose)); ++col) - etoile(&pixelrow[col]); + etoile(&pixelrow[col], gaussP); /* Right stars */ for (col = cols/2 + (lcos + StarClose); col < cols; ++col) - etoile(&pixelrow[col]); + etoile(&pixelrow[col], gaussP); } static void -genplanet(bool const stars, - bool const clouds, - float * const a, - unsigned int const cols, - unsigned int const rows, - unsigned int const n, - unsigned int const rseed) { +genplanet(bool const stars, + bool const clouds, + float * const a, + unsigned int const cols, + unsigned int const rows, + unsigned int const n, + unsigned int const rseed, + struct Gauss * const gaussP) { /*---------------------------------------------------------------------------- Generate planet from elevation array. @@ -971,13 +1006,13 @@ genplanet(bool const stars, clouds ? "clouds" : "planet", rseed, fracdim, powscale, meshsize); createPlanetStuff(clouds, a, n, &u, &u1, &bxf, &bxc, &cp, &sunvec, - cols, maxval); + cols, maxval, gaussP); } pixelrow = ppm_allocrow(cols); for (row = 0; row < rows; ++row) { if (stars) - generateStarrySkyRow(pixelrow, cols); + generateStarrySkyRow(pixelrow, cols, gaussP); else { double const by = (n - 1) * uprj(row, rows); int const byf = floor(by) * n; @@ -993,7 +1028,8 @@ genplanet(bool const stars, generatePlanetRow(pixelrow, row, rows, cols, t, t1, u, u1, cp, bxc, bxf, byc, byf, sunvec, - maxval); + maxval, + gaussP); } ppm_writeppmrow(stdout, pixelrow, cols, maxval, FALSE); } @@ -1098,14 +1134,15 @@ planet(unsigned int const cols, -----------------------------------------------------------------------------*/ float * a; bool error; + struct Gauss gauss; - initgauss(rseed); + initgauss(&gauss, rseed); if (stars) { a = NULL; error = FALSE; } else { - spectralsynth(&a, meshsize, 3.0 - fracdim); + spectralsynth(&a, meshsize, 3.0 - fracdim, &gauss); if (a == NULL) { error = TRUE; } else { @@ -1117,7 +1154,7 @@ planet(unsigned int const cols, } } if (!error) - genplanet(stars, clouds, a, cols, rows, meshsize, rseed); + genplanet(stars, clouds, a, cols, rows, meshsize, rseed, &gauss); if (a != NULL) free(a); @@ -1159,10 +1196,10 @@ main(int argc, const char ** argv) { cols = (MAX(cmdline.height, cmdline.width) + 1) & (~1); rows = cmdline.height; - success = planet(cols, rows, cmdline.night, cmdline.clouds, cmdline.seed); + success = planet(cols, rows, cmdline.night, + cmdline.clouds, cmdline.seed); exit(success ? 0 : 1); } - |