diff options
| -rw-r--r-- | main.c | 30 | ||||
| -rw-r--r-- | util.c | 33 | ||||
| -rw-r--r-- | util.h | 3 |
3 files changed, 49 insertions, 17 deletions
@@ -44,6 +44,7 @@ typedef enum { typedef struct { unsigned int bit_depth; mode_t mode; + unsigned int seed; color_space_t color_space; bool animate; const char *filename; @@ -83,9 +84,6 @@ main(int argc, char *argv[]) return EXIT_SUCCESS; } - // For consistent images - srand(0); - state_t state; init_state(&state, &options); generate_image(&state); @@ -170,6 +168,7 @@ print_usage(FILE *file, const char *command) fprintf(file, "Usage:\n"); fprintf(file, " $ %s [-b|--bit-depth DEPTH]\n", command); fprintf(file, " %s [-s|--hue-sort] [-r|--random]\n", whitespace); + fprintf(file, " %s [-e|--seed SEED]\n", whitespace); fprintf(file, " %s [-c|--color-space RGB|Lab|Luv]\n", whitespace); fprintf(file, " %s [-a|--animate]\n", whitespace); fprintf(file, " %s [-o|--output PATH]\n", whitespace); @@ -178,6 +177,7 @@ print_usage(FILE *file, const char *command) fprintf(file, " -b, --bit-depth DEPTH: Use all DEPTH-bit colors (default: 24)\n\n"); fprintf(file, " -s, --hue-sort: Sort colors by hue first (default)\n"); fprintf(file, " -r, --random: Randomize colors first\n\n"); + fprintf(file, " -e, --seed SEED: Seed the random number generator (default: 0)\n\n"); fprintf(file, " -c, --color-space RGB|Lab|Luv:\n"); fprintf(file, " Use the given color space (default: Lab)\n\n"); fprintf(file, " -a, --animate: Generate frames of an animation\n\n"); @@ -193,6 +193,7 @@ parse_options(options_t *options, int argc, char *argv[]) // Set defaults options->bit_depth = 24; options->mode = MODE_HUE_SORT; + options->seed = 0; options->color_space = COLOR_SPACE_LAB; options->animate = false; options->filename = NULL; @@ -215,6 +216,11 @@ parse_options(options_t *options, int argc, char *argv[]) options->mode = MODE_HUE_SORT; } else if (parse_arg(argc, argv, "-r", "--random", NULL, &i, &error)) { options->mode = MODE_RANDOM; + } else if (parse_arg(argc, argv, "-e", "--seed", &value, &i, &error)) { + if (!str_to_uint(value, &options->seed)) { + fprintf(stderr, "Invalid random seed: `%s'\n", value); + error = true; + } } else if (parse_arg(argc, argv, "-a", "--animate", NULL, &i, &error)) { options->animate = true; } else if (parse_arg(argc, argv, "-o", "--output", &value, &i, &error)) { @@ -249,18 +255,6 @@ parse_options(options_t *options, int argc, char *argv[]) return result; } -static unsigned int -rand_in(unsigned int range) -{ - // Compensate for bias if (RAND_MAX + 1) isn't a multiple of range - unsigned int limit = RAND_MAX + 1U - ((RAND_MAX + 1U)%range); - unsigned int res; - do { - res = rand(); - } while (res >= limit); - return res%range; -} - static uint32_t * create_colors(const state_t *state) { @@ -288,7 +282,7 @@ create_colors(const state_t *state) case MODE_RANDOM: // Fisher-Yates shuffle for (unsigned int i = state->size; i-- > 0;) { - unsigned int j = rand_in(i + 1); + unsigned int j = xrand(i + 1); uint32_t temp = colors[i]; colors[i] = colors[j]; colors[j] = temp; @@ -314,6 +308,8 @@ create_bitmap(const state_t *state) static void init_state(state_t *state, const options_t *options) { + xsrand(options->seed); + state->options = options; state->width = 1U << (options->bit_depth + 1)/2; // Round up state->height = 1U << options->bit_depth/2; // Round down @@ -387,7 +383,7 @@ next_neighbor(const state_t *state, kd_node_t *node) return NULL; } - return neighbors[rand_in(size)]; + return neighbors[xrand(size)]; } static void @@ -31,3 +31,36 @@ xrealloc(void *ptr, size_t size) } return ret; } + +// Based on sample rand() implementation from POSIX.1-2001 + +static unsigned long xrand_next = 0; + +void xsrand(unsigned int seed) { + xrand_next = seed; +} + +static unsigned int xrand_simple(void) { + xrand_next = xrand_next*1103515245 + 12345; + return (unsigned int)(xrand_next/65536)%32768; +} + +static unsigned int xrand_full(void) { + unsigned int low = xrand_simple(); + unsigned int high = xrand_simple(); + return low | (high << 15); +} + +#define XRAND_RANGE 1073741824U + +unsigned int +xrand(unsigned int range) +{ + // Compensate for bias if XRAND_RANGE isn't a multiple of range + unsigned int limit = XRAND_RANGE - XRAND_RANGE%range; + unsigned int res; + do { + res = xrand_full(); + } while (res >= limit); + return res%range; +} @@ -17,4 +17,7 @@ void *xmalloc(size_t size); void *xrealloc(void *ptr, size_t size); +unsigned int xrand(unsigned int range); +void xsrand(unsigned int seed); + #endif // UTIL_H |