Simple Noise Map Generator (noisemap.c)

/* simple noise map generator
 * Usage: noisemap <size> <saturation>
 *     size:       1..MAXSIZE (default = 5)
 *     saturation: 1..100     (default = 50%)
 */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define DRAWCHAR "#. "
#define MAXSIZE 50
#define PERCENT_SATURATION 50

#define min(a,b) \
    ( (a) < (b) ? (a) : (b) )

#define max(a,b) \
    ( (a) > (b) ? (a) : (b) )

#define minmax(a,b,c) \
    ( max((a), min((b), (c))) )

#define setint(lvalue, arg) \
    ( (lvalue = atoi(argv[arg])), 1 )

static int saturation = PERCENT_SATURATION;

void
draw_row(int size, int rownum)
{
    printf("%2i ", rownum);

    while(size--)
        printf("%c%c", DRAWCHAR[rand() % 100 > saturation], DRAWCHAR[2]);

    putchar('\n');
}

void
draw_header(int size)
{
    fputs("   ", stdout);

    for(int i = 1; i <= size; i++)
        if(i % 10 == 0)
            printf("%i ", i / 10);
        else
            fputs("  ", stdout);

    fputs("\n   ", stdout);

    for(int i = 1; i <= size; i++)
        printf("%i ", i % 10);

    putchar('\n');
}

int
main(int argc, char **argv)
{
    int size = 5;

    if(argc > 1 && setint(size, 1))
        size = minmax(1, MAXSIZE, size);

    if(argc > 2 && setint(saturation, 2))
        saturation = minmax(1, 100, saturation);

    srand(time(NULL));
    draw_header(size);

    for(int i = 1; i <= size; i++)
        draw_row(size, i);

    return 0;
}