Festive Matrix-like terminal animation

Party like it's 1999. With Neo.

Compile with -lncurses.

Press 1 when it's running to get it to run slightly faster.

/* Funky Matrix-screen lookalike, (c) 1999 Stian Sletner <stian@sletner.com>
 *
 * To compile: gcc -o matrix matrix.c -lncurses
 */

#include <ncurses.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

#define        DEFAULT_DELAY   5

#define        MAX_X                   256
#define        MAX_Y                   128

#define MATRICES               (COLS * 1.5)

#define        MATRIX_BRIGHT   COLOR_PAIR(1) | A_BOLD
#define        MATRIX_MIDDLE   COLOR_PAIR(1)
#define        MATRIX_DARK             COLOR_PAIR(2) | A_BOLD

int LINES, COLS;

int main(int argc, char **argv) {
       char key;
       int i, x[MAX_X], y[MAX_Y];

       if (argc != 1) {
               fprintf(stderr, "Usage: %s\n", argv[0]);
               fprintf(stderr, "   use 0-9 to change speed, q to quit\n");
               return -1;
       }

       if (LINES >= MAX_X || COLS >= MAX_Y) {
               fprintf(stderr, "Your terminal is too large, edit MAX_X and MAX_Y\n");
               return -1;
       }

       initscr();
       cbreak();
       noecho();

       if (has_colors() == FALSE) {
               fprintf(stderr, "Your terminal lacks color capability\n");
               return -1;
       }

       start_color();

       init_pair(1, COLOR_GREEN, COLOR_BLACK);
       init_pair(2, COLOR_BLACK, COLOR_BLACK);

       halfdelay(DEFAULT_DELAY);
       curs_set(0);

       srand(time(NULL));

       for (i = 0; i < MATRICES; i++) {
               y[i] = rand() % LINES;
               x[i] = rand() % COLS;
       }

       while ((key = getch()) != 'q') {
               if (key < '9' && key > '0')
                       halfdelay(key - '0');

               for (i = 0; i < MATRICES; i++) {
                       y[i]++;

                       if (y[i] >= LINES + 6) {
                               y[i] = 0;
                               x[i] = rand() % COLS;
                       }

                       attrset(MATRIX_BRIGHT);
                       mvaddch(y[i], x[i], rand() % 10 + '0');

                       attrset(MATRIX_MIDDLE);
                       mvaddch(y[i] - 3, x[i], rand() % 10 + '0');

                       attrset(MATRIX_DARK);
                       mvaddch(y[i] - 6, x[i], rand() % 10 + '0');
               }

               refresh();
       }

       endwin();

       return 0;
}