Snake in C using Ncurses

snake.c

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


#define MINSCRX     150
#define MINSCRY     50

#define UP      0
#define RIGHT   1
#define DOWN    2
#define LEFT    3

#define BEGINSPEED  50000000L


typedef struct {
        int     x;
        int     y;
        char    ch;
} Particle;


void checkscrsize()
{
        /* This checks if the terminal is big enough (MINSCRX x MINSCRY) */
        int scry, scrx;
        getmaxyx(stdscr, scry, scrx);
        if ( scry < MINSCRY || scrx < MINSCRX )
        {
                printw("Terminal too small, please resize to at least %dx%d.\n", MINSCRX, MINSCRY);
                printw("Current size: %dx%d\n", scrx, scry);
                refresh();
                getch();
                endwin();
                exit(1);
        }
}


void printoutlines()
{
        int i, j;
        for ( i=0; i<MINSCRX-1; i++ )
                addch(ACS_CKBOARD);
        printw("\n");
        for ( i=0; i<(MINSCRY-2); i++ )
        {
                addch(ACS_CKBOARD);
                for ( j=0; j<(MINSCRX-3); j++ )
                    printw(" ");
                addch(ACS_CKBOARD);
                printw("\n");
        }
        for ( i=0; i<MINSCRX-1; i++ )
                addch(ACS_CKBOARD);
}


void setup()
{
        /* Setup function for all things ncurses related */
        initscr();              //Start curses mode
        cbreak();               //Line buffering disabled
        keypad(stdscr, TRUE);   //Enable arrow keys
        noecho();               //Don't echo user input
        checkscrsize();         //Check if screensize is appropriate
        nodelay(stdscr, 1);     //No delay for keyboard input (0 for testing)
        printoutlines();
        curs_set(0);            //Remove cursor
}


void changetail(Particle *tail, Particle head, int dir, int length) {
    for(; length; length--) {
        tail[length].x = tail[length-1].x;
        tail[length].y = tail[length-1].y;
    }

    tail[0].x = head.x;
    tail[0].y = head.y;

}


int main(void)
{
        /* Setting game timer (0 to x nanoseconds per frame) */
        struct timespec _time, _time1;
        _time.tv_sec = 0;
        _time.tv_nsec = BEGINSPEED;

        srand( time(NULL) );    //Seed rand for apple coords

        int score, dir, key, i;
        score = 0;
        dir = RIGHT;            //Starting direction


        Particle head;
        head.ch = '$';
        head.x = 8;
        head.y = 10;

        Particle apple;
        apple.ch = '@';
        apple.x = ( rand() % 148 ) + 1;
        apple.y = ( rand() % 48 ) + 1;

        Particle tail[100];
        tail[0].ch = '#';
        tail[0].x = 9;
        tail[0].y = 10;


        setup();    //Set up ncurses


        bool hit = false;

        /* Game loop */
        while (1) {

            /* Direction handling */
            switch (dir) {
                case UP:
                    changetail(tail, head, UP, score);
                    head.y--;
                    break;
                case RIGHT:
                    changetail(tail, head, RIGHT, score);
                    head.x++;
                    break;
                case DOWN:
                    changetail(tail, head, DOWN, score);
                    head.y++;
                    break;
                case LEFT:
                    changetail(tail, head, LEFT, score);
                    head.x--;
                    break;
            }

            /* Apple collision detection */
            if ( head.x == apple.x && head.y == apple.y ) {
                score++;
                tail[score].ch = '#';
                apple.x = ( rand() % 148 ) + 1;
                apple.y = ( rand() % 48 ) + 1;
            }

            /* Tail or wall collision detection */
            for ( i = 0; i <= score; i++ ) {
                if ( head.x == tail[i].x && head.y == tail[i].y ||
                    MINSCRX-2 <= head.x || head.x <= 0 || MINSCRY-1 <= head.y || head.y <= 0 )
                    hit = true;
            }
            if ( hit ) break;

            /* Read user input and change Direction
               Also changes speed because down- and upwards would
               be too fast otherwise
            */
            key = getch();
            switch (key) {
                case KEY_UP:
                    if ( DOWN != dir ) {
                        dir = UP;
                        _time.tv_nsec *= 1.7;
                    }
                    break;
                case KEY_RIGHT:
                    if ( LEFT != dir ) {
                        dir = RIGHT;
                        _time.tv_nsec = BEGINSPEED;
                    }
                    break;
                case KEY_DOWN:
                    if ( UP != dir ) {
                        dir = DOWN;
                        _time.tv_nsec *= 1.7;
                    }
                    break;
                case KEY_LEFT:
                    if ( RIGHT != dir ) {
                        dir = LEFT;
                        _time.tv_nsec = BEGINSPEED;
                    }
                    break;
            }

            /* Print all the stuff */
            erase();
            printoutlines();
            mvprintw(head.y, head.x, "%c", head.ch);

            for ( i=0; i<=score; i++ )
                mvprintw(tail[i].y, tail[i].x, "%c", tail[i].ch);

            mvprintw(apple.y, apple.x, "%c", apple.ch);
            mvprintw(0, 2, "Score: %3d", score);
            nanosleep(&_time, &_time1);
            refresh();
        }

        nodelay(stdscr, 0);
        mvprintw(25, 65, "Game over! Score: %d", score);
        refresh();
        getch();
        endwin();   //End curses mode

        return 0;
}