viiper.c

   1 /*******************************************************************************
   2  viiper 0.1
   3  By Tobias Girstmair, 2018
   4
   5  ./viiper 40x25
   6  (see ./viiper -h for full list of options)
   7
   8  KEYBINDINGS:  - hjkl to move
   9                - p to pause and resume
  10                - r to restart
  11                - q to quit
  12                - (see `./minesviiper -h' for all keybindings)
  13
  14  GNU GPL v3, see LICENSE or https://www.gnu.org/licenses/gpl-3.0.txt
  15 *******************************************************************************/
  16
  17
  18 #define _POSIX_C_SOURCE 2 /*for getopt and sigaction in c99, sigsetjmp*/
  19 #include <setjmp.h>
  20 #include <signal.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <sys/ioctl.h>
  24 #include <sys/time.h>
  25 #include <termios.h>
  26 #include <time.h>
  27 #include <unistd.h>
  28
  29 #include "viiper.h"
  30 #include "schemes.h"
  31
  32 #define MIN(a,b) (a>b?b:a)
  33 #define MAX(a,b) (a>b?a:b)
  34 #define CLAMP(a,m,M) (a<m?m:(a>M?M:a))
  35 #define printm(n, s) for (int _loop = 0; _loop < n; _loop++) fputs (s, stdout)
  36 #define print(str) fputs (str?str:"", stdout)
  37 #define CTRL_ 0x1F &
  38
  39 #define OPPOSITE(dir) ( \
  40         dir == EAST  ? WEST  :   \
  41         dir == WEST  ? EAST  :   \
  42         dir == NORTH ? SOUTH :   \
  43         dir == SOUTH ? NORTH : -1)
  44
  45 #define COL_OFFSET 1
  46 #define LINE_OFFSET 1
  47 #define LINES_AFTER 1
  48 #define CW op.scheme->cell_width
  49
  50 struct game {
  51         int w; /* field width */
  52         int h; /* field height */
  53         int d; /* direction the snake is looking */
  54         int t; /* time of game start */
  55         int p; /* score */
  56         float v; /* velocity in moves per second */
  57         struct snake* s; /* snek */
  58         struct item* i; /* items (food, boni) */
  59         struct directions {
  60                 int h; /* write head */
  61                 int n; /* number of elements */
  62                 int c[16];
  63         } k; /* ring buffer for direction events */
  64 } g;
  65
  66 struct opt {
  67         int l; /* initial snake length */
  68         int s; /* initial snake speed */
  69         struct scheme* scheme;
  70 } op;
  71
  72 jmp_buf game_over;
  73
  74 int main (int argc, char** argv) {
  75         /* defaults: */
  76         g.w = 30; //two-char-width
  77         g.h = 20;
  78         op.l = 10;
  79         op.s = 8;
  80         op.scheme = &unic0de;
  81
  82         int optget;
  83         opterr = 0; /* don't print message on unrecognized option */
  84         while ((optget = getopt (argc, argv, "+s:dh")) != -1) {
  85                 switch (optget) {
  86                 case 's':
  87                         op.s = atof(optarg);
  88                         if (op.s < 1) {
  89                                 fprintf (stderr, "speed must be >= 1\n");
  90                                 return 1;
  91                         }
  92                         break;
  93                 case 'd': op.scheme = &vt220_charset; break;
  94                 case 'h':
  95                 default:
  96                         fprintf (stderr, SHORTHELP LONGHELP, argv[0]);
  97                         return !(optget=='h');
  98                 }
  99         } if (optind < argc) { /* parse Fieldspec */
 100                 int n = sscanf (argv[optind], "%dx%d", &g.w, &g.h);
 101
 102                 if (n < 2) {
 103                         fprintf(stderr,"FIELDSIZE is WxH (width 'x' height)\n");
 104                         return 1;
 105                 }
 106         }
 107
 108         clamp_fieldsize();
 109
 110         srand(time(0));
 111         signal_setup();
 112         screen_setup(1);
 113         atexit (*quit);
 114
 115         if (sigsetjmp(game_over, 1)) {
 116                 timer_setup(0);
 117                 show_playfield();
 118                 move_ph (g.h/2+LINE_OFFSET, g.w);
 119                 printf ("snek ded :(");
 120                 fflush(stdout);
 121                 sleep(2);
 122                 exit(0);
 123         }
 124
 125         //TODO: call viiper() in a game loop
 126         viiper();
 127 quit:
 128         return 0;
 129 }
 130
 131 int viiper(void) {
 132         init_snake();
 133         show_playfield ();
 134         g.d = EAST;
 135         g.v = op.s;
 136
 137         timer_setup(1);
 138         g.t = time(NULL);
 139
 140         spawn_item(FOOD, rand() % NUM_FOODS, NULL); //TODO: shape distribution, so bigger values get selected less
 141
 142         for(;;) {
 143                 switch (getctrlseq()) {
 144                 case CTRSEQ_CURSOR_LEFT: case 'h':append_movement(WEST);  break;
 145                 case CTRSEQ_CURSOR_DOWN: case 'j':append_movement(SOUTH); break;
 146                 case CTRSEQ_CURSOR_UP:   case 'k':append_movement(NORTH); break;
 147                 case CTRSEQ_CURSOR_RIGHT:case 'l':append_movement(EAST);  break;
 148                 case 'p':
 149                         timer_setup(0);
 150                         move_ph (g.h/2+LINE_OFFSET, g.w*CW/2);
 151                         printf ("\033[5mPAUSE\033[0m"); /* blinking text */
 152                         if (getchar() == 'q') exit(0);
 153                         show_playfield();
 154                         timer_setup(1);
 155                         break;
 156                 case 'r': /*TODO:restart*/ return 0;
 157                 case 'q': return 0;
 158                 case CTRL_'L':
 159                         screen_setup(1);
 160                         show_playfield();
 161                         break;
 162                 case 0x02: /* STX; gets sent when returning from SIGALRM */
 163                         continue;
 164                 }
 165         }
 166
 167 }
 168
 169 #define pop_dir() (g.k.n? g.k.c[(16+g.k.h-g.k.n--)%16] : NONE)
 170 void snake_advance (void) {
 171         int new_dir = pop_dir();
 172         /* switch direction if new one is in the buffer and it won't kill us: */
 173         if (new_dir && g.d != OPPOSITE(new_dir)) g.d = new_dir;
 174
 175         int new_row = g.s->r +(g.d==SOUTH) -(g.d==NORTH);
 176         int new_col = g.s->c +(g.d==EAST)  -(g.d==WEST);
 177
 178         /* detect food hit and spawn a new food */
 179         for (struct item* i = g.i; i; i = i->next) {
 180                 if (i->r == new_row && i->c == new_col) {
 181                         consume_item (i);
 182                         spawn_item(FOOD, rand() % NUM_FOODS, i);
 183                 }
 184         }
 185
 186         if (new_row >= g.h || new_col >= g.w || new_row < 0 || new_col < 0)
 187                 siglongjmp(game_over, 1/*<-will be the retval of setjmp*/);
 188
 189         struct snake* new_head;
 190         struct snake* new_tail; /* former second-to-last element */
 191         for (new_tail = g.s; new_tail->next->next; new_tail = new_tail->next)
 192                 /*use the opportunity of looping to check if we eat ourselves:*/
 193                 if(new_tail->next->r == new_row && new_tail->next->c == new_col)
 194                         siglongjmp(game_over, 1);
 195         int old_tail[2] = {new_tail->next->r, new_tail->next->c};/*gets erased*/
 196         new_head = new_tail->next; /* reuse element instead of malloc() */
 197         new_tail->next = NULL;
 198
 199         new_head->r = new_row;
 200         new_head->c = new_col;
 201         new_head->next = g.s;
 202
 203         g.s = new_head;
 204
 205         draw_sprites (old_tail[0], old_tail[1]);
 206 }
 207
 208 void spawn_item (int type, int value, struct item* p_item) {
 209         int row, col;
 210 try_again:
 211         row = rand() % g.h;
 212         col = rand() % g.w;
 213         /* loop through snake to check if we aren't on it */
 214         //WARN: inefficient as snake gets longer; near impossible in the end
 215         for (struct snake* s = g.s; s; s = s->next)
 216                 if (s->r == row && s->c == col) goto try_again; //TODO: appears to not work all the time
 217
 218         /* if we got a item buffer reuse it, otherwise create a new one: */
 219         struct item* new_item;
 220         if (p_item) new_item = p_item;
 221         else new_item = malloc (sizeof(struct item));
 222
 223         new_item->r = row;
 224         new_item->c = col;
 225         new_item->t = type;
 226         new_item->v = value;
 227         new_item->s = time(0);
 228         if (g.i) g.i->prev = new_item;
 229         new_item->next = g.i;
 230         new_item->prev = NULL;
 231
 232         g.i = new_item;
 233 }
 234
 235 void consume_item (struct item* i) {
 236         switch (i->t) {
 237         case FOOD:
 238                 switch (i->v) {
 239                 case FOOD_5:  g.p +=  5; break;
 240                 case FOOD_10: g.p += 10; break;
 241                 case FOOD_20: g.p += 20; break;
 242                 }
 243                 snake_append(&g.s, 0,0);  /* position doesn't matter, as item */
 244                 break;       /* will be reused as the head before it is drawn */
 245         case BONUS:
 246                 //TODO: handle bonus
 247                 break;
 248         }
 249
 250         if (i->next) i->next->prev = i->prev;
 251         if (i->prev) i->prev->next = i->next;
 252         else g.i = i->next;
 253 }
 254
 255 void show_playfield (void) {
 256         move_ph (0,0);
 257
 258         /* top border */
 259         print(BORDER(T,L));
 260         printm (g.w, BORDER(T,C));
 261         printf ("%s\n", BORDER(T,R));
 262
 263         /* main area */
 264         for (int row = 0; row < g.h; row++)
 265                 printf ("%s%*s%s\n", BORDER(C,L), CW*g.w, "", BORDER(C,R));
 266
 267         /* bottom border */
 268         print(BORDER(B,L));
 269         printm (g.w, BORDER(B,C));
 270         print (BORDER(B,R));
 271
 272         draw_sprites (0,0);
 273 }
 274
 275 void draw_sprites (int erase_r, int erase_c) {
 276         /* erase old tail */
 277         move_ph (erase_r+LINE_OFFSET, erase_c*CW+COL_OFFSET);
 278         printm (CW, " ");
 279
 280         /* print snake */
 281         struct snake* last = NULL;
 282         int color = 2;
 283         for (struct snake* s = g.s; s; s = s->next) {
 284                 move_ph (s->r+LINE_OFFSET, s->c*CW+COL_OFFSET); /*NOTE: all those are actually wrong; draws snake 1 col too far left*/
 285
 286                 int predecessor = (last==NULL)?NONE:
 287                         (last->r < s->r) ? NORTH:
 288                         (last->r > s->r) ? SOUTH:
 289                         (last->c > s->c) ? EAST:
 290                         (last->c < s->c) ? WEST:NONE;
 291                 int successor = (s->next == NULL)?NONE:
 292                         (s->next->r < s->r) ? NORTH:
 293                         (s->next->r > s->r) ? SOUTH:
 294                         (s->next->c > s->c) ? EAST:
 295                         (s->next->c < s->c) ? WEST:NONE;
 296
 297                 printf ("\033[%sm", op.scheme->color[color]);
 298                 print (op.scheme->snake[predecessor][successor]);
 299                 printf ("\033[0m");
 300                 last = s;
 301                 color = !color;
 302         }
 303
 304         /* print item queue */
 305         for (struct item* i = g.i; i; i = i->next) {
 306                 move_ph (i->r+LINE_OFFSET, i->c*CW+COL_OFFSET);
 307                 if (i->t == FOOD) print (op.scheme->item[i->v]);
 308                 else if (i->t==BONUS) /* TODO: print bonus */;
 309         }
 310
 311         /* print score */
 312         int score_width = g.p > 9999?6:4;
 313         move_ph (0, (g.w*CW-score_width)/2-COL_OFFSET);
 314         printf ("%s %0*d %s", BORDER(S,L), score_width, g.p, BORDER(S,R));
 315 }
 316
 317 void snake_append (struct snake** s, int row, int col) {
 318         struct snake* new = malloc (sizeof(struct snake));
 319         new->r = row;
 320         new->c = col;
 321         new->next = NULL;
 322
 323         if (*s) {
 324                 struct snake* p = *s;
 325                 while (p->next) p = p->next;
 326                 p->next = new;
 327         } else {
 328                 *s = new;
 329         }
 330 }
 331
 332 void init_snake() {
 333         for (int i = 0; i < op.l; i++) {
 334                 if (g.w/2-i < 0) /* go upwards if we hit left wall */
 335                         snake_append(&g.s, g.h/2-(i-g.w/2), 0);
 336                 else /* normally just keep goint left */
 337                         snake_append(&g.s, g.h/2, g.w/2-i);
 338         }
 339 }
 340
 341 #define free_ll(head) do{ \
 342         while (head) { \
 343                 void* tmp = head; \
 344                 head = head->next; \
 345                 free(tmp); \
 346         } \
 347 }while(0)
 348
 349 void quit (void) {
 350         screen_setup(0);
 351         free_ll(g.s);
 352         free_ll(g.i);
 353 }
 354
 355 enum esc_states {
 356         START,
 357         ESC_SENT,
 358         CSI_SENT,
 359         MOUSE_EVENT,
 360 };
 361 int getctrlseq (void) {
 362         int c;
 363         int state = START;
 364         while ((c = getchar()) != EOF) {
 365                 switch (state) {
 366                 case START:
 367                         switch (c) {
 368                         case '\033': state=ESC_SENT; break;
 369                         default: return c;
 370                         }
 371                         break;
 372                 case ESC_SENT:
 373                         switch (c) {
 374                         case '[': state=CSI_SENT; break;
 375                         default: return CTRSEQ_INVALID;
 376                         }
 377                         break;
 378                 case CSI_SENT:
 379                         switch (c) {
 380                         case 'A': return CTRSEQ_CURSOR_UP;
 381                         case 'B': return CTRSEQ_CURSOR_DOWN;
 382                         case 'C': return CTRSEQ_CURSOR_RIGHT;
 383                         case 'D': return CTRSEQ_CURSOR_LEFT;
 384                         default: return CTRSEQ_INVALID;
 385                         }
 386                         break;
 387                 default:
 388                         return CTRSEQ_INVALID;
 389                 }
 390         }
 391         return 2;
 392 }
 393
 394 void append_movement (int dir) {
 395         if (g.k.n > 15) return; /* no space in buffer */
 396         if (g.k.n && g.k.c[(16+g.k.h-1)%16] == dir)
 397                 return; /* don't add the same direction twice */
 398
 399         g.k.c[g.k.h] = dir;
 400         g.k.n++;
 401         g.k.h = ++g.k.h % 16;
 402 }
 403
 404 void move_ph (int line, int col) {
 405         /* move printhead to zero-indexed position */
 406         printf ("\033[%d;%dH", line+1, col+1);
 407 }
 408
 409 void clamp_fieldsize (void) {
 410         /* clamp field size to terminal size and mouse maximum: */
 411         struct winsize w;
 412         ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
 413
 414         if (g.w < 10) g.w = 10;
 415         if (g.h < 10) g.h = 10;
 416
 417         if (COL_OFFSET + g.w*CW + COL_OFFSET > w.ws_col)
 418                 g.w = (w.ws_col - (COL_OFFSET+COL_OFFSET))/CW; //TODO: does not work in `-d' (in xterm)
 419         if (LINE_OFFSET + g.h + LINES_AFTER > w.ws_row)
 420                 g.h = w.ws_row - (LINE_OFFSET+LINES_AFTER);
 421 }
 422
 423 void timer_setup (int enable) {
 424         static struct itimerval tbuf;
 425         tbuf.it_interval.tv_sec  = 0;//TODO: make it speed up automatically
 426         tbuf.it_interval.tv_usec = (1000000/g.v)-1; /*WARN: 1 <= g.v <= 999999*/
 427
 428         if (enable) {
 429                 tbuf.it_value.tv_sec  = tbuf.it_interval.tv_sec;
 430                 tbuf.it_value.tv_usec = tbuf.it_interval.tv_usec;
 431         } else {
 432                 tbuf.it_value.tv_sec  = 0;
 433                 tbuf.it_value.tv_usec = 0;
 434         }
 435
 436         if ( setitimer(ITIMER_REAL, &tbuf, NULL) == -1 ) {
 437                 perror("setitimer");
 438                 exit(1);
 439         }
 440
 441 }
 442
 443 void signal_setup (void) {
 444         struct sigaction saction;
 445
 446         saction.sa_handler = signal_handler;
 447         sigemptyset(&saction.sa_mask);
 448         saction.sa_flags = 0;
 449         if (sigaction(SIGALRM, &saction, NULL) < 0 ) {
 450                 perror("SIGALRM");
 451                 exit(1);
 452         }
 453
 454         if (sigaction(SIGINT, &saction, NULL) < 0 ) {
 455                 perror ("SIGINT");
 456                 exit (1);
 457         }
 458
 459         if (sigaction(SIGCONT, &saction, NULL) < 0 ) {
 460                 perror ("SIGCONT");
 461                 exit (1);
 462         }
 463 }
 464
 465 void signal_handler (int signum) {
 466         switch (signum) {
 467         case SIGALRM:
 468                 snake_advance();
 469                 break;
 470         case SIGINT:
 471                 exit(128+SIGINT);
 472         case SIGCONT:
 473                 siglongjmp(game_over, 1);/*TODO:returning from ^Z breaks input*/
 474         }
 475 }
 476
 477 void screen_setup (int enable) {
 478         if (enable) {
 479                 raw_mode(1);
 480                 printf ("\033[s\033[?47h"); /* save cursor, alternate screen */
 481                 printf ("\033[H\033[J"); /* reset cursor, clear screen */
 482                 printf ("\033[?25l"); /* hide cursor */
 483                 print (op.scheme->init_seq); /* swich charset, if necessary */
 484         } else {
 485                 print (op.scheme->reset_seq); /* reset charset, if necessary */
 486                 printf ("\033[?25h"); /* show cursor */
 487                 printf ("\033[?47l\033[u"); /* primary screen, restore cursor */
 488                 raw_mode(0);
 489         }
 490 }
 491
 492 /* http://users.csc.calpoly.edu/~phatalsk/357/lectures/code/sigalrm.c */
 493 void raw_mode(int enable) {
 494         static struct termios saved_term_mode;
 495         struct termios raw_term_mode;
 496
 497         if (enable) {
 498                 tcgetattr(STDIN_FILENO, &saved_term_mode);
 499                 raw_term_mode = saved_term_mode;
 500                 raw_term_mode.c_lflag &= ~(ICANON | ECHO);
 501                 raw_term_mode.c_cc[VMIN] = 1 ;
 502                 raw_term_mode.c_cc[VTIME] = 0;
 503                 tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw_term_mode);
 504         } else {
 505                 tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_term_mode);
 506         }
 507 }