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* n;/* next direction events to process */
  60 } g;
  61
  62 struct opt {
  63         int l; /* initial snake length */
  64         int s; /* initial snake speed */
  65         struct scheme* scheme;
  66 } op;
  67
  68 jmp_buf game_over;
  69
  70 int main (int argc, char** argv) {
  71         /* defaults: */
  72         g.w = 30; //two-char-width
  73         g.h = 20;
  74         op.l = 10;
  75         op.s = 8;
  76         op.scheme = &unic0de;
  77
  78         int optget;
  79         opterr = 0; /* don't print message on unrecognized option */
  80         while ((optget = getopt (argc, argv, "+s:dh")) != -1) {
  81                 switch (optget) {
  82                 case 's':
  83                         op.s = atof(optarg);
  84                         if (op.s < 1) {
  85                                 fprintf (stderr, SHORTHELP "speed must be >= 1\n", argv[0]);
  86                                 return 1;
  87                         }
  88                         break;
  89                 case 'd': op.scheme = &vt220_charset; break;
  90                 case 'h':
  91                 default:
  92                         fprintf (stderr, SHORTHELP LONGHELP, argv[0]);
  93                         return !(optget=='h');
  94                 }
  95         } if (optind < argc) { /* parse Fieldspec */
  96                 int n = sscanf (argv[optind], "%dx%d", &g.w, &g.h);
  97
  98                 if (n < 2) {
  99                         fprintf (stderr, SHORTHELP "FIELDSIZE is WxH (width 'x' height)\n", argv[0]);
 100                         return 1;
 101                 }
 102         }
 103
 104         clamp_fieldsize();
 105
 106         srand(time(0));
 107         signal_setup();
 108         screen_setup(1);
 109         atexit (*quit);
 110
 111         if (sigsetjmp(game_over, 1)) {
 112                 timer_setup(0);
 113                 move_ph (g.h/2+LINE_OFFSET, g.w);
 114                 printf ("snek ded :(");
 115                 fflush(stdout);
 116                 sleep(2);
 117                 exit(0);
 118         }
 119
 120         //TODO: call viiper() in a game loop
 121         viiper();
 122 quit:
 123         return 0;
 124 }
 125
 126 int viiper(void) {
 127         init_snake();
 128         show_playfield ();
 129         g.d = EAST;
 130         g.v = op.s;
 131
 132         timer_setup(1);
 133         g.t = time(NULL);
 134
 135         spawn_item(FOOD, rand() % NUM_FOODS, NULL); //TODO: shape distribution, so bigger values get selected less
 136
 137         for(;;) {
 138                 switch (getctrlseq()) {
 139                 case CTRSEQ_CURSOR_LEFT: case 'h':append_movement(WEST);  break;
 140                 case CTRSEQ_CURSOR_DOWN: case 'j':append_movement(SOUTH); break;
 141                 case CTRSEQ_CURSOR_UP:   case 'k':append_movement(NORTH); break;
 142                 case CTRSEQ_CURSOR_RIGHT:case 'l':append_movement(EAST);  break;
 143                 case 'p':
 144                         timer_setup(0);
 145                         move_ph (g.h/2+LINE_OFFSET, g.w*CW/2);
 146                         printf ("\033[5mPAUSE\033[0m"); /* blinking text */
 147                         if (getchar() == 'q') exit(0);
 148                         timer_setup(1);
 149                         break;
 150                 case 'r': /*TODO:restart*/ return 0;
 151                 case 'q': return 0;
 152                 case CTRL_'L':
 153                         screen_setup(1);
 154                         show_playfield();
 155                         break;
 156                 case 0x02: /* STX; gets sent when returning from SIGALRM */
 157                         break;
 158                 }
 159
 160                 show_playfield ();//TODO: only redraw diff
 161         }
 162
 163 }
 164
 165 void snake_advance (void) {
 166         if (g.n) {/* new direction in the buffer */
 167                 int possible_new_dir = get_movement();
 168                 if (g.d != OPPOSITE(possible_new_dir))
 169                         g.d = possible_new_dir;
 170         }
 171
 172         int new_row = g.s->r +(g.d==SOUTH) -(g.d==NORTH);
 173         int new_col = g.s->c +(g.d==EAST)  -(g.d==WEST);
 174
 175         /* detect food hit and spawn a new food */
 176         for (struct item* i = g.i; i; i = i->next) {
 177                 if (i->r == new_row && i->c == new_col) {
 178                         consume_item (i);
 179                         spawn_item(FOOD, rand() % NUM_FOODS, i);
 180                 }
 181         }
 182
 183         /* NOTE: we are drawing the snake 1 column too far to the left, so it
 184         can directly touch the vertical walls. this also means that we essen-
 185         tially extend the width by 1 cell, so we need to check against g.w+1. */
 186         if (new_row >= g.h || new_col >= g.w+1 || 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/*<-will be the retval of setjmp*/);
 195         new_head = new_tail->next; /* reuse element instead of malloc() */
 196         new_tail->next = NULL;
 197
 198         new_head->r = new_row;
 199         new_head->c = new_col;
 200         new_head->next = g.s;
 201
 202         g.s = new_head;
 203 }
 204
 205 void spawn_item (int type, int value, struct item* p_item) {
 206         int row, col;
 207 try_again:
 208         row = rand() % g.h;
 209         col = rand() % g.w;
 210         /* loop through snake to check if we aren't on it */
 211         //WARN: inefficient as snake gets longer; near impossible in the end
 212         for (struct snake* s = g.s; s; s = s->next)
 213                 if (s->r == row && s->c == col) goto try_again;
 214
 215         struct item* new_item;
 216         if (p_item) new_item = p_item;
 217         else new_item = malloc (sizeof(struct item));
 218
 219         new_item->r = row;
 220         new_item->c = col;
 221         new_item->t = type;
 222         new_item->v = value;
 223         new_item->s = time(0);
 224         if (g.i) g.i->prev = new_item;
 225         new_item->next = g.i;
 226         new_item->prev = NULL;
 227
 228         g.i = new_item;
 229 }
 230
 231 void consume_item (struct item* i) {
 232         switch (i->t) {
 233         case FOOD:
 234                 switch (i->v) {
 235                 case FOOD_5:  g.p +=  5; break;
 236                 case FOOD_10: g.p += 10; break;
 237                 case FOOD_20: g.p += 20; break;
 238                 }
 239                 snake_append(&g.s, 0,0);  /* position doesn't matter, as item */
 240                 break;       /* will be reused as the head before it is drawn */
 241         case BONUS:
 242                 //TODO: handle bonus
 243                 break;
 244         }
 245
 246         if (i->next) i->next->prev = i->prev;
 247         if (i->prev) i->prev->next = i->next;
 248         else g.i = i->next;
 249 }
 250
 251 void show_playfield (void) {
 252         move_ph (0,0);
 253
 254         /* top border */
 255         print(BORDER(T,L));
 256         printm (g.w, BORDER(T,C));
 257         printf ("%s\n", BORDER(T,R));
 258
 259         /* main area */
 260         for (int row = 0; row < g.h; row++)
 261                 printf ("%s%*s%s\n", BORDER(C,L), CW*g.w, "", BORDER(C,R));
 262
 263         /* bottom border */
 264         print(BORDER(B,L));
 265         printm (g.w, BORDER(B,C));
 266         print (BORDER(B,R));
 267
 268         /* print score */
 269         int score_width = g.p > 9999?6:4;
 270         move_ph (0, (g.w*CW-score_width)/2);
 271         printf ("%s %0*d %s", BORDER(S,L), score_width, g.p, BORDER(S,R));
 272
 273         /* print snake */
 274         struct snake* last = NULL;
 275         int color = 2;
 276         for (struct snake* s = g.s; s; s = s->next) {
 277                 move_ph (s->r+LINE_OFFSET, s->c*CW+COL_OFFSET);
 278
 279                 int predecessor = (last==NULL)?NONE:
 280                         (last->r < s->r) ? NORTH:
 281                         (last->r > s->r) ? SOUTH:
 282                         (last->c > s->c) ? EAST:
 283                         (last->c < s->c) ? WEST:NONE;
 284                 int successor = (s->next == NULL)?NONE:
 285                         (s->next->r < s->r) ? NORTH:
 286                         (s->next->r > s->r) ? SOUTH:
 287                         (s->next->c > s->c) ? EAST:
 288                         (s->next->c < s->c) ? WEST:NONE;
 289
 290                 printf ("\033[%sm", op.scheme->color[color]);
 291                 print (op.scheme->snake[predecessor][successor]);
 292                 printf ("\033[0m");
 293                 last = s;
 294                 color = !color;
 295         }
 296
 297         /* print item queue */
 298         for (struct item* i = g.i; i; i = i->next) {
 299                 move_ph (i->r+LINE_OFFSET, i->c*CW+COL_OFFSET);
 300                 if (i->t == FOOD) print (op.scheme->item[i->v]);
 301                 else if (i->t==BONUS) /* TODO: print bonus */;
 302         }
 303 }
 304
 305 void snake_append (struct snake** s, int row, int col) {
 306         struct snake* new = malloc (sizeof(struct snake));
 307         new->r = row;
 308         new->c = col;
 309         new->next = NULL;
 310
 311         if (*s) {
 312                 struct snake* p = *s;
 313                 while (p->next) p = p->next;
 314                 p->next = new;
 315         } else {
 316                 *s = new;
 317         }
 318 }
 319
 320 void init_snake() {
 321         for (int i = 0; i < op.l; i++) {
 322                 if (g.w/2-i < 0) break; /* stop if we hit left wall */
 323                 snake_append(&g.s, g.h/2, g.w/2-i);
 324         }
 325 }
 326
 327 #define free_ll(head) do{ \
 328         while (head) { \
 329                 void* tmp = head; \
 330                 head = head->next; \
 331                 free(tmp); \
 332         } \
 333 }while(0)
 334
 335 void quit (void) {
 336         screen_setup(0);
 337         free_ll(g.s);
 338         free_ll(g.i);
 339         free_ll(g.n);
 340 }
 341
 342 enum esc_states {
 343         START,
 344         ESC_SENT,
 345         CSI_SENT,
 346         MOUSE_EVENT,
 347 };
 348 int getctrlseq (void) {
 349         int c;
 350         int state = START;
 351         int offset = 0x20; /* never sends control chars as data */
 352         while ((c = getchar()) != EOF) {
 353                 switch (state) {
 354                 case START:
 355                         switch (c) {
 356                         case '\033': state=ESC_SENT; break;
 357                         default: return c;
 358                         }
 359                         break;
 360                 case ESC_SENT:
 361                         switch (c) {
 362                         case '[': state=CSI_SENT; break;
 363                         default: return CTRSEQ_INVALID;
 364                         }
 365                         break;
 366                 case CSI_SENT:
 367                         switch (c) {
 368                         case 'A': return CTRSEQ_CURSOR_UP;
 369                         case 'B': return CTRSEQ_CURSOR_DOWN;
 370                         case 'C': return CTRSEQ_CURSOR_RIGHT;
 371                         case 'D': return CTRSEQ_CURSOR_LEFT;
 372                         default: return CTRSEQ_INVALID;
 373                         }
 374                         break;
 375                 default:
 376                         return CTRSEQ_INVALID;
 377                 }
 378         }
 379         return 2;
 380 }
 381
 382 void append_movement (int dir) {
 383         struct directions* n;
 384         for (n = g.n; n && n->next; n = n->next); /* advance to the end */
 385         if (n && n->d == dir) return; /* don't add the same direction twice */
 386         if (n && n->d == OPPOSITE(dir)) return; /* don't add impossible dir. */
 387
 388         struct directions* new_event = malloc (sizeof(struct directions));
 389         new_event->d = dir;
 390         new_event->next = NULL;
 391
 392         if (g.n == NULL)
 393                 g.n = new_event;
 394         else
 395                 n->next = new_event;
 396 }
 397
 398 int get_movement (void) {
 399         if (g.n == NULL) return -1;
 400
 401         int retval = g.n->d;
 402         struct directions* delet_this = g.n;
 403         g.n = g.n->next;
 404         free(delet_this);
 405         return retval;
 406 }
 407
 408 void move_ph (int line, int col) {
 409         /* move printhead to zero-indexed position */
 410         printf ("\033[%d;%dH", line+1, col+1);
 411 }
 412
 413 void clamp_fieldsize (void) {
 414         /* clamp field size to terminal size and mouse maximum: */
 415         struct winsize w;
 416         ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
 417
 418         if (g.w < 10) g.w = 10;
 419         if (g.h < 10) g.h = 10;
 420
 421         if (COL_OFFSET + g.w*CW + COL_OFFSET > w.ws_col)
 422                 g.w = (w.ws_col - COL_OFFSET - COL_OFFSET)/CW-1; //TODO: does not work in `-d' (in xterm)
 423         if (LINE_OFFSET + g.h + LINES_AFTER > w.ws_row)
 424                 g.h = w.ws_row - (LINE_OFFSET+LINES_AFTER);
 425 }
 426
 427 void timer_setup (int enable) {
 428         static struct itimerval tbuf;
 429         tbuf.it_interval.tv_sec  = 0;//TODO: make it speed up automatically
 430         tbuf.it_interval.tv_usec = (1000000/g.v)-1; /*WARN: 1 <= g.v <= 999999*/
 431
 432         if (enable) {
 433                 tbuf.it_value.tv_sec  = tbuf.it_interval.tv_sec;
 434                 tbuf.it_value.tv_usec = tbuf.it_interval.tv_usec;
 435         } else {
 436                 tbuf.it_value.tv_sec  = 0;
 437                 tbuf.it_value.tv_usec = 0;
 438         }
 439
 440         if ( setitimer(ITIMER_REAL, &tbuf, NULL) == -1 ) {
 441                 perror("setitimer");
 442                 exit(1);
 443         }
 444
 445 }
 446
 447 void signal_setup (void) {
 448         struct sigaction saction;
 449
 450         saction.sa_handler = signal_handler;
 451         sigemptyset(&saction.sa_mask);
 452         saction.sa_flags = 0;
 453         if (sigaction(SIGALRM, &saction, NULL) < 0 ) {
 454                 perror("SIGALRM");
 455                 exit(1);
 456         }
 457
 458         if (sigaction(SIGINT, &saction, NULL) < 0 ) {
 459                 perror ("SIGINT");
 460                 exit (1);
 461         }
 462 }
 463
 464 void signal_handler (int signum) {
 465         switch (signum) {
 466         case SIGALRM:
 467                 snake_advance();
 468                 break;
 469         case SIGINT:
 470                 exit(128+SIGINT);
 471         }
 472 }
 473
 474 void screen_setup (int enable) {
 475         if (enable) {
 476                 raw_mode(1);
 477                 printf ("\033[s\033[?47h"); /* save cursor, alternate screen */
 478                 printf ("\033[H\033[J"); /* reset cursor, clear screen */
 479                 printf ("\033[?25l"); /* hide cursor */
 480                 print (op.scheme->init_seq); /* swich charset, if necessary */
 481         } else {
 482                 print (op.scheme->reset_seq); /* reset charset, if necessary */
 483                 printf ("\033[?25h"); /* show cursor */
 484                 printf ("\033[?47l\033[u"); /* primary screen, restore cursor */
 485                 raw_mode(0);
 486         }
 487 }
 488
 489 /* http://users.csc.calpoly.edu/~phatalsk/357/lectures/code/sigalrm.c */
 490 void raw_mode(int enable) {
 491         static struct termios saved_term_mode;
 492         struct termios raw_term_mode;
 493
 494         if (enable) {
 495                 tcgetattr(STDIN_FILENO, &saved_term_mode);
 496                 raw_term_mode = saved_term_mode;
 497                 raw_term_mode.c_lflag &= ~(ICANON | ECHO);
 498                 raw_term_mode.c_cc[VMIN] = 1 ;
 499                 raw_term_mode.c_cc[VTIME] = 0;
 500                 tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw_term_mode);
 501         } else {
 502                 tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_term_mode);
 503         }
 504 }