snake_c

public

Small snake game in C

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#include <unistd.h>

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>

#include <time.h>
#include <sys/time.h>
#include <string.h>
#include <termios.h>

#define RIGHT_CODE 'C'
#define LEFT_CODE 'D'
#define UP_CODE 'A'
#define DOWN_CODE 'B'

#define WIDTH 50
#define HEIGHT 50

#define SPEED 100 /* in ms */

#define MAX_LENGTH 1000
#define STARTING_LENGTH 2

typedef enum {
  UP, DOWN, LEFT, RIGHT
} direction;

typedef enum {
  EMPTY, SNAKE, HEAD, FRUIT
} field_content;

typedef struct selected {
  int16_t x;
  int16_t y;
} selected;

typedef struct snake {
  selected position[MAX_LENGTH];
  uint16_t length;
} snake;


void update_field(snake my_snake, field_content board[HEIGHT][WIDTH], selected fruit);
selected new_fruit(field_content board[HEIGHT][WIDTH]);

void draw_board(field_content board[HEIGHT][WIDTH], bool redraw);
void draw_pause();

direction read_direction (char* string, direction shift);


int main() {

  struct termios old, new;

  tcgetattr(STDIN_FILENO, &old);

  new = old;

  new.c_lflag &= ~(ECHO | ICANON);
  new.c_cc[VMIN] = 0;
  new.c_cc[VTIME] = 1;

  tcsetattr(STDIN_FILENO, TCSANOW, &new);

  srand(time(NULL));


  snake my_snake = {};  
  my_snake.length = STARTING_LENGTH;

  {
    uint16_t i;
    
    my_snake.position[0].x = HEIGHT >> 1;
    my_snake.position[0].y = WIDTH >> 1;
    for (i = 1; i < my_snake.length; i++) {
      my_snake.position[i].y = -1;
      my_snake.position[i].x = -1;
    }
  }

  selected fruit = {-1, -1};

  field_content board[HEIGHT][WIDTH] = {0};

  update_field(my_snake, board, fruit);

  fruit = new_fruit(board);
  update_field(my_snake, board, fruit);


  printf("\033[?25l");
  draw_board(board, false);


  direction shift = RIGHT;


  struct timeval start, current;

  gettimeofday(&start, NULL);


  bool paused = false;
  bool run = true;

  while (run) {

    char string[1000] = {};
    ssize_t n = read(STDIN_FILENO, string, sizeof(string) - 1);
    
    gettimeofday(&current, NULL);

    if (n > 0) {
      string[n] = '\0';
  
      if (!paused)
        shift = read_direction(string, shift);

      if (strstr(string, "q"))
        run = false;

       if (strstr(string, "p")) {
          paused = !paused;
          if (paused)
            draw_pause();
      }
    }

    uint64_t time_diff = (current.tv_sec - start.tv_sec) * 1000000 + (current.tv_usec - start.tv_usec);

    if ((time_diff >= SPEED * 1000) && !paused) {
      
      start = current;

      uint16_t i;
      for (i = my_snake.length; i > 0; i--) {
        my_snake.position[i].y = my_snake.position[i - 1].y;
        my_snake.position[i].x = my_snake.position[i - 1].x;
      }

      switch (shift) {
        case UP:
          my_snake.position[0].y = ((my_snake.position[0].y + HEIGHT - 1) % HEIGHT);
          break;
        case DOWN:
          my_snake.position[0].y = ((my_snake.position[0].y + 1) % HEIGHT);
          break;
        case LEFT:
          my_snake.position[0].x = ((my_snake.position[0].x + WIDTH - 1) % WIDTH);
          break;
        case RIGHT:
          my_snake.position[0].x = ((my_snake.position[0].x + 1) % WIDTH);
          break;
      }
    
      uint8_t head_y = my_snake.position[0].y;
      uint8_t head_x = my_snake.position[0].x;

            if (head_y == fruit.y && head_x == fruit.x) {
        my_snake.length++;
        fruit = new_fruit(board);
      }


      update_field(my_snake, board, fruit);
      draw_board(board, true);

      for (i = 1; i < my_snake.length; i++) {
        int16_t x = my_snake.position[i].x;
        int16_t y = my_snake.position[i].y;

        if (
          x == head_x && 
          y == head_y
        ) {
          printf("\n\nHAHA LOST!!!\n\n");
          goto end_of_program;
        }
      }

    }

  }

end_of_program:

  tcsetattr(STDIN_FILENO, TCSANOW, &old);
  printf("\033[?25h");

  return 0;
}





void update_field(snake my_snake, field_content board[HEIGHT][WIDTH], selected fruit) {
  
  uint8_t i, j;

  for (i = 0; i < HEIGHT; i++) {
    for (j = 0; j < WIDTH; j++) {   
      board[i][j] = EMPTY;
    }
  }

  for (i = 0; i < my_snake.length; i++) {
    int16_t x = my_snake.position[i].x;
    int16_t y = my_snake.position[i].y;
    if (x >= 0 && y >= 0)
      board[y][x] = (i == 0) ? HEAD : SNAKE;
  }
  
  if (fruit.x >= 0 && fruit.y >= 0)
    board[fruit.y][fruit.x] = FRUIT;
}


selected new_fruit(field_content board[HEIGHT][WIDTH]) {
  bool found_space = false;

  uint8_t x;
  uint8_t y;

  while (!found_space) {
    x = rand() % WIDTH;
    y = rand() % HEIGHT;

    if (board[y][x] == EMPTY)
      found_space = true;
  }

  selected fruit = {y, x};

  return fruit;
}


void draw_board (field_content board[HEIGHT][WIDTH], bool redraw) {
  
  uint8_t i, j; 

  if (redraw) {
    for (i = 0; i < HEIGHT + 2; i++)
      printf("\033[A");
    printf("\r");
  }

  printf("+");
  for (i = 0; i < WIDTH; i++)
    printf("--");
  printf("+\n");

  for ( i = 0; i < HEIGHT; i++) {

    printf("|");

    for (j = 0; j < WIDTH; j++) {

      switch (board[i][j]) {
        case EMPTY:
          printf("  ");
          break;
        case SNAKE:
          printf("\033[31m x\033[0m");
          break;
        case HEAD:
          printf("\033[32m X\033[0m");
          break;
        case FRUIT:
          printf("\033[34m O\033[0m");
          break;
      }
    }
    printf("|\n");
  }

    printf("+");
  for (i = 0; i < WIDTH; i++)
    printf("--");
  printf("+\n");
}


void draw_pause() {

  const uint8_t height = 5;
  const uint8_t width = 14;

  char *pause_menu [] = {
    "+------------+",
    "|            |",
    "|   PAUSED   |",
    "|            |",
    "+------------+"
  };

  uint8_t i, j;

  const uint8_t going_up = (HEIGHT + height) >> 1;
  const uint8_t going_right = (WIDTH * 2 - width) >> 1;

  for (i = 0; i < going_up; i++)
    printf("\033[%c", UP_CODE);
  printf("\r");

  for (i = 0; i < height; i++) {
    for (j = 0; j < going_right; j++)
      printf("\033[%c", RIGHT_CODE);

    printf("\033[30m%s\033[0m\033[%c\r", pause_menu[i], DOWN_CODE);
  }

  for (i = 0; i < going_up - height; i++)
    printf("\033[%c", DOWN_CODE);
  printf("\r");

  fflush(stdout);
}


direction read_direction (char* string, direction shift) {

  if (strlen(string) >= 3) {
    if (string[0] == '\033') {
      if (string[1] == '[') {
       
        switch (string[2]) {
          case RIGHT_CODE:
            if (shift != LEFT)
              return RIGHT;
            break;
          case LEFT_CODE:
            if (shift != RIGHT)
              return LEFT;
            break;
          case UP_CODE:
            if (shift != DOWN)
              return UP;
            break;
          case DOWN_CODE:
            if (shift != UP)
              return DOWN;
            break;
        }          
      }
    }
  }

  return shift;
}

1	#include <unistd.h>
2
3	#include <stdio.h>
4	#include <stdint.h>
5	#include <stdbool.h>
6	#include <stdlib.h>
7
8	#include <time.h>
9	#include <sys/time.h>
10	#include <string.h>
11	#include <termios.h>
12
13	#define RIGHT_CODE 'C'
14	#define LEFT_CODE 'D'
15	#define UP_CODE 'A'
16	#define DOWN_CODE 'B'
17
18	#define WIDTH 50
19	#define HEIGHT 50
20
21	#define SPEED 100 /* in ms */
22
23	#define MAX_LENGTH 1000
24	#define STARTING_LENGTH 2
25
26	typedef enum {
27	UP, DOWN, LEFT, RIGHT
28	} direction;
29
30	typedef enum {
31	EMPTY, SNAKE, HEAD, FRUIT
32	} field_content;
33
34	typedef struct selected {
35	int16_t x;
36	int16_t y;
37	} selected;
38
39	typedef struct snake {
40	selected position[MAX_LENGTH];
41	uint16_t length;
42	} snake;
43
44
45	void update_field(snake my_snake, field_content board[HEIGHT][WIDTH], selected fruit);
46	selected new_fruit(field_content board[HEIGHT][WIDTH]);
47
48	void draw_board(field_content board[HEIGHT][WIDTH], bool redraw);
49	void draw_pause();
50
51	direction read_direction (char* string, direction shift);
52
53
54	int main() {
55
56	struct termios old, new;
57
58	tcgetattr(STDIN_FILENO, &old);
59
60	new = old;
61
62	new.c_lflag &= ~(ECHO \| ICANON);
63	new.c_cc[VMIN] = 0;
64	new.c_cc[VTIME] = 1;
65
66	tcsetattr(STDIN_FILENO, TCSANOW, &new);
67
68	srand(time(NULL));
69
70
71	snake my_snake = {};
72	my_snake.length = STARTING_LENGTH;
73
74	{
75	uint16_t i;
76
77	my_snake.position[0].x = HEIGHT >> 1;
78	my_snake.position[0].y = WIDTH >> 1;
79	for (i = 1; i < my_snake.length; i++) {
80	my_snake.position[i].y = -1;
81	my_snake.position[i].x = -1;
82	}
83	}
84
85	selected fruit = {-1, -1};
86
87	field_content board[HEIGHT][WIDTH] = {0};
88
89	update_field(my_snake, board, fruit);
90
91	fruit = new_fruit(board);
92	update_field(my_snake, board, fruit);
93
94
95	printf("\033[?25l");
96	draw_board(board, false);
97
98
99	direction shift = RIGHT;
100
101
102	struct timeval start, current;
103
104	gettimeofday(&start, NULL);
105
106
107	bool paused = false;
108	bool run = true;
109
110	while (run) {
111
112	char string[1000] = {};
113	ssize_t n = read(STDIN_FILENO, string, sizeof(string) - 1);
114
115	gettimeofday(&current, NULL);
116
117	if (n > 0) {
118	string[n] = '\0';
119
120	if (!paused)
121	shift = read_direction(string, shift);
122
123	if (strstr(string, "q"))
124	run = false;
125
126	if (strstr(string, "p")) {
127	paused = !paused;
128	if (paused)
129	draw_pause();
130	}
131	}
132
133	uint64_t time_diff = (current.tv_sec - start.tv_sec) * 1000000 + (current.tv_usec - start.tv_usec);
134
135	if ((time_diff >= SPEED * 1000) && !paused) {
136
137	start = current;
138
139	uint16_t i;
140	for (i = my_snake.length; i > 0; i--) {
141	my_snake.position[i].y = my_snake.position[i - 1].y;
142	my_snake.position[i].x = my_snake.position[i - 1].x;
143	}
144
145	switch (shift) {
146	case UP:
147	my_snake.position[0].y = ((my_snake.position[0].y + HEIGHT - 1) % HEIGHT);
148	break;
149	case DOWN:
150	my_snake.position[0].y = ((my_snake.position[0].y + 1) % HEIGHT);
151	break;
152	case LEFT:
153	my_snake.position[0].x = ((my_snake.position[0].x + WIDTH - 1) % WIDTH);
154	break;
155	case RIGHT:
156	my_snake.position[0].x = ((my_snake.position[0].x + 1) % WIDTH);
157	break;
158	}
159
160	uint8_t head_y = my_snake.position[0].y;
161	uint8_t head_x = my_snake.position[0].x;
162
163	if (head_y == fruit.y && head_x == fruit.x) {
164	my_snake.length++;
165	fruit = new_fruit(board);
166	}
167
168
169	update_field(my_snake, board, fruit);
170	draw_board(board, true);
171
172	for (i = 1; i < my_snake.length; i++) {
173	int16_t x = my_snake.position[i].x;
174	int16_t y = my_snake.position[i].y;
175
176	if (
177	x == head_x &&
178	y == head_y
179	) {
180	printf("\n\nHAHA LOST!!!\n\n");
181	goto end_of_program;
182	}
183	}
184
185	}
186
187	}
188
189	end_of_program:
190
191	tcsetattr(STDIN_FILENO, TCSANOW, &old);
192	printf("\033[?25h");
193
194	return 0;
195	}
196
197
198
199
200
201	void update_field(snake my_snake, field_content board[HEIGHT][WIDTH], selected fruit) {
202
203	uint8_t i, j;
204
205	for (i = 0; i < HEIGHT; i++) {
206	for (j = 0; j < WIDTH; j++) {
207	board[i][j] = EMPTY;
208	}
209	}
210
211	for (i = 0; i < my_snake.length; i++) {
212	int16_t x = my_snake.position[i].x;
213	int16_t y = my_snake.position[i].y;
214	if (x >= 0 && y >= 0)
215	board[y][x] = (i == 0) ? HEAD : SNAKE;
216	}
217
218	if (fruit.x >= 0 && fruit.y >= 0)
219	board[fruit.y][fruit.x] = FRUIT;
220	}
221
222
223	selected new_fruit(field_content board[HEIGHT][WIDTH]) {
224	bool found_space = false;
225
226	uint8_t x;
227	uint8_t y;
228
229	while (!found_space) {
230	x = rand() % WIDTH;
231	y = rand() % HEIGHT;
232
233	if (board[y][x] == EMPTY)
234	found_space = true;
235	}
236
237	selected fruit = {y, x};
238
239	return fruit;
240	}
241
242
243	void draw_board (field_content board[HEIGHT][WIDTH], bool redraw) {
244
245	uint8_t i, j;
246
247	if (redraw) {
248	for (i = 0; i < HEIGHT + 2; i++)
249	printf("\033[A");
250	printf("\r");
251	}
252
253	printf("+");
254	for (i = 0; i < WIDTH; i++)
255	printf("--");
256	printf("+\n");
257
258	for ( i = 0; i < HEIGHT; i++) {
259
260	printf("\|");
261
262	for (j = 0; j < WIDTH; j++) {
263
264	switch (board[i][j]) {
265	case EMPTY:
266	printf(" ");
267	break;
268	case SNAKE:
269	printf("\033[31m x\033[0m");
270	break;
271	case HEAD:
272	printf("\033[32m X\033[0m");
273	break;
274	case FRUIT:
275	printf("\033[34m O\033[0m");
276	break;
277	}
278	}
279	printf("\|\n");
280	}
281
282	printf("+");
283	for (i = 0; i < WIDTH; i++)
284	printf("--");
285	printf("+\n");
286	}
287
288
289	void draw_pause() {
290
291	const uint8_t height = 5;
292	const uint8_t width = 14;
293
294	char *pause_menu [] = {
295	"+------------+",
296	"\| \|",
297	"\| PAUSED \|",
298	"\| \|",
299	"+------------+"
300	};
301
302	uint8_t i, j;
303
304	const uint8_t going_up = (HEIGHT + height) >> 1;
305	const uint8_t going_right = (WIDTH * 2 - width) >> 1;
306
307	for (i = 0; i < going_up; i++)
308	printf("\033[%c", UP_CODE);
309	printf("\r");
310
311	for (i = 0; i < height; i++) {
312	for (j = 0; j < going_right; j++)
313	printf("\033[%c", RIGHT_CODE);
314
315	printf("\033[30m%s\033[0m\033[%c\r", pause_menu[i], DOWN_CODE);
316	}
317
318	for (i = 0; i < going_up - height; i++)
319	printf("\033[%c", DOWN_CODE);
320	printf("\r");
321
322	fflush(stdout);
323	}
324
325
326	direction read_direction (char* string, direction shift) {
327
328	if (strlen(string) >= 3) {
329	if (string[0] == '\033') {
330	if (string[1] == '[') {
331
332	switch (string[2]) {
333	case RIGHT_CODE:
334	if (shift != LEFT)
335	return RIGHT;
336	break;
337	case LEFT_CODE:
338	if (shift != RIGHT)
339	return LEFT;
340	break;
341	case UP_CODE:
342	if (shift != DOWN)
343	return UP;
344	break;
345	case DOWN_CODE:
346	if (shift != UP)
347	return DOWN;
348	break;
349	}
350	}
351	}
352	}
353
354	return shift;
355	}