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#include <ncurses.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
enum colorpair {
C_BLANK = 1,
C_WALL,
C_SEGMENT0,
C_SEGMENT1,
C_APPLE
};
enum direction {
D_UP,
D_DOWN,
D_LEFT,
D_RIGHT
};
enum state {
S_NORMAL,
S_WON,
S_FAIL
};
struct segment {
uint32_t x, y;
};
struct snake {
struct segment segments[UINT16_MAX];
uint16_t head, tail;
enum direction direction;
} snake;
struct apple {
uint32_t x, y;
};
struct {
struct snake snake;
struct apple apple;
uint32_t width, height;
bool running;
enum state state;
} game;
void init_game(void);
void init_ncurses(void);
void main_loop(void);
int main(void)
{
init_ncurses();
init_game();
main_loop();
return EXIT_SUCCESS;
}
void init_ncurses(void)
{
initscr();
cbreak();
noecho();
nonl();
start_color();
intrflush(stdscr, FALSE);
keypad(stdscr, TRUE);
nodelay(stdscr, TRUE);
init_pair(C_BLANK, COLOR_BLACK, COLOR_BLACK);
init_pair(C_WALL, COLOR_WHITE, COLOR_WHITE);
init_pair(C_SEGMENT0, COLOR_YELLOW, COLOR_YELLOW);
init_pair(C_SEGMENT1, COLOR_GREEN, COLOR_GREEN);
init_pair(C_APPLE, COLOR_RED, COLOR_RED);
bkgd(COLOR_PAIR(C_BLANK));
}
void init_game(void)
{
game.running = true;
game.state = S_NORMAL;
game.snake.direction = D_UP;
getmaxyx(stdscr, game.height, game.width);
game.snake.head = 1;
game.snake.tail = 0;
game.snake.segments[game.snake.tail].x = game.width / 2;
game.snake.segments[game.snake.tail].y = game.height / 2;
game.snake.segments[game.snake.head].x = game.width / 2;
game.snake.segments[game.snake.head].y = game.height / 2 - 1;
game.apple.x = game.width / 2;
game.apple.y = game.height / 2 + 1;
}
void print_board(void);
void poll_input(void);
void simulate(void);
void main_loop(void)
{
while (true) {
poll_input();
if (!game.running)
break;
simulate();
if (!game.running)
break;
print_board();
usleep(100000);
}
}
void print_board(void)
{
erase();
for (uint16_t i = game.snake.tail; i <= game.snake.head; i++) {
chtype ch;
if (!!(i % 2))
ch = ACS_BLOCK | COLOR_PAIR(C_SEGMENT0);
else
ch = ACS_BLOCK | COLOR_PAIR(C_SEGMENT1);
mvaddch(game.snake.segments[i].y, game.snake.segments[i].x, ch);
}
mvaddch(game.apple.y, game.apple.x, ACS_BLOCK | COLOR_PAIR(C_APPLE));
refresh();
}
void redirect(enum direction desired_dir);
void poll_input(void)
{
int c;
while ((c = getch()) != ERR)
switch (c) {
case 'h': redirect(D_LEFT); break;
case 'j': redirect(D_DOWN); break;
case 'k': redirect(D_UP); break;
case 'l': redirect(D_RIGHT); break;
case 'q': game.running = false; break;
}
}
void redirect(enum direction desired_dir)
{
struct segment *current = &game.snake.segments[game.snake.head];
struct segment *previous = &game.snake.segments[game.snake.head - 1];
if (desired_dir == game.snake.direction)
return;
if (current->x == previous->x)
if (current->y > previous->y) {
if (desired_dir == D_UP)
return;
} else {
if (desired_dir == D_DOWN)
return;
}
else if (current->y == previous->y)
if (current->x > previous->x) {
if (desired_dir == D_LEFT)
return;
} else {
if (desired_dir == D_RIGHT)
return;
}
game.snake.direction = desired_dir;
}
inline uint16_t rand_to_max(uint16_t max)
{
double random;
while ((random = rand()) == (double)RAND_MAX);
return random / (double)RAND_MAX * (double)max;
}
bool part_of_snake(uint16_t x, uint16_t y);
void replace_apple(void)
{
uint16_t x, y;
while (true) {
x = rand_to_max(game.width);
y = rand_to_max(game.height);
if (part_of_snake(x, y))
continue;
game.apple.x = x;
game.apple.y = y;
break;
}
}
void simulate(void)
{
struct segment *current = &game.snake.segments[game.snake.head];
int64_t dx = 0, dy = 0, nx, ny;
switch (game.snake.direction) {
case D_UP: dy = -1; break;
case D_DOWN: dy = 1; break;
case D_LEFT: dx = -1; break;
case D_RIGHT: dx = 1; break;
}
nx = (int64_t)current->x + dx;
ny = (int64_t)current->y + dy;
if (nx < 0 || nx >= game.width || ny < 0 || ny >= game.height) {
game.running = false;
game.state = S_FAIL;
return;
}
if (nx == game.apple.x && ny == game.apple.y) {
game.snake.head++;
game.snake.segments[game.snake.head].x = nx;
game.snake.segments[game.snake.head].y = ny;
replace_apple();
return;
}
if (part_of_snake(nx, ny)) {
game.running = false;
game.state = S_FAIL;
return;
}
game.snake.head++;
game.snake.segments[game.snake.head].x = nx;
game.snake.segments[game.snake.head].y = ny;
game.snake.tail++;
}
bool part_of_snake(uint16_t x, uint16_t y)
{
for (uint16_t i = game.snake.tail; i != game.snake.head; i++)
if (game.snake.segments[i].x == x && game.snake.segments[i].y == y)
return true;
return false;
}
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