diff options
Diffstat (limited to 'snake.c')
| -rw-r--r-- | snake.c | 331 |
1 files changed, 331 insertions, 0 deletions
@@ -0,0 +1,331 @@ +/* + * A simple implementation of the snake game. + * Compile with: `make LDLIBS=-lncurses snake' + * + * Copyright (C) 2015 Tomasz Kramkowski <tk@the-tk.com> + * + * This program is free software. It is licensed under version 3 of the + * GNU General Public License. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see [http://www.gnu.org/licenses/]. + */ +#include <argp.h> +#include <ncurses.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdlib.h> +#include <unistd.h> + +#define USEC_SECOND 1000000 + +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; +}; + +struct apple { + uint32_t x, y; +}; + +struct { + struct snake snake; + struct apple apple; + uint32_t width, height; + bool running; + enum state state; + bool alternate_color; +} game; + +struct arguments { + useconds_t delay; + uint16_t desired_width, desired_height; + bool alternate_color; +} arguments; + +const char *argp_program_version = "1.0rc1"; +const char *argp_program_bug_address = "<snake@the-tk.com>"; + +void init_ncurses(void) +{ + cbreak(); + initscr(); + 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) +{ + erase(); + + for (uint16_t i = game.snake.tail; i <= game.snake.head; i++) { + chtype ch; + + if ((i - game.snake.head * !arguments.alternate_color) % 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) +{ + 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; +} + +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; + } +} + +inline uint16_t rand_to_max(uint16_t max) +{ + double random; + + while ((random = rand()) == (double)RAND_MAX); + return random / (double)RAND_MAX * (double)max; +} + +inline 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; +} + +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 *head = &game.snake.segments[game.snake.head]; + struct segment *tail = &game.snake.segments[game.snake.tail]; + 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)head->x + dx; + ny = (int64_t)head->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) && !(tail->x == nx && tail->y == 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++; +} + +void main_loop(void) +{ + print_board(); + poll_input(); + + while (game.running) { + usleep(arguments.delay); + poll_input(); + simulate(); + print_board(); + } +} + +error_t parse_arg(int key, char *arg, struct argp_state *state) +{ + struct arguments *arguments = state->input; + + switch (key) { + case 'w': + fprintf(stderr, "Width setting is not yet implemented.\n"); + arguments->desired_width = strtol(arg, NULL, 10); + break; + case 'h': + fprintf(stderr, "Height setting is not yet implemented.\n"); + arguments->desired_height = strtol(arg, NULL, 10); + break; + case 'a': + arguments->alternate_color = true; + break; + case 'd': + arguments->delay = strtod(arg, NULL) * (double)USEC_SECOND; + break; + default: + return ARGP_ERR_UNKNOWN; + } + + return 0; +} + +void parse_args(int argc, char **argv) +{ + char *doc = "An ncurses implementation of snake in c."; + + struct argp_option options[] = { + {"width", 'w', "<width>", 0, "Desired width.", 0}, + {"height", 'h', "<height>", 0, "Desired height.", 0}, + {"alternate", 'a', NULL, 0, "Alternate snake colour.", 0}, + {"delay", 'd', "<seconds>", 0, "Delay between ticks in seconds. (default: 0.1)", 0}, + {0} + }; + + struct argp argp = {options, parse_arg, NULL, doc, NULL, NULL, NULL}; + + arguments.desired_width = 0; + arguments.desired_height = 0; + arguments.alternate_color = false; + arguments.delay = (double)USEC_SECOND * 0.1; + + argp_parse(&argp, argc, argv, 0, 0, &arguments); +} + +int main(int argc, char **argv) +{ + parse_args(argc, argv); + init_ncurses(); + init_game(); + + main_loop(); + + endwin(); + return EXIT_SUCCESS; +} |