From 614ce60ee66189eada508a0bfb9185689c09c601 Mon Sep 17 00:00:00 2001
From: Tomasz Kramkowski <tk@the-tk.com>
Date: Sun, 22 Mar 2015 15:27:54 +0000
Subject: snake game, link with -lncurses

---
 snake.c | 266 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 266 insertions(+)
 create mode 100644 snake.c

diff --git a/snake.c b/snake.c
new file mode 100644
index 0000000..019228a
--- /dev/null
+++ b/snake.c
@@ -0,0 +1,266 @@
+#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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