snake.c: Visual enhancements and argument parsing.

1 files changed, 92 insertions, 15 deletions

diff --git a/snake.c b/snake.c
index bda1c1d..50adaed 100644
--- a/snake.c
+++ b/snake.c
@@ -1,9 +1,24 @@
+/*
+ * 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,
@@ -33,7 +48,7 @@ struct snake {
 	struct segment segments[UINT16_MAX];
 	uint16_t head, tail;
 	enum direction direction;
-} snake;
+};
 
 struct apple {
 	uint32_t x, y;
@@ -45,12 +60,22 @@ struct {
 	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)
 {
-	initscr();
 	cbreak();
+	initscr();
 	noecho();
 	nonl();
 	start_color();
@@ -97,7 +122,7 @@ void print_board(void)
 	for (uint16_t i = game.snake.tail; i <= game.snake.head; i++) {
 		chtype ch;
 
-		if (i % 2)
+		if ((i - game.snake.head * !arguments.alternate_color) % 2)
 			ch = ACS_BLOCK | COLOR_PAIR(C_SEGMENT0);
 		else
 			ch = ACS_BLOCK | COLOR_PAIR(C_SEGMENT1);
@@ -160,7 +185,7 @@ inline uint16_t rand_to_max(uint16_t max)
 	return random / (double)RAND_MAX * (double)max;
 }
 
-bool part_of_snake(uint16_t x, uint16_t y)
+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)
@@ -189,7 +214,8 @@ void replace_apple(void)
 
 void simulate(void)
 {
-	struct segment *current = &game.snake.segments[game.snake.head];
+	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) {
@@ -199,8 +225,8 @@ void simulate(void)
 	case D_RIGHT: dx = 1; break;
 	}
 
-	nx = (int64_t)current->x + dx;
-	ny = (int64_t)current->y + dy;
+	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;
@@ -217,7 +243,7 @@ void simulate(void)
 		return;
 	}
 
-	if (part_of_snake(nx, ny)) {
+	if (part_of_snake(nx, ny) && !(tail->x == nx && tail->y == ny)) {
 		game.running = false;
 		game.state = S_FAIL;
 		return;
@@ -226,28 +252,79 @@ void simulate(void)
 	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)
 {
-	while (true) {
+	print_board();
+	poll_input();
+
+	while (game.running) {
+		usleep(arguments.delay);
 		poll_input();
-		if (!game.running)
-			break;
 		simulate();
-		if (!game.running)
-			break;
 		print_board();
-		usleep(100000);
 	}
 }
 
-int main(void)
+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;
 }