wordclock/games/snake/snake_game.c

#include "../../config.h"
#include "../../compat/pgmspace.h"
#include "../../menu/menu.h"
#include "../../pixel.h"
#include "../../random/prng.h"
#include "../../util.h"
#include "../../joystick/joystick.h"

// if defined, joystick controls are NOT as "seen"
// by the snake but absolute, that is, if pressing
// up, snake goes up, etc.
#define GAME_SNAKE_NEWCONTROL

void snake_game();

#ifdef MENU_SUPPORT
// MSB is leftmost pixel
static uint8_t icon[8] PROGMEM =
{0xff, 0x81, 0xbd, 0xa5, 0xa5, 0xad, 0xa1, 0xbf}; // Snake icon

game_descriptor_t snake_game_descriptor __attribute__((section(".game_descriptors"))) =
		{&snake_game, icon};
#endif

void snake_game()
{
	pixel pixels[64] = {{4, NUM_ROWS - 2}, {4, NUM_ROWS - 3}};
	pixel *head = &pixels[1];
	pixel *tail = &pixels[0];
	pixel old_head;

	pixel apples[10];
	unsigned char apple_num = 0;
	direction dir = up;

	clear_screen(0);

	unsigned char apple_found = 0;
	unsigned char j;

	unsigned char x, y, dead = 0;
	uint8_t joy, joy_old = 0xff, joy_cmd = 0xff;

	// zeichne Rahmen
	for (x = 0; x < NUM_COLS; x++)
	{
		for (y = 0; y < NUM_ROWS; y++)
		{
			if (((x == 0) || (x == NUM_COLS - 1)) || ((y == 0) || (y
					== NUM_ROWS - 1)))
			{
				setpixel((pixel) {x, y}, 3);
			}
		}
	}

	x = 0;
	while (1)
	{
		x++;
		old_head = *head;
		if (++head == pixels + 64)
			head = pixels;

#ifdef GAME_SNAKE_NEWCONTROL			
		if (joy_cmd != 0xff)
		{
			if ((dir == left && joy_cmd != right) || (dir == right && joy_cmd
					!= left) || (dir == up && joy_cmd != down) || (dir == down
					&& joy_cmd != up))
				dir = joy_cmd;
		}
#else
		if (joy_cmd == right)
		{
			dir = direction_r(dir);
			joy_cmd = 0xff;
		}
		else if (joy_cmd == left)
		{
			dir = direction_r(dir);
			dir = direction_r(dir);
			dir = direction_r(dir);
			joy_cmd = 0xff;
		}
#endif

		// kopf einen weiter bewegen
		*head = next_pixel(old_head, dir);

		apple_found = 0;

		// pr?fen ob man auf nen Apfel drauf ist 
		for (j = 0; j < apple_num; j++)
		{
			if ((head->x == apples[j].x) && (head->y == apples[j].y))
			{
				apple_found = 1;
				for (; j < apple_num - 1; j++)
				{
					apples[j] = apples[j + 1];
				}
				apple_num--;
				goto apple_se;
			}
		}
		if (get_pixel(*head))
		{
			dead = 1;
		}
		apple_se:

		if (!dead)
		{
			setpixel(*head, 3);

			// setze neue ?pfel
			if ((apple_num < 9) && (random8() < 10))
			{
				pixel new_apple = (pixel) {(random8() % (NUM_COLS-2))+1, 
										   (random8() % (NUM_ROWS-2))+1};
				if (!get_pixel(new_apple))
				{
					apples[apple_num++] = new_apple;
				}
			}
			// l?sche Ende
			if (!apple_found && !dead)
			{
				clearpixel(*tail);
				if (++tail == pixels + 64)
					tail = pixels;
			}
		}
		else
		{
			while (tail != head)
			{
				clearpixel(*tail);
				if ((++tail) > pixels + 64)
					tail = pixels;
				wait(60);
			}
			break;
		}

		for (j = 0; j < apple_num; j++)
		{
			if (x % 2)
			{
				setpixel(apples[j], 3);
			}
			else
			{
				clearpixel(apples[j]);
			}
		}
		for (j = 0; j < 20; j++)
		{
			if (JOYISLEFT)
			{
				joy = left;
			}
			else if (JOYISRIGHT)
			{
				joy = right;
#ifdef GAME_SNAKE_NEWCONTROL
			}
			else if (JOYISUP)
			{
				joy = up;
			}
			else if (JOYISDOWN)
			{
				joy = down;
#endif
			}
			else
			{
				joy = 0xff;
			}
			if (joy != joy_old)
			{
				joy_cmd = joy;
			}
			joy_old = joy;
			wait(5);
		}
	}
}