Ping Pong

Main.c
------------
#include "display.h"
#include "game.h"

#define MIN(x,y) ((x)>(y) ? (y) : (x))
#define DELAY        2
#define PAD_OFFSET    4
#define PAD_LEN_RATIO 5

#define LEFT  -1
#define RIGHT  1
#define UP    -1
#define DOWN   1

/* Starting pad1 position */
static struct position pad1_pos(int height, int width);

/* Starting pad2 position */
static struct position pad2_pos(int height, int width);

/* Starting ball position */
static struct position ball_pos(int height, int width);

/* Starting direction position */
static struct position ball_dir(void);

/* Pad length */
static int pad_len(int height);


int main() {
	int STOP = 0, cont = 0, height, width;
	unsigned int s1, s2;
	#ifdef REG
	FILE *fp;
	fp=fopen("record.txt","w");
	#endif

	display_open(&height,&width);

	#ifdef REG
	fprintf(fp,"%d %d\n",height,width);
	#endif

	setup_game(height,width,ball_pos(height,width),ball_dir(),
						pad1_pos(height,width),pad2_pos(height,width),pad_len(height));

	display_start();

	do {
		// Add a delay to move_ball()
		if((cont = (cont + 1) % DELAY) == 0) {
			move_ball();
			display_table();
			#ifdef REG
			fprintf(fp,"M");
      #endif
		}
    switch (display_read()) {
      case P1_DOWN: move_pad1_down();
										#ifdef REG
										fprintf(fp,"z");
										#endif
										break;
      case P1_UP:   move_pad1_up();
										#ifdef REG
										fprintf(fp,"a");
										#endif
										break;
      case P2_UP:   move_pad2_up();
										#ifdef REG
										fprintf(fp,"u");
										#endif
										break;
      case P2_DOWN: move_pad2_down();
										#ifdef REG
										fprintf(fp,"d");
										#endif
										break;
      case PAUSE:   display_pause();  break;
      case QUIT:    STOP = 1;         break;
    }
		display_table();
  } while(!STOP && ((s1 = get_pad1_score()) != 9 && (s2 = get_pad2_score()) != 9));

	if(s1 == 9 || s2 == 9)
		display_win(s1 == 9 ? 1 : 2);

	display_quit();
	display_close();
	#ifdef REG
	fclose(fp);
  #endif
}

/* Starting pad1 position */
static struct position pad1_pos(int height, int width) {
  struct position pos;
  pos.x = PAD_OFFSET;
  pos.y = height/2;
  return pos;
}

/* Starting pad2 position */
static struct position pad2_pos(int height, int width) {
  struct position pos;
  pos.x = width-PAD_OFFSET;
  pos.y = height/2;
  return pos;
}

/* Starting ball position */
static struct position ball_pos(int height, int width) {
  struct position pos;
  pos.x = width/2;
  pos.y = height/2;
  return pos;
}

/* Starting direction position */
static struct position ball_dir(void) {
  struct position pos = {DOWN,RIGHT};
  return pos;
}

/* Pad length */
static int pad_len(int height) {
  return MIN(height/2+1,height/PAD_LEN_RATIO);
}
-------------------------------------------------------
game.h
#ifndef GAME_H
#define GAME_H

struct position {
	int x;
	int y;
};

/*
 * Setup a game with the following starting configuration:
 * - table dimension equal to heigth*width
 * - ball starting position at ball_pos
 * - ball starting direction towards ball_dir
 * - pad1 starting position at pad1_pos
 * - pad2 starting position at pad2_pos
 * - pad length equal to pad_len
 */
void setup_game(int height, int width,
                struct position ball_pos, struct position ball_dir,
                struct position pad1_pos, struct position pad2_pos, int pad_len);

/* Moves pad1 one position up. */
void move_pad1_up(void);

/* Moves pad2 one poisiton up */
void move_pad2_up(void);

/* Moves pad1 one position down. */
void move_pad1_down(void);

/* Moves pad2 one position down. */
void move_pad2_down(void);

/* Moves the ball in the current direction */
void move_ball(void);

/* Returns ball current position */
struct position get_ball_pos(void);

/* Returns pad1 current position */
struct position get_pad1_pos(void);

/* Returns pad2 current position */
struct position get_pad2_pos(void);

/* Returns the pad length */
unsigned int get_pad_len(void);

/* Returns pad1 current score */
unsigned int get_pad1_score(void);

/* Returns pad2 current score */
unsigned int get_pad2_score(void);

#endif
-----------------------------------------
game.c

struct position {
	int x;
	int y;
};

struct position pad1;
struct position pad2;
static int len;
struct position ball_position;
struct position ball_direction;
static int w, h;
static int pad1_score = 0, pad2_score = 0 ;

/*
 * Setup a game with the following starting configuration:
 * - table dimension equal to heigth*width
 * - ball starting position at ball_pos
 * - ball starting direction towards ball_dir
 * - pad1 starting position at pad1_pos
 * - pad2 starting position at pad2_pos
 * - pad length equal to pad_len
 */
void setup_game(int height, int width,
	struct position ball_pos, struct position ball_dir,
	struct position pad1_pos, struct position pad2_pos, int pad_len) {
	pad1.x = pad1_pos.x;
	pad1.y = pad1_pos.y;
	pad2.x = pad2_pos.x;
	pad2.y = pad2_pos.y;
	len = pad_len;
	ball_position = ball_pos;
	ball_direction = ball_dir;
	w = width; h = height;
}

/* Moves pad1 one position up. */
void move_pad1_up(void) {
	if (!(pad1.y == 0)) {
		if (!((ball_position.y == pad1.y || ball_position.y == pad1.y - 1) && (ball_position.x == pad1.x || ball_position.x == pad1.x + 1 || ball_position.x == pad1.x - 1))) {
			pad1.y -=1;
		}
	}
}

/* Moves pad2 one poisiton up */
void move_pad2_up(void) {
	if (!(pad2.y == 0)) {
		if (!((ball_position.y == pad2.y || ball_position.y == pad2.y - 1) && (ball_position.x + 2 == pad2.x || ball_position.x + 1 == pad2.x || ball_position.x == pad2.x))) {
			pad2.y -= 1;
		}
	}
}

/* Moves pad1 one position down. */
void move_pad1_down(void) {
	if (!(pad1.y + len - 1 == h)) {
		if (!(ball_position.y == pad1.y + len && (ball_position.x == pad1.x || ball_position.x == pad1.x + 1 || ball_position.x == pad1.x - 1))) {
			pad1.y += 1;
		}
	}
}

/* Moves pad2 one position down. */
void move_pad2_down(void) {
	if (!(pad2.y + len - 1 == h)) {
		if (!(ball_position.y == pad2.y + len && (ball_position.x + 2 == pad2.x || ball_position.x + 1 == pad2.x + 1 || ball_position.x == pad2.x))) {
			pad2.y += 1;
		}
	}
}

/* Moves the ball in the current direction */
void move_ball(void) {
	//tocco bordi
	ball_position.y += ball_direction.y;
	ball_position.x += ball_direction.x;

	//assegnazione punti
	if (ball_position.x == w) {
		pad1_score++;
		ball_position.x = w / 2;
		ball_position.y = h / 2;
	}

	if (ball_position.x == 0) {
		pad2_score++;
		ball_position.x = w / 2;
		ball_position.y = h / 2;
	}

	if (ball_position.y == h || ball_position.y == 0) ball_direction.y = -ball_direction.y;
	//pieno 1
	if (ball_position.x == pad1.x + 1 && (ball_position.y >= pad1.y && ball_position.y <= pad1.y - 1 + len)) {
		ball_direction.x = 1;
	}

	//pieno 2
	if (ball_position.x == pad2.x - 2 && (ball_position.y >= pad2.y && ball_position.y <= pad2.y - 1 + len)) {
		ball_direction.x = -1;
	}

	//tocco bordo sup pad1
	if ((ball_position.y == pad1.y - 1) && (ball_position.x == pad1.x || ball_position.x == pad1.x + 1 || ball_position.x == pad1.x + 1 || ball_position.x == pad1.x - 1)) {
		if (ball_position.y != 0) {
			ball_direction.y = -1;
		}
		ball_direction.x = 1;
	}

	//tocco bordo sup pad2
	if ((ball_position.y == pad2.y - 1) && (ball_position.x == pad2.x || ball_position.x == pad2.x - 2 || ball_position.x == pad2.x + 1 || ball_position.x == pad2.x - 1)) {
		if (ball_position.y != 0) {
			ball_direction.y = -1;
		}
		ball_direction.x = -1;
	}

	//tocco inf pad1
	if (ball_position.y == pad1.y + len && (ball_position.x == pad1.x || ball_position.x == pad1.x + 1 || ball_position.x == pad1.x - 1)) {
		if (ball_position.y != h) {
			ball_direction.y = 1;
	}
		ball_direction.x = 1;
	}

	//tocco inf pad2
	if (ball_position.y == pad2.y + len && (ball_position.x == pad2.x || ball_position.x == pad2.x - 2 || ball_position.x == pad2.x + 1 || ball_position.x == pad2.x - 1)) {
		if (ball_position.y != h) {
			ball_direction.y = 1;
		}
		ball_direction.x = -1;
	}
}
/* Returns ball current position */
struct position get_ball_pos(void) { return ball_position; }

/* Returns pad1 current position */
struct position get_pad1_pos(void) { return pad1; }

/* Returns pad2 current position */
struct position get_pad2_pos(void) { return pad2; }

/* Returns the pad length */
unsigned int get_pad_len(void) { return len; }

/* Returns pad1 current score */
unsigned int get_pad1_score(void) { return pad1_score; }

/* Returns pad2 current score */
unsigned int get_pad2_score(void) { return pad2_score; }