ghost_ai.c

/* TODO: Some extraneous comments can be removed*/

#include "ghost_ai.h"
#include "print_number.h"

/* Initialises the positions of the four ghosts
 * Whenever a level is completed or a life is lost,
 * this method can be called.
 */
void init_ghosts(game* game_ptr){
  /*TODO FREE.*/
  game_ptr->ghosts_ptr         = malloc (sizeof(ghosts));
  game_ptr->ghosts_ptr->blinky = malloc(sizeof(ghost));
  game_ptr->ghosts_ptr->pinky  = malloc(sizeof(ghost));
  game_ptr->ghosts_ptr->inky   = malloc(sizeof(ghost));
  game_ptr->ghosts_ptr->clyde  = malloc(sizeof(ghost));

  /*Initialise position of BLINKY - RED*/
  game_ptr->ghosts_ptr->blinky->turn = 0;
  game_ptr->ghosts_ptr->blinky->vec.x=-1;
  game_ptr->ghosts_ptr->blinky->vec.y=0;
  game_ptr->ghosts_ptr->blinky->x=BLINKY_PEN_X;
  game_ptr->ghosts_ptr->blinky->y=BLINKY_PEN_Y;
  game_ptr->ghosts_ptr->blinky->temp_x = BLINKY_PEN_X;
  game_ptr->ghosts_ptr->blinky->temp_y = BLINKY_PEN_Y;
  game_ptr->ghosts_ptr->blinky->nearly_ending = 0;

  /*Initialise position of PINKY - PINK*/
  game_ptr->ghosts_ptr->pinky->turn = 1;
  game_ptr->ghosts_ptr->pinky->vec.x=0;
  game_ptr->ghosts_ptr->pinky->vec.y=-1;
  game_ptr->ghosts_ptr->pinky->x=PINKY_PEN_X;
  game_ptr->ghosts_ptr->pinky->y=PINKY_PEN_Y;
  game_ptr->ghosts_ptr->pinky->temp_x = PINKY_PEN_X;
  game_ptr->ghosts_ptr->pinky->temp_y = PINKY_PEN_Y;
  game_ptr->ghosts_ptr->pinky->nearly_ending = 0;

  /*Initialise position of INKY - BLUE*/
  game_ptr->ghosts_ptr->inky->turn = 1;
  game_ptr->ghosts_ptr->inky->vec.x=1;
  game_ptr->ghosts_ptr->inky->vec.y=0;
  game_ptr->ghosts_ptr->inky->x=INKY_PEN_X;
  game_ptr->ghosts_ptr->inky->y=INKY_PEN_Y;
  game_ptr->ghosts_ptr->inky->temp_x = INKY_PEN_X;
  game_ptr->ghosts_ptr->inky->temp_y = INKY_PEN_Y;
  game_ptr->ghosts_ptr->inky->nearly_ending = 0;

  /*Initialise position of CLYDE - ORANGE*/
  game_ptr->ghosts_ptr->blinky->turn = 1;
  game_ptr->ghosts_ptr->clyde->vec.x=-1;
  game_ptr->ghosts_ptr->clyde->vec.y=0;
  game_ptr->ghosts_ptr->clyde->x=CLYDE_PEN_X;
  game_ptr->ghosts_ptr->clyde->y=CLYDE_PEN_Y;
  game_ptr->ghosts_ptr->clyde->temp_x = CLYDE_PEN_X;
  game_ptr->ghosts_ptr->clyde->temp_y = CLYDE_PEN_Y;
  game_ptr->ghosts_ptr->clyde->nearly_ending = 0;

  /*Initialise state and previous state*/
  game_ptr->ghosts_ptr->blinky->prev_state = none;
  game_ptr->ghosts_ptr->pinky->prev_state = none;
  game_ptr->ghosts_ptr->inky->prev_state = none;
  game_ptr->ghosts_ptr->clyde->prev_state = none;

  /*Initialise its velocity*/
  game_ptr->ghosts_ptr->blinky->speed = 0.75;
  game_ptr->ghosts_ptr->pinky->speed  = 0.75;
  game_ptr->ghosts_ptr->inky->speed   = 0.75;
  game_ptr->ghosts_ptr->clyde->speed  = 0.75;
}

void set_speed(uint8_t change_all, game* game_ptr, ghost* ghost_ptr, float speed) {
  if (change_all) {
    game_ptr->ghosts_ptr->blinky->speed = speed;
    game_ptr->ghosts_ptr->pinky->speed = speed;
    game_ptr->ghosts_ptr->inky->speed = speed;
    game_ptr->ghosts_ptr->clyde->speed = speed;
  } else {
    ghost_ptr->speed = speed;
  }
}

void change_state(uint8_t change_all, game* game_ptr, ghost* ghosts_ptr, ghost_state state) {
  /* change_all is a boolean, either 1 or 0.*/
  /* 1 means that every ghost's state is going to be changed*/
  if (change_all) {
    /*EATEN OR PEN*/
    if (!(game_ptr->ghosts_ptr->blinky->state == PEN || game_ptr->ghosts_ptr->blinky->state == EATEN)) {
      game_ptr->ghosts_ptr->blinky->prev_state
        = game_ptr->ghosts_ptr->blinky->state;
    }

    if (!(game_ptr->ghosts_ptr->pinky->state == PEN || game_ptr->ghosts_ptr->pinky->state == EATEN)) {
      game_ptr->ghosts_ptr->pinky->prev_state
        = game_ptr->ghosts_ptr->pinky->state;
    }

    if (!(game_ptr->ghosts_ptr->inky->state == PEN || game_ptr->ghosts_ptr->inky->state == EATEN)) {
      game_ptr->ghosts_ptr->inky->prev_state
        = game_ptr->ghosts_ptr->inky->state;
    }

    if (!(game_ptr->ghosts_ptr->clyde->state == PEN || game_ptr->ghosts_ptr->clyde->state == EATEN)) {
      game_ptr->ghosts_ptr->clyde->prev_state
        = game_ptr->ghosts_ptr->clyde->state;
    }

    switch(state) {
      case CHASE:
        chase_all(game_ptr);
        break;
      case SCATTER:
        scatter_all(game_ptr);
        break;
      case FRIGHTENED:
        frightened_all(game_ptr);
        break;
      case EATEN:
        eaten_all(game_ptr);
        break;
      case PEN:
        pen_all(game_ptr);
        break;
      case none:
        break;
    }
  } else {
    ghosts_ptr->prev_state = ghosts_ptr->state;
    ghosts_ptr->state = state;
  }
}

void scatter_all(game* game_ptr){
  if (!(game_ptr->ghosts_ptr->blinky->state == PEN
        || game_ptr->ghosts_ptr->blinky->state == EATEN)) {
    game_ptr->ghosts_ptr->blinky->state = SCATTER;
  }
  if (!(game_ptr->ghosts_ptr->pinky->state == PEN
        || game_ptr->ghosts_ptr->pinky->state == EATEN)) {
    game_ptr->ghosts_ptr->pinky->state = SCATTER;
  }

  if (!(game_ptr->ghosts_ptr->inky->state == PEN
        || game_ptr->ghosts_ptr->inky->state == EATEN)) {
    game_ptr->ghosts_ptr->inky->state = SCATTER;
  }

  if (!(game_ptr->ghosts_ptr->clyde->state == PEN
        || game_ptr->ghosts_ptr->clyde->state == EATEN)) {
    game_ptr->ghosts_ptr->clyde->state = SCATTER;
  }
}

void chase_all(game* game_ptr){
  if (!(game_ptr->ghosts_ptr->blinky->state == PEN
        || game_ptr->ghosts_ptr->blinky->state == EATEN)) {
    game_ptr->ghosts_ptr->blinky->state = CHASE;
  }
  if (!(game_ptr->ghosts_ptr->pinky->state == PEN
        || game_ptr->ghosts_ptr->pinky->state == EATEN)) {
    game_ptr->ghosts_ptr->pinky->state = CHASE;
  }
  if (!(game_ptr->ghosts_ptr->inky->state == PEN
        || game_ptr->ghosts_ptr->inky->state == EATEN)) {
    game_ptr->ghosts_ptr->inky->state = CHASE;
  }
  if (!(game_ptr->ghosts_ptr->clyde->state == PEN
        || game_ptr->ghosts_ptr->clyde->state == EATEN)) {
    game_ptr->ghosts_ptr->clyde->state = CHASE;
  }
}

void frightened_all(game* game_ptr){
  if (!(game_ptr->ghosts_ptr->blinky->state == PEN
        || game_ptr->ghosts_ptr->blinky->state == EATEN)
      && !(
        game_ptr->ghosts_ptr->blinky->x == 112
        && 92 <= game_ptr->ghosts_ptr->blinky->y
        && game_ptr->ghosts_ptr->blinky->y <= 116
        )
     ) {
    game_ptr->ghosts_ptr->blinky->state = FRIGHTENED;
  }
  if (!(game_ptr->ghosts_ptr->pinky->state == PEN
        || game_ptr->ghosts_ptr->pinky->state == EATEN)) {
    game_ptr->ghosts_ptr->pinky->state = FRIGHTENED;
  }
  if (!(game_ptr->ghosts_ptr->inky->state == PEN
        || game_ptr->ghosts_ptr->inky->state == EATEN)) {
    game_ptr->ghosts_ptr->inky->state = FRIGHTENED;
  }
  if (!(game_ptr->ghosts_ptr->clyde->state == PEN
        || game_ptr->ghosts_ptr->clyde->state == EATEN)) {
    game_ptr->ghosts_ptr->clyde->state = FRIGHTENED;
  }
}

void eaten_all(game* game_ptr){
  if (!(game_ptr->ghosts_ptr->blinky->state == PEN
        || game_ptr->ghosts_ptr->blinky->state == EATEN)) {
    game_ptr->ghosts_ptr->blinky->state = EATEN;
  }
  if (!(game_ptr->ghosts_ptr->pinky->state == PEN
        || game_ptr->ghosts_ptr->pinky->state == EATEN)) {
    game_ptr->ghosts_ptr->pinky->state = EATEN;
  }
  if (!(game_ptr->ghosts_ptr->inky->state == PEN
        || game_ptr->ghosts_ptr->inky->state == EATEN)) {
    game_ptr->ghosts_ptr->inky->state = EATEN;
  }
  if (!(game_ptr->ghosts_ptr->clyde->state == PEN
        || game_ptr->ghosts_ptr->clyde->state == EATEN)) {
    game_ptr->ghosts_ptr->clyde->state = EATEN;
  }
}

void pen_all(game* game_ptr){
  if (!(game_ptr->ghosts_ptr->blinky->state == PEN
        || game_ptr->ghosts_ptr->blinky->state == EATEN)) {
    game_ptr->ghosts_ptr->blinky->state = PEN;
  }
  if (!(game_ptr->ghosts_ptr->pinky->state == PEN
        || game_ptr->ghosts_ptr->pinky->state == EATEN)) {
    game_ptr->ghosts_ptr->pinky->state = PEN;
  }
  if (!(game_ptr->ghosts_ptr->inky->state == PEN
        || game_ptr->ghosts_ptr->inky->state == EATEN)) {
    game_ptr->ghosts_ptr->inky->state = PEN;
  }
  if (!(game_ptr->ghosts_ptr->clyde->state == PEN
        || game_ptr->ghosts_ptr->clyde->state == EATEN)) {
    game_ptr->ghosts_ptr->clyde->state = PEN;
  }
}

void speed_setter(ghost* ghost_ptr){
  float speed = 1.0;
  switch (ghost_ptr->state) {
    case CHASE:
      speed = 0.75;
      break;
    case SCATTER:
      speed = 0.75;
      break;
    case FRIGHTENED:
      speed = 0.50;
      break;
    case EATEN:
      speed = 0.75;
      break;
    case PEN:
      speed = 0.4;
      break;
    default:
      /*Do nothing*/
      break;
  }
  set_speed(0, NULL, ghost_ptr, speed);
}

/*Calls each individual AI function and set the direction of the ghosts.*/
void shortest_path_helper(game* game_ptr){
  ghost* ghost_set[4] = {
    game_ptr->ghosts_ptr->blinky,
    game_ptr->ghosts_ptr->pinky,
    game_ptr->ghosts_ptr->inky,
    game_ptr->ghosts_ptr->clyde
  };

  int blinky_x;
  int blinky_y;
  int pinky_x;
  int pinky_y;
  int inky_x;
  int inky_y;
  int clyde_x;
  int clyde_y;


  blinky_ai(game_ptr, ghost_set[0], &blinky_x, &blinky_y);
  pinky_ai (game_ptr, ghost_set[1], &pinky_x,  &pinky_y);
  inky_ai  (game_ptr, ghost_set[2], &inky_x,   &inky_y);
  clyde_ai (game_ptr, ghost_set[3], &clyde_x,  &clyde_y);

  int xs[4] = {blinky_x, pinky_x, inky_x, clyde_x};
  int ys[4] = {blinky_y, pinky_y, inky_y, clyde_y};


  for (int i = 0; i < 4; ++i) {
    speed_setter(ghost_set[i]);
    shortest_path(ghost_set[i], game_ptr->board, xs[i], ys[i]);
  }

  game_ptr->ghosts_ptr->blinky->prev_state
    = game_ptr->ghosts_ptr->blinky->state;
  game_ptr->ghosts_ptr->pinky->prev_state
    = game_ptr->ghosts_ptr->pinky->state;
  game_ptr->ghosts_ptr->inky->prev_state
    = game_ptr->ghosts_ptr->inky->state;
  game_ptr->ghosts_ptr->clyde->prev_state
    = game_ptr->ghosts_ptr->clyde->state;
}

void shortest_path(ghost* ghost_ptr, uint8_t* board, int x, int y){
  uint8_t upwards_movement[3] = {0, 0, 0};
  int target_tile_x = x;
  int target_tile_y = y;
  int curr_x = ghost_ptr->x, curr_y = ghost_ptr->y;
  int curr_V_x = ghost_ptr->vec.x, curr_V_y = ghost_ptr->vec.y;
  int current_tile_x = curr_x/8, current_tile_y = curr_y/8;

  if (ghost_ptr->state == EATEN) {
    if (curr_x == 112 && 91 <= curr_y && curr_y < 116) {
      ghost_ptr->turn =  0;
      ghost_ptr->vec.x = 0;
      ghost_ptr->vec.y = 1;
      return;
    }
  }

  if (ghost_ptr->state == CHASE || ghost_ptr->state == SCATTER) {
    if (curr_x == 112 && curr_y == 92 && curr_V_y == -1) {
      ghost_ptr->turn =  0;
      ghost_ptr->vec.x = 1;
      ghost_ptr->vec.y = 0;
      return;
    } else if (curr_x == 112 && 92 < curr_y && curr_y <= 116) {
      ghost_ptr->turn =  0;
      ghost_ptr->vec.x = 0;
      ghost_ptr->vec.y = -1;
      return;
    }
  }

  if ((curr_x % 8 != 3 && curr_x % 8 != 4) || (curr_y % 8 != 3 && curr_y % 8 != 4)) {
    return;
  }

  if (!ghost_ptr->turn) {
    ghost_ptr->turn = 1;
    return;
  }

  /* At this point, Mr. Ghost is at a position where he can turn*/
  /* Mr. Ghost, who never reverses his direction, has 3 possible directions.
   * This includes Left, Right and forward (based on prespective).
   * Here we compute all the three possible directions. We choose what costs
   * Mr. Ghost the least*/

  vector forward_v, left_v, right_v;
  forward_v.x = curr_V_x;
  forward_v.y = curr_V_y;
  left_v.x    = curr_V_y;
  left_v.y    = -curr_V_x;
  right_v.x   = -curr_V_y;
  right_v.y   = curr_V_x;

  int forward_pixel_x = curr_x + forward_v.x;
  int forward_pixel_y = curr_y + forward_v.y;
  int left_pixel_x    = curr_x + left_v.x;
  int left_pixel_y    = curr_y + left_v.y;
  int right_pixel_x   = curr_x + right_v.x;
  int right_pixel_y   = curr_y + right_v.y;

  int forward_x = current_tile_x + forward_v.x;
  int forward_y = current_tile_y + forward_v.y;
  int left_x    = current_tile_x + left_v.x;
  int left_y    = current_tile_y + left_v.y;
  int right_x   = current_tile_x + right_v.x;
  int right_y   = current_tile_y + right_v.y;

  if (forward_v.y == -1) {
    upwards_movement[0] = 1;
  }

  if (left_v.y == -1) {
    upwards_movement[1] = 1;
  }

  if (right_v.y == -1) {
    upwards_movement[2] = 1;
  }

  /*Forward, left, right*/
  int distances[3] = {-1, -1, -1};
  uint8_t min_set = 0;
  /*Index of minimum*/
  int min = 0;
  vector relative_vectors[3] = {forward_v, left_v, right_v};

  if (legal_tile(forward_pixel_x, forward_pixel_y, forward_x, forward_y, board, upwards_movement[0])) {
    distances[0] = dist(forward_x, forward_y, target_tile_x, target_tile_y);
  }

  if (legal_tile(left_pixel_x, left_pixel_y, left_x, left_y, board, upwards_movement[1])) {
    distances[1] = dist(left_x, left_y, target_tile_x, target_tile_y);
  }

  if (legal_tile(right_pixel_x, right_pixel_y, right_x, right_y, board, upwards_movement[2])) {
    distances[2] = dist(right_x, right_y, target_tile_x, target_tile_y);
  }

  for (int i = 0; i < 3; ++i) {
    if (distances[i] != -1 && !min_set) {
      min = i;
      min_set = 1;
    } else if (min_set && distances[i] != -1 && distances[i] < distances[min]) {
      min = i;
    }
  }

  ghost_ptr->turn =  0;
  ghost_ptr->vec.x = relative_vectors[min].x;
  ghost_ptr->vec.y = relative_vectors[min].y;
}
/*
 * Ghosts are forced to reverse their direction when the following changes happen
 * chase-to-scatter, chase-to-frightened, scatter-to-chase,
 * and scatter-to-frightened.
 */
void blinky_ai(game* game_ptr, ghost* blinky, int* x, int* y){
  switch(blinky->state) {
    case CHASE:
      if (blinky->prev_state == SCATTER) {
        blinky->vec.x *= -1;
        blinky->vec.y *= -1;
      }
      *x = ((game_ptr->pacman_ptr->x)/8);
      *y = ((game_ptr->pacman_ptr->y)/8);
      blinky->prev_state = CHASE;
      break;
    case SCATTER:
      if (blinky->prev_state == CHASE) {
        blinky->vec.x *= -1;
        blinky->vec.y *= -1;
      }
      *x = BLINKY_CORNER_X;
      *y = BLINKY_CORNER_Y;
      blinky->prev_state = SCATTER;
      break;
    case FRIGHTENED:
      if (blinky->prev_state == CHASE) {
        blinky->vec.x *= -1;
        blinky->vec.y *= -1;
      } else if (blinky->prev_state == SCATTER) {
        blinky->vec.x *= -1;
        blinky->vec.y *= -1;
      }
      blinky->prev_state = FRIGHTENED;
      *x = rand() % GAME_BOARD_X;
      *y = rand() % GAME_BOARD_Y;
      break;
    case EATEN:
      if (!(blinky->x == PINKY_PEN_X && blinky->y == PINKY_PEN_Y)) {
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
      } else {
        blinky->vec.x = 0;
        blinky->vec.y = -1;
        change_state(0, game_ptr, blinky, CHASE);
        blinky->speed = 0.75;
        *x = game_ptr->pacman_ptr->x/8;
        *y = game_ptr->pacman_ptr->y/8;
      }
      blinky->prev_state = EATEN;
      break;
    case PEN:
      /*Do nothing*/
      break;
    case none:
      /*do nothing*/
      break;
  }
}

void pinky_ai(game* game_ptr, ghost* pinky, int* x, int* y){
  static uint64_t timer = 1;
  switch(pinky->state) {
    case CHASE:
      if (pinky->prev_state == SCATTER) {
        pinky->vec.x *= -1;
        pinky->vec.y *= -1;
      }
      if (game_ptr->pacman_ptr->x) {
        if (game_ptr->pacman_ptr->x == 1) {
          /*Right*/
          *x = (game_ptr->pacman_ptr->x/8)+4;
          *y = (game_ptr->pacman_ptr->y/8);
        } else {
          /*Left*/
          *x = (game_ptr->pacman_ptr->x/8)-4;
          *y = (game_ptr->pacman_ptr->y/8);
        }
      } else {
        if (game_ptr->pacman_ptr->y == 1) {
          /*Down*/
          *x = (game_ptr->pacman_ptr->x/8);
          *y = (game_ptr->pacman_ptr->y/8) + 4;
        } else {
          /*Up*/
          *x = (game_ptr->pacman_ptr->x/8)-4;
          *y = (game_ptr->pacman_ptr->y/8)-4;
        }
      }
      pinky->prev_state = CHASE;
      break;
    case SCATTER:
      if (pinky->prev_state == CHASE) {
        pinky->vec.x *= -1;
        pinky->vec.y *= -1;
      }
      *x = PINKY_CORNER_X;
      *y = PINKY_CORNER_Y;
      pinky->prev_state = SCATTER;
      break;
    case FRIGHTENED:
      if (pinky->prev_state == CHASE) {
        pinky->vec.x *= -1;
        pinky->vec.y *= -1;
      } else if (pinky->prev_state == SCATTER) {
        pinky->vec.x *= -1;
        pinky->vec.y *= -1;
      }
      pinky->prev_state = FRIGHTENED;
      *x = rand() % GAME_BOARD_X;
      *y = rand() % GAME_BOARD_Y;
      break;
    case EATEN:
      if (!(pinky->x == PINKY_PEN_X && pinky->y == PINKY_PEN_Y)) {
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
      } else {
        pinky->vec.x = 0;
        pinky->vec.y = -1;
        timer = 1;
        pinky->state = PEN;
      }
      pinky->prev_state = EATEN;
      break;
    case PEN:
      if (timer < PINKY_PEN_TIME) {
        if (timer == 1) {
          pinky->vec.x = 0;
          pinky->vec.y = 1;
        } else if (pinky->x == PINKY_PEN_X && pinky->y == PINKY_PEN_Y + 4) {
          pinky->vec.x = 0;
          pinky->vec.y = -1;
        } else if (pinky->x == PINKY_PEN_X && pinky->y == PINKY_PEN_Y - 4){
          pinky->vec.x = 0;
          pinky->vec.y = 1;
        }
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
        timer += 1;
      } else {
        pinky->vec.x = 0;
        pinky->vec.y = -1;
        pinky->state = CHASE;
      }
      pinky->prev_state = PEN;
      break;
    case none:
      /*do nothing*/
      break;
  }
}

void inky_ai(game* game_ptr, ghost* inky, int*x, int* y){
  static uint64_t timer = 1;
  switch(inky->state) {
    case CHASE:
      {
        if (inky->prev_state == SCATTER) {
          inky->vec.x *= -1;
          inky->vec.y *= -1;
        }
        int offset_x;
        int offset_y;
        if (game_ptr->pacman_ptr->vec.y == -1) {
          /*Two tiles up and two tiles left if pacman is moving upwards*/
          offset_x =
            (game_ptr->pacman_ptr->x)/8 - 2;
          offset_y =
            (game_ptr->pacman_ptr->y)/8 + 2*(game_ptr->pacman_ptr->vec.y);
        } else {
          offset_x =
            (game_ptr->pacman_ptr->x)/8 + 2*(game_ptr->pacman_ptr->vec.x);
          offset_y =
            (game_ptr->pacman_ptr->y)/8 + 2*(game_ptr->pacman_ptr->vec.y);
        }
        int shift_x = offset_x - ((game_ptr->ghosts_ptr->blinky->x)/8);
        int shift_y = offset_y - ((game_ptr->ghosts_ptr->blinky->y)/8);
        *x = offset_x + shift_x;
        *y = offset_y + shift_y;
        inky->prev_state = CHASE;
        break;
      }
    case SCATTER:
      if (inky->prev_state == CHASE) {
        inky->vec.x *= -1;
        inky->vec.y *= -1;
      }
      *x = INKY_CORNER_X;
      *y = INKY_CORNER_Y;
      inky->prev_state = SCATTER;
      break;
    case FRIGHTENED:
      if (inky->prev_state == CHASE) {
        inky->vec.x *= -1;
        inky->vec.y *= -1;
      } else if (inky->prev_state == SCATTER) {
        inky->vec.x *= -1;
        inky->vec.y *= -1;
      }
      inky->prev_state = FRIGHTENED;
      *x = rand() % GAME_BOARD_X;
      *y = rand() % GAME_BOARD_Y;
      break;
    case EATEN:
      if (!(inky->x == PINKY_PEN_X && inky->y == PINKY_PEN_Y)) {
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
      } else {
        inky->vec.x = 0;
        inky->vec.y = -1;
        timer = 1;
        inky->state = PEN;
      }
      inky->prev_state = EATEN;
      break;
    case PEN:
      if (timer < INKY_PEN_TIME) {
        if (timer == 1) {
          inky->vec.x = 0;
          inky->vec.y = 1;
        } else if (inky->x == PINKY_PEN_X && inky->y == PINKY_PEN_Y + 4) {
          inky->vec.x = 0;
          inky->vec.y = -1;
        } else if (inky->x == PINKY_PEN_X && inky->y == PINKY_PEN_Y - 4){
          inky->vec.x = 0;
          inky->vec.y = 1;
        }
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
        timer += 1;
      } else {
        inky->vec.x = 0;
        inky->vec.y = -1;
        inky->state = CHASE;
      }
      inky->prev_state = PEN;
      break;
    case none:
      /*do nothing*/
      break;
  }
}

void clyde_ai(game* game_ptr, ghost* clyde, int*x, int* y){
  static uint64_t timer = 1;
  switch(clyde->state) {
    case CHASE:
      {
        if (clyde->prev_state == SCATTER) {
          clyde->vec.x *= -1;
          clyde->vec.y *= -1;
        }
        int radius = dist(clyde->x/8, clyde->y/8, game_ptr->pacman_ptr->x/8, game_ptr->pacman_ptr->y/8);
        if (radius >= 64) {
          *x = game_ptr->pacman_ptr->x/8;
          *y = game_ptr->pacman_ptr->y/8;
        } else {
          *x = CLYDE_CORNER_X;
          *y = CLYDE_CORNER_Y;
        }
        clyde->prev_state = CHASE;
        break; }
    case SCATTER:
      if (clyde->prev_state == CHASE) {
        clyde->vec.x *= -1;
        clyde->vec.y *= -1;
      }
      *x = CLYDE_CORNER_X;
      *y = CLYDE_CORNER_Y;
      break;
      clyde->prev_state = SCATTER;
    case FRIGHTENED:
      if (clyde->prev_state == CHASE) {
        clyde->vec.x *= -1;
        clyde->vec.y *= -1;
      } else if (clyde->prev_state == SCATTER) {
        clyde->vec.x *= -1;
        clyde->vec.y *= -1;
      }
      clyde->prev_state = FRIGHTENED;
      *x = rand() % GAME_BOARD_X;
      *y = rand() % GAME_BOARD_Y;
      break;
    case EATEN:
      if (!(clyde->x == PINKY_PEN_X && clyde->y == PINKY_PEN_Y)) {
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
      } else {
        clyde->vec.x = 0;
        clyde->vec.y = -1;
        timer = 1;
        clyde->state = PEN;
      }
      clyde->prev_state = EATEN;
      break;
    case PEN:
      if (timer < CLYDE_PEN_TIME) {
        if (timer == 1) {
          clyde->vec.x = 0;
          clyde->vec.y = 1;
        } else if (clyde->x == PINKY_PEN_X && clyde->y == PINKY_PEN_Y + 4) {
          clyde->vec.x = 0;
          clyde->vec.y = -1;
        } else if (clyde->x == PINKY_PEN_X && clyde->y == PINKY_PEN_Y - 4){
          clyde->vec.x = 0;
          clyde->vec.y = 1;
        }
        *x = PINKY_PEN_X/8;
        *y = PINKY_PEN_Y/8;
        timer += 1;
      } else {
        clyde->vec.x = 0;
        clyde->vec.y = -1;
        clyde->state = CHASE;
      }
      clyde->prev_state = PEN;
      break;
    case none:
      /*do nothing*/
      break;
  }
}

uint8_t legal_tile(int x_pixel, int y_pixel, int x_tile, int y_tile, uint8_t* board, uint8_t upwards) {
  return ((0 <= x_tile && x_tile < GAME_BOARD_X) && (0 <= y_tile && y_tile < GAME_BOARD_Y)
      && get_board_value(x_tile, y_tile, board));
}

void get_ghost_board_coord(ghost *ghost_ptr, int *bx, int *by) {
  int x = ghost_ptr->x;
  int y = ghost_ptr->y;
  *bx = x / 8;
  *by = y / 8;
}