alex

/* *****************************************************************************
 * A.L.E (Arcade Learning Environment)
 * Copyright (c) 2009-2013 by Yavar Naddaf, Joel Veness, Marc G. Bellemare and
 *   the Reinforcement Learning and Artificial Intelligence Laboratory
 * Released under the GNU General Public License; see License.txt for details.
 *
 * Based on: Stella  --  "An Atari 2600 VCS Emulator"
 * Copyright (c) 1995-2007 by Bradford W. Mott and the Stella team
 *
 * *****************************************************************************
 */

#include "Tennis.hpp"

#include "../RomUtils.hpp"

namespace ale {

TennisSettings::TennisSettings() { reset(); }

/* create a new instance of the rom */
RomSettings* TennisSettings::clone() const {
  return new TennisSettings(*this);
}

/* process the latest information from ALE */
void TennisSettings::step(const System& system) {
  // update the reward
  int my_score = readRam(&system, 0xC5);
  int oppt_score = readRam(&system, 0xC6);
  int my_points = readRam(&system, 0xC7);
  int oppt_points = readRam(&system, 0xC8);
  int delta_score = my_score - oppt_score;
  int delta_points = my_points - oppt_points;

  // a reward for the game
  if (m_prev_delta_points != delta_points)
    m_reward = delta_points - m_prev_delta_points;
  // a reward for each point
  else if (m_prev_delta_score != delta_score)
    m_reward = delta_score - m_prev_delta_score;
  else
    m_reward = 0;

  m_prev_delta_points = delta_points;
  m_prev_delta_score = delta_score;

  // update terminal status
  m_terminal = (my_points >= 6 && delta_points >= 2) ||
               (oppt_points >= 6 && -delta_points >= 2) ||
               (my_points == 7 || oppt_points == 7);
}

/* is end of game */
bool TennisSettings::isTerminal() const { return m_terminal; };

/* get the most recently observed reward */
reward_t TennisSettings::getReward() const { return m_reward; }

/* is an action part of the minimal set? */
bool TennisSettings::isMinimal(const Action& a) const {
  switch (a) {
    case PLAYER_A_NOOP:
    case PLAYER_A_FIRE:
    case PLAYER_A_UP:
    case PLAYER_A_RIGHT:
    case PLAYER_A_LEFT:
    case PLAYER_A_DOWN:
    case PLAYER_A_UPRIGHT:
    case PLAYER_A_UPLEFT:
    case PLAYER_A_DOWNRIGHT:
    case PLAYER_A_DOWNLEFT:
    case PLAYER_A_UPFIRE:
    case PLAYER_A_RIGHTFIRE:
    case PLAYER_A_LEFTFIRE:
    case PLAYER_A_DOWNFIRE:
    case PLAYER_A_UPRIGHTFIRE:
    case PLAYER_A_UPLEFTFIRE:
    case PLAYER_A_DOWNRIGHTFIRE:
    case PLAYER_A_DOWNLEFTFIRE:
      return true;
    default:
      return false;
  }
}

/* reset the state of the game */
void TennisSettings::reset() {
  m_reward = 0;
  m_prev_delta_points = 0;
  m_prev_delta_score = 0;
  m_terminal = false;
}

/* saves the state of the rom settings */
void TennisSettings::saveState(Serializer& ser) {
  ser.putInt(m_reward);
  ser.putBool(m_terminal);

  ser.putInt(m_prev_delta_points);
  ser.putInt(m_prev_delta_score);
}

// loads the state of the rom settings
void TennisSettings::loadState(Deserializer& ser) {
  m_reward = ser.getInt();
  m_terminal = ser.getBool();

  m_prev_delta_points = ser.getInt();
  m_prev_delta_score = ser.getInt();
}

// returns a list of mode that the game can be played in
ModeVect TennisSettings::getAvailableModes() {
  return {0, 2};
}

// set the mode of the game
// the given mode must be one returned by the previous function
void TennisSettings::setMode(
    game_mode_t m, System& system,
    std::unique_ptr<StellaEnvironmentWrapper> environment) {
  if (m == 0 || m == 2) {
    // read the mode we are currently in
    unsigned char mode = readRam(&system, 0x80);
    // press select until the correct mode is reached
    while (mode != m) {
      environment->pressSelect(2);
      mode = readRam(&system, 0x80);
    }
    //reset the environment to apply changes.
    environment->softReset();
  } else {
    throw std::runtime_error("This mode doesn't currently exist for this game");
  }
}

DifficultyVect TennisSettings::getAvailableDifficulties() {
  return {0, 1, 2, 3};
}

}  // namespace ale