pong.cpp

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/*
 * Copyright (c) 2011, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */


#include <interactive_markers/interactive_marker_server.h>

#include <ros/ros.h>
#include <math.h>
#include <boost/thread/mutex.hpp>

using namespace visualization_msgs;

static const float FIELD_WIDTH = 12.0;
static const float FIELD_HEIGHT = 8.0;
static const float BORDER_SIZE = 0.5;
static const float PADDLE_SIZE = 2.0;
static const float UPDATE_RATE = 1.0 / 30.0;
static const float PLAYER_X = FIELD_WIDTH * 0.5 + BORDER_SIZE;
static const float AI_SPEED_LIMIT = 0.25;


class PongGame
{
public:

  PongGame() :
  server_("pong", "", false),
  last_ball_pos_x_(0),
  last_ball_pos_y_(0)
  {
    player_contexts_.resize(2);

    makeFieldMarker();
    makePaddleMarkers();
    makeBallMarker();

    reset();
    updateScore();

    ros::NodeHandle nh;
    game_loop_timer_ =  nh.createTimer(ros::Duration(UPDATE_RATE), boost::bind( &PongGame::spinOnce, this ) );
  }

private:

  // main control loop
  void spinOnce()
  {
    if ( player_contexts_[0].active || player_contexts_[1].active )
    {
      float ball_dx = speed_ * ball_dir_x_;
      float ball_dy = speed_ * ball_dir_y_;

      ball_pos_x_ += ball_dx;
      ball_pos_y_ += ball_dy;

      // bounce off top / bottom
      float t = 0;
      if ( reflect ( ball_pos_y_, last_ball_pos_y_, FIELD_HEIGHT * 0.5, t ) )
      {
        ball_pos_x_ -= t * ball_dx;
        ball_pos_y_ -= t * ball_dy;

        ball_dir_y_ *= -1.0;

        ball_dx = speed_ * ball_dir_x_;
        ball_dy = speed_ * ball_dir_y_;
        ball_pos_x_ += t * ball_dx;
        ball_pos_y_ += t * ball_dy;
      }

      int player = ball_pos_x_ > 0 ? 1 : 0;

      // reflect on paddles
      if ( fabs(last_ball_pos_x_) < FIELD_WIDTH * 0.5 &&
           fabs(ball_pos_x_) >= FIELD_WIDTH * 0.5 )
      {
        // check if the paddle is roughly at the right position
        if ( ball_pos_y_ > player_contexts_[player].pos - PADDLE_SIZE * 0.5 - 0.5*BORDER_SIZE &&
             ball_pos_y_ < player_contexts_[player].pos + PADDLE_SIZE * 0.5 + 0.5*BORDER_SIZE )
        {
          reflect ( ball_pos_x_, last_ball_pos_x_, FIELD_WIDTH * 0.5, t );
          ball_pos_x_ -= t * ball_dx;
          ball_pos_y_ -= t * ball_dy;

          // change direction based on distance to paddle center
          float offset = (ball_pos_y_ - player_contexts_[player].pos) / PADDLE_SIZE;

          ball_dir_x_ *= -1.0;
          ball_dir_y_ += offset*2.0;

          normalizeVel();

          // limit angle to 45 deg
          if ( fabs(ball_dir_y_) > 0.707106781 )
          {
            ball_dir_x_ = ball_dir_x_ > 0.0 ? 1.0 : -1.0;
            ball_dir_y_ = ball_dir_y_ > 0.0 ? 1.0 : -1.0;
            normalizeVel();
          }

          ball_dx = speed_ * ball_dir_x_;
          ball_dy = speed_ * ball_dir_y_;
          ball_pos_x_ += t * ball_dx;
          ball_pos_y_ += t * ball_dy;
        }
      }

      // ball hits the left/right border of the playing field
      if ( fabs(ball_pos_x_) >= FIELD_WIDTH * 0.5 + 1.5*BORDER_SIZE )
      {
        reflect ( ball_pos_x_, last_ball_pos_x_, FIELD_WIDTH * 0.5 + 1.5*BORDER_SIZE, t );
        ball_pos_x_ -= t * ball_dx;
        ball_pos_y_ -= t * ball_dy;
        updateBall();

        player_contexts_[1-player].score++;
        updateScore();

        server_.applyChanges();
        reset();
        ros::Duration(1.0).sleep();
      }
      else
      {
        updateBall();
      }

      last_ball_pos_x_ = ball_pos_x_;
      last_ball_pos_y_ = ball_pos_y_;

      // control computer player
      if ( !player_contexts_[0].active || !player_contexts_[1].active )
      {
        int player = player_contexts_[0].active ? 1 : 0;
        float delta = ball_pos_y_ - player_contexts_[player].pos;
        // limit movement speed
        if ( delta > AI_SPEED_LIMIT ) delta = AI_SPEED_LIMIT;
        if ( delta < -AI_SPEED_LIMIT ) delta = -AI_SPEED_LIMIT;
        setPaddlePos( player, player_contexts_[player].pos + delta );
      }

      speed_ += 0.0003;
    }

    server_.applyChanges();
  }

  void setPaddlePos( unsigned player, float pos )
  {
    if ( player > 1 )
    {
      return;
    }

    // clamp
    if ( pos > (FIELD_HEIGHT - PADDLE_SIZE) * 0.5 )
    {
      pos = (FIELD_HEIGHT - PADDLE_SIZE) * 0.5;
    }
    if ( pos < (FIELD_HEIGHT - PADDLE_SIZE) * -0.5 )
    {
      pos = (FIELD_HEIGHT - PADDLE_SIZE) * -0.5;
    }

    player_contexts_[player].pos = pos;

    geometry_msgs::Pose pose;
    pose.position.x = (player == 0) ? -PLAYER_X : PLAYER_X;
    pose.position.y = pos;

    std::string marker_name = (player == 0) ? "paddle0" : "paddle1";
    server_.setPose( marker_name, pose );
    server_.setPose( marker_name+"_display", pose );
  }

  void processPaddleFeedback( unsigned player, const visualization_msgs::InteractiveMarkerFeedbackConstPtr &feedback )
  {
    if ( player > 1 )
    {
      return;
    }

    std::string control_marker_name = feedback->marker_name;
    geometry_msgs::Pose pose = feedback->pose;

    setPaddlePos( player, pose.position.y );

    if ( feedback->event_type == visualization_msgs::InteractiveMarkerFeedback::MOUSE_DOWN )
    {
      player_contexts_[player].active = true;
    }
    if ( feedback->event_type == visualization_msgs::InteractiveMarkerFeedback::MOUSE_UP )
    {
      player_contexts_[player].active = false;
    }
  }

  // restart round
  void reset()
  {
    speed_ = 6.0 * UPDATE_RATE;
    ball_pos_x_ = 0.0;
    ball_pos_y_ = 0.0;
    ball_dir_x_ = ball_dir_x_ > 0.0 ? 1.0 : -1.0;
    ball_dir_y_ = rand() % 2 ? 1.0 : -1.0;
    normalizeVel();
  }

  // set length of velocity vector to 1
  void normalizeVel()
  {
    float l = sqrt( ball_dir_x_*ball_dir_x_ + ball_dir_y_*ball_dir_y_ );
    ball_dir_x_ /= l;
    ball_dir_y_ /= l;
  }

  // compute reflection
  // returns true if the given limit has been surpassed
  // t [0...1] says how much the limit has been surpassed, relative to the distance
  // between last_pos and pos
  bool reflect( float &pos, float last_pos, float limit, float &t )
  {
    if ( pos > limit )
    {
      t = (pos - limit) / (pos - last_pos);
      return true;
    }
    if ( -pos > limit )
    {
      t = (-pos - limit) / (last_pos - pos);
      return true;
    }
    return false;
  }

  // update ball marker
  void updateBall()
  {
    geometry_msgs::Pose pose;
    pose.position.x = ball_pos_x_;
    pose.position.y = ball_pos_y_;
    server_.setPose( "ball", pose );
  }

  // update score marker
  void updateScore()
  {
    InteractiveMarker int_marker;
    int_marker.header.frame_id = "base_link";
    int_marker.name = "score";

    InteractiveMarkerControl control;
    control.always_visible = true;

    Marker marker;
    marker.type = Marker::TEXT_VIEW_FACING;
    marker.color.r = 1.0;
    marker.color.g = 1.0;
    marker.color.b = 1.0;
    marker.color.a = 1.0;
    marker.scale.x = 1.5;
    marker.scale.y = 1.5;
    marker.scale.z = 1.5;

    std::ostringstream s;
    s << player_contexts_[0].score;
    marker.text = s.str();
    marker.pose.position.y = FIELD_HEIGHT*0.5 + 4.0*BORDER_SIZE;
    marker.pose.position.x = -1.0 * ( FIELD_WIDTH * 0.5 + BORDER_SIZE );
    control.markers.push_back( marker );

    s.str("");
    s << player_contexts_[1].score;
    marker.text = s.str();
    marker.pose.position.x *= -1;
    control.markers.push_back( marker );

    int_marker.controls.push_back( control );

    server_.insert( int_marker );
  }

  void makeFieldMarker()
  {
    InteractiveMarker int_marker;
    int_marker.header.frame_id = "base_link";
    int_marker.name = "field";

    InteractiveMarkerControl control;
    control.always_visible = true;

    Marker marker;
    marker.type = Marker::CUBE;
    marker.color.r = 1.0;
    marker.color.g = 1.0;
    marker.color.b = 1.0;
    marker.color.a = 1.0;

    // Top Border
    marker.scale.x = FIELD_WIDTH + 6.0 * BORDER_SIZE;
    marker.scale.y = BORDER_SIZE;
    marker.scale.z = BORDER_SIZE;
    marker.pose.position.x = 0;
    marker.pose.position.y = FIELD_HEIGHT*0.5 + BORDER_SIZE;
    control.markers.push_back( marker );

    // Bottom Border
    marker.pose.position.y *= -1;
    control.markers.push_back( marker );

    // Left Border
    marker.scale.x = BORDER_SIZE;
    marker.scale.y = FIELD_HEIGHT + 3.0*BORDER_SIZE;
    marker.scale.z = BORDER_SIZE;
    marker.pose.position.x = FIELD_WIDTH*0.5 + 2.5*BORDER_SIZE;
    marker.pose.position.y = 0;
    control.markers.push_back( marker );

    // Right Border
    marker.pose.position.x *= -1;
    control.markers.push_back( marker );

    // store
    int_marker.controls.push_back( control );
    server_.insert( int_marker );
  }

  void makePaddleMarkers()
  {
    InteractiveMarker int_marker;
    int_marker.header.frame_id = "base_link";

    // Add a control for moving the paddle
    InteractiveMarkerControl control;
    control.always_visible = false;
    control.interaction_mode = InteractiveMarkerControl::MOVE_AXIS;
    control.orientation.w = 1;
    control.orientation.z = 1;

    // Add a visualization marker
    Marker marker;
    marker.type = Marker::CUBE;
    marker.color.r = 1.0;
    marker.color.g = 1.0;
    marker.color.b = 1.0;
    marker.color.a = 0.0;
    marker.scale.x = BORDER_SIZE + 0.1;
    marker.scale.y = PADDLE_SIZE + 0.1;
    marker.scale.z = BORDER_SIZE + 0.1;
    marker.pose.position.z = 0;
    marker.pose.position.y = 0;

    control.markers.push_back( marker );

    int_marker.controls.push_back( control );

    // Control for player 1
    int_marker.name = "paddle0";
    int_marker.pose.position.x = -PLAYER_X;
    server_.insert( int_marker );
    server_.setCallback( int_marker.name, boost::bind( &PongGame::processPaddleFeedback, this, 0, _1 ) );

    // Control for player 2
    int_marker.name = "paddle1";
    int_marker.pose.position.x = PLAYER_X;
    server_.insert( int_marker );
    server_.setCallback( int_marker.name, boost::bind( &PongGame::processPaddleFeedback, this, 1, _1 ) );

    // Make display markers
    marker.scale.x = BORDER_SIZE;
    marker.scale.y = PADDLE_SIZE;
    marker.scale.z = BORDER_SIZE;
    marker.color.r = 0.5;
    marker.color.a = 1.0;

    control.interaction_mode = InteractiveMarkerControl::NONE;
    control.always_visible = true;

    // Display for player 1
    int_marker.name = "paddle0_display";
    int_marker.pose.position.x = -PLAYER_X;

    marker.color.g = 1.0;
    marker.color.b = 0.5;

    int_marker.controls.clear();
    control.markers.clear();
    control.markers.push_back( marker );
    int_marker.controls.push_back( control );
    server_.insert( int_marker );

    // Display for player 2
    int_marker.name = "paddle1_display";
    int_marker.pose.position.x = PLAYER_X;

    marker.color.g = 0.5;
    marker.color.b = 1.0;

    int_marker.controls.clear();
    control.markers.clear();
    control.markers.push_back( marker );
    int_marker.controls.push_back( control );
    server_.insert( int_marker );
  }

  void makeBallMarker()
  {
    InteractiveMarker int_marker;
    int_marker.header.frame_id = "base_link";

    InteractiveMarkerControl control;
    control.always_visible = true;

    // Ball
    int_marker.name = "ball";

    control.interaction_mode = InteractiveMarkerControl::NONE;
    control.orientation.w = 1;
    control.orientation.y = 1;

    Marker marker;
    marker.color.r = 1.0;
    marker.color.g = 1.0;
    marker.color.b = 1.0;
    marker.color.a = 1.0;
    marker.type = Marker::CYLINDER;
    marker.scale.x = BORDER_SIZE;
    marker.scale.y = BORDER_SIZE;
    marker.scale.z = BORDER_SIZE;
    control.markers.push_back( marker );

    int_marker.controls.push_back( control );

    server_.insert( int_marker );
  }

  interactive_markers::InteractiveMarkerServer server_;

  ros::Timer game_loop_timer_;

  InteractiveMarker field_marker_;

  struct PlayerContext
  {
    PlayerContext(): pos(0),active(false),score(0) {}
    float pos;
    bool active;
    int score;
  };

  std::vector<PlayerContext> player_contexts_;

  float last_ball_pos_x_;
  float last_ball_pos_y_;

  float ball_pos_x_;
  float ball_pos_y_;

  float ball_dir_x_;
  float ball_dir_y_;
  float speed_;
};



int main(int argc, char** argv)
{
  ros::init(argc, argv, "pong");

  PongGame pong_game;
  ros::spin();
  ROS_INFO("Exiting..");
}