Index: code/branches/tetris/src/modules/pong/Pong.cc
===================================================================
--- code/branches/tetris/src/modules/pong/Pong.cc	(revision 8103)
+++ code/branches/tetris/src/modules/pong/Pong.cc	(revision 8104)
@@ -27,4 +27,9 @@
  */
 
+/**
+    @file Pong.cc
+    @brief Implementation of the Pong class.
+*/
+
 #include "Pong.h"
 
@@ -32,4 +37,5 @@
 #include "core/EventIncludes.h"
 #include "core/command/Executor.h"
+
 #include "PongCenterpoint.h"
 #include "PongBall.h"
@@ -40,4 +46,5 @@
 namespace orxonox
 {
+    // Events to allow to react to scoring of a player, in the level-file.
     CreateEventName(PongCenterpoint, right);
     CreateEventName(PongCenterpoint, left);
@@ -45,4 +52,8 @@
     CreateUnloadableFactory(Pong);
 
+    /**
+    @brief
+        Constructor. Registers and initializes the object.
+    */
     Pong::Pong(BaseObject* creator) : Deathmatch(creator)
     {
@@ -56,10 +67,16 @@
         this->setHUDTemplate("PongHUD");
 
+        // Pre-set the timer, but don't start it yet.
         this->starttimer_.setTimer(1.0, false, createExecutor(createFunctor(&Pong::startBall, this)));
         this->starttimer_.stopTimer();
 
+        // Set the type of Bots for this particular Gametype.
         this->botclass_ = Class(PongBot);
     }
 
+    /**
+    @brief
+        Destructor. Cleans up, if initialized.
+    */
     Pong::~Pong()
     {
@@ -68,7 +85,11 @@
     }
 
+    /**
+    @brief
+        Cleans up the Gametype by destroying the ball and the bats.
+    */
     void Pong::cleanup()
     {
-        if (this->ball_)
+        if (this->ball_ != NULL) // Destroy the ball, if present.
         {
             this->ball_->destroy();
@@ -76,7 +97,8 @@
         }
 
+        // Destroy both bats, if present.
         for (size_t i = 0; i < 2; ++i)
         {
-            if (this->bat_[0])
+            if (this->bat_[0] != NULL)
             {
                 this->bat_[0]->destroy();
@@ -86,14 +108,20 @@
     }
 
+    /**
+    @brief
+        Starts the Pong minigame.
+    */
     void Pong::start()
     {
-        if (this->center_)
-        {
-            if (!this->ball_)
+        if (this->center_ != NULL) // There needs to be a PongCenterpoint, i.e. the area the game takes place.
+        {
+            if (this->ball_ == NULL) // If there is no ball, create a new ball.
             {
                 this->ball_ = new PongBall(this->center_);
+                // Apply the template for the ball specified by the centerpoint.
                 this->ball_->addTemplate(this->center_->getBalltemplate());
             }
 
+            // Attach the ball to the centerpoint and set the parameters as specified in the centerpoint, the ball is attached to.
             this->center_->attach(this->ball_);
             this->ball_->setPosition(0, 0, 0);
@@ -103,15 +131,15 @@
             this->ball_->setBatLength(this->center_->getBatLength());
 
-            if (!this->bat_[0])
+            // If one of the bats is missing, create it. Apply the template for the bats as specified in the centerpoint.
+            for (size_t i = 0; i < 2; ++i)
             {
-                this->bat_[0] = new PongBat(this->center_);
-                this->bat_[0]->addTemplate(this->center_->getBattemplate());
+                if (this->bat_[i] == NULL)
+                {
+                    this->bat_[i] = new PongBat(this->center_);
+                    this->bat_[i]->addTemplate(this->center_->getBattemplate());
+                }
             }
-            if (!this->bat_[1])
-            {
-                this->bat_[1] = new PongBat(this->center_);
-                this->bat_[1]->addTemplate(this->center_->getBattemplate());
-            }
-
+
+            // Attach the bats to the centerpoint and set the parameters as specified in the centerpoint, the bats are attached to.
             this->center_->attach(this->bat_[0]);
             this->center_->attach(this->bat_[1]);
@@ -127,29 +155,43 @@
             this->bat_[1]->setLength(this->center_->getBatLength());
 
+            // Set the bats for the ball.
             this->ball_->setBats(this->bat_);
         }
-        else
+        else // If no centerpoint was specified, an error is thrown.
         {
             COUT(1) << "Error: No Centerpoint specified." << std::endl;
-        }
-
+            // TODO: End the game?
+        }
+
+        // Start the timer. After it has expired the ball is started.
         this->starttimer_.startTimer();
 
-
+        // Set variable to temporarily force the player to spawn.
         bool temp = this->bForceSpawn_;
         this->bForceSpawn_ = true;
 
+        // Call start for the parent class.
         Deathmatch::start();
 
+        // Reset the variable.
         this->bForceSpawn_ = temp;
     }
 
+    /**
+    @brief
+        Ends the Pong minigame.
+    */
     void Pong::end()
     {
         this->cleanup();
 
+        // Call end for the parent class.
         Deathmatch::end();
     }
 
+    /**
+    @brief
+        Spawns players, and fills the rest up with bots.
+    */
     void Pong::spawnPlayersIfRequested()
     {
@@ -164,20 +206,32 @@
     }
 
+    /**
+    @brief
+        Spawns the input player.
+    @param player
+        The player tp be spawned.
+    */
     void Pong::spawnPlayer(PlayerInfo* player)
     {
-        if (!this->bat_[0]->getPlayer())
+        assert(player);
+
+        // If the first (left) bat has no player.
+        if (this->bat_[0]->getPlayer() == NULL)
         {
             player->startControl(this->bat_[0]);
             this->players_[player].state_ = PlayerState::Alive;
         }
-        else if (!this->bat_[1]->getPlayer())
+        // If the second (right) bat has no player.
+        else if (this->bat_[1]->getPlayer() == NULL)
         {
             player->startControl(this->bat_[1]);
             this->players_[player].state_ = PlayerState::Alive;
         }
+        // If both bats are taken.
         else
             return;
 
-        if (player && player->getController() && player->getController()->isA(Class(PongAI)))
+        // If the player is an AI, it receives a pointer to the ball.
+        if (player->getController() != NULL && player->getController()->isA(Class(PongAI)))
         {
             PongAI* ai = orxonox_cast<PongAI*>(player->getController());
@@ -186,10 +240,15 @@
     }
 
+    /**
+    @brief
+        Is called when the player scored.
+    */
     void Pong::playerScored(PlayerInfo* player)
     {
         Deathmatch::playerScored(player);
 
-        if (this->center_)
-        {
+        if (this->center_ != NULL) // If there is a centerpoint.
+        {
+            // Fire an event for the player that has scored, to be able to react to it in the level, e.g. by displaying fireworks.
             if (player == this->getRightPlayer())
                 this->center_->fireEvent(FireEventName(PongCenterpoint, right));
@@ -197,9 +256,11 @@
                 this->center_->fireEvent(FireEventName(PongCenterpoint, left));
 
-            if (player)
+            // Also announce, that the player has scored.
+            if (player != NULL)
                 this->gtinfo_->sendAnnounceMessage(player->getName() + " scored");
         }
 
-        if (this->ball_)
+        // If there is a ball present, reset its position, velocity and acceleration.
+        if (this->ball_ != NULL)
         {
             this->ball_->setPosition(Vector3::ZERO);
@@ -209,5 +270,6 @@
         }
 
-        if (this->bat_[0] && this->bat_[1])
+        // If there are bats reset them to the middle position.
+        if (this->bat_[0] != NULL && this->bat_[1] != NULL)
         {
             this->bat_[0]->setPosition(-this->center_->getFieldDimension().x / 2, 0, 0);
@@ -215,16 +277,27 @@
         }
 
+        // Restart the timer to start the ball.
         this->starttimer_.startTimer();
     }
 
+    /**
+    @brief
+        Starts the ball with some default speed.
+    */
     void Pong::startBall()
     {
-        if (this->ball_ && this->center_)
+        if (this->ball_ != NULL && this->center_ != NULL)
             this->ball_->setSpeed(this->center_->getBallSpeed());
     }
 
+    /**
+    @brief
+        Get the left player.
+    @return
+        Returns a pointer to the player playing on the left. If there is no left player, NULL is returned.
+    */
     PlayerInfo* Pong::getLeftPlayer() const
     {
-        if (this->bat_ && this->bat_[0])
+        if (this->bat_ != NULL && this->bat_[0] != NULL)
             return this->bat_[0]->getPlayer();
         else
@@ -232,7 +305,13 @@
     }
 
+    /**
+    @brief
+        Get the right player.
+    @return
+        Returns a pointer to the player playing on the right. If there is no right player, NULL is returned.
+    */
     PlayerInfo* Pong::getRightPlayer() const
     {
-        if (this->bat_ && this->bat_[1])
+        if (this->bat_ != NULL && this->bat_[1] != NULL)
             return this->bat_[1]->getPlayer();
         else
Index: code/branches/tetris/src/modules/pong/Pong.h
===================================================================
--- code/branches/tetris/src/modules/pong/Pong.h	(revision 8103)
+++ code/branches/tetris/src/modules/pong/Pong.h	(revision 8104)
@@ -27,4 +27,10 @@
  */
 
+/**
+    @file Pong.h
+    @brief Declaration of the Pong class.
+    @ingroup Pong
+*/
+
 #ifndef _Pong_H__
 #define _Pong_H__
@@ -33,37 +39,55 @@
 
 #include "tools/Timer.h"
+
 #include "gametypes/Deathmatch.h"
 
 namespace orxonox
 {
+
+    /**
+    @brief
+        Implements a Pong minigame.
+
+        //TODO: Add details to different classes used and how.
+        PongBall, is the ball, PongBats are the things that can be moved by the players (ControllableEntities), PongCenterpoint is the playing field. (x-z area)
+
+    @author
+        Fabian 'x3n' Landau
+
+    @ingroup Pong
+    */
     class _PongExport Pong : public Deathmatch
     {
         public:
-            Pong(BaseObject* creator);
-            virtual ~Pong();
+            Pong(BaseObject* creator); //!< Constructor. Registers and initializes the object.
+            virtual ~Pong(); //!< Destructor. Cleans up, if initialized.
 
-            virtual void start();
-            virtual void end();
+            virtual void start(); //!< Starts the Pong minigame.
+            virtual void end(); ///!< Ends the Pong minigame.
 
-            virtual void spawnPlayer(PlayerInfo* player);
+            virtual void spawnPlayer(PlayerInfo* player); //!< Spawns the input player.
 
-            virtual void playerScored(PlayerInfo* player);
+            virtual void playerScored(PlayerInfo* player); //!< Is called when the player scored.
 
+            /**
+            @brief Set the PongCenterpoint (the playing field).
+            @param center A pointer to the PongCenterpoint to be set.
+            */
             void setCenterpoint(PongCenterpoint* center)
                 { this->center_ = center; }
 
-            PlayerInfo* getLeftPlayer() const;
-            PlayerInfo* getRightPlayer() const;
+            PlayerInfo* getLeftPlayer() const; //!< Get the left player.
+            PlayerInfo* getRightPlayer() const; //!< Get the right player.
 
         protected:
-            virtual void spawnPlayersIfRequested();
+            virtual void spawnPlayersIfRequested(); //!< Spawns players, and fills the rest up with bots.
 
-            void startBall();
-            void cleanup();
+            void startBall(); //!< Starts the ball with some default speed.
+            void cleanup(); //!< Cleans up the Gametype by destroying the ball and the bats.
 
-            WeakPtr<PongCenterpoint> center_;
-            WeakPtr<PongBall> ball_;
-            WeakPtr<PongBat> bat_[2];
-            Timer starttimer_;
+            WeakPtr<PongCenterpoint> center_; //!< The playing field.
+            WeakPtr<PongBall> ball_; //!< The Pong ball.
+            WeakPtr<PongBat> bat_[2]; //!< The two bats.
+            Timer starttimer_; //!< A timer to delay the start of the game.
     };
 }
Index: code/branches/tetris/src/modules/pong/PongBall.cc
===================================================================
--- code/branches/tetris/src/modules/pong/PongBall.cc	(revision 8103)
+++ code/branches/tetris/src/modules/pong/PongBall.cc	(revision 8104)
@@ -27,9 +27,16 @@
  */
 
+/**
+    @file PongBall.cc
+    @brief Implementation of the PongBall class.
+*/
+
 #include "PongBall.h"
 
 #include "core/CoreIncludes.h"
 #include "core/GameMode.h"
+
 #include "gametypes/Gametype.h"
+
 #include "PongBat.h"
 
@@ -40,4 +47,8 @@
     const float PongBall::MAX_REL_Z_VELOCITY = 1.5;
 
+    /**
+    @brief
+        Constructor. Registers and initializes the object.
+    */
     PongBall::PongBall(BaseObject* creator)
         : MovableEntity(creator)
@@ -57,4 +68,8 @@
     }
 
+    /**
+    @brief
+        Destructor.
+    */
     PongBall::~PongBall()
     {
@@ -68,4 +83,8 @@
     }
 
+    /**
+    @brief
+        Register variables to synchronize over the network.
+    */
     void PongBall::registerVariables()
     {
@@ -79,15 +98,26 @@
     }
 
+    /**
+    @brief
+        Is called every tick.
+        //TODO: Explain in detail what happens here.
+    @param dt
+        The time since the last tick.
+    */
     void PongBall::tick(float dt)
     {
         SUPER(PongBall, tick, dt);
 
+        // Get the current position, velocity and acceleration of the ball.
         Vector3 position = this->getPosition();
         Vector3 velocity = this->getVelocity();
         Vector3 acceleration = this->getAcceleration();
 
+        // If the ball has gone over the top or bottom boundary of the playing field (i.e. the ball has hit the top or bottom delimiters).
         if (position.z > this->fieldHeight_ / 2 || position.z < -this->fieldHeight_ / 2)
         {
+            // Its velocity in z-direction is inverted (i.e. it bounces off).
             velocity.z = -velocity.z;
+            // And its position is set as to not overstep the boundary it has just crossed.
             if (position.z > this->fieldHeight_ / 2)
                 position.z = this->fieldHeight_ / 2;
@@ -98,17 +128,23 @@
         }
 
+        // If the ball has crossed the left or right boundary of the playing field (i.e. a player has just scored, if the bat isn't there to parry).
         if (position.x > this->fieldWidth_ / 2 || position.x < -this->fieldWidth_ / 2)
         {
             float distance = 0;
 
-            if (this->bat_)
+            if (this->bat_ != NULL) // If there are bats.
             {
-                if (position.x > this->fieldWidth_ / 2 && this->bat_[1])
+                // If the right boundary has been crossed.
+                if (position.x > this->fieldWidth_ / 2 && this->bat_[1] != NULL)
                 {
+                    // Calculate the distance (in z-direction) between the ball and the center of the bat, weighted by half of the effective length of the bat (with additional 10%)
                     distance = (position.z - this->bat_[1]->getPosition().z) / (this->fieldHeight_ * (this->batlength_ * 1.10f) / 2);
-                    if (fabs(distance) <= 1)
-                    {
+                    if (fabs(distance) <= 1) // If the bat is there to parry.
+                    {
+                        // Set the ball to be exactly at the boundary.
                         position.x = this->fieldWidth_ / 2;
+                        // Invert its veloxity in x-direction (i.e. it bounces off).
                         velocity.x = -velocity.x;
+                        // Adjust the velocity in the z-direction, depending on where the ball hit the bat.
                         velocity.z = distance * distance * sgn(distance) * PongBall::MAX_REL_Z_VELOCITY * this->speed_;
                         acceleration = this->bat_[1]->getVelocity() * this->accelerationFactor_ * -1;
@@ -116,4 +152,5 @@
                         this->fireEvent();
                     }
+                    // If the left player scores.
                     else if (GameMode::isMaster() && position.x > this->fieldWidth_ / 2 * (1 + this->relMercyOffset_))
                     {
@@ -125,11 +162,16 @@
                     }
                 }
-                if (position.x < -this->fieldWidth_ / 2 && this->bat_[0])
+                // If the left boundary has been crossed.
+                else if (position.x < -this->fieldWidth_ / 2 && this->bat_[0] != NULL)
                 {
+                    // Calculate the distance (in z-direction) between the ball and the center of the bat, weighted by half of the effective length of the bat (with additional 10%)
                     distance = (position.z - this->bat_[0]->getPosition().z) / (this->fieldHeight_ * (this->batlength_ * 1.10f) / 2);
-                    if (fabs(distance) <= 1)
-                    {
+                    if (fabs(distance) <= 1) // If the bat is there to parry.
+                    {
+                        // Set the ball to be exactly at the boundary.
                         position.x = -this->fieldWidth_ / 2;
+                        // Invert its veloxity in x-direction (i.e. it bounces off).
                         velocity.x = -velocity.x;
+                        // Adjust the velocity in the z-direction, depending on where the ball hit the bat.
                         velocity.z = distance * distance * sgn(distance) * PongBall::MAX_REL_Z_VELOCITY * this->speed_;
                         acceleration = this->bat_[0]->getVelocity() * this->accelerationFactor_ * -1;
@@ -137,4 +179,5 @@
                         this->fireEvent();
                     }
+                    // If the right player scores.
                     else if (GameMode::isMaster() && position.x < -this->fieldWidth_ / 2 * (1 + this->relMercyOffset_))
                     {
@@ -149,4 +192,5 @@
         }
 
+        // Set the position, velocity and acceleration of the ball, if they have changed.
         if (acceleration != this->getAcceleration())
             this->setAcceleration(acceleration);
@@ -157,14 +201,21 @@
     }
 
+    /**
+    @brief
+        Set the speed of the ball (in x-direction).
+    @param speed
+        The speed to be set.
+    */
     void PongBall::setSpeed(float speed)
     {
-        if (speed != this->speed_)
+        if (speed != this->speed_) // If the speed changes
         {
             this->speed_ = speed;
 
+            // Set the speed in the direction of the balls current velocity.
             Vector3 velocity = this->getVelocity();
             if (velocity.x != 0)
                 velocity.x = sgn(velocity.x) * this->speed_;
-            else
+            else // If the balls current velocity is zero, the speed is set in a random direction.
                 velocity.x = this->speed_ * sgn(rnd(-1,1));
 
@@ -173,4 +224,8 @@
     }
 
+    /**
+    @brief
+        Set the 
+    */
     void PongBall::setBats(WeakPtr<PongBat>* bats)
     {
Index: code/branches/tetris/src/modules/pong/PongBall.h
===================================================================
--- code/branches/tetris/src/modules/pong/PongBall.h	(revision 8103)
+++ code/branches/tetris/src/modules/pong/PongBall.h	(revision 8104)
@@ -27,4 +27,10 @@
  */
 
+/**
+    @file PongBall.h
+    @brief Declaration of the PongBall class.
+    @ingroup Pong
+*/
+
 #ifndef _PongBall_H__
 #define _PongBall_H__
@@ -33,8 +39,22 @@
 
 #include "util/Math.h"
+
 #include "worldentities/MovableEntity.h"
 
 namespace orxonox
 {
+
+    /**
+    @brief
+        This class manages the ball for Pong.
+
+        //TODO: Describe what it's responnsibilities are.
+        Only moves in x-z area.
+
+    @author
+        Fabian 'x3n' Landau
+
+    @ingroup Pong
+    */
     class _PongExport PongBall : public MovableEntity
     {
