diff --git a/game/CMakeLists.txt b/game/CMakeLists.txt
index 64fc26a..05fc7d1 100644
--- a/game/CMakeLists.txt
+++ b/game/CMakeLists.txt
@@ -8,10 +8,20 @@ set(GAME_SRC
     main.cpp
     opengl.cpp
     glclasses.cpp
-    config.cpp
-    simulation.cpp
     renderer.cpp
-  )
+    game_window.cpp
+    triangle_window.cpp
+
+    util.cpp
+    game.cpp
+    state/object.cpp
+    state/state.cpp
+    state/player.cpp
+    state/planet.cpp
+    state/missile.cpp
+    state/commands.cpp
+    state/state.cpp
+)
 
 set(GAME_HEADERS
   opengl.h
@@ -20,7 +30,7 @@ set(GAME_HEADERS
   config.h
   simulation.h
   renderer.h
-  )
+)
 
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/game/game.cpp b/game/game.cpp
new file mode 100644
index 0000000..36ffc64
--- /dev/null
+++ b/game/game.cpp
@@ -0,0 +1,67 @@
+#include "game.hpp"
+
+#include "state/commands.hpp"
+
+#include "util.hpp"
+
+#include <cmath>
+
+Game::Game()
+{
+    // advance simulation with 100 Hz
+    m_time_step = 1.0 / 100.0;
+    m_time_for_next_step = 0.0;
+
+    m_state = new game::State();
+    m_state->init();
+
+    m_state->addPlayer(0);
+    m_state->addPlayer(1);
+    m_state->addPlayer(2);
+    m_state->addPlayer(3);
+    //m_state->addPlayer(2);
+}
+
+bool Game::cycle(float dt)
+{
+    static float acc = 0.0;
+    acc += dt;
+
+    float spawnInterval = 0.1;
+    while(acc > spawnInterval) {
+        acc -= spawnInterval;
+
+        float a = 2.0 * M_PI * util::randf_0_1();
+        float speed = 0.002;
+        m_state->players[0]->addCommand(new game::ShootCommand(a, speed));
+    }
+
+#if 1
+    if (dt >= 10.0) {
+        //std::cout<<"time to big: " << dt << std::endl;
+        dt = m_time_step;
+    }
+
+    //std::cout<<"adding dt: " << dt << std::endl;
+    m_time_for_next_step += dt;
+
+    int steps = 0;
+    while(m_time_for_next_step >= m_time_step) {
+        //std::cout<<"time now: " << m_time_for_next_step << std::endl;
+        m_time_for_next_step -= m_time_step;
+
+        m_state->advance(m_time_step);
+        steps++;
+    }
+
+    //std::cout << m_time_for_next_step << " s remaining time, " << steps << " steps taken." << std::endl;
+
+    return true;
+#else
+    (void) dt;
+
+    m_state->advance(dt);
+
+    return true;
+#endif
+}
diff --git a/game/game.hpp b/game/game.hpp
new file mode 100644
index 0000000..9c9512a
--- /dev/null
+++ b/game/game.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include "state/state.hpp"
+
+class Game {
+public:
+    Game();
+
+    // main method of the game. run this regulary
+    // return false if want to exit.
+    bool cycle(float dt);
+
+    // for rendering
+    const game::State *state() const { return m_state; }
+
+private:
+    game::State *m_state;
+
+    float m_time_for_next_step;
+    float m_time_step;
+};
diff --git a/game/game_window.cpp b/game/game_window.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/game/game_window.h b/game/game_window.h
new file mode 100644
index 0000000..a5659a5
--- /dev/null
+++ b/game/game_window.h
@@ -0,0 +1,89 @@
+#pragma once
+
+#include "opengl.h"
+#include "renderer.h"
+
+#include "game.hpp"
+
+#include "state/object.hpp"
+#include "state/missile.hpp"
+#include "state/player.hpp"
+#include "state/planet.hpp"
+#include "state/ship.hpp"
+
+class GameWindow : public endofthejedi::GLWindow {
+private:
+protected:
+    void init() override {
+        glClearColor(0.5f, 0.6f, 0.7f, 1.0f);
+        resize();
+
+        glEnable(GL_DEPTH_TEST);
+    }
+
+    void render(double time) override {
+        //static bool once = false;
+        //if (!once) {
+        //    once = true;
+        //    for (int i=0; i<1000; i++) {
+        //        m_game.cycle(time);
+        //    }
+        //}
+
+        if (!m_game.cycle(static_cast<float>(time/1000000000.0))) {
+            std::cout<<"stopping the game..." << std::endl;
+            stop();
+        }
+
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        for (const game::Planet *planet : m_game.state()->planets) {
+            drawPlanet(planet->position, planet->radius);
+        }
+
+        for (const game::Ship *ship : m_game.state()->ships) {
+            drawShip(ship->position);
+        }
+
+        for (const game::Player *player : m_game.state()->players) {
+            for (const game::Missile *missile : player->missiles) {
+                drawMissile(missile->position);
+            }
+        }
+    }
+
+    void resize() override { glViewport(0, 0, getwidth(), getheight()); }
+
+    void drawShip(const glm::vec2 &pos)
+    {
+        //std::cout<<"draw ship @ " << pos.x << ", " << pos.y << std::endl;
+        glm::vec3 color = glm::vec3(0.2, 1.0, 0.3);
+
+        float radius = m_game.state()->shipRadius();
+
+        m_renderer.drawCircle(pos.x, pos.y, radius, color.x, color.y, color.z, 12);
+    }
+
+    void drawPlanet(const glm::vec2 &pos, float radius)
+    {
+        glm::vec3 color = glm::vec3(0.7, 0.1, 0.2);
+
+        //std::cout<<"draw planet @ " << pos.x << ", " << pos.y << std::endl;
+        m_renderer.drawCircle(pos.x, pos.y, radius, color.x, color.y, color.z, 32);
+    }
+
+    void drawMissile(const glm::vec2 &pos)
+    {
+        glm::vec3 color = glm::vec3(1.0, 1.0, 0.3);
+        m_renderer.drawCircle(pos.x, pos.y, 0.005, color.x, color.y, color.z, 5);
+    }
+
+public:
+    GameWindow(unsigned int width, unsigned int height)
+        : endofthejedi::GLWindow(width, height) {}
+
+private:
+    Game                   m_game;
+    endofthejedi::Renderer m_renderer;
+};
+
diff --git a/game/main.cpp b/game/main.cpp
index 5a7aead..a63380e 100644
--- a/game/main.cpp
+++ b/game/main.cpp
@@ -1,36 +1,11 @@
 #include "opengl.h"
 #include <iostream>
 
-class MainWindow : public endofthejedi::GLWindow {
-private:
-protected:
-  void init() override {
-    glClearColor(0.5f, 0.6f, 0.7f, 1.0f);
-    resize();
-
-    glEnable(GL_DEPTH_TEST);
-  }
-  void render(double time) override {
-    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-
-    glBegin(GL_TRIANGLES);
-    glColor3f(1.0f, 0.0f, 0.0f);
-    glVertex3f(0.0f, -1.0f, 0.0f);
-    glColor3f(0.0f, 1.0f, 0.0f);
-    glVertex3f(-1.0f, 1.0f, 0.0f);
-    glColor3f(0.0f, 0.0f, 1.0f);
-    glVertex3f(1.0f, 1.0f, 0.0f);
-    glEnd();
-  }
-  void resize() override { glViewport(0, 0, getwidth(), getheight()); }
-
-public:
-  MainWindow(unsigned int width, unsigned int height)
-      : endofthejedi::GLWindow(width, height) {}
-};
+//#include "triangle_window.h"
+#include "game_window.h"
 
 int main(int argc, const char *argv[]) {
-  MainWindow window(500, 500);
+  GameWindow window(500, 500);
   window.set_maxfps(60.0);
   window.loop();
   window.stop();
diff --git a/game/renderer.cpp b/game/renderer.cpp
index bed3c3d..93b4dc0 100644
--- a/game/renderer.cpp
+++ b/game/renderer.cpp
@@ -7,12 +7,12 @@ endofthejedi::Renderer::Renderer() {
 endofthejedi::Renderer::~Renderer() {}
 
 void endofthejedi::Renderer::drawCircle(float x, float y, float radius, float r,
-                                        float g, float b) {
+                                        float g, float b, int numSides) {
   glBegin(GL_TRIANGLE_FAN);
   glVertex2f(x, y); // center of circle
-  for (int i = 0; i <= 64; i++) {
+  for (int i = 0; i <= numSides; i++) {
     glColor3f(r,g,b);
-    glVertex2f(x + (radius * cos(i * 2 * M_PI / 64)), y + (radius * sin(i * 2 * M_PI / 64)));
+    glVertex2f(x + (radius * cos(i * 2 * M_PI / numSides)), y + (radius * sin(i * 2 * M_PI / numSides)));
   }
   glEnd();
 }
diff --git a/game/renderer.h b/game/renderer.h
index d5b4f63..53a4058 100644
--- a/game/renderer.h
+++ b/game/renderer.h
@@ -19,7 +19,7 @@ class Renderer {
   Renderer();
   ~Renderer();
   void drawCircle(float x, float y, float radius, float r,
-                  float g, float b);
+                  float g, float b, int numSides=12);
 };
 
 }
diff --git a/game/state/commands.cpp b/game/state/commands.cpp
new file mode 100644
index 0000000..f656dc6
--- /dev/null
+++ b/game/state/commands.cpp
@@ -0,0 +1,22 @@
+#include "commands.hpp"
+
+namespace game {
+    void ShootCommand::apply(Player *player, State *state) const
+    {
+        (void) state;
+        // TODO spawn missile if alive and enough energy
+        //std::cout<<"apply command " << name() << std::endl;
+
+        player->energy -= m_speed;
+        player->missiles.push_back(new Missile(player->id, player->ship->position, m_angle, m_speed));
+    }
+
+    bool ShootCommand::allowed(const Player *player, const State *state) const
+    {
+        (void) state;
+
+        // TODO
+        return player->alive && player->energy >= m_speed;
+        //return player->alive;
+    }
+}
diff --git a/game/state/commands.hpp b/game/state/commands.hpp
new file mode 100644
index 0000000..5c8ff97
--- /dev/null
+++ b/game/state/commands.hpp
@@ -0,0 +1,56 @@
+#pragma once
+
+#include "state.hpp"
+#include "player.hpp"
+#include "ship.hpp"
+#include "planet.hpp"
+#include "missile.hpp"
+
+#include <iostream>
+
+namespace game {
+    class Command {
+    public:
+        Command()
+        {
+        }
+
+        virtual ~Command()
+        {
+        }
+
+        virtual bool allowed(const Player *player, const State *state) const
+        {
+            (void) player;
+            (void) state;
+
+            return true;
+        }
+
+        virtual void apply(Player *player, State *state) const
+        {
+            (void) state;
+            (void) player;
+
+            std::cout<<"Command '" << name() << "' not yet implemented!" << std::endl;
+        }
+
+        virtual std::string name() const { return "<unnamed>"; }
+    };
+
+    class ShootCommand : public Command {
+    public:
+        ShootCommand(float angle, float speed) : m_angle(angle), m_speed(speed)
+        {
+        }
+
+        std::string name() const { return "<shoot>"; }
+
+        void apply(        Player *player,       State *state) const;
+        bool allowed(const Player *player, const State *state) const;
+
+    private:
+        float m_angle;
+        float m_speed;
+    };
+}
diff --git a/game/state/explosion.cpp b/game/state/explosion.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/game/state/explosion.hpp b/game/state/explosion.hpp
new file mode 100644
index 0000000..2cf92ef
--- /dev/null
+++ b/game/state/explosion.hpp
@@ -0,0 +1,17 @@
+#pragma once
+
+#if 0
+class Explosion {
+public:
+    enum class Kind {
+        Normal,
+        MissileWithShip
+    };
+
+    glm::vec2 position;
+
+    Explosion(Kind kind);
+
+public:
+};
+#endif
diff --git a/game/state/missile.cpp b/game/state/missile.cpp
new file mode 100644
index 0000000..b060ca3
--- /dev/null
+++ b/game/state/missile.cpp
@@ -0,0 +1,82 @@
+#include "missile.hpp"
+
+#include <cmath>
+
+#include "state.hpp"
+#include "player.hpp"
+
+#include <glm/gtx/norm.hpp>
+
+namespace game {
+    Missile::Missile(int playerId, const glm::vec2 &pos, float angle, float speed)
+        : playerId(playerId)
+        , position(pos)
+    {
+        velocity = speed * glm::vec2(std::sin(angle), std::cos(angle));
+
+        //std::cout << "spawned missile for player " << playerId << " @ ("
+        //    << pos.x << ", " << pos.y << ") speed = " << speed << std::endl;
+    }
+
+    Missile::~Missile()
+    {
+        //std::cout<<"destroyed missile" << std::endl;
+    }
+
+    Missile::Event Missile::advance(const game::State *state, float dt)
+    {
+        glm::vec2 gravityForce = glm::vec2(0.0, 0.0);
+
+        for (const Player *other : state->players) {
+            if (other->ship != nullptr && other->id != playerId) {
+                glm::vec2 diff = other->ship->position - position;
+                float dist = glm::length(diff);
+                if (dist <= other->ship->radius) {
+                    // TODO: collect all hits and return the first one only
+                    // TODO: find exact hit position!
+                    return Missile::Event(position, playerId, other->id);
+                }
+            }
+        }
+
+        // get forces
+        for (const Planet *planet : state->planets) {
+            glm::vec2 diff = planet->position - position;
+            float dist = glm::length(diff);
+            if (dist <= planet->radius) {
+                // TODO: collect all hits and return the first one only
+                // TODO: find exact hit position!
+                return Missile::Event(position, Missile::HitObject::HitPlanet);
+            }
+
+            dist *= 20.0;
+            if (dist > 0.001) {
+                float G = 0.1;
+                gravityForce += G * diff / (1.0f + dist*dist);
+            }
+        }
+
+        // simple (and bad) euler integration.
+        position += 0.5f * gravityForce*dt*dt + velocity*dt;
+        velocity += gravityForce * dt;
+
+        //const float thr = 0.01;
+        //float s = glm::length(velocity);
+        //if (s > thr) {
+        //    velocity = glm::normalize(velocity) * thr;
+        //}
+
+        glm::vec2 nextPos = position + velocity;
+
+        // TODO: collision checks
+        position = nextPos;
+
+        // check if distance to center of the universe is getting too big
+        float distToCenter = glm::length(position);
+        if (distToCenter > state->maxMissileDistance()) {
+            return Missile::Event(position, Missile::HitObject::LeftUniverse);
+        }
+
+        return Missile::Event(position);
+    }
+}
diff --git a/game/state/missile.hpp b/game/state/missile.hpp
new file mode 100644
index 0000000..b1f0f96
--- /dev/null
+++ b/game/state/missile.hpp
@@ -0,0 +1,68 @@
+#pragma once
+
+#include <glm/vec2.hpp>
+#include <glm/vec3.hpp>
+
+#include "state.hpp"
+
+#include "ship.hpp"
+#include "planet.hpp"
+
+namespace game {
+    class State;
+
+    // missile belongs to a player and optionally fills a trace behind it.
+    // trace then belongs to the player.
+    class Missile {
+    public:
+        enum class HitObject {
+            Nothing,
+            HitPlayer,
+            HitPlanet,
+            // HitMissile,
+            LeftUniverse
+        };
+
+        // missile advances to pos. if hit != Nothing, it hits something and
+        // stops existing afterwards.
+        class Event {
+        public:
+            Event(const glm::vec2 &pos) : Event(pos, HitObject::Nothing)
+            {
+            }
+
+            Event(const glm::vec2 &pos, HitObject hit)
+                : hit(hit), pos(pos)
+            {
+            }
+
+            Event(const glm::vec2 &pos, int playerIdKiller, int playerIdVictim)
+                : Event(pos, HitObject::HitPlayer)
+            {
+                  this->playerIdKiller = playerIdKiller;
+                  this->playerIdVictim = playerIdVictim;
+            }
+
+            HitObject hit;
+            glm::vec2 pos;
+
+            int playerIdKiller;
+            int playerIdVictim;
+        };
+
+        // XXX
+        int       playerId; // owner won't be hit by own missiles
+        glm::vec2 position;
+        glm::vec2 velocity;
+        //Trace *trace;
+
+        Missile(int playerId, const glm::vec2 &pos, float angle, float speed);
+
+        ~Missile();
+
+        // try to advance. if something will be hit, return the first hit in
+        // time.
+        Missile::Event advance(const game::State *state, float dt);
+    };
+}
+
diff --git a/game/state/object.cpp b/game/state/object.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/game/state/object.hpp b/game/state/object.hpp
new file mode 100644
index 0000000..2909acc
--- /dev/null
+++ b/game/state/object.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <glm/vec2.hpp>
+#include <glm/vec3.hpp>
+
+class Object {
+public:
+    Object(const glm::vec2 &pos, float r) : position(pos), radius(r)
+    {
+    }
+
+    const glm::vec2 position;
+    const float     radius;
+};
+
diff --git a/game/state/planet.cpp b/game/state/planet.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/game/state/planet.hpp b/game/state/planet.hpp
new file mode 100644
index 0000000..0407683
--- /dev/null
+++ b/game/state/planet.hpp
@@ -0,0 +1,12 @@
+#pragma once
+
+#include "object.hpp"
+
+namespace game {
+    class Planet : public Object {
+    public:
+        Planet(const glm::vec2 &pos, float r) : Object(pos, r)
+        {
+        }
+    };
+}
diff --git a/game/state/player.cpp b/game/state/player.cpp
new file mode 100644
index 0000000..255c844
--- /dev/null
+++ b/game/state/player.cpp
@@ -0,0 +1,33 @@
+#include "player.hpp"
+
+#include <iostream>
+
+#include "commands.hpp"
+
+#include "ship.hpp"
+
+namespace game {
+    void Player::popCommand()
+    {
+        //std::cout<<"popCommand()" << std::endl;
+
+        Command *cmd = commands.front();
+        commands.erase(commands.begin());
+        delete(cmd);
+    }
+
+    Command *Player::peekCommand()
+    {
+        return commands.front();
+    }
+
+    bool Player::hasCommandInQueue()
+    {
+        return !commands.empty();
+    }
+
+    void Player::addCommand(Command *cmd)
+    {
+        commands.push_back(cmd);
+    }
+}
diff --git a/game/state/player.hpp b/game/state/player.hpp
new file mode 100644
index 0000000..199a411
--- /dev/null
+++ b/game/state/player.hpp
@@ -0,0 +1,36 @@
+#pragma once
+
+#include <deque>
+#include <vector>
+
+#include <glm/vec2.hpp>
+#include <glm/vec3.hpp>
+
+namespace game {
+    class Ship;
+    class Command;
+    class Missile;
+
+    class Player {
+    public:
+        int        id;
+        bool       alive;
+        float      energy;
+        float      deadTimeCounter;
+        Ship      *ship;
+        std::vector<Missile*> missiles;
+
+        Player(int id) : id(id), alive(true), energy(0.0), ship(nullptr)
+        {
+        }
+
+        void addCommand(Command *cmd);
+        bool hasCommandInQueue();
+
+        Command *peekCommand();
+        void popCommand();
+
+    private:
+        std::deque<Command*> commands;
+    };
+}
diff --git a/game/state/ship.cpp b/game/state/ship.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/game/state/ship.hpp b/game/state/ship.hpp
new file mode 100644
index 0000000..bffb754
--- /dev/null
+++ b/game/state/ship.hpp
@@ -0,0 +1,12 @@
+#pragma once
+
+#include "object.hpp"
+
+namespace game {
+    class Ship : public Object {
+    public:
+        Ship(const glm::vec2 &pos, float r) : Object(pos, r)
+        {
+        }
+    };
+}
diff --git a/game/state/state.cpp b/game/state/state.cpp
new file mode 100644
index 0000000..462f62a
--- /dev/null
+++ b/game/state/state.cpp
@@ -0,0 +1,262 @@
+#include "state.hpp"
+
+#include <cmath>
+
+#include <glm/vec2.hpp>
+#include <glm/vec3.hpp>
+#include <glm/gtx/norm.hpp>
+
+#include "object.hpp"
+#include "missile.hpp"
+#include "player.hpp"
+#include "planet.hpp"
+#include "ship.hpp"
+#include "commands.hpp"
+
+#include "util.hpp"
+
+namespace game {
+    void State::init()
+    {
+        m_shipRadius         = 0.05;
+        m_maxMissileDistance = 2.0;
+        m_playerRespawnTime  = 2.0;
+        m_defaultEnergy      = 10.0;
+
+        bool planetsOnCircle = false;
+
+        int numPlanets = 10;
+        for (int i=0; i<numPlanets; i++) {
+            float t = i / static_cast<float>(numPlanets);
+            t *= 2.0*M_PI;
+
+            // distribute but not in the center
+            int tries = 0;
+            glm::vec2 pos;
+            do {
+                float cr = 0.7;
+                if (planetsOnCircle) {
+                    pos = cr * glm::vec2(std::sin(t), std::cos(t));
+                } else {
+                    pos = cr * util::randv2_m1_1();
+                }
+            } while(glm::length(pos) < 0.2 && tries++ < 1000);
+
+            planets.push_back(new Planet(pos, 0.03 + 0.07*util::randf_0_1()));
+        }
+    }
+
+    bool State::spawnShipForPlayer(Player *player)
+    {
+        glm::vec2 spawnPos;
+        if (!findFreePositionWithRadius(5.0 * m_shipRadius, spawnPos)) {
+            return false;
+        }
+
+        player->ship = new Ship(spawnPos, m_shipRadius);
+        ships.push_back(player->ship);
+
+        player->energy = m_defaultEnergy;
+
+        return true;
+    }
+
+    void State::addPlayer(int playerId)
+    {
+        Player *player = new Player(playerId);
+        players.push_back(player);
+    }
+
+    void State::playerLeft(int playerId)
+    {
+        (void) playerId;
+    }
+
+    void State::advancePlayerShipSpawns(float dt)
+    {
+        (void) dt;
+
+        for (Player *player : players) {
+            if (!player->alive) {
+                player->deadTimeCounter += dt;
+                if (player->deadTimeCounter >= m_playerRespawnTime) {
+                    player->deadTimeCounter = 0;
+                    player->alive = true;
+                    std::cout<<"respawning player " << player->id << " now!" << std::endl;
+                }
+            }
+
+            if (player->alive && player->ship == NULL) {
+                if (!spawnShipForPlayer(player)) {
+                    std::cout<<"could not spawn ship for player!" << std::endl;
+                }
+            }
+        }
+    }
+
+    void State::advancePlayerCommands(float dt)
+    {
+        (void) dt;
+        for (Player *player : players) {
+            if (player->alive) {
+                player->energy += dt;
+            }
+
+            // try to execute as much queued commands as possible.
+            while (player->hasCommandInQueue()) {
+                Command *command = player->peekCommand();
+                if (!command->allowed(player, this)) {
+                    break;
+                }
+
+                command->apply(player, this);
+                player->popCommand();
+            }
+        }
+    }
+
+    void State::playerKillsPlayer(Player *killer, Player *victim)
+    {
+        if (killer == nullptr || victim == nullptr) {
+            std::cerr <<"error: killer / victim is NULL!" << std::endl;
+            exit(-1);
+            return;
+        }
+
+        std::cout<<"player " << killer->id << " killed " << victim->id << std::endl;
+
+        // destroy ship
+        size_t i;
+        for (i=0; i<ships.size(); i++) {
+            if (ships[i] == victim->ship) {
+                ships.erase(ships.begin() + i);
+                break;
+            }
+        }
+
+        delete(victim->ship);
+        victim->ship = nullptr;
+
+        victim->alive = false;
+        victim->deadTimeCounter = 0.0;
+
+        // TODO
+        // add points
+        //
+        // TODO
+        // message
+        //
+        // TODO
+        // respawn timer
+    }
+
+    void State::advancePlayerMissiles(float dt)
+    {
+        // advance missiles
+        for (Player *player : players) {
+            size_t i = 0;
+            while (i<player->missiles.size()) {
+                Missile *missile = player->missiles[i];
+
+                //std::cout<<"missile: " << (long unsigned int) missile << std::endl;
+                const Missile::Event evt = missile->advance(this, dt);
+
+                if (evt.hit == Missile::HitObject::Nothing) {
+                    i++;
+
+                } else {
+                    switch(evt.hit) {
+                        case Missile::HitObject::HitPlanet:
+                            //std::cout<<"hit Planet" << std::endl;
+                            break;
+
+                        case Missile::HitObject::HitPlayer:
+                            //std::cout<<"hit Player" << std::endl;
+                            playerKillsPlayer(playerForId(evt.playerIdKiller), playerForId(evt.playerIdVictim));
+                            break;
+
+                        case Missile::HitObject::LeftUniverse:
+                            //std::cout<<"missile left the universe." << std::endl;
+                            break;
+
+                        default:
+                            break;
+                    }
+
+                    player->missiles.erase(player->missiles.begin() + i);
+                    delete(missile);
+                    //std::cout<<std::endl;
+                }
+
+                // TODO
+                // add trace to the missile
+            }
+        }
+    }
+
+    void State::advance(float dt)
+    {
+        //std::cout<<"advance ship spawns" << std::endl;
+        advancePlayerShipSpawns(dt);
+
+        //std::cout<<"advance commands" << std::endl;
+        advancePlayerCommands(dt);
+
+        //std::cout<<"advance missiles" << std::endl;
+        advancePlayerMissiles(dt);
+    }
+
+    Player *State::playerForId(int playerId)
+    {
+        for (Player *p : players) {
+            if (p->id == playerId) {
+                return p;
+            }
+        }
+
+        return nullptr;
+    }
+
+    bool State::findFreePositionWithRadius(float radius, glm::vec2 &pos)
+    {
+        bool first = ships.size() == 0;
+
+        int tries = 0;
+        while(true) {
+            bool noCollision = true;
+
+            //pos = glm::linearRand2(-1.0, 1.0);
+            if (first) {
+                first = false;
+                pos = glm::vec2(0.0, 0.0);
+            } else {
+                pos = glm::vec2(util::randf_0_1(), util::randf_m1_1());
+                        //glm::linearRand(-1.0, 1.0), glm::linearRand(-1.0, 1.0));
+            }
+
+            for (Planet *p : planets) {
+                if (glm::distance(p->position, pos) <= radius) {
+                    noCollision = false;
+                    break;
+                }
+            }
+
+            if (noCollision) {
+                return true;
+            }
+
+            if (tries++ >= 1000) {
+                pos = glm::vec2(0.0, 0.0);
+                return false;
+            }
+        }
+    }
+
+    void State::commandForPlayer(int playerId, game::Command *cmd)
+    {
+        Player *player = playerForId(playerId);
+        if (player != nullptr) {
+            player->addCommand(cmd);
+        }
+    }
+}
diff --git a/game/state/state.hpp b/game/state/state.hpp
new file mode 100644
index 0000000..1182147
--- /dev/null
+++ b/game/state/state.hpp
@@ -0,0 +1,64 @@
+#pragma once
+
+#include <vector>
+#include <queue>
+
+#include <iostream>
+
+#include <glm/vec2.hpp>
+
+namespace game {
+    class Command;
+    class Missile;
+    class Player;
+    class Planet;
+    class Ship;
+
+    // trace of a missile. exists without a missile at player.
+    //class Trace {
+    //public:
+    //    std::vector<glm::vec2> points;
+    //};
+
+    class State {
+    public:
+        void init();
+        void advance(float dt);
+
+        // the (network) layer calling these three functions should keep id's
+        // unique and give one (network) input an id.
+        void addPlayer(int playerId);
+        void playerLeft(int playerId);
+        void commandForPlayer(int playerId, Command *cmd);
+
+        // lookup. return nullptr on invalid playerId
+        Player *playerForId(int playerId);
+
+        float maxMissileDistance() const { return m_maxMissileDistance; }
+        float shipRadius()         const { return m_shipRadius; }
+
+        std::vector<Planet*>  planets;
+        std::vector<Ship*>    ships;
+        std::vector<Player*>  players;
+
+    private:
+        void playerKillsPlayer(Player *killer, Player *victim);
+
+        void advancePlayerShipSpawns(float dt);
+        void advancePlayerCommands(float dt);
+        void advancePlayerMissiles(float dt);
+
+        // try to spawn a ship for this player.
+        // return true on success, false on failure to find a spot.
+        bool spawnShipForPlayer(Player *player);
+
+        // find some place where nothing is placed nearby (ships/planets).
+        // usefule for spanwing things
+        bool findFreePositionWithRadius(float r, glm::vec2 &pos);
+
+        float m_maxMissileDistance;
+        float m_playerRespawnTime;
+        float m_shipRadius;
+        float m_defaultEnergy;
+    };
+};
diff --git a/game/triangle_window.cpp b/game/triangle_window.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/game/triangle_window.h b/game/triangle_window.h
new file mode 100644
index 0000000..84a0636
--- /dev/null
+++ b/game/triangle_window.h
@@ -0,0 +1,36 @@
+#pragma once
+
+#include "opengl.h"
+
+class TriangleWindow : public endofthejedi::GLWindow {
+private:
+protected:
+    void init() override {
+        glClearColor(0.5f, 0.6f, 0.7f, 1.0f);
+        resize();
+
+        glEnable(GL_DEPTH_TEST);
+    }
+    void render(double time) override {
+        (void) time;
+
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        glBegin(GL_TRIANGLES);
+        glColor3f(1.0f, 0.0f, 0.0f);
+        glVertex3f(0.0f, -1.0f, 0.0f);
+        glColor3f(0.0f, 1.0f, 0.0f);
+        glVertex3f(-1.0f, 1.0f, 0.0f);
+        glColor3f(0.0f, 0.0f, 1.0f);
+        glVertex3f(1.0f, 1.0f, 0.0f);
+        glEnd();
+    }
+    void resize() override { glViewport(0, 0, getwidth(), getheight()); }
+
+public:
+    TriangleWindow(unsigned int width, unsigned int height)
+        : endofthejedi::GLWindow(width, height)
+    {
+    }
+};
+
diff --git a/game/util.cpp b/game/util.cpp
new file mode 100644
index 0000000..99970d0
--- /dev/null
+++ b/game/util.cpp
@@ -0,0 +1,25 @@
+#include "util.hpp"
+
+#include <cstdlib>
+
+namespace util {
+    float randf_m1_1()
+    {
+        return 2.0f*randf_0_1() - 1.0f;
+    }
+
+    float randf_0_1()
+    {
+        return static_cast<float>(static_cast<double>(rand()) / (double) RAND_MAX);
+    }
+
+    glm::vec2 randv2_m1_1()
+    {
+        return glm::vec2(randf_m1_1(), randf_m1_1());
+    }
+
+    glm::vec2 randv2_0_1()
+    {
+        return glm::vec2(randf_0_1(), randf_0_1());
+    }
+}
diff --git a/game/util.hpp b/game/util.hpp
new file mode 100644
index 0000000..041968b
--- /dev/null
+++ b/game/util.hpp
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <glm/vec2.hpp>
+
+namespace util {
+
+    float randf_0_1();
+    float randf_m1_1();
+
+    glm::vec2 randv2_m1_1();
+    glm::vec2 randv2_0_1();
+}