Palestra apresentada no evento The Developer's Conference (TDC) na edição de São Paulo em 25 de julho de 2015.

1. {Programação de Jogos}
Bruno Cicanci @ TDC SP 2015

2. {Design Patterns}
● Command
● Flyweight
● Observer
● Prototype
● States
● Singleton

3. {Command: Problema}
void InputHandler::handleInput()
{
if (isPressed(BUTTON_X)) jump();
else if (isPressed(BUTTON_Y)) fireGun();
else if (isPressed(BUTTON_A)) swapWeapon();
else if (isPressed(BUTTON_B)) reloadWeapon();
}
http://gameprogrammingpatterns.com/command.html

4. {Command: Solução}
class Command
{
public:
virtual ~Command() {}
virtual void execute() = 0;
};
class JumpCommand : public Command
{
public:
virtual void execute() { jump(); }
};
void InputHandler::handleInput()
{
if (isPressed(BUTTON_X))
buttonX_->execute();
else if (isPressed(BUTTON_Y))
buttonY_->execute();
else if (isPressed(BUTTON_A))
buttonA_->execute();
else if (isPressed(BUTTON_B))
buttonB_->execute();
}
http://gameprogrammingpatterns.com/command.html

5. {Command: Uso}
● Input
● Undo
● Redo

6. {Flyweight: Problema}
class Tree
{
private:
Mesh mesh_;
Texture bark_;
Texture leaves_;
Vector position_;
double height_;
double thickness_;
Color barkTint_;
Color leafTint_;
};
http://gameprogrammingpatterns.com/flyweight.html

7. {Flyweight: Solução}
class TreeModel
{
private:
Mesh mesh_;
Texture bark_;
Texture leaves_;
};
class Tree
{
private:
TreeModel* model_;
Vector position_;
double height_;
double thickness_;
Color barkTint_;
Color leafTint_;
};
http://gameprogrammingpatterns.com/flyweight.html

8. {Flyweight: Uso}
● Milhares de instâncias
● Tile maps

9. {Observer: Problema}
void Physics::updateEntity(Entity& entity)
{
bool wasOnSurface = entity.isOnSurface();
entity.accelerate(GRAVITY);
entity.update();
if (wasOnSurface && !entity.isOnSurface())
{
notify(entity, EVENT_START_FALL);
}
}
http://gameprogrammingpatterns.com/observer.html

10. {Observer: Solução parte 1}
class Observer
{
public:
virtual ~Observer() {}
virtual void onNotify(const Entity& entity, Event event) = 0;
};
class Achievements : public Observer
{
public:
virtual void onNotify(const Entity& entity, Event event)
{
switch (event)
{
case EVENT_ENTITY_FELL:
if (entity.isHero() && heroIsOnBridge_)
{
unlock(ACHIEVEMENT_FELL_OFF_BRIDGE);
}
break;
}
}
}; http://gameprogrammingpatterns.com/observer.html

11. {Observer: Solução parte 2}
class Subject
{
private:
Observer* observers_[MAX_OBSERVERS];
int numObservers_;
protected:
void notify(const Entity& entity, Event event)
{
for (int i = 0; i < numObservers_; i++)
{
observers_[i]->onNotify(entity, event);
}
}
};
class Physics : public Subject
{
public:
void updateEntity(Entity& entity);
};
http://gameprogrammingpatterns.com/observer.html

12. {Observer: Uso}
● Achievements
● Efeitos sonoros / visuais
● Eventos
● Mensagens
● Expirar demo
● Callback async

13. {Prototype: Problema}
class Monster
{
// Stuff...
};
class Ghost : public Monster {};
class Demon : public Monster {};
class Sorcerer : public Monster {};
http://gameprogrammingpatterns.com/prototype.html
class Spawner
{
public:
virtual ~Spawner() {}
virtual Monster* spawnMonster() = 0;
};
class GhostSpawner : public Spawner
{
public:
virtual Monster* spawnMonster()
{
return new Ghost();
}
};

14. {Prototype: Solução parte 1}
class Monster
{
public:
virtual ~Monster() {}
virtual Monster* clone() = 0;
// Other stuff...
};
http://gameprogrammingpatterns.com/prototype.html
class Ghost : public Monster {
public:
Ghost(int health, int speed)
: health_(health),
speed_(speed)
{}
virtual Monster* clone()
{
return new Ghost(health_, speed_);
}
private:
int health_;
int speed_;
};

15. {Prototype: Solução parte 2}
class Spawner
{
public:
Spawner(Monster* prototype)
: prototype_(prototype)
{}
Monster* spawnMonster()
{
return prototype_->clone();
}
private:
Monster* prototype_;
}; http://gameprogrammingpatterns.com/prototype.html

16. {Prototype: Uso}
● Spawner
● Tiros
● Loot

17. {States: Problema}
void Heroine::handleInput(Input input)
{
if (input == PRESS_B)
{
if (!isJumping_ && !isDucking_)
{
// Jump...
}
}
else if (input == PRESS_DOWN)
{
if (!isJumping_)
{
isDucking_ = true;
}
} http://gameprogrammingpatterns.com/state.html
else if (input == RELEASE_DOWN)
{
if (isDucking_)
{
isDucking_ = false;
}
}
}

18. {States: Solução}
void Heroine::handleInput(Input input)
{
switch (state_)
{
case STATE_STANDING:
if (input == PRESS_B)
{
state_ = STATE_JUMPING;
}
else if (input == PRESS_DOWN)
{
state_ = STATE_DUCKING;
}
break;
http://gameprogrammingpatterns.com/state.html
case STATE_JUMPING:
if (input == PRESS_DOWN)
{
state_ = STATE_DIVING;
}
break;
case STATE_DUCKING:
if (input == RELEASE_DOWN)
{
state_ = STATE_STANDING;
}
break;
}
}

19. {States: Uso}
● Controle de animação
● Fluxo de telas
● Movimento do personagem

20. {Singleton: Problema}
“Garante que uma classe tenha somente uma instância
E fornecer um ponto global de acesso para ela”
Gang of Four, Design Patterns

21. {Singleton: Solução}
class FileSystem
{
public:
static FileSystem& instance()
{
if (instance_ == NULL) instance_ = new FileSystem();
return *instance_;
}
private:
FileSystem() {}
static FileSystem* instance_;
};
http://gameprogrammingpatterns.com/singleton.html

22. {Singleton: Uso}
“Friends don’t let friends create singletons”
Robert Nystrom, Game Programming Patterns

23. {Outros Design Patterns}
Double Buffer
Game Loop
Update Method
Bytecode
Subclass Sandbox
Type Object
Component
Event Queue
Service Locator
Data Locality
Dirty Flag
Object Pool
Spatial Partition

24. {Livro: Game Programming Patterns}
http://gameprogrammingpatterns.com

25. {Outros livros}
Física
Physics for Game Developers
Computação Gráfica
3D Math Primer for Graphics and Game
Game Design
Game Design Workshop
Level Up! The Guide to Great Game Design
Produção
The Game Production Handbook
Agile Game Development with Scrum
Programação
Code Complete
Clean Code
Programação de Jogos
Game Programming Patterns
Game Programming Algorithms and Techniques
Game Coding Complete
Inteligência Artificial
Programming Game AI by Example

26. {Blog: gamedeveloper.com.br}

27. {Obrigado}
E-mail: bruno@gamedeveloper.com.br
Twitter: @cicanci
PSN: cicanci42