C++ Game Development

with Oxygine

Advantages/disadvantages

Actions before starting

Game Project Structure and Mechanics

Oxygine framework

C++ AdvantagesNo extra plugins required for running programs.

Many powerful libs and tools can be applied with c++ programs and this framework

One or two week entrance barrier for C++ junior developers

Engine exist for more than 5 years. Based on SDL2

C++ DisadvantagesNot much web resources about C++ game dev (gamedev.net gamedev.stackexchange.net)

C++98, C++11, C++14 conflicts in many OS build version

Hard to debug C++ game events

A lot of code.

Quotes from web: It takes 10x as many lines of code to do simpleThings.

C++ is dangerous

Before you startingGame design patterns and Activities.

IDE(VS,Qtcreator,Clion,Eclipse,vim/emacs)

Team and resources

In GeneralMemory : Supports smart pointers.

Support culling and fast rendering and compress atlasses.

spGrass grass = new Grass();grass->setCull(true);

spMainMenu _menu = new MainMenu();menu ->addEventListener(TouchEvent::TOUCH, CLOSURE(this, &Game::onTouch));void Game::onTouch(Event* e){_menu->close();};~Game(){removeAllListeners();}// just need to worry about this

DECLARE_SMART(Player, spPlayer);

A lot of things take from ActionScript3.

Grass Tile

In GeneralVectors ,matrices,math and coordinates systems

Vector2 v = target - getPosition();

Vector2 resnorm = v.Normalized() * max_velocityVector;

Vector2 velocity = resnorm - velocityVector;

void Game::onScrollDown(Event*){ Transform is size,position and angle of a object.

Transform t = getTransform(); // game form on scene

t.scale(Vector2(0.9, 0.9));;

setTransform(t);

Rect r = compoundBounds(t);

}

world

Scene

Sprite

TextField with font

Sprite with tweens animations

Main classesActor

Actor is a base class in scene graph. It can be moved, rotated, scaled, animated. Actors can have other actors as children. When a parent is transformed, all its children are transformed as well.

spActor player = new Player(this,x,y);

Sprite

You would widely use Sprites in your app. Sprite is subclass of Actor. It is using for displaying images and animations.

Polygon

Polygon is subclass of Sprite. It is used for rendering custom vertices array.

ColorRectSprite

ColorRectSprite is subclass of Sprite. It is rectangle filled with one color.

Render hierarchy

core::init_desc desc;

desc.title = "Oxygine Application";

#if OXYGINE_SDL || OXYGINE_EMSCRIPTEN

// The initial window size can be set up

here on SDL builds

desc.w = 960;

desc.h = 640;

#endif

core::init(&desc);

Stage::instance = new Stage(true); // your

stage attach to video driver output

Point size = core::getDisplaySize();

getStage()->setSize(size);

game_init();

while (1)

{

int done = mainloop();

if (done)

break;

}

// shut down resources

game_destroy();

// Releases all internal

components and the stage

core::release();

Game begins with entry point

Simplify main function game_init();

while (1)

{

int done = mainloop();

if (done)

break;

}

// shut down resources

game_destroy();

}

MainLoop renderint mainloop()

{

bool done = core::update(); game_update();

getStage()->update();

if (core::beginRendering()){

Color clearColor(32, 32, 32, 255); Rect viewport(Point(0, 0),

core::getDisplaySize());

getStage()->render(clearColor, viewport);

core::swapDisplayBuffers();

}

return done ? 1 : 0;

}

Init Game function//called from main.cpp

void game_init()

{

//load xml file with resources definition

gameResources.loadXML("res.xml");

sound.loadXml(“sound.xml”);

magic_particles.loadXml(“magic.xml”);

//lets create our client code simple actor

spMainActor actor = new MainActor;

//and add it to Stage as child

getStage()->addChild(actor);

}

YourGame.h/cpp fileclass MainActor: public Actor

{

public:

spTextField _text;

spSprite _button;

MainActor()

{

//create button Sprite

spSprite button = new Sprite();

//setup it:

//set button.png image. Resource 'button' defined in 'res.xml'

button->setResAnim(gameResources.getResAnim("button"));

//centered button at screen

Vector2 pos = getStage()->getSize() / 2 - button->getSize() / 2;

button->setPosition(pos);

addChild(button);

}

Animations

Sprite Animations

ResAnim* resAnim = resources.getResAnim("run");

spTween tween = sprite->addTween(TweenAnim(resAnim), duration);

tween->addEventListener(TweenEvent::DONE, [](Event*){

log::messageln("tween done");

});

spTweenQueue tween = new TweenQueue;

tween->add(Actor::TweenX(100), 500);

tween->add(Actor::TweenY(100), 250);

tween->add(Actor::TweenAlpha(0), 300);

sprite->addTween(tween);

MAKEproject (FirstGame)

add_subdirectory(../../../ oxygine-framework)

add_definitions(${OXYGINE_DEFINITIONS})

include_directories(${OXYGINE_INCLUDE_DIRS})

link_directories(${OXYGINE_LIBRARY_DIRS})

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OXYGINE_CXX_FLAGS}")

add_executable(HelloWorld ../src/firstgame.cpp ../src/main.cpp ../src/firstgame.h )

target_link_libraries(FirstGame ${OXYGINE_CORE_LIBS})

.gen_template.py -all // create all make files for all platforms // for users

g++ -pthread -std=c++11 -Ioxygen/oxygine-framework/oxygine/src/ -Ioxygen/SDL/include/ -Loxygen/oxygine-framework/libs -Loxygen/oxygine-framework/examples/Hello/oxygine-framework -o 123 123.cpp -loxygine-framework -lSDL2 -lSDL2main -lGL -ljpeg -lpng -lz

Project structure<?xml version="1.0"?>

<resources>

<set path = "images" />

<atlas>

<image file="anim.png" cols = "8" />

<image file="button.png"/>

</atlas>

<set path = "fonts" />

<font file="main.fnt" />

</resources>

Game ObjectGame object is anything that gets rendered on a game scene. What we need is to update, trigger, collide, calculate or draw objects.

Lifecycle:Init();update(const UpdateStatus&)

GameObject Include:SoundDynamic DataPhysicsRenderEvent Listening

GameObject.hclass Unit : public Object

{

public:

Unit();

virtual ~Unit();

void destroy();

void init(MainActor* game);

void init(MainActor*,float x,float y);

void init(MainActor*, pugi::xml_node*);

void update(const UpdateState &us);

void setPosition(const Vector2 &pos);

b2Body* _body;

spActor _view;

Game* _game;

enum Type

{ Player, Enemy}

};

}

class Zombie : public Unit { }class Npc : public Unit{}class Player: public Unit{}

Box2D A 2D Physics Engine for Games b2BodyDef myBodyDef;

myBodyDef.type = b2_dynamicBody; //this will be a dynamic body

myBodyDef.position.Set(0, 20); //set the starting position

myBodyDef.angle = 0; //set the starting angle

b2Body* dynamicBody = m_world->CreateBody(&myBodyDef);

b2PolygonShape boxShape;

boxShape.SetAsBox(1,1);

b2FixtureDef boxFixtureDef;

boxFixtureDef.shape = &boxShape;

boxFixtureDef.density = 1;

dynamicBody->CreateFixture(&boxFixtureDef);

Dynamic data

Mouse, Keyboard, Phone, Game Events etc.void clickHandler(Event*) {}

submitButton->addEventListener(TouchEvent::CLICK, CLOSURE(this, &SomeClass::clickHandler));

Event targeting

.

AchieveEarnedEvent event("awesome");

target->dispatchEvent(&event);

getStage()->addEventListener

(Event::MouseEvent,Event::Scroll_DOWN);

Oxygine key:api:

bool wasPressed(keycode);

bool wasReleased(keycode);

Oxygine.orghttps://github.com/oxygine // sound,flow,magicparticles,social,billing modules

https://github.com/oxygine/oxygine-framework/wiki/

Has forum and skype group