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create scene in cocos2dx

When we create first project the project composite like this.
in classes folder.
AppDelegate.cpp
AppDelegate.h
HelloWorldScene.cpp
HelloWorldScene.h

in AppDelegate.cpp

bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    auto director = Director::getInstance();
    auto glview = director->getOpenGLView();
    if(!glview) {
        glview = GLViewImpl::create("My Game");
        director->setOpenGLView(glview);
    }

    // turn on display FPS
    director->setDisplayStats(true);

    // set FPS. the default value is 1.0/60 if you don't call this
    director->setAnimationInterval(1.0 / 60);

    register_all_packages();

    // create a scene. it's an autorelease object
    auto scene = HelloWorld::createScene();

    // run
    director->runWithScene(scene);

    return true;
}		
		
		

There are many unknown classes.
Director::getInstance();
What is Director?

Director

The books said like this.
"containers comes the all knowing Director and
all-encompassing cache objects."
"The Director object manages scenes and know about our applications."

It means manager singletone object
I wonder singleton is not good

create a scene

Using a Director object we can begin scene like this.

bool AppDelegate::applicationDidFinishLaunching() {
	// ...
    // create a scene. it's an autorelease object
    auto scene = HelloWorld::createScene();
    // run
    director->runWithScene(scene);

    return true;
}			
		

HelloWorld class Inherited cocos2d::Layer.
Layer is a Layer.One screen
director->runWithScene(scene)
Mean start "scene"

add sprite in a scene

How to draw a sprite?
It is written in the HelloWorld init method.

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !Layer::init() )
    {
        return false;
    }
    
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();

    /////////////////////////////
    // 2. add a menu item with "X" image, which is clicked to quit the program
    //    you may modify it.

    // add a "close" icon to exit the progress. it's an autorelease object
    auto closeItem = MenuItemImage::create(
                                           "CloseNormal.png",
                                           "CloseSelected.png",
                                           CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));
    
	closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
                                origin.y + closeItem->getContentSize().height/2));

    // create menu, it's an autorelease object
    auto menu = Menu::create(closeItem, NULL);
    menu->setPosition(Vec2::ZERO);
    this->addChild(menu, 1);

    /////////////////////////////
    // 3. add your codes below...

    // add a label shows "Hello World"
    // create and initialize a label
    auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);
    
    // position the label on the center of the screen
    label->setPosition(Vec2(origin.x + visibleSize.width/2,
                            origin.y + visibleSize.height - label->getContentSize().height));

    // add the label as a child to this layer
    this->addChild(label, 1);

    // add "HelloWorld" splash screen"
    // here is!
    auto sprite = Sprite::create("HelloWorld.png");

    // position the sprite on the center of the screen
    sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));

    // add the sprite as a child to this layer
    this->addChild(sprite, 0);
    
    return true;
}
		

// create sprite from "HelloWorld.png"
auto sprite = Sprite::create("HelloWorld.png");
// position the sprite on the center of the screen
sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y)); // add the sprite as a child to this layer
this->addChild(sprite, 0);

In summary.
1.create a sprite
2.define sprite position.
3.add sprite in node

And We can draw object with texture.