cocos2dx已经封装了很多关于opengl的函数，可以方便的使用，在3.0v以前，是在draw编写绘制代码，3.0v以后，还是在draw函数里，但发生了点变化。
先来看一下Node类关于draw函数的申明
virtual void draw(Renderer *renderer,const Mat4& transform,uint32_t flags);
virtual void draw() final;
第二函数已经被声明为final，也就是不能重载（C++11规定，final函数必需要加关键词virtual).所以不能再像老版本一样使用。
重写第一个方法来绘制你自己的节点。
被TransitionFadeTR,TransitionSplitColsTransitionTurnOffTilesTransitionCrossFadeSpriteLayerColorLabelRenderTextureSpriteBatchNodePhysicsSpriteProgressTimerParticleSystemQuadParticleBatchNodeTransitionSceneDrawNodeMotionStreakVideoPlayerTransitionPageTurnAtlasNodePhysicsDebugNode重载.
下面给出一个例子，先看结果图
可以拖动四个结点改变曲线
#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__
#include "cocos2d.h"
class HelloWorld : public cocos2d::Layer
{
public:
// there's no 'id' in cpp,so we recommend returning the class instance pointer
static cocos2d::Scene* createScene();
// Here's a difference. Method 'init' in cocos2d-x returns bool,instead of returning 'id' in cocos2d-iphone
virtual bool init();
// a selector callback
void menuCloseCallback(cocos2d::Ref* pSender);
virtual void draw(cocos2d::Renderer *renderer,const cocos2d::Mat4 &transform,uint32_t flags) override;
// implement the "static create()" method manually
CREATE_FUNC(HelloWorld);
private:
cocos2d::Sprite *yellow,*bule,*orange,*red;
bool onTouchBegan(cocos2d::Touch *touch,cocos2d::Event *event);
void onTouchMoved(cocos2d::Touch*touch,cocos2d::Event *event);
};
#endif // __HELLOWORLD_SCENE_H__
@H_
502_77@// 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 = LabelTTF::create("Hello World","Arial",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"
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);
red = Sprite::create("red.png");
red->setPosition(10,10);
this->addChild(red,3);
yellow = Sprite::create("yellow.png");
yellow->setPosition(200,200);
this->addChild(yellow,3);
bule = Sprite::create("bule.png");
bule->setPosition(400,400);
this->addChild(bule,3);
orange = Sprite::create("orang.png");
orange->setPosition(500,500);
this->addChild(orange,4);
auto listener = EventListenerTouchOneByOne::create();
listener->onTouchBegan = CC_CALLBACK_2( HelloWorld::onTouchBegan,this);
listener->onTouchMoved = CC_CALLBACK_2(HelloWorld::onTouchMoved,this);
this->getEventDispatcher()->addEventListenerWithSceneGra
PHPriority(listener,bule);
this->getEventDispatcher()->addEventListenerWithSceneGra
PHPriority(listener->clone(),orange);
this->getEventDispatcher()->addEventListenerWithSceneGra
PHPriority(listener->clone(),yellow);
this->getEventDispatcher()->addEventListenerWithSceneGra
PHPriority(listener->clone(),red);
return true;
}
void HelloWorld::menuCloseCallback(Ref* pSender)
{
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WP8) || (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
Message
Box("You pressed the close button. Windows Store Apps do not implement a close button.","Alert");
return;
#endif
Director::getInstance()->end();
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
exit(0);
#endif
}
void HelloWorld::draw(Renderer* renderer,const Mat4 &transform,uint32_t flags){
auto array = PointArray::create(10);
ccDrawLine(Vec2(100,100),Vec2(900,100));
ccDrawLine(Vec2(100,Vec2(100,600));
array->addControlPoint(Vec2(100,100));
array->addControlPoint(red->getPosition());
array->addControlPoint(bule->getPosition());
array->addControlPoint(yellow->getPosition());
array->addControlPoint(orange->getPosition());
ccDrawCardinalSpline(array,100);
}
bool HelloWorld::onTouchBegan(cocos2d::Touch *touch,cocos2d::Event *event){
auto sprite = static_cast<Sprite*>(event->getCurrentTarget());
auto point = sprite->convertToNodeSpace(touch->getLocation());
auto rect = Rect(0,sprite->getContentSize().width,sprite->getContentSize().height);
if (rect.containsPoint(poi
