cocos2dx 利用随机数模拟雪花飘落、粒子系统

概述运行截图 随机数 注意随机种子的设定需要在for循环的外面 用到了cocos2dx的 CCRANDOM_0_1 /** @def CCRANDOM_0_1 returns a random float between 0 and 1 */#define CCRANDOM_0_1() ((float)rand()/RAND_MAX) TIMEVAL psv;gettimeofday(&psv, 运行截图 随机数 注意随机种子的设定需要在for循环的外面 用到了cocos2dx的 CCRANDOM_0_1

/** @def CCRANDOM_0_1 returns a random float between 0 and 1 */#define CCRANDOM_0_1() ((float)rand()/RAND_MAX)

TIMEVAL psv;gettimeofday(&psv,NulL);// 初始化随机种子// timeval是个结构体，里边有俩个变量，一个是以秒为单位的，一个是以微妙为单位的 unsigned rand_seed = (unsigned)(psv.tv_sec * 1000 + psv.tv_usec / 1000);    //都转化为毫秒 srand(rand_seed);for (int i = 0; i < N; i++){    int a = 0;    int b = visibleSize.wIDth;    float xt = CCRANDOM_0_1() * (b - a + 1) + a;    a = 0;    b = visibleSize.height;    float yt = CCRANDOM_0_1() * (b - a + 1) + a;    vx[i] = origin.x + xt;    vy[i] = origin.y + yt;    labels[i] = Label::createWithSystemFont("*","Arial",24);    // position the label on the center of the screen    labels[i]->setposition(Point(vx[i],vy[i]));    // add the label as a child to this layer    this->addChild(labels[i],1);}

完整代码

.h

#ifndef __HELLOWORLD_SCENE_H__#define __HELLOWORLD_SCENE_H__#include <vector>#include "cocos2d.h"#define N 200USING_NS_CC;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);    // implement the "static create()" method manually    CREATE_FUNC(HelloWorld);public:    virtual voID update(float delta);    voID menuStopCallback(cocos2d::Ref* pSender);    voID menuSlowCallback(cocos2d::Ref* pSender);    voID menuMIDCallback(cocos2d::Ref* pSender);    voID menuFastCallback(cocos2d::Ref* pSender);    MenuItemFont *stop;    //    MenuItemFont *slow;    //    MenuItemFont *mID;    //    MenuItemFont *fast;public:    Size visibleSize;    Point origin;    Label* labels[N];    float speed;    float vx[N];    float vy[N];};#endif // __HELLOWORLD_SCENE_H__

.cpp

#include "HelloWorldScene.h"#include <cstdlib>#include <ctime>USING_NS_CC;Scene* HelloWorld::createScene(){    // 'scene' is an autorelease object    auto scene = Scene::create();    // 'layer' is an autorelease object    auto layer = HelloWorld::create();    // add layer as a child to scene    scene->addChild(layer);    // return the scene    return scene;}// on "init" you need to initialize your instancebool HelloWorld::init(){    //////////////////////////////    // 1. super init first    if ( !Layer::init() )    {        return false;    }    visibleSize = Director::getInstance()->getVisibleSize();    origin = Director::getInstance()->getVisibleOrigin();    // add a label shows "Hello World"    // create and initialize a label#if 0    //LabelTTF* label = LabelTTF::create("1","Arial",24);    Label* label = Label::createWithSystemFont("1",24);    // position the label on the center of the screen    label->setposition(Point(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);#endif    TIMEVAL psv;    gettimeofday(&psv,NulL);    // 初始化随机种子    // timeval是个结构体，里边有俩个变量，一个是以秒为单位的，一个是以微妙为单位的     unsigned rand_seed = (unsigned)(psv.tv_sec * 1000 + psv.tv_usec / 1000);    //都转化为毫秒     srand(rand_seed);    for (int i = 0; i < N; i++)    {        int a = 0;        int b = visibleSize.wIDth;        float xt = CCRANDOM_0_1() * (b - a + 1) + a;        a = 0;        b = visibleSize.height;        float yt = CCRANDOM_0_1() * (b - a + 1) + a;        vx[i] = origin.x + xt;        vy[i] = origin.y + yt;        labels[i] = Label::createWithSystemFont("*",24);        // position the label on the center of the screen        labels[i]->setposition(Point(vx[i],vy[i]));        // add the label as a child to this layer        this->addChild(labels[i],1);    }    speed = 1;    this->scheduleUpdate(); // 定时器    //    MenuItemFont::setFontSize(22);// 系统设定字体大小stop = MenuItemFont::create("stop");    stop->setTarget(this,menu_selector(HelloWorld::menuStopCallback));    //slow = MenuItemFont::create("slow");    slow->setcolor(color3B::RED);    slow->setTarget(this,menu_selector(HelloWorld::menuSlowCallback));    //mID = MenuItemFont::create("mID");    mID->setTarget(this,menu_selector(HelloWorld::menuMIDCallback));    //fast = MenuItemFont::create("fast");    fast->setTarget(this,menu_selector(HelloWorld::menuFastCallback));    //创建一个菜单容器 把菜单栏目放上去    Menu *menu = Menu::create(stop,slow,mID,fast,NulL);    //显示菜单    this->addChild(menu);    //菜单的显示位置    menu->setposition(Point(50,visibleSize.height - 100));    //设置栏目间的宽度距离    menu->alignItemsverticallyWithpadding(10.0);    return true;}voID HelloWorld::update(float delta){    for (int i = 0; i < N; i++)    {        vy[i] -= speed;//2.0;        if (vy[i] <= 0)        {            int a = 0;            int b = visibleSize.wIDth;            vx[i] = origin.x + CCRANDOM_0_1() * (b - a + 1) + a;            vy[i] = visibleSize.height;        }        labels[i]->setposition(Point(vx[i],vy[i]));    }}// 改变下落的速度voID HelloWorld::menuStopCallback(cocos2d::Ref* pSender){    this->unscheduleUpdate();    speed = -1.0;    stop->setcolor(color3B::RED);    slow->setcolor(color3B::WHITE);    mID->setcolor(color3B::WHITE);    fast->setcolor(color3B::WHITE);}voID HelloWorld::menuSlowCallback(cocos2d::Ref* pSender){    if (speed < 0)        this->scheduleUpdate();     speed = 1.0;    stop->setcolor(color3B::WHITE);    slow->setcolor(color3B::RED);    mID->setcolor(color3B::WHITE);    fast->setcolor(color3B::WHITE);}voID HelloWorld::menuMIDCallback(cocos2d::Ref* pSender){    if (speed < 0)        this->scheduleUpdate();    speed = 3.0;    stop->setcolor(color3B::WHITE);    slow->setcolor(color3B::WHITE);    mID->setcolor(color3B::RED);    fast->setcolor(color3B::WHITE);}voID HelloWorld::menuFastCallback(cocos2d::Ref* pSender){    if (speed < 0)        this->scheduleUpdate();    speed = 6.0;    stop->setcolor(color3B::WHITE);    slow->setcolor(color3B::WHITE);    mID->setcolor(color3B::WHITE);    fast->setcolor(color3B::RED);}voID HelloWorld::menuCloseCallback(Ref* pSender){#if (CC_TARGET_PLATFORM == CC_PLATFORM_WP8) || (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)    MessageBox("You pressed the close button. windows Store Apps do not implement a close button.","Alert");    return;#endif    //Director::getInstance()->end();    speed = 10;#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)    exit(0);#endif}

粒子系统实现sNow

参考
cocos2dx中一些自定义的例子系统
http://www.2cto.com/kf/201409/333598.html

Particle System（粒子系统）讲解
http://www.cnblogs.com/shangdahao/archive/2012/04/14/2447571.html

bg.png

sNow.png

#include "HelloWorldScene.h"#include <cstdlib>#include <ctime>USING_NS_CC;Scene* HelloWorld::createScene(){    // 'scene' is an autorelease object    auto scene = Scene::create();    // 'layer' is an autorelease object    auto layer = HelloWorld::create();    // add layer as a child to scene    scene->addChild(layer);    // return the scene    return scene;}// on "init" you need to initialize your instancebool HelloWorld::init(){    //////////////////////////////    // 1. super init first    if ( !Layer::init() )    {        return false;    }    visibleSize = Director::getInstance()->getVisibleSize();    origin = Director::getInstance()->getVisibleOrigin();    auto bg = Sprite::create("bg.png");    bg->setposition(Point(visibleSize.wIDth / 2,visibleSize.height / 2));    this->addChild(bg);#if 0    ParticleSystem* ps = ParticleSNow::createWithTotalParticles(9999);    //ParticleSystem* ps = ParticleSNow::create();    ps->setTexture(Director::getInstance()->getTextureCache()->addImage("sNow.png"));    ps->setposition(Point(visibleSize.wIDth/2,visibleSize.height + 10));//生成的雪花从这个坐标往下落    //ps->setEmissionRate(10);    ps->setSpeed(200);    ps->setlife(10);    this->addChild(ps);#endif#if 1    auto particleSystem = ParticleSystemQuad::createWithTotalParticles(200);    //设置雪花粒子纹理图片    particleSystem->setTexture(TextureCache::getInstance()->addImage("sNow.png"));    //设置发射粒子的持续时间-1表示永远持续    particleSystem->setDuration(-1);    //这个点是相对发射点，x正方向为右，y正方向为上,可以设置发射的方向    particleSystem->setGravity(Point(-10,-20));    //设置角度以及偏差    particleSystem->setAngle(90);    particleSystem->setAngleVar(360);    //设置径向加速度以及偏差    particleSystem->seTradialAccel(10);    particleSystem->seTradialAccelVar(0);    //设置粒子的切向加速度以及偏差    particleSystem->setTangentialAccel(30);    particleSystem->setTangentialAccelVar(30);    // 设置粒子初始化位置偏差    //particleSystem->setposition(CCPoint(400,500));    particleSystem->setPosVar(Point(400,0));    //设置粒子生命期以及偏差    particleSystem->setlife(4);    particleSystem->setlifeVar(2);    //设置粒子开始时候旋转角度以及偏差    particleSystem->setStartSpin(30);    particleSystem->setStartSpinVar(60);    //设置结束时候的旋转角度以及偏差    particleSystem->setEndSpin(60);    particleSystem->setEndSpinVar(60);    //设置开始时候的颜色以及偏差    particleSystem->setStartcolor(color4F(1,1,1));    //设置结束时候的颜色以及偏差    particleSystem->setEndcolor(color4F(0.9,0.9,1));    //设置开始时候粒子大小以及偏差    particleSystem->setStartSize(30);    particleSystem->setStartSizeVar(0);    //设置粒子结束时候大小以及偏差    particleSystem->setEndSize(20.0f);    particleSystem->setEndSizeVar(0);    //设置每秒钟产生粒子的数量    particleSystem->setEmissionRate(100);    // 粒子系统位置    particleSystem->setposition(Point(visibleSize.wIDth * 0.75,visibleSize.height + 50));    this->addChild(particleSystem);#endif    return true;}voID HelloWorld::update(float delta){}

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