How to restore a sprite to its original image after replacing it with another one in coco2dx?
In my game context, the sprite is a smiling child, when the child touches, the current image of the sprite changed to a crying child, and then after 3 seconds of the screaming sound effect has ended, the sprite will return to the smiling child.
My problem
- How do I go back with the previous image?
I changed the smiling child to the crying one, but I have no idea how can I change it to the original smile?
- How to ensure one click at a time? Every time the child copes, the sound starts playing, which is not ideal because I hope the event function is only called after the previous process has finished.
here is my code and thanks a lot!
bool HelloWorld::init()
{
// 1. super init first
if ( !Layer::init() )
{
return false;
}
Size visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();
//add background scene
auto backgroundSprite = Sprite :: create("scene001.jpg");
backgroundSprite->setAnchorPoint(Vec2(0,0));
backgroundSprite->setScaleX((visibleSize.width / backgroundSprite->getContentSize().width) * 1);
backgroundSprite->setScaleY((visibleSize.height / backgroundSprite->getContentSize().height) * 1);
addChild(backgroundSprite);
//add smileBaby sprite
auto smileBabySprite = Sprite :: create("figure001.png");
smileBabySprite -> setPosition(Vec2(500,400));
addChild(smileBabySprite);
//add crying audio
auto audio = CocosDenshion::SimpleAudioEngine::getInstance();
auto babyListener = EventListenerTouchOneByOne::create();
babyListener -> onTouchBegan = [smileBabySprite, audio](Touch* touch, Event* event)
{
//change smileBaby sprite to cryingBaby sprite
smileBabySprite->setTexture(CCTextureCache::sharedTextureCache()->addImage("figure002.png"));
audio -> playEffect("babycry.mp3",false,1.0f,1.0f,1.0f);
return true;
};
babyListener -> onTouchEnded=[smileBabySprite](Touch* touch, Event* event )
{
};
_eventDispatcher -> addEventListenerWithSceneGraphPriority(babyListener, this);
return true;
}
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What you want is to maintain the state whether the baby is crying or not. It is best to keep this logic in a custom subclass Node
.
Here's some (almost pseudo) code to get you started:
Baby.h:
#pragma once
#include "cocos2d.h"
class Baby : public cocos2d::Node
{
private:
cocos2d::Sprite *_sprite; // Weak reference
bool _crying;
float _cryingTime;
public:
CREATE_FUNC(Baby);
protected:
virtual bool init() override;
virtual void update(float delta) override;
public:
void touched();
bool isInside(cocos2d::Touch *touch) const
protected:
void setSprite();
};
Baby.cpp:
#include "Baby.h"
USING_NS_CC;
bool Baby::init()
{
if (!Node::init())
return false;
_crying = false;
setSprite();
scheduleUpdate();
return true;
}
void Baby::update(float delta)
{
Node::update(delta);
if (_crying) {
_cryingTime -= delta;
if (_cryingTime <= 0.0f) {
_crying = false;
setSprite();
}
}
}
void Baby::touched()
{
if (_crying)
return; // Already crying
_crying = true;
_cryingTime = 3.0f; // Length of audio, I guess?
setSprite();
// Start crying sound here
}
bool Baby::isInside(Touch *touch) const
{
Vec2 locationInNode = _sprite->convertToNodeSpace(touch->getLocation());
Size size = _sprite->getContentSize();
Rect rect = Rect(0.0f, 0.0f, size.width, size.height);
return rect.containsPoint(locationInNode);
}
void Baby::setSprite()
{
if (_sprite)
_sprite->removeFromParent();
_sprite = Sprite::initWithFile(_crying ? "baby_crying.png" : "baby.png");
Vec2 size = getContentSize();
_sprite->setPosition(size.width * 0.5f, size.height * 0.5f);
addChild(_sprite);
}
You add a Baby
node to the parent instead of the sprite using:
_baby = Baby::create(); _baby->setPosition(Wherever); addChild(_baby);
Where _baby
is an instance variable and uses a method isInside()
to check if the touch event is within the sprite and calls its method touched()
:
Touch *touch = ...;
if (_baby->isInside(touch)) {
_baby->touched();
}
and the object Baby
ignores touch depending on the state.
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