cocos 2dx getPosition() , always returns initial position instead of current position

问题

I have a sprite with having an action through which, it moves towards right side.

 CCSprite *spaceShip1=CCSprite::create("ufo_1.png");
 spaceShip1->setPosition(ccp(visibleSize.width/8,visibleSize.height/2));
 this->addChild(spaceShip1, 3);
 CCMoveBy* moveleft1 = CCMoveBy::create(3, ccp(visibleSize.width, 0));
 spaceShip1->runAction(moveleft1);

I want to get the current visual position of sprite, as it is moving due to runAction, it should return its updated position.

I am using:

spaceShip1->getPosition();

and this position is utilizing here:

CCParticleSystemQuad* _spaceShip1 = new CCParticleSystemQuad();
_spaceShip1 = CCParticleSystemQuad::create("growingFlare.plist");
_spaceShip1->setPosition(spaceShip1->getPosition());
_spaceShip1->setAngle(180);
_spaceShip1->setScale(5);
_spaceShip1->stopSystem();
this->addChild(_spaceShip1, 4);

That particle effect must take place at the current position of spaceship, but it always took effect at initial position of spaceship.

I'm trying to get the current position of sprite. but it always returns the initial position instead of its current moving position.

What I have to do to get its current position?

回答1:

float xPos = spaceShip->getPositionX();
float yPos = spaceShip->getPositionY();
CCLog("%f     %f", xPos, yPos);

Try this in the method where you want to get the current x,y position of the moving sprite. It won't get the initial position what you get now.

回答2:

That particle initialization happens during init(). Animation is not live then, hence will always give initial position.

You have 2 options.

In your update method. SetPosition() of your particle system every frame to the updated spaceship getPostion.
Make particle system as a child of spaceship. In case of, "this->addChild()", do "_firstSpaceShip->addChild(_particleSystem)" and give it a initial x position like -10, so it always follow behind your spaceship.

回答3:

May be this will help you out

CCParticleSystemQuad* _spaceShip1 = new CCParticleSystemQuad(); _spaceShip1 = CCParticleSystemQuad::create("growingFlare.plist"); _spaceShip1->setPosition(spaceShip1->getPositionX(), spaceShip1->getPositionY());

来源：https://stackoverflow.com/questions/24730270/cocos-2dx-getposition-always-returns-initial-position-instead-of-current-pos

标签

cocos2d-x