title: Cocos2d match target speed to scrolling background
body: <p>I'm Using Cocos2d Android.</p>
  
  <p>I have a scrolling background in Cocos2d, i use this method to make it work :</p>
  
  <pre><code>public void moveBackground(float dt) {
      bg1.setPosition(CGPoint.ccp(bg1.getPosition().x, bg1.getPosition().y
              - speed));
      bg2.setPosition(CGPoint.ccp(bg2.getPosition().x, bg2.getPosition().y
              - speed));
      if (bg1.getPosition().y &lt; -(bg1.getBoundingBox().size.height)) {
          bg1.setPosition(CGPoint.ccp(bg1.getPosition().x,
                  bg2.getPosition().y + bg2.getBoundingBox().size.height - 1));
      }
      if (bg2.getPosition().y &lt; -(bg2.getBoundingBox().size.height)) {
          bg2.setPosition(CGPoint.ccp(bg2.getPosition().x,
                  bg1.getPosition().y + bg1.getBoundingBox().size.height - 1));
      }
  }
  </code></pre>
  
  <p>speed = 5 or 10 or whatever. It is called thanks to a schedule, every frame.</p>
  
  <p>I want to drop targets with the same speed that my background uses to scroll, to add targets i use this method : </p>
  
  <pre><code>public void addTargetFibre(float dt) {
      Random rand = new Random();
      CCSprite target = CCSprite.sprite(RessourcesManager.Players.blue_ball);
      target.setScale(0.3f);
      CGSize winSize = CCDirector.sharedDirector().displaySize();
      int actualX = (int) a;
      int n = rand.nextInt(4);
      switch (n) {
      case 0:
          actualX = (int) a;
          break;
      case 1:
          actualX = (int) b;
          break;
      case 2:
          actualX = (int) c;
          break;
      case 3:
          actualX = (int) d;
          break;
      }
      target.setPosition(actualX, winSize.height
              + (target.getContentSize().height / 2.0f));
      addChild(target, 1);
      float d = ((win_size.height+target.getContentSize().height/2)/(60*speed));
      d = d+(d*(float)1/60);
      CCMoveTo actionMove = CCMoveTo.action(d,
              CGPoint.ccp(actualX, -target.getContentSize().height / 2.0f));
      CCCallFuncN actionMoveDone = CCCallFuncN.action(this,
              "removeSprite");
  
      CCSequence actions = CCSequence.actions(actionMove, actionMoveDone);
      target.runAction(actions);
  
  }
  </code></pre>
  
  <p>What i want is the duration that i need to put in CCMoveTo action.</p>