Cocos2d-x 学习笔记(11.4) ScaleTo ScaleBy

1. ScaleTo ScaleBy

对node进行缩放。ScaleBy是ScaleTo的子类。

1.1 成员变量 create方法

ScaleTo ScaleBy 成员变量一样：

    float _scaleX; 
    float _scaleY;
    float _scaleZ;
    float _startScaleX; // startWithTarget target->getScaleX()
    float _startScaleY;//
    float _startScaleZ;//
    float _endScaleX; // create参数s
    float _endScaleY;//
    float _endScaleZ;//
    float _deltaX;  // startWithTarget ScaleTo: _endScaleX - _startScaleX  ScaleBy: _startScaleX * _endScaleX - _startScaleX;
    float _deltaY;//
    float _deltaZ;//

create方法：

ScaleTo::create(float duration, float s)
ScaleBy::create(float duration, float s)

1.2 startWithTarget

ScaleTo：

    ActionInterval::startWithTarget(target);
    _startScaleX = target->getScaleX();
    _startScaleY = target->getScaleY();
    _startScaleZ = target->getScaleZ();
    _deltaX = _endScaleX - _startScaleX;
    _deltaY = _endScaleY - _startScaleY;
    _deltaZ = _endScaleZ - _startScaleZ;

ScaleBy：

    ScaleTo::startWithTarget(target);
    _deltaX = _startScaleX * _endScaleX - _startScaleX;
    _deltaY = _startScaleY * _endScaleY - _startScaleY;
    _deltaZ = _startScaleZ * _endScaleZ - _startScaleZ;

1.3 update

两者一致：

        _target->setScaleX(_startScaleX + _deltaX * time);
        _target->setScaleY(_startScaleY + _deltaY * time);
        _target->setScaleZ(_startScaleZ + _deltaZ * time);