cocos2d-x实例学习(9)之CCCardinalSplineBy

CCCardinalSplineBy概念
这个类是样条曲线动作，其创建函数CCCardinalSplineBy::create(float duration, cocos2d::CCPointArray *points, float tension)；中duration是时间间隔，points是控制点列表，tension是松紧程度。tension==1时，样条线是分段直线。tension<1向外松弛弯曲，tension>1向内缩紧弯曲。By动作是以当前坐标为新坐标原点。

CCCardinalSplineBy示例–为同一组控制点实现不同的移动路径
   

CCSize s = CCDirector::sharedDirector()->getWinSize();

    CCPointArray *array = CCPointArray::create(20);

    array->addControlPoint(ccp(0, 0));

    array->addControlPoint(ccp(s.width/2-30, 0));

    array->addControlPoint(ccp(s.width/2-30, s.height-80));

    array->addControlPoint(ccp(0, s.height-80));

    array->addControlPoint(ccp(0, 0));

        //

        // sprite 1 (By)

        //

        // Spline with no tension (tension==0)

        //

    CCCardinalSplineBy *action = CCCardinalSplineBy::create(3, array, 0);

    CCActionInterval *reverse = action->reverse();

    CCFiniteTimeAction *seq = CCSequence::create(action, reverse, NULL);

    m_tamara->setPosition(ccp(50, 50));

    m_tamara->runAction(seq);

        //

        // sprite 2 (By)

        //

        // Spline with high tension (tension==1)

        //

    CCCardinalSplineBy *action2 = CCCardinalSplineBy::create(3, array, 1);

    CCActionInterval *reverse2 = action2->reverse();

    CCFiniteTimeAction *seq2 = CCSequence::create(action2, reverse2, NULL);

    m_kathia->setPosition(ccp(s.width/2, 50));

    m_kathia->runAction(seq2);

由于By动作是以当前坐标为新坐标原点，所以在draw函数里设置openGL的原点位置

    // move to 50,50 since the "by" path will start at 50,50

        kmGLPushMatrix();

        kmGLTranslatef(50, 50, 0);

        ccDrawCardinalSpline(m_pArray, 0, 100);

        kmGLPopMatrix();

        CCSize s = CCDirector::sharedDirector()->getWinSize();

        kmGLPushMatrix();

        kmGLTranslatef(s.width/2, 50, 0);

        ccDrawCardinalSpline(m_pArray, 1, 100);

        kmGLPopMatrix();

复制代码

效果图如下：


 

注：
CCPointArray解释 
CCPointArray是一个包含控制点的数组，使用方法如上