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

1. CCSize s = CCDirector::sharedDirector()->getWinSize();
   
2. CCPointArray *array = CCPointArray::create(20);
   
3. array->addControlPoint(ccp(0,0));
   
4. array->addControlPoint(ccp(s.width/2-30,s.height-80));
   
5. 
   
6. //
   
7. // sprite 1 (By)
   
8. // Spline with no tension (tension==0)
   
9. CCCardinalSplineBy *action = CCCardinalSplineBy::create(3,array,0);
   
10. CCActionInterval *reverse = action->reverse();
    
11. CCFiniteTimeAction *seq = CCSequence::create(action,reverse,NULL);
    
12. m_tamara->setPosition(ccp(50,50));
    
13. m_tamara->runAction(seq);
    
14. // sprite 2 (By)
    
15. // Spline with high tension (tension==1)
    
16. CCCardinalSplineBy *action2 = CCCardinalSplineBy::create(3,1);
    
17. CCActionInterval *reverse2 = action2->reverse();
    
18. CCFiniteTimeAction *seq2 = CCSequence::create(action2,reverse2,serif; font-size:12px; line-height:1.8em"> m_kathia->setPosition(ccp(s.width/2,serif; font-size:12px; line-height:1.8em"> m_kathia->runAction(seq2);
    
19. 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
    
20. // move to 50,50 since the "by" path will start at 50,50
    
21. kmGLPushmatrix();
    
22. kmGLTranslatef(50,50,serif; font-size:12px; line-height:1.8em"> ccDrawCardinalSpline(m_pArray,100);
    
23. kmGLPopMatrix();
    
24. CCSize s = CCDirector::sharedDirector()->getWinSize();
    
25. kmGLTranslatef(s.width/2,1,serif; font-size:12px; line-height:1.8em"> 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