cocos2d-x 画线

/*

//绘制矩形  (‘起始点’ , ‘目标点’ , ‘填充颜色’)

    auto rect=DrawNode::create();

    rect->drawRect(Vec2(0,0),Vec2(100,150), Color4F(1.0,0,0,1.0));

    this->addChild(rect);





    //绘制指定曲率的曲线  ('点数组','张力','段落','颜色')

    //参数说明:

    //congfig:点数组

    //tension:张力

    //segments:段落

    //color:颜色

    auto cardinalspline=DrawNode::create();



    auto array = PointArray::create(4);

    array->addControlPoint(Vec2(20, 20));

    array->addControlPoint(Vec2(40, 10));

    array->addControlPoint(Vec2(-10, 10));

    array->addControlPoint(Vec2(60, -10));

    array->addControlPoint(Vec2(10, 50));

    cardinalspline->drawCardinalSpline(array, 3, 10, Color4F(1.0,1.0,1.0,1));

    this->addChild(cardinalspline);





    //绘制默认曲率的曲线

    auto cat=DrawNode::create();

    cat->drawCatmullRom(array, 20, Color4F(1.0, 1.0, 1.0, 1.0));

    this->addChild(cat);





    //绘制圆  参数说明: （‘原点’，‘半径’，‘弧度’，‘分段(越大越接近圆)’，‘原点到弧度的线(bool)’，‘线条x缩放’，‘线条y缩放’，‘颜色’）

    auto circle=DrawNode::create();

    circle->drawCircle(Vec2(0, 0), 100, 45, 100, false, 1.0, 1.0, Color4F(1.0,1.0,1.0,1));

    this->addChild(circle);



    //绘制线段          (‘起点’ , ‘终点’ , ‘半线宽’ , ‘填充颜色’)

    auto segment=DrawNode::create();

    segment->drawSegment(Vec2(0, 0), Vec2(20, 20), 3.0, Color4F(0.4,0.6,0.8,1));

    this->addChild(segment);



    //绘制三角形         (‘顶点1′ , ‘顶点2′ , ‘顶点3′ , ‘填充颜色’)

    auto triangle=DrawNode::create();

    triangle->drawTriangle(Vec2(20,11), Vec2(133,44), Vec2(44,133), Color4F(0.5,0.6,0.7,1));

    this->addChild(triangle);



    //绘制多边形        (‘顶点数组’ , ‘顶点个数’ , ‘填充颜色’ , ‘轮廓粗细’ , ‘轮廓颜色’)

    auto polygon=DrawNode::create();

    Vec2 verts[]={Vec2(12,22),Vec2(56,66),Vec2(88,98),Vec2(124,54),Vec2(144,88)};//顶点数组

    polygon->drawPolygon(verts, 5, Color4F(1.0,0,0,1), 2, Color4F(0,0,1.0,1));

    this->addChild(polygon);



    //绘制二次贝塞尔图形        (‘起点’ , ‘控制点’ , ‘终点’ , ‘分段数’ , ‘填充颜色’)

    auto quad=DrawNode::create();

    quad->drawQuadBezier(Vec2(12,10), Vec2(22,33), Vec2(111,111), 20, Color4F(0.1,1.0,0.2,1));

    this->addChild(quad);



    //绘制三次贝塞尔图形    (‘起点’ , ‘控制点1′ , ‘控制点2′ , ‘终点’ , ‘分段数’ , ‘填充颜色’)

    auto cubic=DrawNode::create();

    cubic->drawCubicBezier(Vec2(0,0), Vec2(33,23), Vec2(75,96), Vec2(44,33), 22, Color4F(0.7,0,0,1));

    this->addChild(cubic);



    //绘制线段  ('起点','终点','宽度','颜色')

    auto dsegment=DrawNode::create();

    dsegment->drawSegment(Vec2(20, 22), Vec2(20,100), 2, Color4F(1.0,0.1,0.8,1));

    this->addChild(dsegment);



    //绘制线   ('起点','终点','颜色')

    auto line=DrawNode::create();

    line->drawLine(Vec2(33,33), Vec2(222,222), Color4F(1.0,1.0,0.2,1));

    this->addChild(line);



    //绘制圆点      (‘位置’ , ‘圆点半径’ , ‘填充颜色’)

    auto dot=DrawNode::create();

    dot->drawDot(Vec2(0,0), 5, Color4F(1.0, 1.0, 1.0, 1.0));

    rect->addChild(dot);



    //设置坐标位置

    rect->setPosition(visibleSize/2);//设置矩形位置居中

    dot->setPosition(Vec2(0, 0));//设置圆点的位置

    cardinalspline->setPosition(visibleSize/2);//设置曲线位置

    circle->setPosition(visibleSize/2);

    segment->setPosition(visibleSize/2);

    triangle->setPosition(visibleSize/2);

    polygon->setPosition(visibleSize/5);

    quad->setPosition(Vec2(230,20));

    cubic->setPosition(visibleSize/2);

    dsegment->setPosition(Vec2(22,22));

    line->setPosition(Vec2(44,22));

    cat->setPosition(Vec2( visibleSize.width/2+50,visibleSize.height/2+20));


      最近在用cocos2d-x做鱼在水池里游动，直线游动比较容易实现，但是要使鱼转弯，绕着圆弧游动就有点难度了，
      不仅鱼的位置是圆的轨迹点，它的方向也要跟着相应变化，并且要准确控制它是顺时针转还是逆时针。
      搞了大半天，不断试验不断修改，终于把它封装成一个CCArcBy的action, 以后可以直接拿来用了。 CCArcBy的初始化方法是

         bool initWithDuration(ccTime duration, float radius, float angle, bool clockwise);

      只要给定转弯的半径，角度，时针方向和时间，就可以让node绕着圆弧进行运动，
      并且相应改变它的方向。具体原理是运行该action时候，会根据当前node的position和rotation创建直线方程lq,
      创建垂直于直线lq并且相交于position的直线方程lq2, 根据时针方向创建与直线lq平行并且距离为radius的直线方程lq3,
      计算lq2和q3的交点就是圆弧的圆心位置了。

       在圆弧运动每次update过程中，调用框架自带的ccpRotateByAngle方法就能得到当前node的位置了，
       而node的方向要减去转弯的角度，这样鱼就能正常转弯游动了，还能不时拜摆摆尾巴！
*/

// 创建一个圆弧
//void drawArc(cocos2d::DrawNode* drawNode, const cocos2d::Vec2& center, float radius, float startAngle, float endAngle, int segments, float width) {
//    // segments 是圆弧分割的线段数，增加segments可以使得弧线更加平滑
//    // width 是弧线的宽度
//    const float coef = 2.0f * (float)M_PI / segments;
//
//    // 计算起始点
//    cocos2d::Vec2 point = center + cocos2d::Vec2(radius * cos(startAngle), radius * sin(startAngle));
//    
//    drawNode->moveTo(point);
//    for (int i = 1; i < segments; ++i) {
//        float angle = startAngle + i * coef;
//        point = center + cocos2d::Vec2(radius * cos(angle), radius * sin(angle));
//        drawNode->lineTo(point);
//    }
//
//    // 画圆弧的结束点
//    point = center + cocos2d::Vec2(radius * cos(endAngle), radius * sin(endAngle));
//    drawNode->lineTo(point);
//}