Cocos2d-x3.1中ClippingNode的使用实例

#include 2d/CCNode.h//用到节点头文件和OPENGL深度缓冲定义头文件#include CCGL.h#include renderer/CCGroupCommand.h//用到GroupCommand和CustomCommand渲染#include renderer/CCCustomCommand.hNS_CC_BEGIN/** ClippingNode is a subclass of Node. It dr

#include "2d/CCNode.h"//用到节点头文件和OPENGL深度缓冲定义头文件
#include "CCGL.h"
#include "renderer/CCGroupCommand.h"//用到GroupCommand和CustomCommand渲染
#include "renderer/CCCustomCommand.h"

NS_CC_BEGIN

/** ClippingNode is a subclass of Node.
 It draws its content (childs) clipped using a stencil.
 The stencil is an other Node that will not be drawn.
 The clipping is done using the alpha part of the stencil (adjusted with an alphaThreshold).
 */
class CC_DLL ClippingNode : public Node
{
public:
 /** Creates and initializes a clipping node without a stencil.
 */
 static ClippingNode* create();//静态创建对象
 
 /** Creates and initializes a clipping node with an other node as its stencil.
 The stencil node will be retained.
 */
 static ClippingNode* create(Node *stencil);//用模板创建裁剪节点

 /** The Node to use as a stencil to do the clipping.
 The stencil node will be retained.
 This default to nil.
 */
 Node* getStencil() const;//获取节点模板
 void setStencil(Node *stencil);//设置节点模板
 
 /** The alpha threshold.
 The content is drawn only where the stencil have pixel with alpha greater than the alphaThreshold.
 Should be a float between 0 and 1.
 This default to 1 (so alpha test is disabled).
 *///ALPHA测试参考值，用于进行ALPHA测试比较，一般比较算法为小于此值的像素会直接被舍弃，这样就实现了图像的镂空
 GLfloat getAlphaThreshold() const;//获取ALPHT的测试参考值
 void setAlphaThreshold(GLfloat alphaThreshold);//设置ALPHA的测试参考值
 
 /** Inverted. If this is set to true,
 the stencil is inverted, so the content is drawn where the stencil is NOT drawn.
 This default to false.
 */
 bool isInverted() const;//获取遮罩运算是否取反设置
 void setInverted(bool inverted);//设置遮罩运算取反

 // Overrides//继承的函数
 /**
 * @js NA
 * @lua NA
 */
 virtual void onEnter() override;
 /**
 * @js NA
 * @lua NA
 */
 virtual void onEnterTransitionDidFinish() override;
 /**
 * @js NA
 * @lua NA
 */
 virtual void onExitTransitionDidStart() override;
 /**
 * @js NA
 * @lua NA
 */
 virtual void onExit() override;
 virtual void visit(Renderer *renderer, const Mat4 &parentTransform, bool parentTransformUpdated) override;
 
CC_CONSTRUCTOR_ACCESS:
 ClippingNode();
 
 /**
 * @js NA
 * @lua NA
 */
 virtual ~ClippingNode();

 /** Initializes a clipping node without a stencil.
 */
 virtual bool init();
 
 /** Initializes a clipping node with an other node as its stencil.
 The stencil node will be retained, and its parent will be set to this clipping node.
 */
 virtual bool init(Node *stencil);

protected:
 /**draw fullscreen quad to clear stencil bits
 */
 void drawFullScreenQuadClearStencil();

 Node* _stencil;
 GLfloat _alphaThreshold;
 bool _inverted;

 //renderData and callback
 void onBeforeVisit();
 void onAfterDrawStencil();
 void onAfterVisit();

 GLboolean _currentStencilEnabled;
 GLuint _currentStencilWriteMask;
 GLenum _currentStencilFunc;
 GLint _currentStencilRef;
 GLuint _currentStencilValueMask;
 GLenum _currentStencilFail;
 GLenum _currentStencilPassDepthFail;
 GLenum _currentStencilPassDepthPass;
 GLboolean _currentDepthWriteMask;

 GLboolean _currentAlphaTestEnabled;
 GLenum _currentAlphaTestFunc;
 GLclampf _currentAlphaTestRef;

 GLint _mask_layer_le;
 
 GroupCommand _groupCommand;
 CustomCommand _beforeVisitCmd;
 CustomCommand _afterDrawStencilCmd;
 CustomCommand _afterVisitCmd;

private:
 CC_DISALLOW_COPY_AND_ASSIGN(ClippingNode);
};

NS_CC_END

3、使用实例

class NewClippingNode : public Layer
{
public:
 CREATE_FUNC(NewClippingNode);
 virtual bool init();
};

boolNewClippingNode::init()
{

 auto s =Director::getInstance()->getWinSize();
 bool bRet =
false;
 do{
 CC_BREAK_IF(!Layer::init());

 
 auto clipper =
ClippingNode::create();
 clipper->setTag(kTagClipperNode);
 clipper->setContentSize(Size(200,200));//设置剪裁区域大小

 clipper->ignoreAnchorPointForPosition(false);
 clipper->setAnchorPoint(Vec2(0.5,0.5));//设置锚点
 clipper->setPosition(Vec2(s.width/2,
 s.height/2));
 this->addChild(clipper);

 
 clipper->setAlphaThreshold(0.05f);//设置透明度的阈值ALPHA值

 //设置剪裁模板
 auto stencil =
Sprite::create("grossini.png");
 stencil->setScale(2);
 stencil->setPosition(Vec2(s.width/2,
 s.height/2));
 clipper->setStencil(stencil);//设置剪裁模板






 //TODO Fix draw node as clip node

// auto stencil = NewDrawNode::create();

// Vec2 rectangle[4];

// rectangle[0] = Vec2(0, 0);

// rectangle[1] = Vec2(clipper->getContentSize().width, 0);

// rectangle[2] = Vec2(clipper->getContentSize().width, clipper->getContentSize().height);

// rectangle[3] = Vec2(0, clipper->getContentSize().height);

//

// Color4F white(1, 1, 1, 1);

// stencil->drawPolygon(rectangle, 4, white, 1, white);

// clipper->setStencil(stencil);










 //设置剪裁节点内容
 auto content =
Sprite::create("background2.png");
 content->setTag(kTagContentNode);

 content->ignoreAnchorPointForPosition(false);
 content->setAnchorPoint(Vec2(0.5,0.5));
 content->setPosition(Vec2(s.width/2,200));
 clipper->addChild(content);

 
 bRet =true;
 }while(0);
 return bRet;
}