1，导致性能悲剧的写法：
class A:public CCNode{
public:
A(){
m_sprite=NULL;
m_isDrawDebug=false;
}
virtual~A(){}
bool init(){
this->CCNode::init();
//create m_sprite
m_sprite=CCSprite::create();
m_sprite->initWithFile("a.png");
addChild(m_sprite);
....
return true;
}
void draw(Renderer* renderer, const Mat4& transform, uint32_t transformFlags){
_customCommand_drawDebug(_globalZOrder);
_customCommand_drawDebug = CC_CALLBACK_0(A::onDrawDebug,this,transform, transformFlags);
renderer->addCommand(&_customCommand_drawDebug);
}
void onDrawDebug(const Mat4 &transform, uint32_t transformFlags){
if(m_isDrawDebug){
//draw debug
...
}
}
public:
CCSprite*m_sprite;
bool m_isDrawDebug;
CustomCommand _customCommand_drawDebug;
};
上面写法，无论m_isDrawDebug是true还是false，如果场景中加1000个zorder相同的对象a，drawCall数量为1000。
2，不损失性能的写法：
class A:public CCNode{
public:
A(){
m_sprite=NULL;
m_isDrawDebug=false;
}
virtual~A(){}
bool init(){
this->CCNode::init();
//create m_sprite
m_sprite=CCSprite::create();
m_sprite->initWithFile("a.png");
addChild(m_sprite);
....
return true;
}
void draw(Renderer* renderer, const Mat4& transform, uint32_t transformFlags){
if(m_isDrawDebug){
_customCommand_drawDebug(_globalZOrder);
_customCommand_drawDebug = CC_CALLBACK_0(A::onDrawDebug,this,transform, transformFlags);
renderer->addCommand(&_customCommand_drawDebug);
}
}
void onDrawDebug(const Mat4 &transform, uint32_t transformFlags){
//draw debug
...
}
public:
CCSprite*m_sprite;
bool m_isDrawDebug;
CustomCommand _customCommand_drawDebug;
};
上面写法当m_isDrawDebug为false时，如果场景中加1000个zorder相同的对象a，则drawCall数量为1。
原文：http://www.cnblogs.com/wantnon/p/4249914.html