Cocos2dx源码记录(4) CCRenderCommandPool

这应该是最简单的类了,只有一个 .h 文件，直接贴代码

template <class T>
class RenderCommandPool
{
public:
    RenderCommandPool()
    {
    }
    ~RenderCommandPool()
    {
//        if( 0 != _usedPool.size())
//        {
//            CCLOG("All RenderCommand should not be used when Pool is released!");
//        }
        _freePool.clear();
        for (typename std::list<T*>::iterator iter = _allocatedPoolBlocks.begin(); iter != _allocatedPoolBlocks.end(); ++iter)
        {
            delete[] *iter;
            *iter = nullptr;
        }
        _allocatedPoolBlocks.clear();
    }

    T* generateCommand()
    {
        T* result = nullptr;
        if(_freePool.empty())
        {
            AllocateCommands();
        }
        result = _freePool.front();
        _freePool.pop_front();
        //_usedPool.insert(result);
        return result;
    }
    
    void pushBackCommand(T* ptr)
    {
//        if(_usedPool.find(ptr) == _usedPool.end())
//        {
//            CCLOG("push Back Wrong command!");
//            return;
//        }
        
        _freePool.push_back(ptr);
        //_usedPool.erase(ptr);
        
    }
private:
    void AllocateCommands()
    {
        static const int COMMANDS_ALLOCATE_BLOCK_SIZE = 32;
        T* commands = new (std::nothrow) T[COMMANDS_ALLOCATE_BLOCK_SIZE];
        _allocatedPoolBlocks.push_back(commands);
        for(int index = 0; index < COMMANDS_ALLOCATE_BLOCK_SIZE; ++index)
        {
            _freePool.push_back(commands+index);
        }
    }

    std::list<T*> _allocatedPoolBlocks;
    std::list<T*> _freePool;
    //std::set<T*> _usedPool;
};

这里使用了 模板和 （std::nothrow）来保证后面各种不同的RenderCommand的创建和销毁不会产生不希望看到的error跟警告 这里使用了两个list pool 来保证不会在对象使用时删除对象所在list的索引导致的迭代错误