今天才发现badkeeper关于Resource Manager的设计真是妙啊！

写出来大概是这个样子，完全没有必要像我写的MemMan那样复杂！

class Resource {

public:

Resource()

{

ResourceManager.attach( this );

}

virtual ~Resource()

{

ResourceManager.detach( this );

}

virtual void streamIn() = 0;

virtual UINT streamOut() = 0;

public:

UINT last_use_time;

};

class ResourceManager {

public:

void attach( Resource *res );

void detach( Resource *res );

UINT get_current_time()

{

return ++current_time;

}

UINT pop()

{

Resource *old_res;

for( UINT i = 0; i < reslist.size(); ++i )

{

Resource *res = reslist[i];

// LRU...

if( res->last_use_time < old_res->last_use_time )

old_res = res;

}

return old_res->steamOut();

}

private:

std::vector<Resource*> reslist;

UINT current_time;

};

class MemoryAllocator {

public:

void *alloc( UINT size )

{

if( memoryAvailable > 0 )

return new char[size];

else

{

UINT got_size = 0;

do {

got_size += ResourceManager.pop();

} while( got_size < size );

return new char[size];

}

}

};

class RayObject : public Resource {

public:

void streamIn()

{

if( compressed )

{

prilist = new RayTriangle [prisize];

compressed = false;

}

last_use_time = ResourceManager.get_current_time();

}

UINT streamOut()

{

if( !compressed )

{

delete [] prilist;

compressed = true;

}

return size;

}

private:

RayTriangle prilist;

bool compressed;

};