I have some conceptual problems for a resource manager to be thread safe (can be called from any thread). The manager has a list of worker threads (one per bundle, a bundle is a zip file).
Traditionally, in a single-threaded manager we do something like this:
// sync load of a texture, loads and returns after texture is fully loaded
Texture* pTex = resourceManager()->load("maka.png");
// we got the texture, use it
int w = pTex->width();
int h = pTex->height();
// do something with w and h
But in an async manager how we do that?
Currently I'm using an observer list with callbacks for when a resource is completely loaded, the Observer is called and you can use the pointer to the resource. In this manager, resources are used as IDs, you do not have direct access to the pointer because you do not know in what state is at some point, it may be removed or modified from another thread.
ResourceId myTextureId = 3493; // or we can use: resourceId("maka.png") to get the id
struct MyResObserver : public IResourceObserver
{
void onResourceLoaded(Resource* pRes)
{
Texture* pTex = dynamic_cast<Texture*>(pRes);
if (pTex && pTex->id() == myTextureId)
{
int w = pTex->width();
int h = pTex->height();
// use w and h
}
}
} myObserver;
///....................
void someClass::someInit()
{
// we add our observer into the manager's list
resourceManager()->addObserver(&myObserver);
// async loading, returns right away, the resource will be loaded later on
resourceManager()->load(myTextureId);
// or we could do: resourceManager()->load(someTextureId, &myObserver);
}
Any other ideas would be welcomed, thanks.
