Hello guys.
I am having a problem with this function:
void InitTask::make_task( AsyncTask::DoneStatus task2, PT(AsyncTaskManager) taskMgr )
{
task = new GenericAsyncTask( "Task", &task2, (void*) NULL );
taskMgr->add(task);
}When i try to compile i get the error
To tell the truth i do not know how to fix it. I mean it must be AsyncTask::DoneStatus and the compiler says it shouldn’t. I would appreciate any ideas, thank you.
You’re passing a reference to the task2 parameter, which is of type AsyncTask::DoneStatus, whereas you should be passing a function pointer to the actual task function.
So for a few days i was trying few things and got to this error:
My base class is declared this way:
class InitWindow
{
public:
...
AsyncTask:: DoneStatus StepInterv( GenericAsyncTask*, void* );
PandaFramework getFrame();
WindowFramework* getWindow();
...
protected:
PandaFramework framework;
WindowFramework* window;
...
};the class that takes the task as argument is:
class InitTask: public InitWindow
{
public:
void make_task( GenericAsyncTask::TaskFunc, PT(AsyncTaskManager) );
GenericAsyncTask* getTask();
void* getData();
private:
PT(GenericAsyncTask) task;
};void InitTask::make_task( GenericAsyncTask::TaskFunc task2, PT(AsyncTaskManager) taskMgr )
{
task = new GenericAsyncTask( "Task", &task2, (void*) NULL );
taskMgr->add(task);
}In the main i create an object of type InitTask:
InitTask movement;
movement.make_task( &InitWindow::StepInterv, act.getTaskMgr() );I made a pointer to the member function but i am missing something again. When i place the StepInterv function out of the class as a global function and pass it just as StepInterv in movement.make_task it works perfect, but the moment i place it in the class as a member function it just starts nagging me about not being able to convert it. What am i missing here ? I have the feeling this is not the right pointer to pass but that’s my opinion.
If i try to declare it GenericAsyncTask::TaskFunc InitWindow::* task2 it get’s this error:
What am i doing wrong?(again)
It should be declared as a static method. If you need to pass a “this” pointer, you can cast it to “void*” and pass it as the additional parameter.
Okay it worked, thank you. There’s one more thing that is bugging me, you mention passing a pointer to void*. Before in one other of my posts you mention that i have to make a struct in which i am to store what i want to pass in the function and pass a pointer to that struct to the extra void* data argument. Okay that i do understand but i still can’t understand pointer to which task am i supposed to pass for the GenericAsyncTask* task argument?
You could pass a pointer to anything to the void* argument; you could pass a pointer to a struct in which you store custom data, or use it to store the “this” pointer of the relevant class it’s in, or a string containing the name of your favourite ice cream.
As for the GenericAsyncTask pointer; well, since it’s Panda that calls this function and not you, you don’t need to worry about it. It’s a pointer to the task object that you created when you did “new GenericAsyncTask”.
So in other words i do not pass pointer made by me for GenericAsyncTask argument, Panda does that for me. But that confuses me because to pass a pointer for the void* argument i have to pass something for the first argument which is GenericAsuncTask.
AsyncTask::DoneStatus InitWindow::TravCol( GenericAsyncTask* task, void* data )If i don’t I get an error that the function doesn’t take only 1 parameter or something simmilar. Is there a way to go around it?
You don’t call TravCol. You call “new GenericAsyncTask”, passing your void* parameter, and then Panda stores that void* parameter and when it calls your TravCol every frame, it passes that same void* parameters as the second argument.
Okay i understand where i call the pointer. But here’s my dillema… I have this class:
class InitWindow
{
public:
...
static AsyncTask:: DoneStatus StepInterv( GenericAsyncTask*, void* );
static AsyncTask:: DoneStatus TravCol( GenericAsyncTask*, void* );
PandaFramework getFrame();
WindowFramework* getWindow();
...
protected:
PandaFramework framework;
WindowFramework* window;
PT(AsyncTaskManager) taskMgr;
PT(CMetaInterval) pandaPace;
CollisionHandlerQueue* queue;
CollisionTraverser traverser;
};Every variable from the protected i call with a get function and pass it as argument to other functions made by me so they could use these variables. Here’s the declaration of the TravCol function:
AsyncTask::DoneStatus InitWindow::TravCol( GenericAsyncTask* task, void* data )
{
traverser.traverse( window->get_render() );
if( queue->get_num_entries() == 1 )
{
pandaPace->pause();
}
return AsyncTask::DS_cont;
}What happens here is that i get error for the traverser, window, queue etc. that they’re are not part of class, union or struct(Error code C2228). First thing i got in mind was to add few more arguments to the function so i can pass the get function for those variables, but because i have to adhere to the Panda function structure i can’t do that. So the last thing i thought about doing is as you suggeste to make a structure with the variables inside and pass a void pointer to that structure so i can call them inside, but here i hit a wall again - with the void pointer i can’t call anything as it doesn’t know where it points. And i’m stuck here…
You cast the void* pointer back into a “this”-like pointer, like this:
AsyncTask::DoneStatus InitWindow::TravCol( GenericAsyncTask* task, void* data )
{
InitWindow *inst = (InitWindow*) data;
inst->traverser.traverse( window->get_render() );Make sure to pass the pointer to InitWindow to the GenericAsyncTask constructor (cast to void*).
Hmm i get an error i haven’t seen. Okay here how my function looks like(as you told me i put those two lines inside):
AsyncTask::DoneStatus InitWindow::TravCol( GenericAsyncTask* task, void* data )
{
InitWindow *inst = (InitWindow*) data;
inst->traverser.traverse( inst->window->get_render() );
if( inst->queue->get_num_entries() == 1 )
{
inst->pandaPace->pause();
}
return AsyncTask::DS_cont;
}For the void* pointer i pass this pointer:
int main(int argc, char *argv[])
{
InitWindow var;
void* ptr = &var;
...
InitTask movement;
movement.make_task( &InitWindow::TravCol, act.getTaskMgr(), ptr );
...
}I tryied to pass a pointer to the struct i made but i get a simmilar error.
And the error i get when debugging:
EDIT:
It is an access violation. I’ll look around and see if i can fix it.
CollisionTraverser is reference counted. So you have to store it in a PT() pointer, like this:
PT(CollisionTraverser) _traverser;
_traverser = new CollisionTraverser;
_traverser->somethingI tryied some things and i found that the problem comes from this line:
inst->traverser.traverse( inst->window->get_render() );and more accurately from inst->traverser.
After that i saw your reply but when i declare PT(CollisiongTransfer) anywhere in my code
i get this error:
For reference, taken from pointerToBase.I:
////////////////////////////////////////////////////////////////////
// Function: PointerToBase::reassign
// Access: Protected
// Description: This is the main work of the PointerTo family. When
// the pointer is reassigned, decrement the old
// reference count and increment the new one.
////////////////////////////////////////////////////////////////////
template<class T>
INLINE void PointerToBase<T>::
reassign(To *ptr) {
if (ptr != (To *)_void_ptr) {
// First save the old pointer; we won't delete it until we have
// assigned the new one. We do this just in case there are
// cascading effects from deleting this pointer that might
// inadvertently delete the new one. (Don't laugh--it's
// happened!)
To *old_ptr = (To *)_void_ptr;
_void_ptr = (void *)ptr;
if (ptr != (To *)NULL) {
ptr->ref(); // The compiler says that the error comes from this line
#ifdef DO_MEMORY_USAGE
if (MemoryUsage::get_track_memory_usage()) {
update_type(ptr);
}
#endif
}
// Now delete the old pointer.
if (old_ptr != (To *)NULL) {
unref_delete(old_ptr);
}
}
}Sorry, I had it so wrong. It’s not reference counted after all. Never mind my previous suggestion.
Could the problem be that you’re (somehow) not getting a valid InitWindow* pointer to the GenericAsyncTask constructor? Try printing out the value of “&var” in your main and the value of “inst” in TaskCol to make sure th they match.
CollisionTraverser is not reference counted, but CollisionHandlerQueue is. So you need PT(CollisionHandlerQueue) instead of CollisionHandlerQueue *.
David
Inst and &var have the same adress. But it seems that traverse doesn’t hold any information. When i check in this function:
void InitQueue:: init_queue( PT(CollisionHandlerQueue) queue, NodePath colNp, WindowFramework* window, CollisionTraverser traverser )
{
queue = new CollisionHandlerQueue();
if( queue != NULL )
{
traverser.add_collider( colNp, queue );
}
}the traverser gets it’s queue and handler, but the moment the function exits the values are lost.
After that when entering function:
AsyncTask::DoneStatus InitWindow::TravCol( GenericAsyncTask* task, void* data )
{
InitWindow *inst = (InitWindow*) data;
inst->traverser.traverse( inst->window->get_render() );
PT(CollisionHandlerQueue) _queue;
_queue = new CollisionHandlerQueue;
if( _queue->get_num_entries() == 1 )
{
inst->pandaPace->pause();
}
return AsyncTask::DS_cont;
}for this line: inst->traverser.traverse( inst->window->get_render() );
i get:
I presume that this error indicates that traverser doesn’t hold any infromation but that’s just my guess.
If i place ampersand infront of the argument traverser for function init_queue, i get violation access for the same line.( inst->traverser.traverse( inst->window->get_render() ); )
Why are you creating a new queue in TravCol? You need to create your queue in the init, and then hold it in a PT(CollisionHandlerQueue) on your class instance.
My bad, fixed it. About the problem, is it possible for the error to come from the inst->window->get_redner() line ?
I fixed the pointers that gave me the access errors. But i got stuck elsewhere. In the function init_queue i am working with the pointer queue, but after the function exits the information is lost.
Here is the function:
void InitQueue:: init_queue( PT(CollisionHandlerQueue) queue, NodePath colNp, WindowFramework* window, CollisionTraverser &traverser )
{
queue = new CollisionHandlerQueue();
if( queue != NULL )
{
traverser.add_collider( colNp, queue );
}
traverser.show_collisions( window->get_render() );
}In main:
int main(int argc, char *argv[])
{
InitWindow winframe;
...
InitQueue sequence;
sequence.init_queue( winframe.getQueue(), col.init_collision_fobj( act.getActor() ), winframe.getWindow(), winframe.getTraverser() );
cerr << " \n MAIN \n";
cerr << winframe.getQueue();
cerr << " \n ---- \n ";
...
}The “cerr << winframe.getQueue();” line returns only zeros. I may be wrong but i think that PT deletes the adress stored in queue after function return. If it is true i have to store the information queue holds somewhere but i can’t understand where. What i want to ask is a tip on what i am doing wrong, the rest i’ll do on my own.
Are you sure you’re holding it in a PT and not a regular pointer? In your original code you had this in your struct:
CollisionHandlerQueue* queue;Whereas it should be:
PT(CollisionHandlerQueue) queue;