Task and classes

C++ coding using Panda3D
1

Hi, Just started experimenting with Panda3D, which I chose to build a prototype for a game. I want to use solely C++. I did the basic Hello World panda tutorial, and everything works and compiles just fine (after figuring out the missing libraries, such as pthread).

As for the style, I need some guidance. All of the samples converted to C++ put all of the code in a class, including the task function (making it a member function). Looks fine, until you realise that in order to put that function in the task manager, you need to send its pointer. C++ forbids using a pointer to a member function. gcc enforces that, but I would assume its not the case of whatever was used to write/build the samples.

So my question was how to people usually use task? Where are they declared and implemented? Also, I would be happy to see some proper example (not the samples) of C++ game with Panda3D using a proper (and legal) style, I have been unsuccessful in finding any such example on Google (although there are heaps for Python).

Thank you!
Tom

2

The most common approach is to make the task method in question static, and passing the class instance by reference as an optional argument.

MyClass.h

class MyClass
{
    public:
        MyClass();

        static AsyncTask::DoneStatus example_method(GenericAsyncTask *task, void *data);

    private:
        PT(AsyncTaskManager) task_mgr;
        PT(GenericAsyncTask) example_task;
}

MyClass.cpp

MyClass::MyClass()
{
    this->task_mgr = AsyncTaskManager::get_global_ptr();

    this->example_task = new GenericAsyncTask("exampleTask", example_method, this);
    this->task_mgr->add(this->example_task);
}

AsyncTask::DoneStatus MyClass::example_method(GenericAsyncTask *task, void *data)
{
	MyClass *self = (MyClass*)data;

	return AsyncTask::DS_cont;
}
3

Another way is to have a class that inherits from AsyncTask and implements the virtual DoneStatus do_task(); method.

5

@ksmit799 Genius! Looks exactly what I was looking for :smile: