Manual

How to use Kernel/Task? subsystem

Most of the games has got a main-loop. During the execution of one cycle of the loop a game engine has to perfrom a lot of tasks, e.g. checking user input, rendering, physic update and so on.
nrEngine's Kernel/Task? subsystems provides a simple but powerfull interface to manage the main loop. The engine does contains a Kernel which runs in the background of the engine. A Task can be bound to the kernel, so that it gets updated every cycle. A task can be any user derived class which has to perform repetitive jobs, e.g. check for user input or stream data from the disk.
Moreover a task can get a specific order number or it can depend on another task. Hence the engine does provide a simple graph based task execution system. The functionality of the nrEngine's kernel is similar to the operating system's one, but in a very simple form.
And finally a task can be shifted to a thread, so that it executes in parallel to the main application.

The following code show you how to use the engine's kernel subsystem for a simple managment of tasks in your application/game:

#include <nrEngine/nrEngine.h>

using namespace nrEngine;

//! This is a simpel task performing sound output
class SoundTask :  public ITask
{       
public: 
  
        SoundTask();
        ~SoundTask();

        //! This method will be called when the task stops                              
        Result stopTask();      
        
        //! Task was added to the kernel, so initilize it
        Result onAddTask();
        
        //! This is called every cycle, so that SoundTask can react on it
        Result updateTask();

        ...
};

void main()
{
        // Initialize engine
        ...


        // Add the sound task to the kernel with a low order number
        Engine::sKernel()->AddTask(new SoundTask(), ORDER_LOW);

        // Executes engine's kernel, hence execute all tasks which are in the kernel
        // The function returns if there are no more tasks in the kernel (i.e. if all tasks stops)
        Engine::sKernel()->Execute();
}

See also: ManualPage