| 33 | |
| 34 | Each game has a main game 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. [[BR]] |
| 35 | 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. [[BR]] |
| 36 | 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 operatin gsystem kernel, but in a very simple form. [[BR]] |
| 37 | And finally a task can be shifted to a thread, so that it executes in parallel to the main application. |
| 38 | |
| 39 | The following code show you how to use the engine's kernel subsystem for a simple managment of tasks in your application/game: |
| 40 | {{{ |
| 41 | #include <nrEngine/nrEngine.h> |
| 42 | |
| 43 | using namespace nrEngine; |
| 44 | |
| 45 | //! This is a simpel task performing sound output |
| 46 | class SoundTask : public ITask |
| 47 | { |
| 48 | public: |
| 49 | |
| 50 | SoundTask(); |
| 51 | ~SoundTask(); |
| 52 | |
| 53 | //! This method will be called when the task stops |
| 54 | Result stopTask(); |
| 55 | |
| 56 | //! Task was added to the kernel, so initilize it |
| 57 | Result onAddTask(); |
| 58 | |
| 59 | //! This is called every cycle, so that SoundTask can react on it |
| 60 | Result updateTask(); |
| 61 | |
| 62 | ... |
| 63 | }; |
| 64 | |
| 65 | void main() |
| 66 | { |
| 67 | // Initialize engine |
| 68 | ... |
| 69 | |
| 70 | |
| 71 | // Add the sound task to the kernel with a low order number |
| 72 | Engine::sKernel()->AddTask(new SoundTask(), ORDER_LOW); |
| 73 | |
| 74 | // Executes engine's kernel, hence execute all tasks which are in the kernel |
| 75 | // The function returns if there are no more tasks in the kernel (i.e. if all tasks stops) |
| 76 | Engine::sKernel()->Execute(); |
| 77 | } |
| 78 | }}} |
| 79 | |