Application Logic System

In UNIGINE, you can implement application logic in the following ways:

• in C++ or C#
• combining C++ or C# with UnigineScript — in this case, the execution sequence for each implemented method, corresponding to a certain stage of the application's life cycle (i.e., init(), update(), postUpdate(), etc.), is the following:
  1. UnigineScript function
  2. C++/C# method

The application logic has three basic components that have different lifetimes:

• World logic. It takes effect only when the world is loaded. For projects that use UnigineScript only, the logic is written to the world script (each particular world can have its own script). A default script is created as a *.usc file named after your project at the project creation. Such files are stored in the data/ folder.
  For applications that use C++ AppWorldLogic.cpp is created, and for C# applications — AppWorldLogic.cs. These files are stored in the <your_project_folder>/source/ folder and stay loaded during the whole engine runtime. They have implemented methods to put your logic code inside. WorldLogic in C++/C# (unlike UnigineScript) works with every loaded world, so you can't assign a specific WorldLogic to a certain world.
• System logic. It exists during the application life cycle. The logic is implemented in the default system script named unigine.usc and stored in the data/ folder of your project as the core.ung archive. You can put your logic in this file if you use UnigineScript only. You can also inherit SystemLogic class and implement your logic in C++ or C#.

• Editor logic. This component is to be used in case you need to implement your own Editor. It has more implemented methods providing you with clear understanding of the current Engine events (a node has been created, a property has been deleted, a material has been changed, etc.). You can inherit EditorLogic class and implement your logic in C++ or C#.
  Default UnigineScript logic for the Editor is loaded from the editor2/editor.usc file stored inside editor2.ung. You can override this UnigineScript logic file by creating a folder named editor2 in your data folder and putting there the editor.usc file with the following code (you can modify this script, but do not remove existing include lines as they are required for Editor operation):

  editor.usc

  Source code

  #include <editor2/editor_tracker.h>
  #include <editor2/editor_video_grabber.h>
  
  int init() {
  	return 1;
  }
  
  int update() {
  	return 1;
  }
  
  int shutdown() {
  	return 1;
  }

  Notice

  When you create a new C++ / C# project, it has already inherited World Logic class (AppWorldLogic), System Logic class (AppSystemLogic), and Editor Logic class (AppEditorLogic) with implemented methods to put your logic code inside.

If a project uses UnigineScript only, its execution sequence is strictly defined in scripts and cannot be modified.
If a project is created using C++ or C#, a programmer can control the execution sequence by manually calling Engine's init(), update(), postUpdate(), swap(), and shutdown() methods when required and add logic anywhere between these blocks, as shown in the C++ sample <UnigineSDK>/source/samples/Api/Render/Screenshot/Screenshot.cpp.

If the World Logic is implemented in UnigineScript, it is loaded or unloaded at the same time as the world itself is loaded or unloaded. The World Logic implemented in C++/C# stays loaded during the whole UNIGINE engine runtime. The World Logic may use the following methods, which are available for both UnigineScript and C++/C#:

#include "AppWorldLogic.h"

AppWorldLogic::AppWorldLogic() {

}

AppWorldLogic::~AppWorldLogic() {

}

int AppWorldLogic::init() {

	return 1;
}

int AppWorldLogic::update() {

	return 1;
}

int AppWorldLogic::postUpdate() {

	return 1;
}

int AppWorldLogic::updatePhysics() {

	return 1;
}

int AppWorldLogic::shutdown() {

	return 1;
}

int AppWorldLogic::save(const Unigine::StreamPtr &stream) {
	UNIGINE_UNUSED(stream);
	return 1;
}

int AppWorldLogic::restore(const Unigine::StreamPtr &stream) {
	UNIGINE_UNUSED(stream);
	return 1;
}

init() function#

updateAsyncThread() function#

updateSyncThread() function#

update() function#

postUpdate() function#

updatePhysics() function#

swap() function#

shutdown() function#

save() and restore() functions#

The System Logic stays loaded during the whole UNIGINE Engine runtime. It may use the following methods, which are available for both UnigineScript and C++/C#:

#include "AppSystemLogic.h"

AppSystemLogic::AppSystemLogic() {

}

AppSystemLogic::~AppSystemLogic() {

}

int AppSystemLogic::init() {
	return 1;
}

int AppSystemLogic::update() {
	return 1;
}

int AppSystemLogic::postUpdate() {
	return 1;
}

int AppSystemLogic::shutdown() {
	return 1;
}

init() function#

update() function#

postUpdate() function#

shutdown() function#

This component is to be used in case you need to implement your own Editor. It has more implemented methods providing you with clear understanding of the current Engine events (a node has been created, a property has been deleted, a material has been changed, etc.).

The Editor Logic may use the following methods, which are available for both UnigineScript and C++/C#:

#include "AppEditorLogic.h"

AppEditorLogic::AppEditorLogic() {
	
}

AppEditorLogic::~AppEditorLogic() {
	
}

int AppEditorLogic::init() {
	return 1;
}

int AppEditorLogic::update() {
	return 1;
}

int AppEditorLogic::postUpdate() {
	return 1;
}

int AppEditorLogic::shutdown() {
	return 1;
}

int AppEditorLogic::worldInit() {
	return 1;
}

int AppEditorLogic::worldShutdown() {
	return 1;
}

int AppEditorLogic::worldSave() {
	return 1;
}

init() function#

update() function#

postUpdate() function#

shutdown() function#

worldInit() function#

worldShutdown() function#

worldSave() function#