New WorldLogic Class for corresponding World

[matthew.clifton]

Hi all,

Created a new World and now want to create a new WorldLogic class. I can see the UnigineScript class being created with the new World, but how do I create the equivalent c++ link between world and a c++ WorldLogic? Each world seems to be calling the template AppWorldLogic. I can create a new class derived from Unigine::WorldLogic, but I don't know where to instantiate it etc.

I've been hunting the demos and samples but they all seem to be just a single world. I hope the above made some sense.

 

Best regards in advance,

Matt.

 

[fox]

Hi Matt,

Suppose in your project you have a default world named "world1" and another one named "world2" and you want to have two separate world logic classes for each of these worlds. Suppose you want to switch between these worlds by pressing PGUP and PGDOWN keys.

The basic recommended workflow is to have a single AppWorldLogic class to process all worlds in your project. You can split world-specific code between separate classes inherited from Unigine::WorldLogic (in this example that would be WorldLogic1 and WorldLogic2) and use the AppWorldLogic class as a manager calling corresponding methods (init, update, render, etc.) for the current world logic.

First, we just inherit two new classes (WorldLogic1 and WorldLogic2) from Unigine::WorldLogic. You can simply copy the contents of AppWorldLogic.h and AppWorldLogic.cpp files and modify their init() methods like this:

// WorldLogic1.cpp file
int WorldLogic1::init()
{
	// reporting that we're processing the first world and displaying its name
	Log::message("This is WORLD 1 named %s\n", World::get()->getName());

	return 1;
}

// WorldLogic2.cpp file
int WorldLogic2::init()
{
	// reporting that we're processing the second world and displaying its name
	Log::message("This is WORLD 2 named %s\n", World::get()->getName());

	return 1;
}

Then we put everything related to changing world logics to theAppWorldLogic.

// AppWorldLogic.h

#include <UnigineLogic.h>
#include <UnigineStreams.h>
#include "AppWorldLogic1.h"		//<-- include world logic class declaration for the first world
#include "AppWorldLogic2.h"		//<-- include world logic class declaration for the first world
class AppWorldLogic : public Unigine::WorldLogic {
	
public:
	//...

	Unigine::WorldLogic *current_world_logic = &wl1;	//<-- pointer to the current world logic
	AppWorldLogic1 wl1;							//<-- world logic for the first world
	AppWorldLogic2 wl2;							//<-- world logic for the second world
};

#endif // __APP_WORLD_LOGIC_H__

Inside each method of the AppWorldLogic class we simply call the corresponding method of the current world logic class. In the init() method, as it is called each time a new world is loaded, we also should change the current world logic if necessary:

// AppWorldLogic.cpp
#include <UnigineWorld.h>

// ...
int AppWorldLogic::init()
{
	// checking the name of the loaded world and updating current world logic
	if (strcmp(World::get()->getName(), "world1") == 0)
		current_world_logic = &wl1;
	else if (strcmp(World::get()->getName(), "world2") == 0)
		current_world_logic = &wl2;

	// calling init method of the current world
	current_world_logic->init();
	
	return 1;
}

// ...

Switching between the worlds is to be performed in the AppSystemLogic class, so we should modify implementation of its update() method in the AppSystemLogic.cpp file like this:

// AppSystemLogic.cpp
#include <UnigineApp.h>
#include <UnigineWorld.h>
// ...
int AppSystemLogic::update()
{
	// checking key states and loading worlds
	if (App::get()->clearKeyState(App::KEY_PGUP))
	{	// loading the second world if it is not already loaded
		if (strcmp(World::get()->getName(), "world2") != 0)
			World::get()->loadWorld("world2");
	}
	else if (App::get()->clearKeyState(App::KEY_PGDOWN))
	{	// loading the first world if it is not already loaded
		if (strcmp(World::get()->getName(), "world1") != 0)
			World::get()->loadWorld("world1");
	}
	
	return 1;
}

// ...

Hope this helps!

Thank you!
 

 

[matthew.clifton]

Hi fox,

Thank you so much for the detailed reply!! I'll give it a shot just as soon as I get home this evening.

I'm only a week into this engine (only dabbled with worlds and assets up to now), and i'm loving it!

Best Regards,
Matt.

 

[Valuna]

On 10/31/2018 at 8:19 AM, fox said:

current_world_logic = &wl2; World::get()->loadWorld("world2");

Wouldn't this mean that you call wl2::shutdown() on loadworld(wl2) instead of wl1::shutdown()?

Edited November 8, 2018 by Valuna
spelling error

[fox]

 

Sorry, my bad, the code is fixed!

Thank you for reporting!