6. Creating and Deleting Nodes at Runtime

#ifndef __APP_WORLD_LOGIC_H__
#define __APP_WORLD_LOGIC_H__

#include <UnigineLogic.h>
#include <UnigineStreams.h>
#include <UnigineObjects.h>

using namespace Unigine;

class AppWorldLogic : public WorldLogic {
	
public:
	AppWorldLogic();
	virtual ~AppWorldLogic();
	
	virtual int init();
	
	virtual int update();
	virtual int postUpdate();
	virtual int updatePhysics();
	
	virtual int shutdown();
	virtual int destroyRenderResources();
	
	virtual int save(const StreamPtr &stream);
	virtual int restore(const StreamPtr &stream);
private:

	//auxiliary functions
	int addMeshToScene(const char *file_name, const char *mesh_name, const char *material_name, Math::Vec3 position);

	// initialization functions
	int initObjects();

	// scene objects vector
	Vector<ObjectMeshDynamicPtr> Objects;
};

#endif // __APP_WORLD_LOGIC_H__

#include "AppWorldLogic.h"
// World logic, it takes effect only when the world is loaded.
// These methods are called right after corresponding world script's (UnigineScript) methods.
//-----------------------------------------------------------------------------------------------------------------------------
//---------------------------------------------- AUXILIARY FUNCTIONS AND METHODS ----------------------------------------------
//-----------------------------------------------------------------------------------------------------------------------------

/// method adding a Dynamic Mesh Object to the scene. If an empty filename is passed the method creates a default box; otherwise, loads a mesh-file with a given name.
int AppWorldLogic::addMeshToScene(const char *file_name, const char *mesh_name, const char *material_name, Math::Vec3 position)
{
	MeshPtr mesh = Mesh::create();
	ObjectMeshDynamicPtr omd;

	if (file_name) {				// loading a mesh from a specified file
		if (!mesh->load(file_name))
		{
			Log::error("\nError opening .mesh file!\n");
			mesh.clear();

			return 0;
		}
		else omd = ObjectMeshDynamic::create(mesh);
	}
	else																// creating a default box
	{
		mesh->addBoxSurface("box_surface", Math::vec3(0.5f));

		omd = ObjectMeshDynamic::create(mesh);
	}

	// setting node material, name and position
	omd->setMaterial(material_name, "*");
	omd->setName(mesh_name);
	omd->setWorldPosition(position);

	// updating the list of scene objects
	Objects.append(omd);

	// reporting progress to the console
	Log::message("-> Object %s added to the scene.\n", mesh_name);

	// clearing the mesh
	mesh.clear();

	return 1;

}
//-----------------------------------------------------------------------------------------------------------------------------
//---------------------------------------------- INITIALIZATION METHODS -------------------------------------------------------
//-----------------------------------------------------------------------------------------------------------------------------
/// method performing initialization of the set of 4 boxes
int AppWorldLogic::initObjects()
{
	int index = 0;

	for (int x = 0; x < 2; x++)
	{
		for (int y = 0; y < 2; y++)
		{
			addMeshToScene(NULL, String::format("my_meshdynamic_%d", index), "mesh_base", Math::Vec3(x, y, 1.0f));
			index++;
		}
	}

	// reporting progress to the console
	Log::warning("Objects generation OK!\n\n");

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
AppWorldLogic::AppWorldLogic() {

}

AppWorldLogic::~AppWorldLogic() {

}

int AppWorldLogic::init() {
	// Write here code to be called on world initialization: initialize resources for your world scene during the world start.

	// creating objects
	initObjects();

	return 1;
}

// start of the main loop
int AppWorldLogic::update() {
	// Write here code to be called before updating each render frame: specify all graphics-related functions you want to be called every frame while your application executes.

	return 1;
}

int AppWorldLogic::postUpdate() {
	// The engine calls this function before rendering each render frame: correct behavior after the state of the node has been updated.

	return 1;
}

int AppWorldLogic::updatePhysics() {
	// Write here code to be called before updating each physics frame: control physics in your application and put non-rendering calculations.
	// The engine calls updatePhysics() with the fixed rate (60 times per second by default) regardless of the FPS value.
	// WARNING: do not create, delete or change transformations of nodes here, because rendering is already in progress.

	return 1;
}
// end of the main loop

int AppWorldLogic::shutdown() {

	// deleting all created nodes
	for (int i = 0; i < Objects.size(); i++)
	{
		// removing current node from the scene
		Objects[i]->deleteLater();
	}

	// updating the list of scene objects
	Objects.clear();

	return 1;
}

int AppWorldLogic::destroyRenderResources() {
	// Write here code to be called when the video mode is changed or the application is restarted (i.e. video_restart is called). It is used to reinitialize the graphics context.

	return 1;
}

int AppWorldLogic::save(const StreamPtr &stream) {
	// Write here code to be called when the world is saving its state (i.e. state_save is called): save custom user data to a file.

	UNIGINE_UNUSED(stream);
	return 1;
}

int AppWorldLogic::restore(const StreamPtr &stream) {
	// Write here code to be called when the world is restoring its state (i.e. state_restore is called): restore custom user data to a file here.

	UNIGINE_UNUSED(stream);
	return 1;
}