16. Creating User Interface

#ifndef __APP_WORLD_LOGIC_H__
#define __APP_WORLD_LOGIC_H__

#include <UnigineLogic.h>
#include <UnigineStreams.h>
#include <UnigineObjects.h>
#include <UnigineEditor.h>
#include <UnigineGame.h>
#include <UnigineLights.h>
#include <UnigineMaterials.h>
#include <UnigineApp.h>
#include <UnigineConsole.h>
#include <UnigineUserInterface.h>

// auxiliary constants
const float DELTA_ANGLE = 60.0f;		// delta angle of objects rotation
const float MOVING_SPEED = 3.0f;		// speed of objects movement
const float CHANGE_INTERVAL = 1.0f;		// the interval between changes of objects' parameters, in seconds
const float SUN_ROTATION_RATE = 10.0f;	// rotation rate of the sun

class AppWorldLogic : public Unigine::WorldLogic {
	
public:
	AppWorldLogic();
	virtual ~AppWorldLogic();
	
	virtual int init();
	
	virtual int update();
	virtual int render();
	virtual int flush();
	
	virtual int shutdown();
	virtual int destroy();
	
	virtual int save(const Unigine::StreamPtr &stream);
	virtual int restore(const Unigine::StreamPtr &stream);
	
	// GUI event handlers
	int onButtonDelClicked();
	int onButtonCloseClicked();
	int onButtonFopenClicked();
	int onButtonWloadClicked();
	int onDlgCancelClicked();
	int onDlgOKClicked();
	int onMeshParamsOKClicked();
	int onSliderChanged();

private:
	Unigine::Editor *editor;
	Unigine::App *app;
	Unigine::Materials *materials;
	Unigine::Properties *properties;
	Unigine::PlayerSpectatorPtr player;

	// pointers to the GUI elements
	Unigine::GuiPtr gui;
	Unigine::UserInterfacePtr ui;
	Unigine::WidgetLabelPtr widget_label;
	Unigine::WidgetSliderPtr widget_slider;
	Unigine::WidgetCheckBoxPtr widget_checkbox;
	Unigine::WidgetButtonPtr widget_button_del;
	Unigine::WidgetButtonPtr widget_button_close;
	Unigine::WidgetButtonPtr widget_button_fopen;
	Unigine::WidgetButtonPtr widget_button_wload;
	Unigine::WidgetComboBoxPtr widget_combo;
	Unigine::WidgetDialogFilePtr widget_file_dialog;
	Unigine::WidgetPtr mesh_parameters_window;


	// pointers to light sources
	Unigine::LightWorldPtr thesun;
	Unigine::LightOmniPtr light_omni;
	Unigine::LightProjPtr projector;

	// auxiliary functions
	int addMeshToScene(const char *file_name, const char *mesh_name, const char *material_name, Unigine::Math::Vec3 position);
	int removeMeshFromScene(const char *node_name);
	int transformNode(Unigine::NodePtr node, float ifps);

	// initialization functions
	int initObjects();
	int initPlayer();
	int initLights();
	int initMaterials();
	int initProperties();
	int initGUI();

	// update functions
	int updateLights();
	int updateObjects();

	// shutdown functions
	int clearMaterials();
	int removeObjects();

	// scene objects vector
	Unigine::Vector <Unigine::ObjectMeshDynamicPtr> Objects;
	
	Unigine::ObjectPtr old_selection;												// pointer to previously selected object
	Unigine::Math::vec3 current_objects_scale = Unigine::Math::vec3(1.0f);			// current scaling vector for objects
	Unigine::Math::Vec3 forward_direction = Unigine::Math::Vec3(0.0f, -1.0f, 0.0f);	// current forward direction vector for objects
	float elapsed_time = CHANGE_INTERVAL;											// current time left to change current scale and forward direction of our objects
	float sun_angle = 0.0f;															// current sun position
};

#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.
using namespace Unigine;
// auxiliary variable to store the time of rendering the last frame
float ifps;

//-----------------------------------------------------------------------------------------------------------------------------
//------------------------------------------------------- GUI EVENT HANDLERS --------------------------------------------------
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the Close button is clicked in the main window
int AppWorldLogic::onButtonCloseClicked()
{
	// removing generated materials and properties
	clearMaterials();

	// saving current world to my_world.world file
	Console::get()->run("world_save my_world");

	// executing all pending console commands before exiting
	Console::get()->flush();

	// closing the application
	App::get()->exit();

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the Load world button is clicked in the main window
int AppWorldLogic::onButtonWloadClicked()
{
	// reporting to console
	Log::warning("\n\n --- RELOADING A DEFAULT WORLD --- \n\n");

	// loading a world from default.world file
	Console::get()->run("world_load default");

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the Cancel button is clicked in the main window
int AppWorldLogic::onButtonFopenClicked()
{
	widget_file_dialog->setHidden(0);

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the slider position is changed in the main window
int AppWorldLogic::onSliderChanged()
{
	// updating the position of the Sun
	sun_angle = widget_slider->getValue();

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the Delete button is clicked in the main window
int AppWorldLogic::onButtonDelClicked()
{
	String node_name;

	if (widget_combo->getCurrentItem() == 0)									// deleting all objects 
	{
		removeObjects();

		// disabling Delete button in the main window
		widget_button_del->setEnabled(0);
	}
	else																		// deleting an object selected in the combo box
	{
		// retrieving currently selected node name in the combo box
		node_name = widget_combo->getCurrentItemText();

		// checking if a node with a given name exists and removing it from the scene
		if (editor->findNode(node_name.get()) != -1)
		{
			removeMeshFromScene(node_name.get());
		}
	}

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the Cancel button is clicked in the File Open dialog
int AppWorldLogic::onDlgCancelClicked()
{
	// hiding the file selecton dialog
	widget_file_dialog->setHidden(1);

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the OK button is clicked in the File Open dialog
int AppWorldLogic::onDlgOKClicked()
{
	// checking if the file exists
	if (FILE *file = fopen(widget_file_dialog->getFile(), "r")) {
		fclose(file);

		//setting initial values of the fields in the Mesh Parameters window
		String object_name = String::format("Object_%d", widget_combo->getNumItems() - 1);
		WidgetEditLine::cast(ui->getWidget(ui->findWidget("object_name")))->setText(object_name.get());
		WidgetEditLine::cast(ui->getWidget(ui->findWidget("coord_x")))->setText("0.0");
		WidgetEditLine::cast(ui->getWidget(ui->findWidget("coord_y")))->setText("0.0");
		WidgetEditLine::cast(ui->getWidget(ui->findWidget("coord_z")))->setText("0.0");

		// hiding the File Open dialog and showing Mesh Parameters window using different ways
		widget_file_dialog->setHidden(1);
		mesh_parameters_window->setHidden(0);

		return 1;
	}

	// reporting an error to the console
	Log::error("Loading mesh: can't open \"%s\" file\n", widget_file_dialog->getFile());
	return 0;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method to be called when the OK button is clicked in the Mesh Parameters window
int AppWorldLogic::onMeshParamsOKClicked()
{
	//retrieving pointers to UI elements
	WidgetEditLinePtr name = WidgetEditLine::cast(ui->getWidget(ui->findWidget("object_name")));
	WidgetEditLinePtr x = WidgetEditLine::cast(ui->getWidget(ui->findWidget("coord_x")));
	WidgetEditLinePtr y = WidgetEditLine::cast(ui->getWidget(ui->findWidget("coord_y")));
	WidgetEditLinePtr z = WidgetEditLine::cast(ui->getWidget(ui->findWidget("coord_z")));

	if ((x->getText() != "") && (y->getText() != "") && (z->getText() != "") && (name->getText() != ""))
	{

		Math::Vec3 pos = Math::Vec3(atof(x->getText()), atof(y->getText()), atof(z->getText()));
		String result = String((addMeshToScene(widget_file_dialog->getFile(), name->getText(), "my_mesh_base3", pos)) ? "Ok!" : "Error!");

		// reporting progress to the console
		Log::message("(%s) mesh load operation status: %s\n", name->getText(), result.get());

		// hiding the Mesh Parameters window
		mesh_parameters_window->setHidden(1);

		return 1;
	}
	Log::error("Wrong mesh parameters!\n");
	return 0;
}
//-----------------------------------------------------------------------------------------------------------------------------
//---------------------------------------------- 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;
	String new_property_name = String::format("%s_property", mesh_name);

	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);

	//inheriting a new property from "surface_base_1"
	properties->inheritProperty("surface_base_1", "my_property_lib.prop", new_property_name.get());

	// assigning the new property to the node and setting values of its parameters
	omd->setProperty(new_property_name.get(), "*");
	omd->getProperty(0)->setParameterString(omd->getProperty(0)->findParameter("material"), material_name);
	omd->getProperty(0)->setParameterInt(omd->getProperty(0)->findParameter("selected"), 0);

	// enabling intersection detection for the first surface (0)
	omd->setIntersection(1, 0);

	// passing node ownership to the editor as a runtime node
	omd->release();
	editor->addNode(omd->getNode());

	// updating combo list and the list of scene objects
	widget_combo->addItem(omd->getName());
	Objects.append(omd);

	// enabling Delete button in the main window
	widget_button_del->setEnabled(1);

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

	// clearing the mesh
	mesh->clear();

	return 1;

}
//-----------------------------------------------------------------------------------------------------------------------------
/// method deleting a Dynamic Mesh Object with a given name from the scene
int AppWorldLogic::removeMeshFromScene(const char *node_name)
{
	// getting a pointer to the node with a given name and downcasting it to ObjectMeshDynamicPtr
	ObjectMeshDynamicPtr object = ObjectMeshDynamic::cast(editor->getNodeByName(node_name));

	if (object)
	{
		if (old_selection)
		{
			// checking if the node to be removed was previously selected
			if (object->getNode() == old_selection->getNode())
			{
				// resetting old_selection pointer to NULL
				old_selection.clear();
			}
		}

		// reporting node deletion to the console
		Log::message("Removing %s node named %s from the scene.\n", object->getTypeName(), node_name);

		// removing the node with a given name from the list of scene objects
		for (int i = 0; i < Objects.size(); i++)
		{
			if (strcmp(Objects[i]->getName(), node_name) == 0) {
				Objects.remove(i);
				widget_combo->removeItem(i + 1);

				break;
			}
		}

		// removing the node from the scene using upcasting
		editor->removeNode(object->getNode());

		return 1;
	}

	return 0;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method performing node transformations 
int AppWorldLogic::transformNode(NodePtr node, float ifps)
{
	// getting current node transformation matrix
	Math::Mat4 transform = node->getTransform();

	// calculating delta rotation around an arbitrary axis
	Math::quat delta_rotation = Math::quat(rand() % 2, rand() % 2, rand() % 2, DELTA_ANGLE * ifps);

	// setting node's scale, rotation and position
	node->setWorldScale(current_objects_scale);
	node->setWorldRotation(node->getWorldRotation() * delta_rotation);
	node->setWorldPosition(node->getWorldPosition() + forward_direction * MOVING_SPEED *ifps);

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// function getting an object under the mouse cursor
ObjectPtr getObjectUnderMouseCursor(const PlayerPtr &player, int mouse_x, int mouse_y, float max_dist)
{
	// setting start point (p0) at the center of player's screen
	Math::Vec3 p0 = player->getWorldPosition();

	// setting end point (p1) according to the position of the mouse cursor
	Math::Vec3 p1 = p0 + Math::Vec3(player->getDirectionFromScreen(mouse_x, mouse_y)) * max_dist;

	WorldIntersectionPtr intersection = WorldIntersection::create();

	// returning the pointer to the first intersected object if any or NULL
	return World::get()->getIntersection(p0, p1, 1, intersection);
}
//-----------------------------------------------------------------------------------------------------------------------------
/// function setting new object as selected and updating previous selection
int selectObject(ObjectPtr new_selected_object, ObjectPtr &old_selected_object)
{
	// checking if new selected object is not NULL and it has a property with parameter "selected" assigned
	if (new_selected_object)
	{
		if (new_selected_object->getProperty(0)->findParameter("selected") != -1)
		{
			// checking if we already have a previously selected object and setting its "selected" parameter of the property to 0
			if (old_selected_object)
			{
				old_selected_object->getProperty(0)->setParameterInt(old_selected_object->getProperty(0)->findParameter("selected"), 0);
			}

			// setting the "selected" parameter of the property to 1 for the new selected object 
			new_selected_object->getProperty(0)->setParameterInt(new_selected_object->getProperty(0)->findParameter("selected"), 1);

			// remembering the object as selected
			old_selected_object = new_selected_object;

			return 1;
		}
	}

	return 0;
}

//-----------------------------------------------------------------------------------------------------------------------------
//---------------------------------------------- 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).get(), String::format("my_mesh_base%d", index).get(), Math::Vec3(x, y, 1.0f));
			index++;
		}
	}

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

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method performing initialization of the player
int AppWorldLogic::initPlayer()
{
	// creating a new PlayerSpectator instance
	player = PlayerSpectator::create();

	// setting player's FOV, ZNear, ZFar
	player->setFov(90.0f);
	player->setZNear(0.1f);
	player->setZFar(10000.0f);

	// setting player's view direction vector and position
	player->setPosition(Math::Vec3(3.0f));
	player->setDirection(Math::vec3(-1.0f), Math::vec3(0.0f, 0.0f, -1.0f));

	// setting the player to the Game singleton instance
	Game::get()->setPlayer(player->getPlayer());
	player->release();

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

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method performing initialization of lights
int AppWorldLogic::initLights()
{
	// creating an omni light and setting up its parameters
	light_omni = LightOmni::create(Math::vec4(1.0f, 1.0f, 1.0f, 1.0f), 10.0f, "");
	light_omni->setWorldPosition(Math::Vec3(0.0f, 0.0f, 5.0f));
	light_omni->setIntensity(0.1f);

	// passing node ownership to the editor
	light_omni->release();
	editor->addNode(light_omni->getNode());

	// reporting progress to the console
	Log::message("-> Created a %s light source.\n", light_omni->getName());

	// creating a world light and setting up its parameters
	thesun = LightWorld::create(Math::vec4(1.0f, 1.0f, 1.0f, 1.0f));
	thesun->setName("Sun");
	thesun->setDisableAngle(90.0f);
	thesun->setIntensity(1.0f);
	thesun->setScattering(LightWorld::SCATTERING_SUN);
	thesun->setWorldRotation(Math::quat(0.0f, 1.0f, 0.0f, 170.0f));

	// passing node ownership to the editor
	thesun->release();
	editor->addNode(thesun->getNode());

	// reporting progress to the console
	Log::message("-> Created a %s light source.\n", thesun->getName());

	// creating a proj light and setting up its parameters
	projector = LightProj::create(Math::vec4(1.0f, 1.0f, 0.5f, 1.0f), 10.0f, 60.0f, "");
	projector->setWorldPosition(Math::Vec3(2.5f, 2.5f, 3.0f));
	projector->setName("projector");
	projector->setRotation(Math::quat(-45.0f, 45.0f, 0.0f));
	projector->setPenumbra(0.425f);
	projector->setIntensity(1.0f);

	// passing node ownership to the editor
	projector->release();
	editor->addNode(projector->getNode());

	// reporting progress to the console
	Log::message("-> Created a %s light source.\n", projector->getName());
	Log::warning("Lights initialization OK!\n");

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method performing initialization of materials
int AppWorldLogic::initMaterials()
{
	// getting a pointer to materials interface
	materials = Materials::get();

	// creating a new child material of the mesh_base and setting its color
	MaterialPtr mesh_base = materials->findMaterial("mesh_base");
	MaterialPtr my_mesh_base = mesh_base->inherit("my_mesh_base0");
	my_mesh_base->setParameter(Material::PARAMETER_COLOR, Math::vec4(255, 0, 0, 255));

	// reporting progress to the console
	Log::message("\n-> Generated %s material.\n", my_mesh_base->getName());

	// creating a new child material of the mesh_base and setting its color
	my_mesh_base = mesh_base->inherit("my_mesh_base1");
	my_mesh_base->setParameter(Material::PARAMETER_COLOR, Math::vec4(0, 255, 0, 255));

	// reporting progress to the console
	Log::message("-> Generated %s material.\n", my_mesh_base->getName());

	//creating a new child material of the mesh_base and setting its color
	my_mesh_base = mesh_base->inherit("my_mesh_base2");
	my_mesh_base->setParameter(Material::PARAMETER_COLOR, Math::vec4(0, 0, 255, 255));

	// reporting progress to the console
	Log::message("-> Generated %s material.\n", my_mesh_base->getName());

	//creating a new child material of the mesh_base and setting its color
	my_mesh_base = mesh_base->inherit("my_mesh_base3");
	my_mesh_base->setParameter(Material::PARAMETER_COLOR, Math::vec4(255, 255, 0, 255));

	// reporting progress to the console
	Log::message("-> Generated %s material.\n", my_mesh_base->getName());
	Log::warning("Material generation OK!\n\n");

	// clearing material pointer
	my_mesh_base.clear();

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method performing initialization of properties
int AppWorldLogic::initProperties()
{
	// getting a pointer to the property manager
	properties = Properties::get();

	return 1;
}
/// method performing initialization of the GUI
int AppWorldLogic::initGUI()
{
	// getting a GUI pointer
	gui = Gui::get();

	// creating a label widget and setting up its parameters
	widget_label = WidgetLabel::create(gui, "Sun position:");
	widget_label->setToolTip("Change sun position");
	widget_label->setPosition(10, 10);

	// creating a slider widget and setting up its parameters
	widget_slider = WidgetSlider::create(gui, 0, 360, 90);
	widget_slider->setToolTip("Change sun position");
	widget_slider->setPosition(100, 10);
	widget_slider->setCallback0(Gui::CHANGED, MakeCallback(this, &AppWorldLogic::onSliderChanged));

	// creating a checkbox widget and setting up its parameters
	widget_checkbox = WidgetCheckBox::create(gui, "Automatic change");
	widget_checkbox->setToolTip("Change sun position automatically");
	widget_checkbox->setPosition(10, 30);
	widget_checkbox->setChecked(1);

	// creating a button widget and setting up its parameters
	widget_button_del = WidgetButton::create(gui, "Delete");
	widget_button_del->setToolTip("Delete object(s) selected in the combo box");
	widget_button_del->setPosition(170, 50);
	widget_button_del->setCallback0(Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onButtonDelClicked));

	// creating a button widget and setting up its parameters
	widget_button_fopen = WidgetButton::create(gui, "Load mesh");
	widget_button_fopen->setToolTip("Load a mesh file");
	widget_button_fopen->setPosition(10, 80);
	widget_button_fopen->setCallback0(Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onButtonFopenClicked));

	// creating a button widget and setting up its parameters
	widget_button_close = WidgetButton::create(gui, "Quit");
	widget_button_close->setToolTip("Close application");
	widget_button_close->setPosition(10, 110);
	widget_button_close->setCallback0(Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onButtonCloseClicked));

	// creating a button widget and setting up its parameters
	widget_button_wload = WidgetButton::create(gui, "Load world");
	widget_button_wload->setToolTip("Load a default world");
	widget_button_wload->setPosition(110, 110);
	widget_button_wload->setCallback0(Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onButtonWloadClicked));

	// creating a combo box widget and setting up its parameters
	widget_combo = WidgetComboBox::create(gui);
	widget_combo->addItem("----ALL-----");
	widget_combo->setPosition(10, 50);

	// creating a File Selection dialog widget and setting up its parameters
	widget_file_dialog = WidgetDialogFile::create(gui, "Select a mesh file");
	widget_file_dialog->setPath("../");
	widget_file_dialog->setHidden(1);
	widget_file_dialog->setFilter(".mesh");
	widget_file_dialog->getCancelButton()->setCallback0(Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onDlgCancelClicked));
	widget_file_dialog->getOkButton()->setCallback0(Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onDlgOKClicked));

	// creating a Mesh Parameters dialog from an external ui-file
	ui = UserInterface::create(gui, "user_interface.ui");
	ui->setCallback0("button_OK", Gui::CLICKED, MakeCallback(this, &AppWorldLogic::onMeshParamsOKClicked));
	mesh_parameters_window = ui->getWidget(ui->findWidget("window"));
	mesh_parameters_window->setHidden(1);

	// adding created widgets to the UI
	gui->addChild(widget_label->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);							// ID: 0 - label
	gui->addChild(widget_slider->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);							// ID: 1 - slider
	gui->addChild(widget_checkbox->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);							// ID: 2 - checkbox
	gui->addChild(widget_button_del->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);						// ID: 3 - delete button
	gui->addChild(widget_button_close->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);						// ID: 4 - close button
	gui->addChild(widget_combo->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);							// ID: 5 - combo box
	gui->addChild(widget_button_fopen->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);						// ID: 6 - Load Mesh button
	gui->addChild(widget_button_wload->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED);						// ID: 7 - Load world button
	gui->addChild(mesh_parameters_window, Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED | Gui::ALIGN_CENTER);			// ID: 8 - Mesh Parameters window
	gui->addChild(widget_file_dialog->getWidget(), Gui::ALIGN_OVERLAP | Gui::ALIGN_FIXED | Gui::ALIGN_CENTER);	// ID: 9 - File Open dialog

	//reporting progress to the console
	for (int k = 0; k < gui->getNumChildren(); k++)
	{
		Log::message("-> Adding UI element %d: %s.\n", k, gui->getChild(k)->getTypeName());
	}
	Log::warning("UI initialized! Number of elements: %d.\n", gui->getNumChildren());

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
//---------------------------------------------------- UPDATE METHODS ---------------------------------------------------------
//-----------------------------------------------------------------------------------------------------------------------------
/// method updating the position of the sun
int AppWorldLogic::updateLights()
{
	// updating the Sun rotation angle
	if (widget_checkbox->isChecked()){
		sun_angle += SUN_ROTATION_RATE * ifps;
		if (sun_angle > 360.0f) sun_angle = 0.0f;
		
		// updating slider position
		widget_slider->setValue(sun_angle);
	}
	// changing the Sun position using the new angle
	LightWorld::cast(editor->getNodeByName("Sun"))->setWorldRotation(Math::quat(Math::vec3(0.0f, 1.0f, 0.0f), 180.0f - sun_angle));

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method updating the initial set of scene objects
int AppWorldLogic::updateObjects()
{
	ObjectMeshDynamicPtr object;

	// changing transformation for all scene objects named "my_meshdynamic_*" (initial set)
	for (auto it = Objects.begin(); it != Objects.end(); it++)
	{
		object = it.get();

		// getting the property assigned to the first surface of the object 
		PropertyPtr p = object->getProperty(0);

		// checking if such property exists and has a "selected" parameter
		if (p)
		{
			int param = p->findParameter("selected");
			if (param != -1)
				if (p->getParameterInt(param) == 1)
				{
					// if "selected" parameter value is 1 assigning "mesh_base" material to the object to highlight it
					object->setMaterial("mesh_base", "*");
				}
				else
				{
					// if "selected" parameter value is 0 assigning the material that is stored in the "material" parameter of its property
					object->setMaterial(p->getParameterString(p->findParameter("material")), "*");
				}
		}

		// if a node is named "my_meshdynamic_*" (it belongs to the initial set) change its transformation
		if (strstr(object->getName(), "my_meshdynamic_"))
		{
			// transform the node
			transformNode(object->getNode(), ifps);
		}
	}

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
//---------------------------------------------------- SHUTDOWN METHODS -------------------------------------------------------
//-----------------------------------------------------------------------------------------------------------------------------
/// method removing all created materials
int AppWorldLogic::clearMaterials()
{
	materials->removeMaterial(materials->findMaterial("my_mesh_base0")->getGUID());
	materials->removeMaterial(materials->findMaterial("my_mesh_base1")->getGUID());
	materials->removeMaterial(materials->findMaterial("my_mesh_base2")->getGUID());
	materials->removeMaterial(materials->findMaterial("my_mesh_base3")->getGUID());

	return 1;
}
//-----------------------------------------------------------------------------------------------------------------------------
/// method removing all created objects
int AppWorldLogic::removeObjects()
{
	while (Objects.size() > 0)
	{
		removeMeshFromScene(Objects.begin()->get()->getName());
	}

	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.

	// getting a pointer to the application
	app = App::get();

	// initializing pseudo-random number generator
	Game::get()->setSeed(time(NULL));

	// getting a pointer to the Editor
	editor = Editor::get();

	// creating materials
	initMaterials();

	// creating properties
	initProperties();

	// creating GUI
	initGUI();
	
	// creating objects
	initObjects();

	// creating a player
	initPlayer();

	// creating lights
	initLights();

	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.

	// getting an inverse FPS value (the time in seconds it took to complete the last frame)
	ifps = Game::get()->getIFps();

	// checking if it's time to change current scale and forward vector direction of our objects
	if (elapsed_time < 0.0f)
	{
		// change current scaling vector for objects
		current_objects_scale = Math::vec3(Game::get()->getRandomFloat(0.8f, 1.2f));

		// change forward direction for objects
		forward_direction = forward_direction * Math::rotateZ(60.0f);

		// resetting elapsed time counter
		elapsed_time = CHANGE_INTERVAL;
	}

	// decreasing the time counter to the next change of current scale and forward vector direction
	elapsed_time -= ifps;

	// if right mouse button is clicked
	if (app->getMouseButtonState(App::BUTTON_RIGHT))
	{
		// get and select object under the mouse cursor
		selectObject(getObjectUnderMouseCursor(Game::get()->getPlayer(), app->getMouseX(), app->getMouseY(), 100.0f), old_selection);
	}

	// closing the application if a 'Q' key is pressed, ignoring the key if the console is opened
	if (app->getKeyState('q') && !Console::get()->getActivity())
	{
		app->exit();
	}

	// updating objects
	updateObjects();

	// updating lights
	updateLights();

	return 1;
}


int AppWorldLogic::render() {
	// 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::flush() {
	// Write here code to be called before updating each physics frame: control physics in your application and put non-rendering calculations.
	// The engine calls flush() 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() {
	// Write here code to be called on world shutdown: delete resources that were created during world script execution to avoid memory leaks.

	// deleting all created nodes
	removeObjects();

	// clearing the player pointer
	player.clear();

	// clearing light sources
	thesun.clear();
	light_omni.clear();
	projector.clear();

	// clearing all created materials
	clearMaterials();

	// clearing gui elements
	gui.clear(); 

	// resetting old_selection pointer
	old_selection.clear();

	return 1;
}

int AppWorldLogic::destroy() {
	// 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 Unigine::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 Unigine::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;
}