Using Manipulators to Transform Objects

#ifndef __APP_SYSTEM_LOGIC_H__
#define __APP_SYSTEM_LOGIC_H__

#include <UnigineLogic.h>
#include <UnigineWidgets.h>
#include <UniginePlayers.h>

class AppSystemLogic : public Unigine::SystemLogic
{
public:
	AppSystemLogic();
	virtual ~AppSystemLogic();

	int init() override;

	int update() override;
	int postUpdate() override;

	int shutdown() override;

	// define auxiliary methods used for the project
	void ApplyTransform();
	Unigine::ObjectPtr GetNodeUnderCursor();
	void SwitchManipulator(Unigine::WidgetManipulatorPtr CurrentManipulator);

private:
	// define a pointer to access object parameters
	Unigine::ObjectPtr obj;

	// define a pointer to access UI
	Unigine::GuiPtr gui;

	// define a pointer to store transformation matrix of an active widget
	Unigine::WidgetManipulatorPtr CurrentObjectManipulator;

	// define pointers to display transformation matrix for each type of transform
	Unigine::WidgetManipulatorTranslatorPtr ManObjTranslator;
	Unigine::WidgetManipulatorRotatorPtr ManObjRotator;
	Unigine::WidgetManipulatorScalerPtr ManObjScaler;
};

#endif // __APP_SYSTEM_LOGIC_H__

#include "AppSystemLogic.h"
#include <UnigineWidgets.h>
#include <UnigineGame.h>
#include <UnigineWorld.h>
#include <UniginePlayers.h>
#include <UnigineMathLib.h>

using namespace Unigine;

// System logic, it exists during the application life cycle.
// These methods are called right after corresponding system script's (UnigineScript) methods.
// method used to apply transformation according to users actions
void AppSystemLogic::ApplyTransform()
{
	if (obj && Input::isMouseButtonPressed(Input::MOUSE_BUTTON::MOUSE_BUTTON_LEFT))
		obj->setWorldTransform(CurrentObjectManipulator->getTransform());
}
// method used to find an object
ObjectPtr AppSystemLogic::GetNodeUnderCursor()
{
	auto player = Game::getPlayer();
	WorldIntersectionPtr intersection;
	
	// take into account main window position to obtain correct direction
	EngineWindowPtr main_window = WindowManager::getMainWindow();
	
	if (!main_window)
		return nullptr;

	// find mouse position on the screen
	Math::ivec2 mouse = Input::getMousePosition();
	Math::ivec2 main_pos = main_window->getPosition();
	mouse.x -= main_pos.x;
	mouse.y -= main_pos.y;
	
	const Math::ivec2 window_size = main_window->getClientSize();

	Math::Vec3 p0;
	Math::Vec3 p1;
	player->getDirectionFromScreen(p0, p1, mouse.x, mouse.y, 0, 0, window_size.x, window_size.y);
	
	// return an object intersected by the ray cast from the cursor position in the direction of the camera 
	return World::getIntersection(p0, p1, 1, intersection);
}
// method used to switch manipulators
void AppSystemLogic::SwitchManipulator(WidgetManipulatorPtr CurrentManipulator)
{
	// move to selected object and display chosen manipulator
	CurrentManipulator->setTransform(obj->getWorldTransform());
	CurrentManipulator->setHidden(false);

	// hide other widget manipulators
	CurrentObjectManipulator = CurrentManipulator;
	if (ManObjTranslator != CurrentObjectManipulator)
		ManObjTranslator->setHidden(true);
	if (ManObjRotator != CurrentObjectManipulator)
		ManObjRotator->setHidden(true);
	if (ManObjScaler != CurrentObjectManipulator)
		ManObjScaler->setHidden(true);
}

AppSystemLogic::AppSystemLogic()
{
}

AppSystemLogic::~AppSystemLogic()
{
}

int AppSystemLogic::init()
{
	// create widget manipulators
	gui = Gui::getCurrent();
	ManObjTranslator = WidgetManipulatorTranslator::create(gui);
	ManObjRotator = WidgetManipulatorRotator::create(gui);
	ManObjScaler = WidgetManipulatorScaler::create(gui);

	// add widgets to the UI
	gui->addChild(ManObjTranslator);
	gui->addChild(ManObjRotator);
	gui->addChild(ManObjScaler);

	// hide manipulators, so that they wouldn't appear after application initialization
	ManObjTranslator->setHidden(true);
	ManObjRotator->setHidden(true);
	ManObjScaler->setHidden(true);
	CurrentObjectManipulator = ManObjTranslator;
	// subscribe each widget manipulator for the Changed event
	ManObjTranslator->getEventChanged().connect(this, &AppSystemLogic::ApplyTransform);
	ManObjRotator->getEventChanged().connect(this, &AppSystemLogic::ApplyTransform);
	ManObjScaler->getEventChanged().connect(this, &AppSystemLogic::ApplyTransform);

	return 1;
}

////////////////////////////////////////////////////////////////////////////////
// start of the main loop
////////////////////////////////////////////////////////////////////////////////

int AppSystemLogic::update()
{
	// set projection and viewmodel for the each widget every frame 
	auto player = Game::getPlayer();
	if (player)
	{
		ManObjTranslator->setProjection(player->getProjection());
		ManObjRotator->setProjection(player->getProjection());
		ManObjScaler->setProjection(player->getProjection());
		ManObjTranslator->setModelview(player->getCamera()->getModelview());
		ManObjRotator->setModelview(player->getCamera()->getModelview());
		ManObjScaler->setModelview(player->getCamera()->getModelview());
	}

	// find object with a right-click
	if (Input::isMouseButtonDown(Input::MOUSE_BUTTON::MOUSE_BUTTON_RIGHT))
	{
		obj = GetNodeUnderCursor();
		CurrentObjectManipulator->setTransform(obj->getWorldTransform());
	}
	// switch widgets on command with Z,X,C keys
	if (obj)
	{
		if (!Input::isMouseButtonPressed(Input::MOUSE_BUTTON::MOUSE_BUTTON_LEFT))
			CurrentObjectManipulator->setTransform(obj->getWorldTransform());
		if (Input::isKeyDown(Input::KEY::KEY_Z))
			SwitchManipulator(ManObjTranslator);
		if (Input::isKeyDown(Input::KEY::KEY_X))
			SwitchManipulator(ManObjRotator);
		if (Input::isKeyDown(Input::KEY::KEY_C))
			SwitchManipulator(ManObjScaler);
	}

	return 1;
}

int AppSystemLogic::postUpdate()
{
	// Write here code to be called after updating each render frame.
	return 1;
}

////////////////////////////////////////////////////////////////////////////////
// end of the main loop
////////////////////////////////////////////////////////////////////////////////

int AppSystemLogic::shutdown()
{
	// Write here code to be called on engine shutdown.
	return 1;
}