Irrlicht Engine Tutorial

As always, we include the header files (conio and curses for getting + user input from the console), and use the irrlicht namespaces. We also + store a pointer to the Irrlicht device, a counter variable for changing + the creation position of a window, and a pointer to a listbox.

+ + + + +

#include <irrlicht.h>
+#include <iostream>

+using namespace irr;

using namespace core;
+using namespace scene;
+using namespace video;
+using namespace io;
+using namespace gui;

#pragma comment(lib, "Irrlicht.lib")

IrrlichtDevice *device = 0;
+s32 cnt = 0;
+IGUIListBox* listbox = 0;
+

The Event Receiver is not only capable of getting keyboard and mouse + input events, but also events of the graphical user interface (gui). + There are events for almost everything: Button click, Listbox selection + change, events that say that a element was hovered and so on. To be + able to react to some of these events, we create
+ an event receiver. We only react to gui events, and if it's such an + event, we get the id of the caller (the gui element which caused the + event) and get the pointer to the gui environment.

+ + + + +

class MyEventReceiver : public IEventReceiver
{
public:
	virtual bool OnEvent(const SEvent& event)
	{
		if (event.EventType == EET_GUI_EVENT)
		{
			s32 id = event.GUIEvent.Caller->getID();
			IGUIEnvironment* env = device->getGUIEnvironment();

            switch(event.GUIEvent.EventType)
+            {

If a scrollbar changed its scroll position, and it is 'our' scrollbar + (the one with id 104), then we change the
+ transparency of all gui elements. This is a very easy task: There is + a skin object, in which all color settings are stored. We simply go + through all colors stored in the skin and change their alpha value. +

+ + + + +

case EGET_SCROLL_BAR_CHANGED:
	if (id == 104)
	{
		s32 pos = ((IGUIScrollBar*)event.GUIEvent.Caller)->getPos();
					
		for (s32 i=0; i<EGDC_COUNT ; ++i)
		{
			SColor col = env->getSkin()->getColor((EGUI_DEFAULT_COLOR)i);
			col.setAlpha(pos);
			env->getSkin()->setColor((EGUI_DEFAULT_COLOR)i, col);
		}
	}
break;

If a button was clicked, it could be one of 'our' three buttons. If + it is the first, we shut down the engine.
+ If it is the second, we create a little window with some text on it. + We also add a string to the list box to log
+ what happened. And if it is the third button, we create a file open + dialog, and add also this as string to the list box.
+ That's all for the event receiver.

+ + + + +

       case EGET_BUTTON_CLICKED:
+              if (id == 101)
+              {
+                 device->closeDevice();
+                 return true;
+              }

              if (id == 102)
+              {
+                 listbox->addItem(L"Window created");
+                 cnt += 30;
+                 if (cnt > 200) 
+                   cnt = 0;

                 IGUIWindow* window = env->addWindow(
+                       rect<s32>(100 + cnt, 100 + cnt, 300 + cnt, 200 + cnt), 
                       false, // modal?
+                       L"Test window");

                 env->addStaticText(L"Please close me", 
+                       rect<s32>(35,35,140,50),
+                       true, // border?,
+                       false, // wordwrap?
+                       window);
+
+                 return true;
+              }

              if (id == 103)
+              {
+                 listbox->addItem(L"File open");
+                 env->addFileOpenDialog(L"Please choose a file.");
+                 return true;
+              }

              break;
+          }
+       }
+       return false;
+    }
+ };

Ok, now for the more interesting part. First, create the Irrlicht device. + As in some examples before, we ask the user which driver he wants to + use for this example:

int main() +{ + // ask user for driver + video::E_DRIVER_TYPE driverType; + + + printf("Please select the driver you want for this example:\n"\
" (a) Direct3D 9.0c\n (b) Direct3D 8.1\n (c) OpenGL 1.5\n"\
" (d) Software Renderer\n (e) Apfelbaum Software Renderer\n"\
" (f) NullDevice\n (otherKey) exit\n\n");

char i;
std::cin >> i;
+ switch(i)
{
case 'a': driverType = video::EDT_DIRECT3D9;break;
case 'b': driverType = video::EDT_DIRECT3D8;break;
case 'c': driverType = video::EDT_OPENGL; break;
case 'd': driverType = video::EDT_SOFTWARE; break;
case 'e': driverType = video::EDT_BURNINGSVIDEO;break;
case 'f': driverType = video::EDT_NULL; break;
default: return 1;
} + + // create device and exit if creation failed + device = createDevice(driverType, core::dimension2d<s32>(640, 480));
+ if (device == 0) + return 1; +

The creation was successful, now we set the event receiver and store + pointers to the driver and to the gui environment.

We add three buttons. The first one closes the engine. The second creates + a window and the third opens a file open dialog. The third parameter is + the id of the button, with which we can easily identify the button in + the event receiver.

Now, we add a static text and a scrollbar, which modifies the transparency + of all gui elements. We set the maximum value of the scrollbar to 255, + because that's the maximal value for a color value.
+ Then we create an other static text and a list box.

env->addStaticText(L"Transparent Control:", rect<s32>(150,20,350,40), true);
IGUIScrollBar* scrollbar = env->addScrollBar(true, + rect<s32>(150, 45, 350, 60), 0, 104);
scrollbar->setMax(255);

while(device->run() && driver)
if (device->isWindowActive())
{
driver->beginScene(true, true, SColor(0,122,65,171)); + env->drawAll(); + driver->endScene(); + } + + device->drop();

	+ + + Tutorial 5.User Interface + +
+ + This tutorial shows how to use the built in User Interface of the Irrlicht + Engine. It will give a brief overview and show how to create and use + windows, buttons, scroll bars, static texts and list boxes. + The program which is described here will look like this: + + + +