# Tutorial 9: Mesh Viewer

Tutorial 9: Mesh Viewer

This tutorial show how to create a more complex application with the engine. We construct a simple mesh viewer using the user interface API and the scene management of Irrlicht. The tutorial show how to create and use Buttons, Windows, Toolbars, Menus, ComboBoxes, Tabcontrols, Editboxes, Images, MessageBoxes, SkyBoxes, and how to parse XML files with the integrated XML reader of the engine.

We start like in most other tutorials: Include all necessary header files, add a comment to let the engine be linked with the correct .lib file in Visual Studio, and declare some global variables. We also add two 'using namespace' statements, so we do not need to write the whole names of all classes. In this tutorial, we use a lot of stuff from the gui namespace.

#include <irrlicht.h>
#include "driverChoice.h"
#include "exampleHelper.h"
using namespace irr;
using namespace gui;
#ifdef _MSC_VER
#pragma comment(lib, "Irrlicht.lib")
#endif

Some global variables used later on

IrrlichtDevice *Device = 0;
io::path StartUpModelFile;
core::stringw MessageText;
core::stringw Caption;
scene::ISceneNode* Model = 0;
scene::ISceneNode* SkyBox = 0;
bool Octree=false;
bool UseLight=false;
scene::ICameraSceneNode* Camera[2] = {0, 0};
// Values used to identify individual GUI elements
enum
{
GUI_ID_DIALOG_ROOT_WINDOW = 0x10000,
GUI_ID_X_SCALE,
GUI_ID_Y_SCALE,
GUI_ID_Z_SCALE,
GUI_ID_OPEN_MODEL,
GUI_ID_SET_MODEL_ARCHIVE,
GUI_ID_LOAD_AS_OCTREE,
GUI_ID_SKY_BOX_VISIBLE,
GUI_ID_TOGGLE_DEBUG_INFO,
GUI_ID_DEBUG_OFF,
GUI_ID_DEBUG_BOUNDING_BOX,
GUI_ID_DEBUG_NORMALS,
GUI_ID_DEBUG_SKELETON,
GUI_ID_DEBUG_WIRE_OVERLAY,
GUI_ID_DEBUG_HALF_TRANSPARENT,
GUI_ID_DEBUG_BUFFERS_BOUNDING_BOXES,
GUI_ID_DEBUG_ALL,
GUI_ID_MODEL_MATERIAL_SOLID,
GUI_ID_MODEL_MATERIAL_TRANSPARENT,
GUI_ID_MODEL_MATERIAL_REFLECTION,
GUI_ID_CAMERA_MAYA,
GUI_ID_CAMERA_FIRST_PERSON,
GUI_ID_POSITION_TEXT,
GUI_ID_ABOUT,
GUI_ID_QUIT,
GUI_ID_TEXTUREFILTER,
GUI_ID_SKIN_TRANSPARENCY,
GUI_ID_SKIN_ANIMATION_FPS,
GUI_ID_BUTTON_SET_SCALE,
GUI_ID_BUTTON_SCALE_MUL10,
GUI_ID_BUTTON_SCALE_DIV10,
GUI_ID_BUTTON_OPEN_MODEL,
GUI_ID_BUTTON_SHOW_ABOUT,
GUI_ID_BUTTON_SHOW_TOOLBOX,
GUI_ID_BUTTON_SELECT_ARCHIVE,
GUI_ID_ANIMATION_INFO,
// And some magic numbers
MAX_FRAMERATE = 80,
DEFAULT_FRAMERATE = 30
};

Toggle between various cameras

void setActiveCamera(scene::ICameraSceneNode* newActive)
{
if (0 == Device)
return;
scene::ICameraSceneNode * active = Device->getSceneManager()->getActiveCamera();
active->setInputReceiverEnabled(false);
newActive->setInputReceiverEnabled(true);
Device->getSceneManager()->setActiveCamera(newActive);
}

Set the skin transparency by changing the alpha values of all skin-colors

void setSkinTransparency(s32 alpha, irr::gui::IGUISkin * skin)
{
for (s32 i=0; i<irr::gui::EGDC_COUNT ; ++i)
{
video::SColor col = skin->getColor((EGUI_DEFAULT_COLOR)i);
col.setAlpha(alpha);
skin->setColor((EGUI_DEFAULT_COLOR)i, col);
}
}

Update the display of the model scaling

void updateScaleInfo(scene::ISceneNode* model)
{
IGUIElement* toolboxWnd = Device->getGUIEnvironment()->getRootGUIElement()->getElementFromId(GUI_ID_DIALOG_ROOT_WINDOW, true);
if (!toolboxWnd)
return;
if (!model)
{
toolboxWnd->getElementFromId(GUI_ID_X_SCALE, true)->setText( L"-" );
toolboxWnd->getElementFromId(GUI_ID_Y_SCALE, true)->setText( L"-" );
toolboxWnd->getElementFromId(GUI_ID_Z_SCALE, true)->setText( L"-" );
}
else
{
core::vector3df scale = model->getScale();
toolboxWnd->getElementFromId(GUI_ID_X_SCALE, true)->setText( core::stringw(scale.X).c_str() );
toolboxWnd->getElementFromId(GUI_ID_Y_SCALE, true)->setText( core::stringw(scale.Y).c_str() );
toolboxWnd->getElementFromId(GUI_ID_Z_SCALE, true)->setText( core::stringw(scale.Z).c_str() );
}
}

Function showAboutText() displays a messagebox with a caption and a message text. The texts will be stored in the MessageText and Caption variables at startup.

void showAboutText()
{
// create modal message box with the text
// loaded from the xml file.
Device->getGUIEnvironment()->addMessageBox(
Caption.c_str(), MessageText.c_str());
}

Function loadModel() loads a model and displays it using an addAnimatedMeshSceneNode and the scene manager. Nothing difficult. It also displays a short message box, if the model could not be loaded.

void loadModel(const io::path& filename)
{
io::path extension;
core::getFileNameExtension(extension, filename);
extension.make_lower();
// if a texture is loaded apply it to the current model..
if (extension == ".jpg" || extension == ".pcx" ||
extension == ".png" || extension == ".ppm" ||
extension == ".pgm" || extension == ".pbm" ||
extension == ".psd" || extension == ".tga" ||
extension == ".bmp" || extension == ".wal" ||
extension == ".rgb" || extension == ".rgba")
{
// Ensure reloading texture by clearing old one out of cache
video::ITexture * texture = Device->getVideoDriver()->findTexture( filename );
if ( texture )
Device->getVideoDriver()->removeTexture(texture);
// Load the new one and put int on the model
texture = Device->getVideoDriver()->getTexture( filename );
if ( texture && Model )
{
Model->setMaterialTexture(0, texture);
}
return;
}
// if a archive is loaded add it to the FileArchive..
else if (extension == ".pk3" || extension == ".zip" || extension == ".pak" || extension == ".npk")
{
Device->getFileSystem()->addFileArchive(filename.c_str());
return;
}
// Remove old model
if (Model)
{
Model->remove();
Model = 0;
}
// .irr is a scene format, so load as scene and set Model pointer to first object in the scene
if (extension==".irr")
{
core::array<scene::ISceneNode*> outNodes;
Device->getSceneManager()->loadScene(filename);
Device->getSceneManager()->getSceneNodesFromType(scene::ESNT_ANIMATED_MESH, outNodes);
if (outNodes.size())
Model = outNodes[0];
return;
}
// load a model into the engine. Also log the time it takes to load it.
u32 then = Device->getTimer()->getRealTime();
scene::IAnimatedMesh* mesh = Device->getSceneManager()->getMesh( filename.c_str() );
Device->getLogger()->log("Loading time (ms): ", core::stringc(Device->getTimer()->getRealTime() - then).c_str());
if (!mesh)
{
// model could not be loaded
if (StartUpModelFile != filename)
Device->getGUIEnvironment()->addMessageBox(
Caption.c_str(), L"The model could not be loaded. " \
L"Maybe it is not a supported file format.");
return;
}
// set default material properties
if (Octree)
Model = Device->getSceneManager()->addOctreeSceneNode(mesh->getMesh(0));
else
{
scene::IAnimatedMeshSceneNode* animModel = Device->getSceneManager()->addAnimatedMeshSceneNode(mesh);
Model = animModel;
}
Model->setMaterialFlag(video::EMF_LIGHTING, UseLight);
Model->setMaterialFlag(video::EMF_NORMALIZE_NORMALS, UseLight);
// Model->setMaterialFlag(video::EMF_BACK_FACE_CULLING, false);
Model->setDebugDataVisible(scene::EDS_OFF);
// we need to uncheck the menu entries. would be cool to fake a menu event, but
// that's not so simple. so we do it brute force
gui::IGUIContextMenu* menu = (gui::IGUIContextMenu*)Device->getGUIEnvironment()->getRootGUIElement()->getElementFromId(GUI_ID_TOGGLE_DEBUG_INFO, true);
if (menu)
for(int item = 1; item < 6; ++item)
menu->setItemChecked(item, false);
updateScaleInfo(Model);
}

Function createToolBox() creates a toolbox window. In this simple mesh viewer, this toolbox only contains a controls to change the scale and animation speed of the model and a control to set the transparency of the GUI-elements.

void createToolBox()
{
// remove tool box if already there
IGUIEnvironment* env = Device->getGUIEnvironment();
IGUIElement* root = env->getRootGUIElement();
IGUIElement* e = root->getElementFromId(GUI_ID_DIALOG_ROOT_WINDOW, true);
if (e)
e->remove();
// create the toolbox window
IGUIWindow* wnd = env->addWindow(core::rect<s32>(600,45,800,480),
false, L"Toolset", 0, GUI_ID_DIALOG_ROOT_WINDOW);
// create tab control and tabs
IGUITabControl* tab = env->addTabControl(
core::rect<s32>(2,20,800-602,480-7), wnd, true, true);
IGUITab* t1 = tab->addTab(L"Config");
// add some edit boxes and a button to tab one
env->addStaticText(L"Scale:",
core::rect<s32>(10,20,60,45), false, false, t1);
env->addStaticText(L"X:", core::rect<s32>(22,48,40,66), false, false, t1);
env->addEditBox(L"1.0", core::rect<s32>(40,46,130,66), true, t1, GUI_ID_X_SCALE);
env->addStaticText(L"Y:", core::rect<s32>(22,82,40,96), false, false, t1);
env->addEditBox(L"1.0", core::rect<s32>(40,76,130,96), true, t1, GUI_ID_Y_SCALE);
env->addStaticText(L"Z:", core::rect<s32>(22,108,40,126), false, false, t1);
env->addEditBox(L"1.0", core::rect<s32>(40,106,130,126), true, t1, GUI_ID_Z_SCALE);
env->addButton(core::rect<s32>(10,134,85,165), t1, GUI_ID_BUTTON_SET_SCALE, L"Set");
// quick scale buttons
env->addButton(core::rect<s32>(65,20,95,40), t1, GUI_ID_BUTTON_SCALE_MUL10, L"* 10");
env->addButton(core::rect<s32>(100,20,130,40), t1, GUI_ID_BUTTON_SCALE_DIV10, L"* 0.1");
updateScaleInfo(Model);
// add transparency control
env->addStaticText(L"GUI Transparency Control:",
core::rect<s32>(10,200,150,225), true, false, t1);
IGUIScrollBar* scrollbar = env->addScrollBar(true,
core::rect<s32>(10,225,150,240), t1, GUI_ID_SKIN_TRANSPARENCY);
scrollbar->setMax(255);
scrollbar->setPos(255);
// add framerate control
env->addStaticText(L":", core::rect<s32>(10,240,150,265), true, false, t1);
env->addStaticText(L"Framerate:",
core::rect<s32>(12,240,75,265), false, false, t1);
// current frame info
env->addStaticText(L"", core::rect<s32>(75,240,200,265), false, false, t1,
GUI_ID_ANIMATION_INFO);
scrollbar = env->addScrollBar(true,
core::rect<s32>(10,265,150,280), t1, GUI_ID_SKIN_ANIMATION_FPS);
scrollbar->setMax(MAX_FRAMERATE);
scrollbar->setMin(-MAX_FRAMERATE);
scrollbar->setPos(DEFAULT_FRAMERATE);
scrollbar->setSmallStep(1);
}

Function updateToolBox() is called each frame to update dynamic information in the toolbox.

void updateToolBox()
{
IGUIEnvironment* env = Device->getGUIEnvironment();
IGUIElement* root = env->getRootGUIElement();
IGUIElement* dlg = root->getElementFromId(GUI_ID_DIALOG_ROOT_WINDOW, true);
if (!dlg )
return;
// update the info we have about the animation of the model
IGUIStaticText * aniInfo = (IGUIStaticText *)(dlg->getElementFromId(GUI_ID_ANIMATION_INFO, true));
if (aniInfo)
{
if ( Model && scene::ESNT_ANIMATED_MESH == Model->getType() )
{
scene::IAnimatedMeshSceneNode* animatedModel = (scene::IAnimatedMeshSceneNode*)Model;
core::stringw str( (s32)core::round_(animatedModel->getAnimationSpeed()) );
str += L" Frame: ";
str += core::stringw((s32)animatedModel->getFrameNr());
aniInfo->setText(str.c_str());
}
else
aniInfo->setText(L"");
}
}
void onKillFocus()
{
// Avoid that the FPS-camera continues moving when the user presses alt-tab while
// moving the camera.
const core::list<scene::ISceneNodeAnimator*>& animators = Camera[1]->getAnimators();
core::list<irr::scene::ISceneNodeAnimator*>::ConstIterator iter = animators.begin();
while ( iter != animators.end() )
{
if ( (*iter)->getType() == scene::ESNAT_CAMERA_FPS )
{
// we send a key-down event for all keys used by this animator
scene::ISceneNodeAnimatorCameraFPS * fpsAnimator = static_cast<scene::ISceneNodeAnimatorCameraFPS*>(*iter);
const core::array<SKeyMap>& keyMap = fpsAnimator->getKeyMap();
for ( irr::u32 i=0; i< keyMap.size(); ++i )
{
irr::SEvent event;
event.EventType = EET_KEY_INPUT_EVENT;
event.KeyInput.Key = keyMap[i].KeyCode;
event.KeyInput.PressedDown = false;
fpsAnimator->OnEvent(event);
}
}
++iter;
}
}

Function hasModalDialog() checks if we currently have a modal dialog open.

bool hasModalDialog()
{
if ( !Device )
return false;
IGUIEnvironment* env = Device->getGUIEnvironment();
IGUIElement * focused = env->getFocus();
while ( focused )
{
if ( focused->isVisible() && focused->hasType(EGUIET_MODAL_SCREEN) )
return true;
focused = focused->getParent();
}
return false;
}

To get all the events sent by the GUI Elements, we need to create an event receiver. This one is really simple. If an event occurs, it checks the id of the caller and the event type, and starts an action based on these values. For example, if a menu item with id GUI_ID_OPEN_MODEL was selected, it opens a file-open-dialog.

class MyEventReceiver : public IEventReceiver
{
public:
virtual bool OnEvent(const SEvent& event)
{
// Key events
if (event.EventType == EET_KEY_INPUT_EVENT &&
event.KeyInput.PressedDown == false)
{
if ( OnKeyUp(event.KeyInput.Key) )
return true;
}
// GUI events
if (event.EventType == EET_GUI_EVENT)
{
s32 id = event.GUIEvent.Caller->getID();
IGUIEnvironment* env = Device->getGUIEnvironment();
switch(event.GUIEvent.EventType)
{
case EGET_MENU_ITEM_SELECTED:
// a menu item was clicked
OnMenuItemSelected( (IGUIContextMenu*)event.GUIEvent.Caller );
break;
case EGET_FILE_SELECTED:
{
// load the model file, selected in the file open dialog
IGUIFileOpenDialog* dialog =
(IGUIFileOpenDialog*)event.GUIEvent.Caller;
loadModel(dialog->getFileNameP());
}
break;
case EGET_SCROLL_BAR_CHANGED:
// control skin transparency
if (id == GUI_ID_SKIN_TRANSPARENCY)
{
const s32 pos = ((IGUIScrollBar*)event.GUIEvent.Caller)->getPos();
setSkinTransparency(pos, env->getSkin());
}
// control animation speed
else if (id == GUI_ID_SKIN_ANIMATION_FPS)
{
const s32 pos = ((IGUIScrollBar*)event.GUIEvent.Caller)->getPos();
if (scene::ESNT_ANIMATED_MESH == Model->getType())
((scene::IAnimatedMeshSceneNode*)Model)->setAnimationSpeed((f32)pos);
}
break;
case EGET_COMBO_BOX_CHANGED:
// control anti-aliasing/filtering
if (id == GUI_ID_TEXTUREFILTER)
{
OnTextureFilterSelected( (IGUIComboBox*)event.GUIEvent.Caller );
}
break;
case EGET_BUTTON_CLICKED:
switch(id)
{
case GUI_ID_BUTTON_SET_SCALE:
{
// set model scale
gui::IGUIElement* root = env->getRootGUIElement();
core::vector3df scale;
core::stringc s;
s = root->getElementFromId(GUI_ID_X_SCALE, true)->getText();
scale.X = (f32)atof(s.c_str());
s = root->getElementFromId(GUI_ID_Y_SCALE, true)->getText();
scale.Y = (f32)atof(s.c_str());
s = root->getElementFromId(GUI_ID_Z_SCALE, true)->getText();
scale.Z = (f32)atof(s.c_str());
if (Model)
Model->setScale(scale);
updateScaleInfo(Model);
}
break;
case GUI_ID_BUTTON_SCALE_MUL10:
if (Model)
Model->setScale(Model->getScale()*10.f);
updateScaleInfo(Model);
break;
case GUI_ID_BUTTON_SCALE_DIV10:
if (Model)
Model->setScale(Model->getScale()*0.1f);
updateScaleInfo(Model);
break;
case GUI_ID_BUTTON_OPEN_MODEL:
env->addFileOpenDialog(L"Please select a model file to open");
break;
case GUI_ID_BUTTON_SHOW_ABOUT:
showAboutText();
break;
case GUI_ID_BUTTON_SHOW_TOOLBOX:
createToolBox();
break;
case GUI_ID_BUTTON_SELECT_ARCHIVE:
env->addFileOpenDialog(L"Please select your game archive/directory");
break;
}
break;
default:
break;
}
}
return false;
}

Handle key-up events

bool OnKeyUp(irr::EKEY_CODE keyCode)
{
// Don't handle keys if we have a modal dialog open as it would lead
// to unexpected application behaviour for the user.
if ( hasModalDialog() )
return false;
// Escape swaps Camera Input
if (keyCode == irr::KEY_ESCAPE)
{
if (Device)
{
scene::ICameraSceneNode * camera =
Device->getSceneManager()->getActiveCamera();
if (camera)
{
camera->setInputReceiverEnabled( !camera->isInputReceiverEnabled() );
}
return true;
}
}
else if (keyCode == irr::KEY_F1)
{
// Swap display of position information about the camera
if (Device)
{
IGUIElement* elem = Device->getGUIEnvironment()->getRootGUIElement()->getElementFromId(GUI_ID_POSITION_TEXT);
if (elem)
elem->setVisible(!elem->isVisible());
}
}
else if (keyCode == irr::KEY_KEY_M)
{
if (Device)
Device->minimizeWindow();
}
else if (keyCode == irr::KEY_KEY_L)
{
UseLight=!UseLight;
if (Model)
{
Model->setMaterialFlag(video::EMF_LIGHTING, UseLight);
Model->setMaterialFlag(video::EMF_NORMALIZE_NORMALS, UseLight);
}
}
return false;
}

Handle "menu item clicked" events.

void OnMenuItemSelected( IGUIContextMenu* menu )
{
s32 id = menu->getItemCommandId(menu->getSelectedItem());
IGUIEnvironment* env = Device->getGUIEnvironment();
switch(id)
{
case GUI_ID_OPEN_MODEL: // File -> Open Model File & Texture
env->addFileOpenDialog(L"Please select a model file to open");
break;
case GUI_ID_SET_MODEL_ARCHIVE: // File -> Set Model Archive
env->addFileOpenDialog(L"Please select your game archive/directory");
break;
case GUI_ID_LOAD_AS_OCTREE: // File -> LoadAsOctree
Octree = !Octree;
menu->setItemChecked(menu->getSelectedItem(), Octree);
break;
case GUI_ID_QUIT: // File -> Quit
Device->closeDevice();
break;
case GUI_ID_SKY_BOX_VISIBLE: // View -> Skybox
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
SkyBox->setVisible(!SkyBox->isVisible());
break;
case GUI_ID_DEBUG_OFF: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem()+1, false);
menu->setItemChecked(menu->getSelectedItem()+2, false);
menu->setItemChecked(menu->getSelectedItem()+3, false);
menu->setItemChecked(menu->getSelectedItem()+4, false);
menu->setItemChecked(menu->getSelectedItem()+5, false);
menu->setItemChecked(menu->getSelectedItem()+6, false);
if (Model)
Model->setDebugDataVisible(scene::EDS_OFF);
break;
case GUI_ID_DEBUG_BOUNDING_BOX: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
if (Model)
Model->setDebugDataVisible((scene::E_DEBUG_SCENE_TYPE)(Model->isDebugDataVisible()^scene::EDS_BBOX));
break;
case GUI_ID_DEBUG_NORMALS: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
if (Model)
Model->setDebugDataVisible((scene::E_DEBUG_SCENE_TYPE)(Model->isDebugDataVisible()^scene::EDS_NORMALS));
break;
case GUI_ID_DEBUG_SKELETON: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
if (Model)
Model->setDebugDataVisible((scene::E_DEBUG_SCENE_TYPE)(Model->isDebugDataVisible()^scene::EDS_SKELETON));
break;
case GUI_ID_DEBUG_WIRE_OVERLAY: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
if (Model)
Model->setDebugDataVisible((scene::E_DEBUG_SCENE_TYPE)(Model->isDebugDataVisible()^scene::EDS_MESH_WIRE_OVERLAY));
break;
case GUI_ID_DEBUG_HALF_TRANSPARENT: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
if (Model)
Model->setDebugDataVisible((scene::E_DEBUG_SCENE_TYPE)(Model->isDebugDataVisible()^scene::EDS_HALF_TRANSPARENCY));
break;
case GUI_ID_DEBUG_BUFFERS_BOUNDING_BOXES: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem(), !menu->isItemChecked(menu->getSelectedItem()));
if (Model)
Model->setDebugDataVisible((scene::E_DEBUG_SCENE_TYPE)(Model->isDebugDataVisible()^scene::EDS_BBOX_BUFFERS));
break;
case GUI_ID_DEBUG_ALL: // View -> Debug Information
menu->setItemChecked(menu->getSelectedItem()-1, true);
menu->setItemChecked(menu->getSelectedItem()-2, true);
menu->setItemChecked(menu->getSelectedItem()-3, true);
menu->setItemChecked(menu->getSelectedItem()-4, true);
menu->setItemChecked(menu->getSelectedItem()-5, true);
menu->setItemChecked(menu->getSelectedItem()-6, true);
if (Model)
Model->setDebugDataVisible(scene::EDS_FULL);
break;
case GUI_ID_ABOUT: // Help->About
showAboutText();
break;
case GUI_ID_MODEL_MATERIAL_SOLID: // View -> Material -> Solid
if (Model)
Model->setMaterialType(video::EMT_SOLID);
break;
case GUI_ID_MODEL_MATERIAL_TRANSPARENT: // View -> Material -> Transparent
if (Model)
Model->setMaterialType(video::EMT_TRANSPARENT_ADD_COLOR);
break;
case GUI_ID_MODEL_MATERIAL_REFLECTION: // View -> Material -> Reflection
if (Model)
Model->setMaterialType(video::EMT_SPHERE_MAP);
break;
case GUI_ID_CAMERA_MAYA:
setActiveCamera(Camera[0]);
break;
case GUI_ID_CAMERA_FIRST_PERSON:
setActiveCamera(Camera[1]);
break;
}
}

Handle the event that one of the texture-filters was selected in the corresponding combobox.

void OnTextureFilterSelected( IGUIComboBox* combo )
{
s32 pos = combo->getSelected();
switch (pos)
{
case 0:
if (Model)
{
Model->setMaterialFlag(video::EMF_BILINEAR_FILTER, false);
Model->setMaterialFlag(video::EMF_TRILINEAR_FILTER, false);
Model->setMaterialFlag(video::EMF_ANISOTROPIC_FILTER, false);
}
break;
case 1:
if (Model)
{
Model->setMaterialFlag(video::EMF_BILINEAR_FILTER, true);
Model->setMaterialFlag(video::EMF_TRILINEAR_FILTER, false);
}
break;
case 2:
if (Model)
{
Model->setMaterialFlag(video::EMF_BILINEAR_FILTER, false);
Model->setMaterialFlag(video::EMF_TRILINEAR_FILTER, true);
}
break;
case 3:
if (Model)
{
Model->setMaterialFlag(video::EMF_ANISOTROPIC_FILTER, true);
}
break;
case 4:
if (Model)
{
Model->setMaterialFlag(video::EMF_ANISOTROPIC_FILTER, false);
}
break;
}
}
};

Most of the hard work is done. We only need to create the Irrlicht Engine device and all the buttons, menus and toolbars. We start up the engine as usual, using createDevice(). To make our application catch events, we set our eventreceiver as parameter. As you can see, there is also a call to IrrlichtDevice::setResizeable(). This makes the render window resizeable, which is quite useful for a mesh viewer.

int main(int argc, char* argv[])
{
// ask user for driver
video::E_DRIVER_TYPE driverType=driverChoiceConsole();
if (driverType==video::EDT_COUNT)
return 1;
// create device and exit if creation failed
MyEventReceiver receiver;
Device = createDevice(driverType, core::dimension2d<u32>(800, 600),
16, false, false, false, &receiver);
if (Device == 0)
return 1; // could not create selected driver.
Device->setResizable(true);
Device->setWindowCaption(L"Irrlicht Engine - Loading...");
video::IVideoDriver* driver = Device->getVideoDriver();
IGUIEnvironment* env = Device->getGUIEnvironment();
scene::ISceneManager* smgr = Device->getSceneManager();
smgr->getParameters()->setAttribute(scene::COLLADA_CREATE_SCENE_INSTANCES, true);
driver->setTextureCreationFlag(video::ETCF_ALWAYS_32_BIT, true);
smgr->addLightSceneNode(0, core::vector3df(200,200,200),
video::SColorf(1.0f,1.0f,1.0f),2000);
smgr->setAmbientLight(video::SColorf(0.3f,0.3f,0.3f));
// add our media directory as "search path"
Device->getFileSystem()->addFileArchive(getExampleMediaPath());

The next step is to read the configuration file. It is stored in the xml format and looks a little bit like this:

        <?xml version="1.0"?>
        <config>
            <startUpModel file="some filename" />
            <messageText caption="Irrlicht Engine Mesh Viewer">
                Hello!
            </messageText>
        </config>

We need the data stored in there to be written into the global variables StartUpModelFile, MessageText and Caption. This is now done using the Irrlicht Engine integrated XML parser:

// read configuration from xml file
io::IXMLReader* xml = Device->getFileSystem()->createXMLReader( L"config.xml");
while(xml && xml->read())
{
switch(xml->getNodeType())
{
case io::EXN_TEXT:
// in this xml file, the only text which occurs is the
// messageText
MessageText = xml->getNodeData();
break;
case io::EXN_ELEMENT:
{
if (core::stringw("startUpModel") == xml->getNodeName())
StartUpModelFile = xml->getAttributeValue(L"file");
else
if (core::stringw("messageText") == xml->getNodeName())
Caption = xml->getAttributeValue(L"caption");
}
break;
default:
break;
}
}
if (xml)
xml->drop(); // don't forget to delete the xml reader
// We can pass a model to load per command line parameter
if (argc > 1)
StartUpModelFile = argv[1];
// set a nicer font
IGUISkin* skin = env->getSkin();
IGUIFont* font = env->getFont("fonthaettenschweiler.bmp");
if (font)
skin->setFont(font);

Now create the Menu. It is possible to create submenus for every menu item. The call menu->addItem(L"File", -1, true, true); for example adds a new menu Item with the name "File" and the id -1. The following parameter says that the menu item should be enabled, and the last one says, that there should be a submenu. The submenu can now be accessed with menu->getSubMenu(0), because the "File" entry is the menu item with index 0.

gui::IGUIContextMenu* menu = env->addMenu();
menu->addItem(L"File", -1, true, true);
menu->addItem(L"View", -1, true, true);
menu->addItem(L"Camera", -1, true, true);
menu->addItem(L"Help", -1, true, true);
gui::IGUIContextMenu* submenu;
submenu = menu->getSubMenu(0);
submenu->addItem(L"Open Model File & Texture...", GUI_ID_OPEN_MODEL);
submenu->addItem(L"Set Model Archive...", GUI_ID_SET_MODEL_ARCHIVE);
submenu->addItem(L"Load as Octree", GUI_ID_LOAD_AS_OCTREE);
submenu->addSeparator();
submenu->addItem(L"Quit", GUI_ID_QUIT);
submenu = menu->getSubMenu(1);
submenu->addItem(L"sky box visible", GUI_ID_SKY_BOX_VISIBLE, true, false, true);
submenu->addItem(L"toggle model debug information", GUI_ID_TOGGLE_DEBUG_INFO, true, true);
submenu->addItem(L"model material", -1, true, true );
submenu = submenu->getSubMenu(1);
submenu->addItem(L"Off", GUI_ID_DEBUG_OFF);
submenu->addItem(L"Bounding Box", GUI_ID_DEBUG_BOUNDING_BOX);
submenu->addItem(L"Normals", GUI_ID_DEBUG_NORMALS);
submenu->addItem(L"Skeleton", GUI_ID_DEBUG_SKELETON);
submenu->addItem(L"Wire overlay", GUI_ID_DEBUG_WIRE_OVERLAY);
submenu->addItem(L"Half-Transparent", GUI_ID_DEBUG_HALF_TRANSPARENT);
submenu->addItem(L"Buffers bounding boxes", GUI_ID_DEBUG_BUFFERS_BOUNDING_BOXES);
submenu->addItem(L"All", GUI_ID_DEBUG_ALL);
submenu = menu->getSubMenu(1)->getSubMenu(2);
submenu->addItem(L"Solid", GUI_ID_MODEL_MATERIAL_SOLID);
submenu->addItem(L"Transparent", GUI_ID_MODEL_MATERIAL_TRANSPARENT);
submenu->addItem(L"Reflection", GUI_ID_MODEL_MATERIAL_REFLECTION);
submenu = menu->getSubMenu(2);
submenu->addItem(L"Maya Style", GUI_ID_CAMERA_MAYA);
submenu->addItem(L"First Person", GUI_ID_CAMERA_FIRST_PERSON);
submenu = menu->getSubMenu(3);
submenu->addItem(L"About", GUI_ID_ABOUT);

Below the menu we want a toolbar, onto which we can place colored buttons and important looking stuff like a senseless combobox.

// create toolbar
gui::IGUIToolBar* bar = env->addToolBar();
video::ITexture* image = driver->getTexture("open.png");
bar->addButton(GUI_ID_BUTTON_OPEN_MODEL, 0, L"Open a model",image, 0, false, true);
image = driver->getTexture("tools.png");
bar->addButton(GUI_ID_BUTTON_SHOW_TOOLBOX, 0, L"Open Toolset",image, 0, false, true);
image = driver->getTexture("zip.png");
bar->addButton(GUI_ID_BUTTON_SELECT_ARCHIVE, 0, L"Set Model Archive",image, 0, false, true);
image = driver->getTexture("help.png");
bar->addButton(GUI_ID_BUTTON_SHOW_ABOUT, 0, L"Open Help", image, 0, false, true);
// create a combobox for texture filters
gui::IGUIComboBox* box = env->addComboBox(core::rect<s32>(250,4,350,23), bar, GUI_ID_TEXTUREFILTER);
box->addItem(L"No filtering");
box->addItem(L"Bilinear");
box->addItem(L"Trilinear");
box->addItem(L"Anisotropic");
box->addItem(L"Isotropic");

To make the editor look a little bit better, we disable transparent gui elements, and add an Irrlicht Engine logo. In addition, a text showing the current frames per second value is created and the window caption is changed.

// disable alpha
for (s32 i=0; i<gui::EGDC_COUNT ; ++i)
{
video::SColor col = env->getSkin()->getColor((gui::EGUI_DEFAULT_COLOR)i);
col.setAlpha(255);
env->getSkin()->setColor((gui::EGUI_DEFAULT_COLOR)i, col);
}
// add a tabcontrol
createToolBox();
// create fps text
IGUIStaticText* fpstext = env->addStaticText(L"",
core::rect<s32>(400,4,570,23), true, false, bar);
IGUIStaticText* postext = env->addStaticText(L"",
core::rect<s32>(10,50,470,80),false, false, 0, GUI_ID_POSITION_TEXT);
postext->setVisible(false);
// set window caption
Caption += " - [";
Caption += driver->getName();
Caption += "]";
Device->setWindowCaption(Caption.c_str());

Now we show the about message box at start up, and load the first model. To make everything look better a skybox is created. We also add a user controlled camera, to make the application more interactive. Finally, everything is drawn in a standard drawing loop.

// show about message box and load default model
if (argc==1)
showAboutText();
loadModel(StartUpModelFile.c_str());
// add skybox
SkyBox = smgr->addSkyBoxSceneNode(
driver->getTexture("irrlicht2_up.jpg"),
driver->getTexture("irrlicht2_dn.jpg"),
driver->getTexture("irrlicht2_lf.jpg"),
driver->getTexture("irrlicht2_rt.jpg"),
driver->getTexture("irrlicht2_ft.jpg"),
driver->getTexture("irrlicht2_bk.jpg"));
// add a camera scene node
Camera[0] = smgr->addCameraSceneNodeMaya();
Camera[0]->setFarValue(20000.f);
// Maya cameras reposition themselves relative to their target, so target the location
// where the mesh scene node is placed.
Camera[0]->setTarget(core::vector3df(0,30,0));
Camera[1] = smgr->addCameraSceneNodeFPS();
Camera[1]->setFarValue(20000.f);
Camera[1]->setPosition(core::vector3df(0,0,-70));
Camera[1]->setTarget(core::vector3df(0,30,0));
setActiveCamera(Camera[0]);
// load the irrlicht engine logo
IGUIImage *img =
env->addImage(driver->getTexture("irrlichtlogo3.png"),
core::position2d<s32>(10, driver->getScreenSize().Height - 128));
// lock the logo's edges to the bottom left corner of the screen
img->setAlignment(EGUIA_UPPERLEFT, EGUIA_UPPERLEFT,
EGUIA_LOWERRIGHT, EGUIA_LOWERRIGHT);
// remember state so we notice when the window does lose the focus
bool hasFocus = Device->isWindowFocused();
// draw everything
while(Device->run() && driver)
{
// Catch focus changes (workaround until Irrlicht has events for this)
bool focused = Device->isWindowFocused();
if ( hasFocus && !focused )
onKillFocus();
hasFocus = focused;
if (Device->isWindowActive())
{
driver->beginScene(video::ECBF_COLOR | video::ECBF_DEPTH, video::SColor(150,50,50,50));
smgr->drawAll();
env->drawAll();
driver->endScene();
// update information about current frame-rate
core::stringw str(L"FPS: ");
str.append(core::stringw(driver->getFPS()));
str += L" Tris: ";
str.append(core::stringw(driver->getPrimitiveCountDrawn()));
fpstext->setText(str.c_str());
// update information about the active camera
scene::ICameraSceneNode* cam = Device->getSceneManager()->getActiveCamera();
str = L"Pos: ";
str.append(core::stringw(cam->getPosition().X));
str += L" ";
str.append(core::stringw(cam->getPosition().Y));
str += L" ";
str.append(core::stringw(cam->getPosition().Z));
str += L" Tgt: ";
str.append(core::stringw(cam->getTarget().X));
str += L" ";
str.append(core::stringw(cam->getTarget().Y));
str += L" ";
str.append(core::stringw(cam->getTarget().Z));
postext->setText(str.c_str());
// update the tool dialog
updateToolBox();
}
else
Device->yield();
}
Device->drop();
return 0;
}