Tutorial 2.Quake3Map

This Tutorial shows how to load a Quake 3 map into the engine, create a SceneNode for optimizing the speed of rendering and how to create a user controlled camera. Please note that you should know the basics of the engine before starting this tutorial, just take a short look at the first tutorial, 1.HelloWorld, if you haven't done this yet.
The result of this example will look like this:

Lets start!

Lets start like the HelloWorld example: We include the irrlicht header files and an additional file to be able
to ask the user for a driver type using the console.

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

As already written in the HelloWorld example, in the Irrlicht Engine, everything can be found in the namespace 'irr'. To get rid of the irr:: in front of the name of every class, we tell the compiler that we use that namespace from now on, and we will not have to write that 'irr::'.
There are 5 other sub namespaces 'core', 'scene', 'video', 'io' and 'gui'. Unlike in the HelloWorld example, we do not a 'using namespace' for these 5 other namespaces because in this way you will see what can be found in which namespace. But if you like, you can also include the namespaces like in the previous example. Code just like you want to.

using namespace irr;

Again, to be able to use the Irrlicht.DLL file, we need to link with the Irrlicht.lib. We could set this option in the project settings, but to make it easy, we use a pragma comment lib:

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

Ok, lets start. Again, we use the main() method as start, not the WinMain(), because its shorter to write.

int main()
{

Like in the HelloWorld example, we create an IrrlichtDevice with createDevice(). The difference now is that we ask the user to select which hardware accelerated driver to use. The Software device would be too slow to draw a huge Quake 3 map, but just for the fun of it, we make this decision possible too.

// ask user for driver

video::E_DRIVER_TYPE driverType = video::EDT_DIRECT3D9;

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

IrrlichtDevice *device =
    createDevice(driverType, core::dimension2d<s32>(640, 480));

if (device == 0)
   return 1;

Get a pointer to the video driver and the SceneManager so that we do not always have to write device->getVideoDriver() and device->getSceneManager().

video::IVideoDriver* driver = device->getVideoDriver();
scene::ISceneManager* smgr = device->getSceneManager();

To display the Quake 3 map, we first need to load it. Quake 3 maps are packed into .pk3 files wich are nothing other than .zip files. So we add the .pk3 file to our FileSystem. After it was added, we are able to read from the files in that archive as they would directly be stored on disk.

device->getFileSystem()->addZipFileArchive("../../media/map-20kdm2.pk3");

Now we can load the mesh by calling getMesh(). We get a pointer returned to a IAnimatedMesh. As you know, Quake 3 maps are not really animated, they are only a huge chunk of static geometry with some materials attached. Hence the IAnimated mesh consists of only one frame,
so we get the "first frame" of the "animation", which is our quake level and create an OctTree scene node with it, using addOctTreeSceneNode(). The OctTree optimizes the scene a little bit, trying to draw only geometry which is currently visible. An alternative to the OctTree would be a AnimatedMeshSceneNode, which would draw always the complete geometry of the mesh, without optimization. Try it out: Write addAnimatedMeshSceneNode instead of addOctTreeSceneNode and compare the primitives drawed by the video driver. (There is a getPrimitiveCountDrawed() method in the IVideoDriver class). Note that this optimization with the Octree is only useful when drawing huge meshes consiting of lots of geometry.

scene::IAnimatedMesh* mesh = smgr->getMesh("20kdm2.bsp");
scene::ISceneNode* node = 0;

if (mesh)
    node = smgr->addOctTreeSceneNode(mesh->getMesh(0));

Because the level was modelled not around the origin (0,0,0), we translate the whole level a little bit.

if (node)
    node->setPosition(core::vector3df(-1300,-144,-1249));

Now we only need a Camera to look at the Quake 3 map. And we want to create a user controlled camera. There are some different cameras available in the Irrlicht engine. For example the Maya Camera which can be controlled compareable to the camera in Maya: Rotate with left mouse button pressed, Zoom with both buttons pressed,
translate with right mouse button pressed. This could be created with addCameraSceneNodeMaya(). But for this example, we want to create a camera which behaves like the ones in first person shooter games (FPS):

smgr->addCameraSceneNodeFPS();

The mouse cursor needs not to be visible, so we make it invisible. 

device->getCursorControl()->setVisible(false);

We have done everything, so lets draw it. We also write the current frames per second and the drawn primitives to the caption of the window. The 'if (device->isWindowActive())' line is optional, but prevents the engine render to set the position of the mouse cursor after task switching when other program are active.

int lastFPS = -1;
while(device->run())
{
  driver->beginScene(true, true, video::SColor(0,200,200,200));
  smgr->drawAll();
  driver->endScene();
  int fps = driver->getFPS();
  if (lastFPS != fps)
  {
     core::stringw str = L"Irrlicht Engine - Quake 3 Map example [";
     str += driver->getName();
     str += "] FPS:";
     str += fps;
     device->setWindowCaption(str.c_str());
     lastFPS = fps;
  }
}

In the end, delete the Irrlicht device.

  device->drop();
  return 0;
}

That's it. Compile and play around with the program.