Irrlicht Engine Tutorial

In the beginning there is nothing special. We include the needed - header files and create an event listener to listen if the user presses - the 'W' key so we can switch to wireframe mode and if he presses 'D' - we toggle to material between solid and detail mapped.

- - - - -

#include <irrlicht.h>
#include <iostream>
using namespace irr;

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

class MyEventReceiver : public IEventReceiver
{
public:
	MyEventReceiver(scene::ISceneNode* terrain)
	{
		// store pointer to terrain so we can change its drawing mode
		Terrain = terrain;
	}

	bool OnEvent(const SEvent& event)
	{
		// check if user presses the key 'W' or 'D'
		if (event.EventType == irr::EET_KEY_INPUT_EVENT && !event.KeyInput.PressedDown)
		{
			switch (event.KeyInput.Key)
			{
			case irr::KEY_KEY_W: // switch wire frame mode
				Terrain->setMaterialFlag(video::EMF_WIREFRAME, !Terrain->getMaterial(0).Wireframe);
				return true;
			case irr::KEY_KEY_D: // toggle detail map
				Terrain->setMaterialType(
					Terrain->getMaterial(0).MaterialType == video::EMT_SOLID ? 
					video::EMT_DETAIL_MAP : video::EMT_SOLID);
				return true;
			}
		}
		return false;
	}

private:
	scene::ISceneNode* Terrain;
};

The start of the main function starts like in most other example. - We ask the user for the desired renderer and start it up.

- - - - -

int main()
{
	// let user select driver type

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

	if (device == 0)
		return 1; // could not create selected driver.

First, we add standard stuff to the scene: A nice irrlicht engine - logo, a small help text, a user controlled camera, and we disable - the mouse cursor.

- - - - -

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

driver->setTextureCreationFlag(video::ETCF_ALWAYS_32_BIT, true);

// add irrlicht logo
env->addImage(driver->getTexture("../../media/irrlichtlogoalpha.tga"),
    core::position2d<s32>(10,10));

-// add some help text
gui::IGUIStaticText* text = env->addStaticText(
	L"Press 'W' to change wireframe mode\nPress 'D' to toggle detail map",
	core::rect<s32>(10,453,200,475), true, true, 0, -1, true);

-// add camera
scene::ICameraSceneNode* camera = 
    smgr->addCameraSceneNodeFPS(0,100.0f,1200.0f);
camera->setPosition(core::vector3df(1900*2,255*2,3700*2));
camera->setTarget(core::vector3df(2397*2,343*2,2700*2));
camera->setFarValue(12000.0f);

// disable mouse cursor
device->getCursorControl()->setVisible(false);

Here comes the terrain renderer scene node: We add it just like - any other scene node to the scene using ISceneManager::addTerrainSceneNode(). - The only parameter we use is a file name to the heightmap we use. - A heightmap is simply a gray scale texture. The terrain renderer loads - it and creates the 3D terrain from it.
- To make the terrain look more big, we change the scale factor of it - to (40, 4.4, 40). Because we don't have any dynamic lights in the - scene, we switch off the lighting, and we set the file terrain-texture.jpg - as texture for the terrain and detailmap3.jpg as second texture, called - detail map. At last, we set the scale values for the texture: The - first texture will be repeated only one time over the whole terrain, - and the second one (detail map) 20 times.

- - - - -

// add terrain scene node
scene::ITerrainSceneNode* terrain = smgr->addTerrainSceneNode( 
      "../../media/terrain-heightmap.bmp");

terrain->setScale(core::vector3df(40, 4.4f, 40));
terrain->setMaterialFlag(video::EMF_LIGHTING, false);

terrain->setMaterialTexture(0, driver->getTexture("../../media/terrain-texture.jpg"));
terrain->setMaterialTexture(1, driver->getTexture("../../media/detailmap3.jpg"));
	
terrain->setMaterialType(video::EMT_DETAIL_MAP);
terrain->scaleTexture(1.0f, 20.0f);

To be able to do collision with the terrain, we create a triangle - selector. If you want to know what triangle selectors do, just take - a look into the collision tutorial. The terrain triangle selector - works together with the terrain. To demonstrate this, we create a - collision response animator and attach it to the camera, so that the - camera will not be able to fly through the terrain.

- - - - -

// create triangle selector for the terrain	
scene::ITriangleSelector* selector =
    smgr->createTerrainTriangleSelector(terrain, 0);
terrain->setTriangleSelector(selector);

// create collision response animator and attach it to the camera
scene::ISceneNodeAnimator* anim = smgr->createCollisionResponseAnimator(
	selector, camera, core::vector3df(60,100,60),
	core::vector3df(0,0,0), 
	core::vector3df(0,50,0));
selector->drop();
camera->addAnimator(anim);
anim->drop();

To make the user be able to switch between normal and wireframe mode, - we create an instance of the event reciever from above and let Irrlicht - know about it. In addition, we add the skybox which we already used - in lots of Irrlicht examples.

- - - - -

// create event receiver
MyEventReceiver receiver(terrain);
device->setEventReceiver(&receiver);

// create skybox
driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, false);

smgr->addSkyBoxSceneNode(
	driver->getTexture("../../media/irrlicht2_up.jpg"),
	driver->getTexture("../../media/irrlicht2_dn.jpg"),
	driver->getTexture("../../media/irrlicht2_lf.jpg"),
	driver->getTexture("../../media/irrlicht2_rt.jpg"),
	driver->getTexture("../../media/irrlicht2_ft.jpg"),
	driver->getTexture("../../media/irrlicht2_bk.jpg"));

-driver->setTextureCreationFlag(video::ETCF_CREATE_MIP_MAPS, true);

That's it, draw everything. Now you know how to use terrain in Irrlicht.

- - - - -

	int lastFPS = -1;

	while(device->run())
	if (device->isWindowActive())
	{
		driver->beginScene(true, true, 0 );

		smgr->drawAll();
		env->drawAll();

		driver->endScene();
-
		// display frames per second in window title
-		int fps = driver->getFPS();

		if (lastFPS != fps)
		{
			core::stringw str = L"Terrain Renderer - Irrlicht Engine [";
			str += driver->getName();
			str += "] FPS:";
			str += fps;
			device->setWindowCaption(str.c_str());
			lastFPS = fps;
		}
	}

	device->drop();
	
	return 0;
}