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<title>Irrlicht Engine Tutorial</title>
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    <td bgcolor="#666699" width="10"><b><a href="http://irrlicht.sourceforge.net" target="_blank"><img src="../../media/irrlichtlogo.jpg" width="88" height="31" border="0"></a></b></td>
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        <div align="left"><b><font color="#FFFFFF">Tutorial 13. Render to Texture</font></b></div>
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      <div align="left"> 
        <p> This tutorial shows how to render to a texture using Irrlicht. Render 
          to texture is a feature with which it is possible to create nice special 
          effects. In addition, this tutorial shows how to enable specular highlights.</p>
        <p>The program which is described here will look like this:</p>
        <p align="center"><img src="../../media/013shot.jpg" width="256" height="200"><br>
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    <td bgcolor="#666699"> <b><font color="#FFFFFF">Lets start!</font></b></td>
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    <td height="90" bgcolor="#eeeeff" valign="top"> <div align="left"> 
        <div align="left"> 
          <p>In the beginning, everything as usual. Include the needed headers, 
            ask the user for the rendering driver, create the Irrlicht Device:</p>
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              <td><pre>#include &lt;irrlicht.h>
#include &lt;iostream>

using namespace irr;

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

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

	video::E_DRIVER_TYPE driverType = video::EDT_DIRECT3D9;

	printf(&quot;Please select the driver you want for this example:\n&quot;\<br>		&quot; (a) Direct3D 9.0c\n (b) Direct3D 8.1\n (c) OpenGL 1.5\n&quot;\<br>		&quot; (d) Software Renderer\n (e) Apfelbaum Software Renderer\n&quot;\<br>		&quot; (f) NullDevice\n (otherKey) exit\n\n&quot;);

	char i;
	std::cin >> i;

	switch(i)<br>	{<br>		case 'a': driverType = video::EDT_DIRECT3D9;break;<br>		case 'b': driverType = video::EDT_DIRECT3D8;break;<br>		case 'c': driverType = video::EDT_OPENGL;   break;<br>		case 'd': driverType = video::EDT_SOFTWARE; break;<br>		case 'e': driverType = video::EDT_BURNINGSVIDEO;break;<br>		case 'f': driverType = video::EDT_NULL;     break;<br>		default: return 1;<br>	}	

	// create device and exit if creation failed

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

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

	video::IVideoDriver* driver = device->getVideoDriver();
	scene::ISceneManager* smgr = device->getSceneManager();
	gui::IGUIEnvironment* env = device->getGUIEnvironment();</pre></td>
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          <p>Now, we load an animated mesh to be displayed. As in most examples, 
            we'll take the fairy md2 model. The difference here: We set the shininess<br>
            of the model to a value other than 0 which is the default value. This 
            enables specular highlights on the model if dynamic lighting is on. 
            The value influences the size of the highlights.</p>
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              <td><pre>// load and display animated fairy mesh

	scene::IAnimatedMeshSceneNode* fairy = smgr->addAnimatedMeshSceneNode(
		smgr->getMesh("../../media/faerie.md2"));

	if (fairy)
	{
		fairy->setMaterialTexture(0, driver->getTexture("../../media/faerie2.bmp")); // set diffuse texture
		fairy->setMaterialFlag(video::EMF_LIGHTING, true); // enable dynamic lighting
		fairy->getMaterial(0).Shininess = 20.0f; // set size of specular highlights
		fairy->setPosition(core::vector3df(-10,0,-100));
	}</pre></td>
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          <p> To make specular highlights appear on the model, we need a dynamic 
            light in the scene. We add one directly in vicinity of the model. 
            In addition, to make the model not that dark, we set the ambient light 
            to gray. </p>
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              <td><pre>
	// add white light
	scene::ILightSceneNode* light = smgr->addLightSceneNode(0,
		core::vector3df(-15,5,-105), video::SColorf(1.0f, 1.0f, 1.0f));

	// set ambient light
	driver->setAmbientLight(video::SColor(0,60,60,60));</pre></td>
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          <p>The next is just some standard stuff: Add a user controlled camera 
            to the scene, disable mouse cursor, and add a test cube and let it 
            rotate to make the scene more interesting.</p>
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              <td><pre>
	// add fps camera
	scene::ICameraSceneNode* fpsCamera = smgr->addCameraSceneNodeFPS();
	fpsCamera->setPosition(core::vector3df(-50,50,-150));

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

	// create test cube
	scene::ISceneNode* test = smgr->addCubeSceneNode(60);

	// let the cube rotate and set some light settings
	scene::ISceneNodeAnimator* anim = smgr->createRotationAnimator(
		core::vector3df(0.3f, 0.3f,0));

	test->setPosition(core::vector3df(-100,0,-100));
	test->setMaterialFlag(video::EMF_LIGHTING, false); // disable dynamic lighting
	test->addAnimator(anim);
	anim->drop();

	// set window caption
	device->setWindowCaption(L"Irrlicht Engine - Render to Texture and Specular Highlights example");</pre></td>
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          <p> To test out the render to texture feature, we need a render target 
            texture. These are not like standard textures, but need to be created 
            first. To create one, we call IVideoDriver::createRenderTargetTexture() 
            and specify the size of the texture. Please don't use sizes bigger 
            than the frame buffer for this, because the render target shares the 
            zbuffer with the frame buffer. And because we want to render the scene 
            not from the user camera into the texture, we add another, fixed camera 
            to the scene. But before we do all this, we check if the current running 
            driver is able to render to textures. If it is not, we simply display 
            a warning text.</p>
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              <td><pre>// create render target
	video::ITexture* rt = 0;
	scene::ICameraSceneNode* fixedCam = 0;
	

	if (driver->queryFeature(video::EVDF_RENDER_TO_TARGET))
	{
		rt = driver->createRenderTargetTexture(core::dimension2d<s32>(256,256));
		test->setMaterialTexture(0, rt); // set material of cube to render target

		// add fixed camera
		fixedCam = smgr->addCameraSceneNode(0, core::vector3df(10,10,-80),
			core::vector3df(-10,10,-100));
	}
	else
	{
		// create problem text
		gui::IGUISkin* skin = env->getSkin();
		gui::IGUIFont* font = env->getFont("../../media/fonthaettenschweiler.bmp");
		if (font)
			skin->setFont(font);

		gui::IGUIStaticText* text = env->addStaticText(
			L"Your hardware or this renderer is not able to use the "\
			L"render to texture feature. RTT Disabled.",
			core::rect<s32>(150,20,470,60));

		text->setOverrideColor(video::SColor(100,255,255,255));
	}</pre></td>
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          <p> Nearly finished. Now we need to draw everything. Every frame, we 
            draw the scene twice. Once from the fixed camera into the render target 
            texture and once as usual. When rendering into the render target, 
            we need to disable the visibilty of the test cube, because it has 
            the render target texture applied to it.<br>
            That's, wasn't quite complicated I hope. :)</p>
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              <td><pre>while(device->run())
	if (device->isWindowActive())
	{
		driver->beginScene(true, true, 0);

		if (rt)
		{
			// draw scene into render target
			
			// set render target texture
			driver->setRenderTarget(rt, true, true, video::SColor(0,0,0,255));     

			// make cube invisible and set fixed camera as active camera
			test->setVisible(false);
			smgr->setActiveCamera(fixedCam);

			// draw whole scene into render buffer
			smgr->drawAll();                 

			// set back old render target
			driver->setRenderTarget(0);      

			// make the cube visible and set the user controlled camera as active one
			test->setVisible(true);
			smgr->setActiveCamera(fpsCamera);
		}
		
		// draw scene normally
		smgr->drawAll(); 
		env->drawAll();

		driver->endScene();
	}

	if (rt)
		rt->drop(); // drop render target because we created if with a create() method

	device->drop(); // drop device
	return 0;
}
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        <p>&nbsp;</p></div>
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<p>&nbsp;</p>
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