/*
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.

In the beginning, everything as usual. Include the needed headers, ask the user for the rendering
driver, create the Irrlicht Device:
*/

#include <irrlicht.h>
#include <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("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) Burning's 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),
		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();
	
	/*
	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
	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.
	*/

	// 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));
		fairy->setMD2Animation ( scene::EMAT_STAND );
	}
	
	/*
	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. 
	*/

	// 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
	smgr->setAmbientLight(video::SColor(0,60,60,60));
	
	/*
	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.
	*/

	// 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");
	
	/*
	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.
	*/

	// 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));
	}
	
	/*
	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.
	That's, wasn't quite complicated I hope. :)
	*/

	int lastFPS = -1;

	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
			// The buffer might have been distorted, so clear it
			driver->setRenderTarget(0, true, true, 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();

		// display frames per second in window title
		int fps = driver->getFPS();
		if (lastFPS != fps)
		{
			core::stringw str = L"Irrlicht Engine - Render to Texture and Specular Highlights example";
			str += " FPS:";
			str += fps;

			device->setWindowCaption(str.c_str());
			lastFPS = fps;
		}
	}

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

	device->drop(); // drop device
	return 0;
}
