基于OGRE实现的光线跟踪算法的问题

luyt86 2010-06-23 01:32:46

前几天看到张赐大牛写的一篇文章：《光线追踪技术的理论和实现》http://blog.csdn.net/zhangci226/archive/2010/06/11/5664313.aspx，与是一时兴起就用OGRE实现了一下，但最后渲染时有问题，找了半天还是找不出原因，请高手解答，实现流程和上面博客说的差不多，我是用一张纹理来存储每束光线的结果。



bool CMyTraceListener::FillPixelBuffer(size_t &width,size_t &height)

{

	Ogre::TexturePtr texPtr=Ogre::TextureManager::getSingleton().getByName("MyTraceTex");

	if(!texPtr.isNull())

	{

		texPtr->getBuffer(0,0)->lock(Ogre::HardwareBuffer::HBL_DISCARD);

		const Ogre::PixelBox &pb=texPtr->getBuffer(0,0)->getCurrentLock();



		Ogre::uint32 *data = static_cast<Ogre::uint32*>(pb.data);



		height= pb.getHeight();

		width = pb.getWidth();

		size_t pitch = pb.rowPitch;





		for(size_t y=0; y<height && y<512; ++y)

		{

			for(size_t x=0;x<width && x<512 ;++x)

			{

				Vector3 color=Tracer(m_vecRay[512*y +x],1); //开始光线跟踪

				data[pitch*y +x]=D3DXCOLOR(color[0],color[1],color[2],1.0);

			}

		}





		texPtr->getBuffer(0,0)->unlock();

	}else

	{

		texPtr = Ogre::TextureManager::getSingleton().createManual(

			"MyTraceTex",

			"General",

			Ogre::TEX_TYPE_2D,

			600, 600,

			0, Ogre::PF_A8R8G8B8);

		if(texPtr.isNull())

			return false;



		texPtr->getBuffer(0,0)->lock(Ogre::HardwareBuffer::HBL_DISCARD);

		const Ogre::PixelBox &pb=texPtr->getBuffer(0,0)->getCurrentLock();



		Ogre::uint32 *data = static_cast<Ogre::uint32*>(pb.data);

		height= pb.getHeight();

		width = pb.getWidth();

		size_t pitch = pb.rowPitch;





		for(size_t y=0; /*y<height && */y<=512; ++y)

		{

			for(size_t x=0;/*x<width &&*/ x<=512 ;++x)

			{

				Vector3 color=Tracer(m_vecRay[512*y +x],1);//开始光线跟踪

				data[pitch*y +x]=D3DXCOLOR(color[0],color[1],color[2],1.0);

			}

		}





		texPtr->getBuffer(0,0)->unlock();

	}

	IDirect3DTexture9 *pTex = static_cast<Ogre::D3D9Texture *>(&*texPtr)->getNormTexture();

	char buf[100];

	int i=0;

	sprintf_s( buf , "../auto_texture_%d.png" , i ) ;

	D3DXSaveTextureToFileA( buf , D3DXIFF_PNG , pTex , NULL ) ;//保存结果到文件



        //创建OGRE材质

	Ogre::MaterialPtr pMat=Ogre::MaterialManager::getSingleton().create("MytraceMat",Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);

	if(pMat.isNull())

		return false;





	pMat->getTechnique(0)->getPass(0)->createTextureUnitState("MyTraceTex");

	pMat->getTechnique(0)->getPass(0)->getTextureUnitState(0)->setTextureFiltering(Ogre::FO_LINEAR,Ogre::FO_LINEAR,Ogre::FO_NONE);

	pMat->getTechnique(0)->getPass(0)->getTextureUnitState(0)->setColourOperation(Ogre::LBO_ALPHA_BLEND);

	pMat->getTechnique(0)->getPass(0)->setSceneBlending(Ogre::SBT_TRANSPARENT_ALPHA);



	pMat->getTechnique(0)->getPass(0)->setCullingMode(Ogre::CULL_NONE);



	return true;

}

光线跟踪的函数：



Vector3 CMyTraceListener::Tracer(Ray ray,int depth)

{

	Vector3 color=Vector3::ZERO;

	Ray Reflect;

	double distance = 10000;

	for(int i=0;i<m_vecObject.size();++i)

	{

		if(m_vecObject[i]->isIntersected(ray,distance) == CGObject::INTERSECTED)

		{

			Vector3 p = ray.getPoint(distance);

			Reflect.setOrigin(p);



			Vector3 rayDir = ray.getDirection();

			

			Vector3 N = m_vecObject[i]->GetNormal(p);



			Vector3 rayRelDir=rayDir.reflect(N);

			//rayRelDir = -rayRelDir;

			Reflect.setDirection(rayRelDir);



			N.normalise();

			for(int j=0;j<m_vecLight.size();++j)

			{

				Vector3 ambient = m_vecLight[j]->EvalAmbient(m_vecObject[i]->GetKa());

				Vector3 L = m_vecLight[j]->GetPosition() - p;

				L.normalise();

				Vector3 diffuse = m_vecLight[j]->EvalDiffuse(m_vecObject[i]->GetKd(),

					N,L);

				Vector3 V = m_vCamPos - p;

				V.normalise();

				Vector3 specular = m_vecLight[j]->EvalSpecular(m_vecObject[i]->GetKs(),

					m_vecObject[i]->GetSininess(),N,L,V);

	

				color = ambient+diffuse+specular;

			}

		}

	}



	if(m_iTotalDepth == depth)

		return color;

	else

	{

		Vector3 c = Tracer(Reflect,++depth);

		color += color*c;

		return color;

	}

}

//创建用于查询的光线的函数



bool CMyTraceListener::InitTraceRay(float width,float height)

{

	for(int y=0;y<=height;++y)

		for(int x=0;x<=width;++x)

		{

			float pixel_x = -20.0 + 40.0/width*x;

			float pixel_y = 20.0 - 40.0/height*y;



			Vector3 dir = Vector3(pixel_x,pixel_y,0) - m_vCamPos;

			dir.normalise();

			Ray ray;

			ray.setDirection(dir);

			ray.setOrigin(m_vCamPos);

			m_vecRay.push_back(ray);

		}



		return true;



}