void calculateray(LPD3DXMESH &mesh)
{
	POINT cursorpos;

	//get cursor pos
	GetCursorPos(&cursorpos);

        //get cursor position within window
	ScreenToClient(get_hwndhandler(), &cursorpos);


	float dx=0.0f;
	float dy=0.0f;
	D3DXVECTOR3 origin,objorigin;
	D3DXVECTOR3 dir,objdir;
	D3DXMATRIX project,view,rview,world,rworld;

        // get the matrix of projection
	d3dd->GetTransform(D3DTS_PROJECTION, &project);
        
        // transform cursor position to projection
	dx=(((2.0f*cursorpos.x)/800)-1.0f)/project(1,1);
	dy=-(((2.0f*cursorpos.y)/600)-1.0f)/project(2,2);
         
        //in dir's z axis i set it to 1.0f
	origin=D3DXVECTOR3(0.0f,0.0f,0.0f);
	dir=D3DXVECTOR3(dx,dy,1.0f);
        
        //get inverse matrix of view
	d3dd->GetTransform(D3DTS_VIEW, &view);
	D3DXMatrixInverse(&rview, NULL, &view);
	
        //after i get inverse matrix of view, i apply to dir and origin vector.
        //mean of this is to translate dir and origin to world space 
	dir.x=dir.x*rview._11 + dir.y*rview._21 + dir.z*rview._31;
	dir.y=dir.y*rview._12 + dir.y*rview._22 + dir.z*rview._32;
	dir.z=dir.z*rview._13 + dir.y*rview._23 + dir.z*rview._33;
	origin.x=rview._41;
	origin.y=rview._42;
	origin.z=rview._43;
	
        //get inverse matrix of world 
	d3dd->GetTransform(D3DTS_WORLD, &world);
	D3DXMatrixInverse(&rworld, NULL, &world);

        //after i get inverse matrix of world, i translate origin and dir
        // to model's space, also normalize dir
        //buy the way, objorigin and objdir are new vectors, i use those
        // to store the origin and dir in model's space 
	D3DXVec3TransformCoord(&objorigin, &origin, &rworld);
	D3DXVec3TransformNormal(&objdir, &dir, &rworld);
	D3DXVec3Normalize(&objdir, &objdir);
	
        //calculate intersection with mesh
        BOOL hit;
	DWORD fi;
	float u,v, dist;
	D3DXIntersect(mesh, &origin, &dir, &hit, &fi, &u, &v, &dist, NULL, NULL);


        // if hit is true than show message box
	if(hit)
		MessageBox(0,"hit","hit test", 0);	

}

void setup()
{
	//get the d3d device 
	d3dd=getd3ddevice();

	HRESULT hr=0;

        // load mesh
	hr=D3DXLoadMeshFromX("tiger.x", D3DXMESH_VB_MANAGED, d3dd, &adjbuffer, &materialbuffer, NULL, &numofmaterial, &mesh);
	
	if(hr!=S_OK)
	{
		MessageBox(0, "load mesh fail", "waring", 0);
		meshload=false;
	}
	
	if(meshload==true)
	{
	 material=(D3DXMATERIAL*)materialbuffer->GetBufferPointer();
	 meshmaterial=new D3DMATERIAL9[numofmaterial];
	 texture=new LPDIRECT3DTEXTURE9[numofmaterial];

	 for(DWORD i=0; i < numofmaterial; i++)
	 {
		meshmaterial.Ambient=meshmaterial.Diffuse;
		meshmaterial=material.MatD3D;

		D3DXCreateTextureFromFile(d3dd, material.pTextureFilename, &texture);

	  }
	
	 adjbuffer->Release();
	 materialbuffer->Release();
	}
	
	//position camera
	D3DXVECTOR3 eye(0.0f,0.0f,-5.0f);
	D3DXVECTOR3 lookat(0.0f,0.0f,0.0f);
	D3DXVECTOR3 up(0.0f,1.0f,0.0f);
	D3DXMATRIX v;
	D3DXMatrixLookAtRH(&v, &eye, &lookat, &up);
	d3dd->SetTransform(D3DTS_VIEW, &v);

	//projection
	D3DXMATRIX proj;
	D3DXMatrixPerspectiveFovRH(&proj, -(float)D3DX_PI*0.5f,  (float)800/(float)600, 1.0f, 1000.0f);
	d3dd->SetTransform(D3DTS_PROJECTION, &proj);
	

	
	//setup rendering state
	d3dd->SetRenderState(D3DRS_LIGHTING,false);	
	d3dd->SetRenderState(D3DRS_ZENABLE,true);
	d3dd->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);

}

void cCamera::GetRay( cRay & r, const cVector3d & v, const cMatrix4x4 & pos ){    cVector3d vec = v;    cVector3d vec1 = v;    vec1.z = 1;	    D3DXVec3Unproject( vec, vec, &m_vp, m_projection, m_view, pos );    D3DXVec3Unproject( vec1, vec1, &m_vp, m_projection, m_view, pos );     r.m_pos = vec;    r.m_length = vec1 - vec;}