#include<d3d9.h> /*this includes d3d9.h, it appears hat the forums can't take the less than and greater than symbols*/

#pragma comment(lib, "d3d(.lib")
#pragma comment(lib, "d3dx9.lib")

#define WINDOW_CLASS "UGPDX"
#define WINDOW_NAME "Drawing Lines"

//function prototypes
bool InitializeD3D(HWND hWnd, bool fullscreen);
bool InitializeObjects();
void RenderScene();
void Shutdown();

//direct3d object and device
LPDIRECT3D9 g_D3D = NULL;
LPDIRECT3DDEVICE9 g_D3DDevice = NULL;

//Vertex Buffer to hold the geometry
LPDIRECT3DVERTEXBUFFER9 g_VertexBuffer = NULL;

//a structure for vertex type
struct stD3DVertex
{
   float x, y, z;
   unsigned long color;
};

//custom FVF, which describes custom vertex structure
#define D3DFVF_VERTEX (D3DFVF_XYZ | D3DFVF_DIFFUSE)

LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp)
{
   switch(msg)
   {
      case WM_DESTROY:
           PostQuitMessage(0);
           return 0;
           break;
           
      case WM_KEYUP:
           if(wp == VK_ESCAPE) PostQuitMessage(0);
           break;
           }
   return DefWindowProc(hWnd, msg, wp, lp);
}

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE prevhInst,
                   LPSTR cmdLine, int show)
                   
{
   //register window class
   WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc,
                     0, 0, GetModuleHandle(NULL), NULL, NULL,
                     NULL, NULL, WINDOW_CLASS, NULL };
   RegisterClassEx(&wc);
   
//create application's window
HWND hWnd = CreateWindow(WINDOW_CLASS, WINDOW_NAME,
                         WS_OVERLAPPEDWINDOW, 100, 100,
                         640, 480, GetDesktopWindow(), NULL,
                         wc.hInstance, NULL);

//Initialize Direct3D
if(InitializeD3D(hWnd, false))
{
   //show the window
   ShowWindow(hWnd, SW_SHOWDEFAULT);
   UpdateWindow(hWnd);
   
   //enter the message loop
   MSG msg;
   ZeroMemory(&msg, sizeof(msg));
   
   while(msg.message != WM_QUIT)
   {
      if(PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE))
      {
         TranslateMessage(&msg);
         DispatchMessage(&msg);
         }
         else
         RenderScene();
         }
      }
   //release all resources
   Shutdown();
   //Unregister our window
   UnregisterClass(WINDOW_CLASS, wc.hInstance);
   return 0;
}

bool InitializeD3D(HWND hWnd, bool fullscreen)
{
   D3DDISPLAYMODE displayMode;
   
   //create the D3D object
   g_D3D = Direct3DCreate9(D3D_SDK_VERSION);
   if(g_D3D == NULL) return false;
   
   //get the desktop display mode
   if(FAILED(g_D3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT,
      &displayMode))) return false;
      
   //set up the structure used to create the d3ddevice
   D3DPRESENT_PARAMETERS d3dpp;
   ZeroMemory(&d3dpp, sizeof(d3dpp));
   
   if(fullscreen)
   {
      d3dpp.Windowed = FALSE;
      d3dpp.BackBufferWidth = 640;
      d3dpp.BackBufferHeight = 480;
}
else
d3dpp.Windowed = TRUE;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.BackBufferFormat = displayMode.Format;
//create the d3ddevice
if(FAILED(g_D3D->CreateDevice(D3DADAPTER_DEFAULT,
   D3DDEVTYPE_HAL, hWnd, D3DCREATE_HARDWARE_VERTEXPROCESSING,
   &d3dpp, &g_D3DDevice))) return false;
   
//Initialize any objects we'll be displaying
if(!InitializeObjects()) return false;

return true;
}

bool InitializeObjects()
{
   unsigned long col = D3DCOLOR_XRGB(255, 255, 255);
   
   //fill in our structure to draw an object
   //x, y, z, color
   stD3DVertex objData[] =
   {
      { 420.0f, 150.0f, 0.5f, col, },
      { 420.0f, 350.0f, 0.5f, col, },
      { 220.0f, 150.0f, 0.5f, col, },
      { 220.0f, 350.0f, 0.5f, col, },
      };
      
//create the vertex buffer
if(FAILED(g_D3DDevice->CreateVertexBuffer(sizeof(objData), 0,
   D3DFVF_VERTEX, D3DPOOL_DEFAULT, &g_VertexBuffer,
   NULL))) return false;
          
//fill the vertex buffer
void *ptr;

if(FAILED(g_VertexBuffer->Lock(0, sizeof(objData),
   (void**)&ptr, 0))) return false;
   
   memcpy(ptr, objData, sizeof(objData));
   
   g_VertexBuffer->Unlock();
   
   return true;
}

void RenderScene()
{
   //clear backbuffer
   g_D3DDevice->Clear(0, NULL, D3DCLEAR_TARGET,
                      D3DCOLOR_XRGB(0,0,0), 1.0f, 0);
                      
   //begin the scene and start rendering
   g_D3DDevice->BeginScene();
   
   //render object
   g_D3DDevice->SetStreamSource(0, g_VertexBuffer, 0,
                                sizeof(stD3DVertex));
   g_D3DDevice->SetFVF(D3DFVF_VERTEX);
   g_D3DDevice->DrawPrimitive(D3DPT_LINELIST, 0, 2);
   //end the scene, stop rendering
   g_D3DDevice->EndScene();
   
   //display the scene
   g_D3DDevice->Present(NULL, NULL, NULL, NULL);
}

void Shutdown()
{
   if(g_D3DDevice != NULL) g_D3DDevice->Release();
   if(g_D3D != NULL) g_D3D->Release();
   if(g_VertexBuffer != NULL) g_VertexBuffer->Release();
   
   g_D3DDevice = NULL;
   g_D3D = NULL;
   g_VertexBuffer = NULL;
}