定点格式？

appleshao

#include<d3d9.h>

#pragma comment(lib, "d3d9.lib")
#pragma comment(lib, "d3dx9.lib")

#define WINDOW_CLASS "UGPDX"
#define WINDOW_NAME  "Drawing a Triangle"

// 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 our custom vertex type
struct stD3DVertex
{
    float x, y, z;
    unsigned long color;
};

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


LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
   switch(msg)
      {
         case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
            break;

         case WM_KEYUP:
            if(wParam == VK_ESCAPE) PostQuitMessage(0);
            break;
      }

   return DefWindowProc(hWnd, msg, wParam, lParam);
}


int WINAPI WinMain(HINSTANCE hInst, HINSTANCE prevhInst, LPSTR cmdLine, int show)
{
   // Register the window class
   WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc, 0L, 0L,
                     GetModuleHandle(NULL), NULL, NULL, NULL, NULL,
                     WINDOW_CLASS, NULL };
   RegisterClassEx(&wc);

   // Create the 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 any and 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_SOFTWARE_VERTEXPROCESSING, &d3dpp, &g_D3DDevice)))
      {
         return false;
      }

   // Initialize any objects we will be displaying.
   if(!InitializeObjects()) return false;

   return true;
}


bool InitializeObjects()
{
   // Fill in our structure to draw a triangle.
   // x, y, z, color.
   stD3DVertex objData[] =
      {
         { 320.0f, 150.0f, 0, D3DCOLOR_XRGB(255, 255, 45), },
         { 420.0f, 350.0f, 0, D3DCOLOR_XRGB(255, 30,50), },
         { 220.0f, 350.0f, 0, D3DCOLOR_XRGB(110, 255, 0), },
      };

   // 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 the backbuffer.
   g_D3DDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(255,255,255), 1.0f, 0);

   // Begin the scene.  Start rendering.
   g_D3DDevice->BeginScene();

      // Bind data to the stream, set fvf so D3D knows how our data
      // is made up, then render the object.
      g_D3DDevice->SetStreamSource(0, g_VertexBuffer, 0, sizeof(stD3DVertex));
      g_D3DDevice->SetFVF(D3DFVF_VERTEX);
      g_D3DDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);

   // End the scene.  Stop rendering.
   g_D3DDevice->EndScene();

   // Display the scene.
   g_D3DDevice-&gtresent(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();
}

程序本来是D3DFVF_XYZRHW，我给改成了D3DFVF_XYZ，并且删除了定点结构的W。为什么这样修改后没有办法显示三角形求解释 [em17]

appleshao

似乎好像用D3DFVF_XYZ 画图元的话，需要自己设置投影什么的？请各位高手指教

onemoo

使用D3DFVF_XYZRHW，D3D会认为数据是变换后的结果，直接按坐标位置绘制。
如果用D3DFVF_XYZ，那么这些数据会经过整个3D流水线的变换。如果你想要绘制到指定位置，就须自行设置相应的投影矩阵。