DX锁定顶点缓存的疑惑
//下面的是那本DirectX教程书附带的源码，目的就是简单的画个四边形//但是作者太懒，都不试试自己的代码行不行就拿出来卖了
//有些疑惑，尤其是红色的部分 望高手指教
#include <d3d9.h> // Direct3D头文件
#define SAFE_RELEASE(p) { if(p) { (p)->Release(); (p)=NULL; } }//防止二次释放
wchar_t *g_pClassName = L"VertexBuffer"; // 窗口类名
wchar_t *g_pWindowName = L"顶点缓存示例"; // 窗口标题名
LPDIRECT3DDEVICE9 g_pd3dDevice = NULL; // Direct3D设备接口
LPDIRECT3DVERTEXBUFFER9 g_pVertexBuf = NULL; // 顶点缓存接口
struct CUSTOMVERTEX
{
FLOAT _x, _y, _z, _rhw; // 顶点的位置
DWORD _color; // 顶点的颜色
CUSTOMVERTEX(FLOAT x, FLOAT y, FLOAT z, FLOAT rhw, DWORD color)
: _x(x), _y(y), _z(z), _rhw(rhw), _color(color) {}
};
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)
HRESULT InitDirect3D(HWND hWnd); // 初始化Direct3D
VOID Direct3DRender(); // 渲染图形
VOID Direct3DCleanup(); // 清理Direct3D资源
// 窗口消息处理函数声明
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
//--------------------------------------------------------------------------------------
// Name: WinMain();
// Desc: Windows应用程序入口函数
//--------------------------------------------------------------------------------------
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nShowCmd)
{
// 初始化窗口类
WNDCLASS wndclass;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); // 窗口背景
wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); // 光标形状
wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION); // 窗口小图标
wndclass.hInstance = hInstance;
wndclass.lpfnWndProc = WndProc;
wndclass.lpszClassName = g_pClassName;
wndclass.lpszMenuName = NULL;
wndclass.style = CS_HREDRAW | CS_VREDRAW;
// 注册窗口类
if (!RegisterClass(&wndclass))
return 0;
// 创建窗口
HWND hWnd = CreateWindow(g_pClassName, g_pWindowName, WS_OVERLAPPEDWINDOW,
100, 100, 640, 480, NULL, NULL, wndclass.hInstance, NULL);
// 初始化Direct3D
InitDirect3D(hWnd);
// 显示、更新窗口
ShowWindow(hWnd, SW_SHOWDEFAULT);
UpdateWindow(hWnd);
// 消息循环
MSG msg;
ZeroMemory(&msg, sizeof(msg));
while (msg.message!=WM_QUIT)
{
if (PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
else
{
Direct3DRender(); // 绘制3D场景
}
}
UnregisterClass(g_pClassName, wndclass.hInstance);
return 0;
}
//--------------------------------------------------------------------------------------
// Name: WndProc()
// Desc: 窗口消息处理函数
//--------------------------------------------------------------------------------------
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_PAINT: // 客户区重绘消息
Direct3DRender(); // 渲染图形
ValidateRect(hWnd, NULL); // 更新客户区的显示
break;
case WM_KEYDOWN: // 键盘按下消息
if (wParam == VK_ESCAPE) // ESC键
DestroyWindow(hWnd); // 销毁窗口, 并发送一条WM_DESTROY消息
break;
case WM_DESTROY: // 窗口销毁消息
Direct3DCleanup(); // 清理Direct3D
PostQuitMessage(0); // 退出程序
break;
}
// 默认的消息处理
return DefWindowProc( hWnd, message, wParam, lParam );
}
//--------------------------------------------------------------------------------------
// Name: InitDirect3D()
// Desc: 初始化Direct3D
//--------------------------------------------------------------------------------------
HRESULT InitDirect3D(HWND hWnd)
{
// 创建IDirect3D接口
LPDIRECT3D9 pD3D = NULL; // IDirect3D9接口
pD3D = Direct3DCreate9(D3D_SDK_VERSION); // 创建IDirect3D9接口对象
if (pD3D == NULL) return E_FAIL;
// 获取硬件设备信息
D3DCAPS9 caps; int vp = 0;
pD3D->GetDeviceCaps( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, &caps );
if( caps.DevCaps & D3DDEVCAPS_HWTRANSFORMANDLIGHT )
vp = D3DCREATE_HARDWARE_VERTEXPROCESSING;
else
vp = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
// 创建Direct3D设备接口
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.BackBufferWidth = 640;
d3dpp.BackBufferHeight = 480;
d3dpp.BackBufferFormat = D3DFMT_A8R8G8B8;
d3dpp.BackBufferCount = 1;
d3dpp.MultiSampleType = D3DMULTISAMPLE_NONE;
d3dpp.MultiSampleQuality = 0;
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.hDeviceWindow = hWnd;
d3dpp.Windowed = true;
d3dpp.EnableAutoDepthStencil = true;
d3dpp.AutoDepthStencilFormat = D3DFMT_D24S8;
d3dpp.Flags = 0;
d3dpp.FullScreen_RefreshRateInHz = D3DPRESENT_RATE_DEFAULT;
d3dpp.PresentationInterval = D3DPRESENT_INTERVAL_IMMEDIATE;
pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL,
hWnd, vp, &d3dpp, &g_pd3dDevice);
pD3D->Release();
//////****************************************************************
// 创建顶点缓存
g_pd3dDevice->CreateVertexBuffer(6 * sizeof(CUSTOMVERTEX), 0,
D3DFVF_CUSTOMVERTEX, D3DPOOL_DEFAULT, &g_pVertexBuf, NULL);
// 填充顶点数据
CUSTOMVERTEX *pVertices = NULL;
g_pVertexBuf->Lock(0,6 * sizeof(CUSTOMVERTEX), (void**)&pVertices, 0);
//在其他成功的例子里上面的第二个参数设为0或整个数组的大小结果都行得通
//然后： 前面声明一个指向一个结构的指针，在下面就直接用pVertice[0]...pVertice[i]
//这样算什么写法？ 作者到底为什么会这样？（虽然没达到效果，但是编译是没错的）
pVertices[0] = CUSTOMVERTEX( 220.0f, 120.0f, 0.5f, -1.0f, D3DCOLOR_XRGB(255, 0, 0)); // V0
pVertices[1] = CUSTOMVERTEX( 420.0f, 120.0f, 0.5f, -1.0f, D3DCOLOR_XRGB(0, 255, 0)); // V1
pVertices[2] = CUSTOMVERTEX( 220.0f, 320.0f, 0.5f, -1.0f, D3DCOLOR_XRGB(255, 255, 0)); // V2
pVertices[3] = CUSTOMVERTEX( 420.0f, 120.0f, 0.5f, -1.0f, D3DCOLOR_XRGB(0, 255, 0)); // V1
pVertices[4] = CUSTOMVERTEX( 420.0f, 320.0f, 0.5f, -1.0f, D3DCOLOR_XRGB(0, 0, 255)); // V3
pVertices[5] = CUSTOMVERTEX( 220.0f, 320.0f, 0.5f, -1.0f, D3DCOLOR_XRGB(255, 255, 0)); // V2
g_pVertexBuf->Unlock();
///////********************************8
return S_OK;
}
//--------------------------------------------------------------------------------------
// Name: Direct3DRender()
// Desc: 绘制3D场景
//--------------------------------------------------------------------------------------
VOID Direct3DRender()
{
g_pd3dDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(45, 50, 170), 1.0f, 0);
g_pd3dDevice->BeginScene(); // 开始绘制
// 渲染正方形
g_pd3dDevice->SetStreamSource(0, g_pVertexBuf, 0, sizeof(CUSTOMVERTEX));
g_pd3dDevice->SetFVF(D3DFVF_CUSTOMVERTEX);
g_pd3dDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);
g_pd3dDevice->EndScene(); // 结束绘制
g_pd3dDevice->Present(NULL, NULL, NULL, NULL); // 翻转
}
//--------------------------------------------------------------------------------------
// Name: Direct3DCleanup()
// Desc: 清理Direct3D, 并释放COM接口
//--------------------------------------------------------------------------------------
VOID Direct3DCleanup()
{
SAFE_RELEASE(g_pVertexBuf); // 释放顶点缓存接口
SAFE_RELEASE(g_pd3dDevice); // 释放D3D设备接口
}
[ 本帖最后由 Nitpicker 于 2013-1-3 18:43 编辑 ]
