现在我们已经知道如何创建一个Win32窗口程序, 我们现在要学习如何访问DirectX图形, 首先我们需要包含DX9的头文件 d3d9.h 和链接 d3d9.lib . 初始化D3D主要需要以下几个步骤:
- 根据D3D版本创建D3D物体.
- 清空并设置显示参数.
- 使用定义的显示参数, 创建D3D设备.
以下为初始化D3D窗口程序的主要代码, 代码中并没有检测系统支持的格式.
//********************************************************************
// Filename: Main.cpp
// Author: Chinafish
// Modifier: Chinafish
// Created: 2008-3-3 17:55
// Updated: 2008-3-3 17:55
// QQ: 149200849
// MSN: china_fish@msn.com
// Purpose: Initialize D3D window
//====================================================================
// Copyright(C) 2004-2008 by Chinafish. All Rights Reserved.
//********************************************************************
#define STRICT
#define WIN32_LEAN_AND_MEAN
#include "windows.h"
// Link D3D
#include "d3d9.h"
#pragma comment(lib, "d3d9.lib")
#define Release_Safe(p){if(p!=NULL) p->Release();}
#define WINDOW_TITLE "www.csinx.org - Initializing D3D Window (DX9+VC7)"
#define WINDOW_WIDTH 800
#define WINDOW_HEIGHT 600
//-----------------------------------------------------------------------------
// GLOBALS
//-----------------------------------------------------------------------------
HWND g_hWnd = NULL;
LPDIRECT3D9 g_pD3D = NULL;
LPDIRECT3DDEVICE9 g_pd3dDevice = NULL;
//-----------------------------------------------------------------------------
// PROTOTYPES
//-----------------------------------------------------------------------------
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,LPSTR lpCmdLine, int nCmdShow);
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
void InitD3D(void);
void ShutDown(void);
void Render(void);
//-----------------------------------------------------------------------------
// Name: WinMain()
// Desc: The application's entry point
//-----------------------------------------------------------------------------
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow )
{
WNDCLASSEX winClass;
MSG uMsg;
memset(&uMsg,0,sizeof(uMsg));
winClass.lpszClassName = "CLASS_INITD3D_WINDOW";
winClass.cbSize = sizeof(WNDCLASSEX);
winClass.style = CS_HREDRAW | CS_VREDRAW;
winClass.lpfnWndProc = WindowProc;
winClass.hInstance = hInstance;
winClass.hIcon = LoadIcon(hInstance, (LPCTSTR)NULL);
winClass.hIconSm = LoadIcon(hInstance, (LPCTSTR)NULL);
winClass.hCursor = LoadCursor(NULL, IDC_ARROW);
winClass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
winClass.lpszMenuName = NULL;
winClass.cbClsExtra = 0;
winClass.cbWndExtra = 0;
if( !RegisterClassEx(&winClass) )
return E_FAIL;
g_hWnd = CreateWindowEx( NULL, "CLASS_INITD3D_WINDOW",
WINDOW_TITLE,
WS_OVERLAPPEDWINDOW | WS_VISIBLE, 0, 0,
WINDOW_WIDTH, WINDOW_HEIGHT, NULL, NULL,
hInstance, NULL );
if( g_hWnd == NULL )
return E_FAIL;
// Adjust window
RECT rect = { 0, 0, WINDOW_WIDTH, WINDOW_HEIGHT };
AdjustWindowRect( &rect, GetWindowLong( g_hWnd, GWL_STYLE ), FALSE );
SetWindowPos( g_hWnd, 0, 0, 0, rect.right - rect.left, rect.bottom - rect.top,
SWP_NOZORDER | SWP_NOMOVE );
ShowWindow( g_hWnd, nCmdShow );
UpdateWindow( g_hWnd );
// Init D3D
InitD3D();
while( uMsg.message != WM_QUIT )
{
if( PeekMessage( &uMsg, NULL, 0, 0, PM_REMOVE ) )
{
TranslateMessage( &uMsg );
DispatchMessage( &uMsg );
}
else
{
// Render a frame
Render();
}
}
ShutDown();
UnregisterClass( "CLASS_INITD3D_WINDOW", winClass.hInstance );
return uMsg.wParam;
}
//-----------------------------------------------------------------------------
// Name: WindowProc()
// Desc: The window's message handler
//-----------------------------------------------------------------------------
LRESULT CALLBACK WindowProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
{
switch( msg )
{
case WM_KEYDOWN:
{
switch( wParam )
{
case VK_ESCAPE:
PostQuitMessage(0);
break;
}
}
break;
case WM_CLOSE:
{
PostQuitMessage(0);
}
case WM_DESTROY:
{
PostQuitMessage(0);
}
break;
default:
{
return DefWindowProc( hWnd, msg, wParam, lParam );
}
break;
}
return 0;
}
//-----------------------------------------------------------------------------
// Name: InitD3D()
// Desc: Initialize Direct 3D
//-----------------------------------------------------------------------------
void InitD3D( void )
{
// Create D3D
g_pD3D = Direct3DCreate9( D3D_SDK_VERSION );
if( !g_pD3D )
{
return;
}
// Fill parameters
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp, sizeof(d3dpp));
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
d3dpp.Windowed = TRUE;
// Create D3D device
if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL,
g_hWnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp, &g_pd3dDevice ) ) )
{
return;
}
}
//-----------------------------------------------------------------------------
// Name: ShutDown()
// Desc: Release all
//-----------------------------------------------------------------------------
void ShutDown( void )
{
Release_Safe(g_pd3dDevice);
Release_Safe(g_pD3D);
}
//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Render something you want
//-----------------------------------------------------------------------------
void Render( void )
{
// Clear screen with D3DCOLOR_XRGB(255, 0, 255)
g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(255, 0, 255), 1.0f, 0 );
g_pd3dDevice->BeginScene();
// Render geometry here...
g_pd3dDevice->EndScene();
g_pd3dDevice->Present( NULL, NULL, NULL, NULL );
}
在以上代码中我们在创建窗口程序后初始化D3D环境. 首先我们通过 Direct3DCreate9 创建一个 D3D物体 , D3D物体用来配置基于系统显卡的支持能力的D3D程序, 在本例中我们仅用于创建 D3D设备 .
然后我们需要填充 D3DPRESENT_PARAMETERS 结构来设置显示参数, 在创建窗口模式我们只需要设置是否为窗口模式,障碍这里我们设置窗口模式为TRUE, 其他主要设置还有像素格式, 后置缓冲显示方式, 后置缓冲数量, 显示模式等.
设置显示参数以后我们通过 IDirect3D9::CreateDevice 来创建一个 D3D设备 . 现在我们已经完成DirectX图形的初始化并可以使用D3D渲染啦.
我们在渲染时需要通过 IDirect3DDevice9::Clear 指定一个颜色填充后置缓冲区(我们需要用来画东西的表面), D3DCOLOR_XRGB 宏用于指定一种颜色. 需要注意的是我们在渲染任何物体之前都要调用 IDirect3DDevice9::BeginScene 函数并且在结束渲染后调用 IDirect3DDevice9::EndScene . 这主要是告诉DirectX我们需要画一些图形并且已经清过后置缓冲区啦. 最后我们通过调用 IDirect3DDevice9::Present 切换后置缓冲区到前置缓冲区, 将我们画的图形显示到屏幕上.
D3D物体 和 D3D设备 都是 COM物体 , 我们需要在程序结束后通过 Release 将资源释放给Window, 在以上代码中我们使用自定义的Release_Safe宏释放资源.
下图为本例代码执行效果:
