DXUT工作模式的简单解析-底层框架

      这里要讨论的是，DXUT中的一般框架。以前看了很多资料了，讲得十分详细。不过我在这里就把一些简单的东西总结一下，比如DXUT的工作机制以及模式。对只想了解一下并且快速上手使用的人应该很有帮助。
      下面要说的只是我自己自学以及领悟到的内容而已，难免有疏漏和错误，希望读者可以帮我指出。

      DXUT，就是DirectX SDK中附带的一个功能齐全的Direct3D底层框架，有各种语言版本，但其实构架都差不多。这里以C++的为标准，SDK版本为June 2008。

      先把DirectX SDK里的EmptyProject安装了，打开工程。

      简单了解的话，只用来看一下这个DXUT.h，我再稍微说一下就应该大概明白了。
      不要被代码吓住！！！往后看吧。这个代码是拿来对照讲的。

// --------------------------------------------------------------------------------------
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// File: DXUT.h
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// --------------------------------------------------------------------------------------
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#pragma once
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#ifndef DXUT_H
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#define DXUT_H
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#ifndef UNICODE
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#error "DXUT requires a Unicode build. See the nearby comments for details"
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//
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// If you are using Microsoft Visual C++ .NET, under the General tab of the project
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// properties change the Character Set to 'Use Unicode Character Set'.
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//
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// Windows XP and later are native Unicode so Unicode applications will perform better.
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// For Windows 98 and Windows Me support, consider using the Microsoft Layer for Unicode (MSLU).
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//
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// To use MSLU, link against a set of libraries similar to this
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// /nod:kernel32.lib /nod:advapi32.lib /nod:user32.lib /nod:gdi32.lib /nod:shell32.lib /nod:comdlg32.lib /nod:version.lib /nod:mpr.lib /nod:rasapi32.lib /nod:winmm.lib /nod:winspool.lib /nod:vfw32.lib /nod:secur32.lib /nod:oleacc.lib /nod:oledlg.lib /nod:sensapi.lib UnicoWS.lib kernel32.lib advapi32.lib user32.lib gdi32.lib shell32.lib comdlg32.lib version.lib mpr.lib rasapi32.lib winmm.lib winspool.lib vfw32.lib secur32.lib oleacc.lib oledlg.lib sensapi.lib dxerr.lib dxguid.lib d3dx9d.lib d3d9.lib comctl32.lib dsound.lib
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// and put the unicows.dll (available for download from msdn.microsoft.com) in the exe's folder.
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//
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// For more details see the MSDN article titled:
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// "MSLU: Develop Unicode Applications for Windows 9x Platforms with the Microsoft Layer for Unicode"
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// at http://msdn.microsoft.com/msdnmag/issues/01/10/MSLU/default.aspx
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//
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#endif
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// --------------------------------------------------------------------------------------
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// Structs
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// --------------------------------------------------------------------------------------
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class CD3DEnumeration;
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struct DXUTDeviceSettings
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{
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UINT AdapterOrdinal;
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D3DDEVTYPE DeviceType;
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D3DFORMAT AdapterFormat;
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DWORD BehaviorFlags;
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D3DPRESENT_PARAMETERS pp;
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} ;
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// --------------------------------------------------------------------------------------
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// Error codes
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// --------------------------------------------------------------------------------------
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#define DXUTERR_NODIRECT3D MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0901)
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#define DXUTERR_NOCOMPATIBLEDEVICES MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0902)
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#define DXUTERR_MEDIANOTFOUND MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0903)
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#define DXUTERR_NONZEROREFCOUNT MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0904)
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#define DXUTERR_CREATINGDEVICE MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0905)
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#define DXUTERR_RESETTINGDEVICE MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0906)
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#define DXUTERR_CREATINGDEVICEOBJECTS MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0907)
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#define DXUTERR_RESETTINGDEVICEOBJECTS MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0908)
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#define DXUTERR_INCORRECTVERSION MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x0909)
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// --------------------------------------------------------------------------------------
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// Callback registration
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// --------------------------------------------------------------------------------------
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typedef bool (CALLBACK * LPDXUTCALLBACKISDEVICEACCEPTABLE)( D3DCAPS9 * pCaps, D3DFORMAT AdapterFormat, D3DFORMAT BackBufferFormat, bool bWindowed, void * pUserContext );
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typedef bool (CALLBACK * LPDXUTCALLBACKMODIFYDEVICESETTINGS)( DXUTDeviceSettings * pDeviceSettings, const D3DCAPS9 * pCaps, void * pUserContext );
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typedef HRESULT (CALLBACK * LPDXUTCALLBACKDEVICECREATED)( IDirect3DDevice9 * pd3dDevice, const D3DSURFACE_DESC * pBackBufferSurfaceDesc, void * pUserContext );
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typedef HRESULT (CALLBACK * LPDXUTCALLBACKDEVICERESET)( IDirect3DDevice9 * pd3dDevice, const D3DSURFACE_DESC * pBackBufferSurfaceDesc, void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKDEVICEDESTROYED)( void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKDEVICELOST)( void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKFRAMEMOVE)( IDirect3DDevice9 * pd3dDevice, double fTime, float fElapsedTime, void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKFRAMERENDER)( IDirect3DDevice9 * pd3dDevice, double fTime, float fElapsedTime, void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKKEYBOARD)( UINT nChar, bool bKeyDown, bool bAltDown, void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKMOUSE)( bool bLeftButtonDown, bool bRightButtonDown, bool bMiddleButtonDown, bool bSideButton1Down, bool bSideButton2Down, int nMouseWheelDelta, int xPos, int yPos, void * pUserContext );
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typedef LRESULT (CALLBACK * LPDXUTCALLBACKMSGPROC)( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, bool * pbNoFurtherProcessing, void * pUserContext );
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typedef void (CALLBACK * LPDXUTCALLBACKTIMER)( UINT idEvent, void * pUserContext );
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// Device callbacks
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void DXUTSetCallbackDeviceCreated( LPDXUTCALLBACKDEVICECREATED pCallbackDeviceCreated, void * pUserContext = NULL );
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void DXUTSetCallbackDeviceReset( LPDXUTCALLBACKDEVICERESET pCallbackDeviceReset, void * pUserContext = NULL );
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void DXUTSetCallbackDeviceLost( LPDXUTCALLBACKDEVICELOST pCallbackDeviceLost, void * pUserContext = NULL );
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void DXUTSetCallbackDeviceDestroyed( LPDXUTCALLBACKDEVICEDESTROYED pCallbackDeviceDestroyed, void * pUserContext = NULL );
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void DXUTSetCallbackDeviceChanging( LPDXUTCALLBACKMODIFYDEVICESETTINGS pCallbackModifyDeviceSettings, void * pUserContext = NULL );
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// Frame callbacks
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void DXUTSetCallbackFrameMove( LPDXUTCALLBACKFRAMEMOVE pCallbackFrameMove, void * pUserContext = NULL );
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void DXUTSetCallbackFrameRender( LPDXUTCALLBACKFRAMERENDER pCallbackFrameRender, void * pUserContext = NULL );
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// Message callbacks
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void DXUTSetCallbackKeyboard( LPDXUTCALLBACKKEYBOARD pCallbackKeyboard, void * pUserContext = NULL );
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void DXUTSetCallbackMouse( LPDXUTCALLBACKMOUSE pCallbackMouse, bool bIncludeMouseMove = false , void * pUserContext = NULL );
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void DXUTSetCallbackMsgProc( LPDXUTCALLBACKMSGPROC pCallbackMsgProc, void * pUserContext = NULL );
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// --------------------------------------------------------------------------------------
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// Initialization
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// --------------------------------------------------------------------------------------
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HRESULT DXUTInit( bool bParseCommandLine = true , bool bHandleDefaultHotkeys = true , bool bShowMsgBoxOnError = true , bool bHandleAltEnter = true );
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// Choose either DXUTCreateWindow or DXUTSetWindow. If using DXUTSetWindow, consider using DXUTStaticWndProc
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HRESULT DXUTCreateWindow( const WCHAR * strWindowTitle = L " Direct3D Window " ,
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HINSTANCE hInstance = NULL, HICON hIcon = NULL, HMENU hMenu = NULL,
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int x = CW_USEDEFAULT, int y = CW_USEDEFAULT );
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HRESULT DXUTSetWindow( HWND hWndFocus, HWND hWndDeviceFullScreen, HWND hWndDeviceWindowed, bool bHandleMessages = true );
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LRESULT CALLBACK DXUTStaticWndProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam );
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// Choose either DXUTCreateDevice or DXUTSetDevice or DXUTCreateDeviceFromSettings
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HRESULT DXUTCreateDevice( UINT AdapterOrdinal = D3DADAPTER_DEFAULT, bool bWindowed = true ,
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int nSuggestedWidth = 0 , int nSuggestedHeight = 0 ,
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LPDXUTCALLBACKISDEVICEACCEPTABLE pCallbackIsDeviceAcceptable = NULL,
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LPDXUTCALLBACKMODIFYDEVICESETTINGS pCallbackModifyDeviceSettings = NULL,
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void * pUserContext = NULL );
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HRESULT DXUTCreateDeviceFromSettings( DXUTDeviceSettings * pDeviceSettings, bool bPreserveInput = false , bool bClipWindowToSingleAdapter = true );
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HRESULT DXUTSetDevice( IDirect3DDevice9 * pd3dDevice );
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// Choose either DXUTMainLoop or implement your own main loop
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HRESULT DXUTMainLoop( HACCEL hAccel = NULL );
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// If not using DXUTMainLoop consider using DXUTRender3DEnvironment
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void DXUTRender3DEnvironment();
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// --------------------------------------------------------------------------------------
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// Finding valid device settings
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// --------------------------------------------------------------------------------------
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enum DXUT_MATCH_TYPE
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{
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DXUTMT_IGNORE_INPUT = 0, // Use the closest valid value to a default
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DXUTMT_PRESERVE_INPUT, // Use input without change, but may cause no valid device to be found
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DXUTMT_CLOSEST_TO_INPUT // Use the closest valid value to the input
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} ;
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struct DXUTMatchOptions
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{
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DXUT_MATCH_TYPE eAdapterOrdinal;
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DXUT_MATCH_TYPE eDeviceType;
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DXUT_MATCH_TYPE eWindowed;
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DXUT_MATCH_TYPE eAdapterFormat;
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DXUT_MATCH_TYPE eVertexProcessing;
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DXUT_MATCH_TYPE eResolution;
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DXUT_MATCH_TYPE eBackBufferFormat;
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DXUT_MATCH_TYPE eBackBufferCount;
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DXUT_MATCH_TYPE eMultiSample;
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DXUT_MATCH_TYPE eSwapEffect;
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DXUT_MATCH_TYPE eDepthFormat;
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DXUT_MATCH_TYPE eStencilFormat;
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DXUT_MATCH_TYPE ePresentFlags;
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DXUT_MATCH_TYPE eRefreshRate;
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DXUT_MATCH_TYPE ePresentInterval;
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} ;
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HRESULT DXUTFindValidDeviceSettings( DXUTDeviceSettings * pOut, DXUTDeviceSettings * pIn = NULL, DXUTMatchOptions * pMatchOptions = NULL );
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150

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// --------------------------------------------------------------------------------------
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// Common Tasks
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// --------------------------------------------------------------------------------------
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void DXUTSetCursorSettings( bool bShowCursorWhenFullScreen, bool bClipCursorWhenFullScreen );
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void DXUTSetMultimonSettings( bool bAutoChangeAdapter );
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void DXUTSetShortcutKeySettings( bool bAllowWhenFullscreen = false , bool bAllowWhenWindowed = true ); // Controls the Windows key, and accessibility shortcut keys
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void DXUTSetWindowSettings( bool bCallDefWindowProc = true );
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void DXUTSetConstantFrameTime( bool bConstantFrameTime, float fTimePerFrame = 0.0163f );
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HRESULT DXUTSetTimer( LPDXUTCALLBACKTIMER pCallbackTimer, float fTimeoutInSecs = 1.0f , UINT * pnIDEvent = NULL, void * pCallbackUserContext = NULL );
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HRESULT DXUTKillTimer( UINT nIDEvent );
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HRESULT DXUTToggleFullScreen();
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HRESULT DXUTToggleREF();
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void DXUTPause( bool bPauseTime, bool bPauseRendering );
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void DXUTResetFrameworkState();
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void DXUTShutdown( int nExitCode = 0 );
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167

168

// --------------------------------------------------------------------------------------
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// State Retrieval
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// --------------------------------------------------------------------------------------
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IDirect3D9 * DXUTGetD3DObject(); // Does not addref unlike typical Get* APIs
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IDirect3DDevice9 * DXUTGetD3DDevice(); // Does not addref unlike typical Get* APIs
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DXUTDeviceSettings DXUTGetDeviceSettings();
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D3DPRESENT_PARAMETERS DXUTGetPresentParameters();
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const D3DSURFACE_DESC * DXUTGetBackBufferSurfaceDesc();
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const D3DCAPS9 * DXUTGetDeviceCaps();
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HINSTANCE DXUTGetHINSTANCE();
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HWND DXUTGetHWND();
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HWND DXUTGetHWNDFocus();
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HWND DXUTGetHWNDDeviceFullScreen();
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HWND DXUTGetHWNDDeviceWindowed();
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RECT DXUTGetWindowClientRect();
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RECT DXUTGetWindowClientRectAtModeChange(); // Useful for returning to windowed mode with the same resolution as before toggle to full screen mode
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RECT DXUTGetFullsceenClientRectAtModeChange(); // Useful for returning to full screen mode with the same resolution as before toggle to windowed mode
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double DXUTGetTime();
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float DXUTGetElapsedTime();
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bool DXUTIsWindowed();
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float DXUTGetFPS();
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LPCWSTR DXUTGetWindowTitle();
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LPCWSTR DXUTGetFrameStats( bool bIncludeFPS = false );
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LPCWSTR DXUTGetDeviceStats();
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bool DXUTIsRenderingPaused();
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bool DXUTIsTimePaused();
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bool DXUTIsActive();
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int DXUTGetExitCode();
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bool DXUTGetShowMsgBoxOnError();
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bool DXUTGetHandleDefaultHotkeys();
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bool DXUTIsKeyDown( BYTE vKey ); // Pass a virtual-key code, ex. VK_F1, 'A', VK_RETURN, VK_LSHIFT, etc
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bool DXUTIsMouseButtonDown( BYTE vButton ); // Pass a virtual-key code: VK_LBUTTON, VK_RBUTTON, VK_MBUTTON, VK_XBUTTON1, VK_XBUTTON2
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bool DXUTGetAutomation(); // Returns true if -automation parameter is used to launch the app
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#endif
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千万别被代码吓住。对于不需要深入理解的我们来说，大多数都是不需要关心的。如果您需要深入理解的话，我非常抱歉我帮不上忙。在CPPBLOG里面有个标题为“天行健君子当自强不息”的一个BLOG里面有专门详细解析DXUT的文章。链接请自己百度一下吧。

于是我们来关注一下这个优美的框架。它定义了很多回调函数，以及留了许多接口。
我们需要关心的是这几个：
DXUTSetCallbackDeviceCreated
      为框架挂接上Direct3D设备创建后的回调函数
DXUTSetCallbackDeviceReset
      挂接Direct3D设备重置后的回调函数
DXUTSetCallbackDeviceLost
      挂接Direct3D设备丢失后的回调函数
DXUTSetCallbackDeviceDestroyed
      挂接Direct3D设备销毁后的回调函数
DXUTSetCallbackFrameRender
      挂接每帧渲染场景时的回调函数
DXUTSetCallbackFrameMove
      挂接每帧渲染前需要更新场景时的回调函数
DXUTSetCallbackMouse
      挂接鼠标事件的回调函数
DXUTSetCallbackKeyboard
      挂接键盘事件的回调函数

于是我们打开EmptyProject.cpp
看着WinMain函数

// --------------------------------------------------------------------------------------
2

// Initialize everything and go into a render loop
3

// --------------------------------------------------------------------------------------
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INT WINAPI WinMain( HINSTANCE, HINSTANCE, LPSTR, int )
5

{
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//设置回调函数
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DXUTSetCallbackDeviceCreated( OnCreateDevice );
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DXUTSetCallbackDeviceReset( OnResetDevice );
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DXUTSetCallbackDeviceLost( OnLostDevice );
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DXUTSetCallbackDeviceDestroyed( OnDestroyDevice );
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DXUTSetCallbackMsgProc( MsgProc );
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DXUTSetCallbackFrameRender( OnFrameRender );
14

DXUTSetCallbackFrameMove( OnFrameMove );
15

DXUTSetCallbackMouse( OnMouseEvent ,true);//第二个参数是指是否包含鼠标移动事件
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DXUTSetCallbackKeyboard( OnKeyEvent );
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// 这里写在程序底层初始化前需要的代码
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// 初始化DXUT、程序窗口、Direct3D设备
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DXUTInit( true, false, true ); // Parse the command line, handle the default hotkeys, and show msgboxes
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DXUTSetCursorSettings( true, true ); // Show the cursor and clip it when in full screen
24

DXUTCreateWindow( “EmptyProject”);//窗口标题
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DXUTCreateDevice( D3DADAPTER_DEFAULT, true, 640, 480, IsDeviceAcceptable, ModifyDeviceSettings );//创建设备
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// 开始DXUT主循环
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DXUTMainLoop();
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// 这里写清理底层的代码
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return DXUTGetExitCode();
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}

看见了么，在这里挂接了需要的回调函数，不如我们将他们叫做“事件”，这样更好理解。
自己看一下就能明白那些代码的意思了

OnCreateDevice OnResetDevice OnLostDevice OnDestroyDevice MSgProc OnFrameRender OnFrameMove OnMouseEvent OnKetEvent
这些都是已经定义好的CALLBACK，我们的框架将从DXUTMainLoop()这里开始

简单来说，我们需要了解的就只有这些事件的触发顺序了。
HRESULT CALLBACK OnCreateDevice( Device* pd3dDevice, const D3DSURFACE_DESC* pBackBufferSurfaceDesc, void* pUserContext )
      这个事件在设备创建完毕时就会触发，最先触发的东西。第一个参数是创建后的设备，第二个是设备的表面参数。pUserContext不需要关心，因此不讨论。下同。

HRESULT CALLBACK OnResetDevice( Device* pd3dDevice, const D3DSURFACE_DESC* pBackBufferSurfaceDesc, void* pUserContext )
      这个事件在设备重置的时候会触发。那么什么叫做设备重置呢？等下会和设备丢失一起说。第一个参数是重置后的设备，第二个是重置后设备的表面参数。

void CALLBACK OnLostDevice( void* pUserContext )
      这个事件在设备丢失的时候会触发。举个简单的例子，把窗口最小化的时候设备会丢失，而恢复的时候设备会重置。从全屏换为窗口的时候也会丢失并且重置。大概就是改变窗口的大小、位置、是否全屏的时候，会导致设备丢失，随后恢复的时候会重置。这两个事件的触发就是为了在窗口改变的时候重新设置一些参数，让画面适应当前窗口设置。

void CALLBACK OnFrameMove( Device* pd3dDevice, double fTime, float fElapsedTime, void* pUserContext )
      这个事件在每帧绘制前会触发，为的是更新场景信息。第一个参数是传入的Direct3D设备，第二个参数是从第一次触发这个事件到现在为止的时间，第三个参数是这次触发此事件距上次的时间。

void CALLBACK OnFrameRender( Device* pd3dDevice, double fTime, float fElapsedTime, void* pUserContext )
      这个事件在每帧渲染屏幕的时候触发。参数意义和OnFrameMove一样。

void CALLBACK OnMouseEvent(bool bLeftButtonDown, bool bRightButtonDown, bool bMiddleButtonDown, bool bSideButton1Down,
         bool bSideButton2Down, int nMouseWheelDelta, int xPos, int yPos, void* pUserContext)
      这个事件在鼠标有动作的时候触发。bLeftButtonDown:左键是否按下，bRighButtonDown:右键是否按下，bMiddleButtonDown:中间键是否按下，bSidebutton1Down:边键1是否按下，bSideButton2Down:边键2是否按下，nMouseWheelDelta:滚轮的滚动值，向手指指的方向滚动一格是-120，反之则为120，xPos:在窗口中的X坐标，yPos:在窗口中的Y坐标。

void CALLBACK OnKeyEvent( UINT nChar, bool bKeyDown, bool bAltDown, void* pUserContext )
      这个事件在键盘有动作的时候触发。nChar:发生动作的键，bKeyDown:发生动作的键是被按下还是被抬起，bAltDown:Alt键是否同时被按下。

这些了解了后，你就可以开始干事儿了。你可以把上面的回调函数都当做事件来看，而且是多线程的，这样更方便。
总结一下事件顺序：

如上图所示，DXUT的工作顺序大概就是这样。对于不需要深入了解DXUT工作细节来说，已经差不多了。

现在应该对框架的工作机制有一定得认识了，这篇简单的文章也就这样结束了。下一篇还是预告了吧，是在DXUT框架下，关于2D方面的东西。

顺便说一些DXUT.h中比较实用的接口
163行:void DXUTPause( bool bPauseTime, bool bPauseRendering ); 让OnFrameMove和OnFrameRender事件暂停或恢复触发，第一个参数为是否停止计时，第二个为是否停止绘制。
178行:HWND DXUTGetHWND();获取目前窗口句柄
182行:RECT DXUTGetWindowClientRect();
188行:float DXUTGetFPS();获取当前的FPS（Frame Per second 每秒帧数）
差不多就这些。

以上的代码在EmptyProject里面全部都有，这篇文章只是帮还没有接触过的新手入门而已。请勿鄙视，有任何意见和建议请提出，谢谢了。

现在已经傻瓜式地把框架搭建好了，并且可以简单使用了。那么下一步该干嘛？干事儿呗。
下一篇：Direct3D中的简单2D运用。有空再写了，先预告了吧。

DXUT工作模式的简单解析-底层框架

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