DXUT框架用來(lái)幫助程序員花更少的時(shí)間來(lái)解決下列問(wèn)題：創(chuàng)建窗口、創(chuàng)建Direct3D設(shè)備、進(jìn)行消息循環(huán)和處理設(shè)備事件。在DXUT框架基礎(chǔ)上編寫(xiě)代碼，可以快速高效地進(jìn)行Direct3D程序設(shè)計(jì)，大多數(shù)Direct3D
SDK示例程序使用了DXUT框架。
下面的代碼是AppFrame示例程序的WinMain函數(shù)：
INT WINAPI wWinMain( HINSTANCE, HINSTANCE, LPWSTR, int )
{
// Enable run-time memory check for debug builds.
#if defined(DEBUG) | defined(_DEBUG)
_CrtSetDbgFlag( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
#endif
// Set the callback functions
DXUTSetCallbackD3D9DeviceAcceptable(IsD3D9DeviceAcceptable);
DXUTSetCallbackD3D9DeviceCreated(OnD3D9CreateDevice);
DXUTSetCallbackD3D9DeviceReset(OnD3D9ResetDevice);
DXUTSetCallbackD3D9FrameRender(OnD3D9FrameRender);
DXUTSetCallbackD3D9DeviceLost(OnD3D9LostDevice);
DXUTSetCallbackD3D9DeviceDestroyed(OnD3D9DestroyDevice);
DXUTSetCallbackDeviceChanging(ModifyDeviceSettings);
DXUTSetCallbackMsgProc(MsgProc);
DXUTSetCallbackFrameMove(OnFrameMove);
// TODO: Perform any application-level initialization here
// Initialize DXUT and create the desired Win32 window and Direct3D device for the application
DXUTInit( true, true ); // Parse the command line and show msgboxes
DXUTSetHotkeyHandling( true, true, true ); // handle the default hotkeys
DXUTSetCursorSettings( true, true ); // Show the cursor and clip it when in full screen
DXUTCreateWindow( L"AppFrame Sample" );
DXUTCreateDevice( true, 640, 480 );
// Start the render loop
DXUTMainLoop();
// TODO: Perform any application-level cleanup here
return DXUTGetExitCode();
}
在上面的代碼中，DXUT框架做了大部分的工作。它創(chuàng)建了一個(gè)窗口和一個(gè)Direct3D設(shè)備，處理消息循環(huán)、并當(dāng)事件發(fā)生時(shí)（例如重新設(shè)置設(shè)備或渲染一幀）調(diào)用應(yīng)用程序提供的回調(diào)函數(shù)。 DXUT框架是模塊化的，所以應(yīng)用程序可以使用DXUT框架的所有函數(shù)或其中的一部分。
下面這組代碼時(shí)一組注冊(cè)函數(shù)的調(diào)用：
// Set the callback functions
DXUTSetCallbackD3D9DeviceAcceptable(IsD3D9DeviceAcceptable);
DXUTSetCallbackD3D9DeviceCreated(OnD3D9CreateDevice);
DXUTSetCallbackD3D9DeviceReset(OnD3D9ResetDevice);
DXUTSetCallbackD3D9FrameRender(OnD3D9FrameRender);
DXUTSetCallbackD3D9DeviceLost(OnD3D9LostDevice);
DXUTSetCallbackD3D9DeviceDestroyed(OnD3D9DestroyDevice);
DXUTSetCallbackDeviceChanging(ModifyDeviceSettings);
DXUTSetCallbackMsgProc(MsgProc);
DXUTSetCallbackFrameMove(OnFrameMove);
以函數(shù)DXUTSetCallbackD3D9DeviceCreated為例，它的聲明如下：
Sets the Direct3D 9 device created callback function.
VOID DXUTSetCallbackD3D9DeviceCreated(
LPDXUTCALLBACKD3D9DEVICECREATED pCallback,
void* pUserContext
);
Parameters
- pCallback
- [in] Pointer to a LPDXUTCALLBACKD3D9DEVICECREATED
callback function. If the callback function is supplied, it will be called
after the Direct3D 9 device has been created. Device creation will happen
during application initialization and if the device is changed. If NULL,
DXUT will not notify the application about device creation.
- pUserContext
- [in] Pointer to a user-defined value which is
passed to the callback function. Typically used by an application to pass a
pointer to a data structure that provides context information for the
callback function. The default value is NULL
Return Values
No return value.
Remarks
This function only needs to be called if the
application supports rendering with Direct3D 9 device.
The LPDXUTCALLBACKD3D9DEVICECREATED callback
function is the appropriate location for the application to create Direct3D 9
device resources that will live through a device reset such as D3DPOOL_MANAGED
or D3DPOOL_SYSTEMMEM memory and that aren't tied to the back buffer size.
Resources created in the LPDXUTCALLBACKD3D9DEVICECREATED callback
function should be released in the LPDXUTCALLBACKD3D9DEVICEDESTROYED callback
function.
LPDXUTCALLBACKD3D9DEVICECREATED
Application-defined resource creation callback
function, called by DXUT after the Direct3D 9 device is created. Passes a
pointer to the newly created Direct3D 9 device.
HRESULT LPDXUTCALLBACKD3D9DEVICECREATED(
IDirect3DDevice9 * pd3dDevice,
CONST D3DSURFACE_DESC * pBackBufferSurfaceDesc,
void* pUserContext
);
Parameters
- pd3dDevice
- [out] Pointer to the newly created Direct3D 9
device.
- pBackBufferSurfaceDesc
- [out] Pointer to the back buffer surface
description
- pUserContext
- [in] Pointer to a user-defined value which is
passed to the callback function. Typically used by an application to pass a
pointer to a data structure that provides context information for the
callback function. The default value is NULL
Return Values
In general, if no error occurs, program the function to
return S_OK. Program the function to return an HRESULT failure code if the
function fails. If DXUT receives a failure HRESULT code, it shuts down the
application.
Remarks
The LPDXUTCALLBACKD3D9DEVICECREATED callback
function is the appropriate location for the application to create Direct3D 9
device resources that will live through a device reset such as D3DPOOL_MANAGED
or D3DPOOL_SYSTEMMEM memory and that aren't tied to the back buffer size.
Resources created in the LPDXUTCALLBACKD3D9DEVICECREATED callback
function should be released in the LPDXUTCALLBACKD3D9DEVICEDESTROYED callback
function.
該注冊(cè)函數(shù)的作用在于通知應(yīng)用程序，在應(yīng)用程序的初始化期間或當(dāng)設(shè)備改變時(shí)，如果需要?jiǎng)?chuàng)建D3DPOOL_MANAGED類(lèi)型的資源，就會(huì)自動(dòng)調(diào)用函數(shù)OnD3D9CreateDevice()進(jìn)行創(chuàng)建。而程序員需要做的就是編寫(xiě)OnD3D9CreateDevice()函數(shù)，告訴應(yīng)用程序創(chuàng)建哪些資源以及如何創(chuàng)建。其他注冊(cè)函數(shù)的作用同樣是通知應(yīng)用程序，使應(yīng)用程序在特定時(shí)機(jī)調(diào)用注冊(cè)函數(shù)指定的具體回調(diào)函數(shù)。程序員的核心工作就是實(shí)現(xiàn)這些具體的回調(diào)函數(shù)，事實(shí)上，這種構(gòu)架正是DXUT框架的核心，也可以把它看成是區(qū)別于Direct3D
API程序的地方。
DXUT框架提供了下列服務(wù)，幫助程序員創(chuàng)建一個(gè)應(yīng)用程序：
（1）簡(jiǎn)化窗口和設(shè)備的創(chuàng)建。
（2）聲明設(shè)備事件（創(chuàng)建、重置、丟失、銷(xiāo)毀）和窗口事件（消息、鍵盤(pán)、鼠標(biāo)）。
（3）在窗口模式和全屏模式間切換，在硬件抽象層設(shè)備和參考設(shè)備間切換。
（4）高分辨率計(jì)時(shí)器。
（5）為自動(dòng)測(cè)試提供命令行支持。
（6）通過(guò)對(duì)話框或API選擇設(shè)備。
（7）紋理GUI控件組，包括IME-enable文本框。
（8）附加雜類(lèi)，例如簡(jiǎn)單的攝像機(jī)類(lèi)。
為使用方便，DXUT框架支持Direct3D設(shè)備和窗口一一對(duì)應(yīng)（一個(gè)設(shè)備只能對(duì)應(yīng)一個(gè)窗口）。對(duì)于需要同時(shí)使用多個(gè)設(shè)備或顯示多個(gè)Direct3D窗口的高級(jí)應(yīng)用程序，該框架不支持。不過(guò)，大多數(shù)應(yīng)用程序只使用一個(gè)窗口和一個(gè)Direct3D設(shè)備，所以大部分應(yīng)用程序都能使用該框架。