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Initializing Communication with the Direct3D Version 10 DDI

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To initialize communication with the user-mode display driver DLL's version 10 DDI, the Direct3D version 10 runtime first loads the DLL if the DLL is not yet loaded. The Direct3D runtime next calls the user-mode display driver's OpenAdapter10 function through the DLL's export table to open an instance of the graphics adapter. The OpenAdapter10 function is the DLL's only exported Direct3D version 10 function.

In the call to the driver's OpenAdapter10 function, the runtime supplies the pfnQueryAdapterInfoCb adapter callback function in the pAdapterCallbacks member of the D3D10DDIARG_OPENADAPTER structure. The runtime also supplies its version in the Interface and Version members of D3D10DDIARG_OPENADAPTER. The user-mode display driver must verify that it can use this version of the runtime. The user-mode display driver must not fail newer versions of the runtime because newer runtime versions can use previous DDI versions and therefore can correctly communicate with drivers that implement those previous DDI versions. The user-mode display driver returns a table of its adapter-specific functions in the pAdapterFuncs member of D3D10DDIARG_OPENADAPTER.

The user-mode display driver should call the pfnQueryAdapterInfoCb adapter callback function to query for the graphics hardware capabilities from the display miniport driver.

The runtime calls the user-mode display driver's CreateDevice(D3D10) function (one of the driver's adapter-specific functions) to create a display device for handling a collection of render state and to complete the initialization. When the initialization is complete, the Direct3D version 10 runtime can call the display driver-supplied Direct3D version 10 functions, and the user-mode display driver can call the runtime-supplied functions.

The user-mode display driver's CreateDevice(D3D10) function is called with a D3D10DDIARG_CREATEDEVICE structure whose members are set up in the following manner to initialize the user-mode display driver's version 10 DDI:

  • The runtime sets Interface to the version of the interface that the runtime requires from the user-mode display driver.

  • The runtime sets Version to a number that the driver can use to identify when the runtime was built. For example, the driver can use the version number to differentiate between a runtime released with Windows Vista and a runtime released with a subsequent service pack, which might contain a fix that the driver requires.

  • The runtime sets hRTDevice to specify the handle that the driver should use when the driver calls back into the runtime.

  • The runtime sets hDrvDevice to specify the handle that the runtime uses in subsequent driver calls.

  • The runtime supplies a table of its device-specific callback functions in the D3DDDI_DEVICECALLBACKS structure to which pKTCallbacks points. The user-mode display driver calls the runtime-supplied callback functions to access kernel-mode services in the display miniport driver.

  • The user-mode display driver returns a table of its device-specific functions in the D3D10DDI_DEVICEFUNCS structure to which pDeviceFuncs points.

  • The runtime supplies a DXGI_DDI_BASE_ARGS structure to which DXGIBaseDDI points. The runtime and the user-mode display driver supply their DirectX Graphics Infrastructure DDI to this structure.

  • The runtime sets hRTCoreLayer to specify the handle that the driver should use when the driver calls back into the runtime to access core Direct3D 10 functionality (that is, in calls to the functions that the pUMCallbacks member specifies).

  • The runtime supplies a table of its core callback functions in the D3D10DDI_CORELAYER_DEVICECALLBACKS structure to which pUMCallbacks points. The user-mode display driver calls the runtime-supplied core callback functions to refresh state.

Note   The number of display devices (graphics contexts) that can exist simultaneously is limited only by available system memory.