DDI Changes for Direct3D Version 9 Drivers
This section applies only to Windows 7 and later operating systems.
XR_BIAS is the only new extended format ability that Windows 7 makes available to user-mode display drivers that only support the Direct3D version 9 DDI.
Such a user-mode display driver can indicate that it supports the D3DDDIFMT_A2B10G10R10_XR_BIAS format value from the D3DDDIFORMAT enumeration. The driver indicates such support by creating an entry in the array of populated FORMATOP structures in the pData member of the D3DDDIARG_GETCAPS structure that the driver returns from a call to its GetCaps function with the D3DDDICAPS_GETFORMATDATA value set in the Type member of D3DDDIARG_GETCAPS. This entry should indicate, in the Operations member of FORMATOP, all of the typical operations that the runtime can perform on surfaces with the D3DDDIFMT_A2B10G10R10_XR_BIAS format. For example, the driver should set the FORMATOP_*_RENDERTARGET bits in Operations. The driver must also set the FORMATOP_DISPLAYMODE and FORMATOP_3DACCELERATION bits in Operations.
If the driver returns a FORMATOP entry for the D3DDDIFMT_A2B10G10R10_XR_BIAS format, the driver can subsequently receive calls to its CreateResource function to create resources with the D3DDDIFMT_A2B10G10R10_XR_BIAS format set in the Format member of the D3DDDIARG_CREATERESOURCE structure.
The driver only receives requests to create resources with the D3DDDIFMT_A2B10G10R10_XR_BIAS format for full-screen flipping chains. The Desktop Windows Manager (DWM) handles windowed presentation of XR_BIAS in shader code. The driver should treat D3DDDIFMT_A2B10G10R10_XR_BIAS-format resources as the D3DDDIFMT_A2B10G10R10 format in all operations except scan out, For example, the driver can treat D3DDDIFMT_A2B10G10R10_XR_BIAS-format resources as the D3DDDIFMT_A2B10G10R10 format for blending, filtering, and format-conversion operations. The only difference is how XR_BIAS affects scan-out. For more information about scan-out, see BGRA Scan-Out Support.