Direct3D rendering performance improvements starting in WDDM 1.3

Windows Display Driver Model (WDDM) 1.3 and later drivers can support Microsoft Direct3D rendering performance improvements that let Direct3D 9 hardware make better use of hardware command buffers and counters and make efficient copies of system memory to subresources. These capabilities, which mirror some of the capabilities available for Direct3D Version 10 hardware, are new starting with Windows 8.1.

New Direct3D 11.1 resource trim and map default performance improvements are also available. The map default scenario is outlined in the Behavior changes section below.

Rendering performance reference

This reference section describes the user-mode device driver interfaces (DDIs):

Direct3D rendering performance functions implemented by the user-mode driver

All functions that user-mode display drivers must implement in order to improve rendering performance for Direct3D Level 9 hardware.

These user-mode structures and enumerations support rendering performance improvements and are new or updated for Windows 8.1. All apply to Direct3D Level 9 drivers except for D3D11_1_DDI_FLUSH_FLAGS.

DDI implementation requirements starting with WDDM 1.3

Starting with WDDM 1.3, the following functions are required or optional for user-mode drivers to implement.

Function groupDescription

Direct3D 9 functions that are optional prior to WDDM 1.3. Now required:

Direct3D 9 functions that are available starting with WDDM 1.3. A driver must either implement all of these functions or none of them:

When the WDDM 1.3 and later optional functions immediately above are implemented, these functions have associated behavior changes:

These scenarios apply when GetCaps is called:

  • If D3DDDICAPS_GETD3DQUERYDATA is set, the driver can optionally report support for time stamps, meaning that the Direct3D runtime won't mask support.
  • If D3DDDICAPS_GET_SIMPLE_INSTANCING_SUPPORT is set, the driver can report optional hardware support for instancing.

These Direct3D 11 functions have associated behavior changes:

 

Behavior changes for calls to resource create, map, and unmap functions

For these functions that are implemented by WDDM 1.3 and later drivers, the Direct3D runtime supplies a restricted set of input values for the map default scenario. These restricted values apply only to drivers that support feature level 11.1 and later.

CreateResource(D3D11) function

These input D3D11DDIARG_CREATERESOURCE structure members are restricted:

MemberDescription

ResourceDimension and Usage

These behavior changes only apply when the Direct3D runtime supplies type D3D10DDIRESOURCE_BUFFER for ResourceDimension and type D3D10_DDI_USAGE_DEFAULT for Usage.

BindFlags

The Direct3D runtime sets only the D3D10_DDI_BIND_SHADER_RESOURCE and D3D11_DDI_BIND_UNORDERED_ACCESS values.

MapFlags

If all the other member requirements listed here are met, the runtime can set D3D10_DDI_MAP_READ, D3D10_DDI_MAP_WRITE, and D3D10_DDI_MAP_READWRITE values. The driver must support these values. Values of D3D10_DDI_MAP_WRITE_DISCARD and D3D10_DDI_MAP_WRITE_NOOVERWRITE are invalid.

MiscFlags

The runtime sets only the D3D11_DDI_RESOURCE_MISC_BUFFER_ALLOW_RAW_VIEWS and D3D11_DDI_RESOURCE_MISC_BUFFER_STRUCTURED values.

Format

The runtime sets only the DXGI_FORMAT_UNKNOWN value.

SampleDesc

The runtime sets the DXGI_SAMPLE_DESC.Count member to 1, and the Quality member to zero.

MipLevels

The runtime sets the value to 1.

ArraySize

The runtime sets the value to 1.

pPrimaryDesc

The runtime sets the value to NULL.

 

ResourceMap function

These input parameters to ResourceMap are restricted:

ParameterDescription

hResource

The Direct3D runtime sets only a D3D10DDIRESOURCE_BUFFER resource when a non-zero value for MapFlags is set in the creation call to CreateResource(D3D11).

The runtime sets only the DXGI_FORMAT_UNKNOWN value.

Subresource

The runtime only sets the value to 0.

DDIMap

If all the other member requirements listed here are met, the runtime can set D3D10_DDI_MAP_READ, D3D10_DDI_MAP_WRITE, or D3D10_DDI_MAP_READWRITE values, matching the MapFlags value set in the creation call to CreateResource(D3D11).

Flags

Although the input value from the runtime isn't restricted, the driver must be able to support the D3D10_DDI_MAP_FLAG_DONOTWAIT value.

pMappedSubResource

Although the input value from the runtime isn't restricted, the driver must assign a valid CPU-cacheable pointer to the D3D10DDI_MAPPED_SUBRESOURCE.pData member and must set the RowPitch and DepthPitch to match the size of the buffer and the data provided in pData.

 

ResourceUnmap function

These input parameters to ResourceUnmap are restricted:

ParameterDescription

hDevice

Although the input value from the Direct3D runtime isn't restricted, the value which match the hDevice value from the original ResourceMap call.

hResource

The runtime sets only a D3D10DDIRESOURCE_BUFFER resource when a non-zero value for MapFlags is set in the creation call to CreateResource(D3D11).

Subresource

The runtime only sets the value to 0.

 

 

 

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