D3DKMTRender function (d3dkmthk.h)

The D3DKMTRender function submits the current command buffer to the Microsoft DirectX graphics kernel subsystem (Dxgkrnl.sys).

Syntax

NTSTATUS D3DKMTRender(
  D3DKMT_RENDER *unnamedParam1
);

Parameters

unnamedParam1

pData [in, out]

A pointer to a D3DKMT_RENDER structure that describes parameters for submitting the current command buffer to the graphics kernel subsystem.

Return value

D3DKMTRender returns one of the following values:

This function might also return other NTSTATUS values.

Remarks

A command buffer typically contains many graphics commands.

If D3DKMTRender returns STATUS_GRAPHICS_ALLOCATION_INVALID, the OpenGL ICD should re-open or re-create the primary handle, replace all references in the command buffer to the previous handle with the new handle, and then call D3DKMTRender again to resubmit the buffer.

After a call to D3DKMTRender, the OpenGL ICD should determine the base address and size of the command buffer that it should use for its next submission from the values that are returned in the pCommandBuffer and CommandBufferSize members of the D3DKMT_RENDER structure that is pointed to by the pData parameter.

For a device that uses guaranteed DMA buffer contract mode (for more information about this mode, see Using the Guaranteed Contract DMA Buffer Model), the size of the DMA buffer that is available to the display miniport driver to translate the command buffer at the next submission is the same as the size of the command buffer itself. For such a device, the OpenGL ICD should also determine the size of the allocation list that will be available to the display miniport driver during the translation of the command buffer at the next submission from the value that is returned in the AllocationListSize member of D3DKMT_RENDER.

For devices that do not use guaranteed DMA buffer contract, the OpenGL ICD can use the information that is returned in the CommandBufferSize and AllocationListSize members to determine the size of the next DMA buffer and allocation list that will be available for translation. However, under low-memory conditions, the actual DMA buffer and allocation list that is provided to the display miniport driver might be smaller than required.

If the OpenGL ICD detects that most of the command buffer flushes are because the driver runs out of space in the command buffer or allocation list, the driver can request for them to be resized. To resize the command buffer, the driver sets the ResizeCommandBuffer bit-field flag in the Flags member of D3DKMT_RENDER and puts the requested size in the CommandBufferSize member of D3DKMT_RENDER. Similarly, to resize the allocation list, the driver sets the ResizeAllocationList bit-field flag in the Flags member of D3DKMT_RENDER and puts the requested number of elements in the AllocationListSize member of D3DKMT_RENDER.

Examples

The following code example demonstrates how an OpenGL ICD can use D3DKMTRender to render 3-D primitives.

HRESULT Render(D3DKMT_HANDLE hDevice, UINT CommandOffset, UINT CommandLength)
{
    D3DKMT_RENDER RenderData;

    memset(&RenderData, 0, sizeof(RenderData));
    RenderData.hDevice = hDevice;
    RenderData.CommandOffset = CommandOffset;
    RenderData.CommandLength = CommandLength;

    if (NT_SUCCESS((*pfnKTRender)(&RenderData))) {
        return S_OK;
    }
    return E_FAIL;
}

Requirements

See also

D3DKMTGetDeviceState

D3DKMT_RENDER