D3DKMTCreateAllocation2 function (d3dkmthk.h)

Article
11/20/2023

The D3DKMTCreateAllocation2 function creates or adds allocations of system or video memory.

Syntax

NTSTATUS D3DKMTCreateAllocation2(
  D3DKMT_CREATEALLOCATION *unnamedParam1
);

Parameters

unnamedParam1

[in, out] pData: A pointer to a D3DKMT_CREATEALLOCATION structure that contains information for creating allocations.

Return value

D3DKMTCreateAllocation2 returns STATUS_SUCCESS if the operation succeeds. Otherwise, it might return an NTSTATUS code such as one of the following values:

Return code	Description
STATUS_DEVICE_REMOVED	The graphics adapter was stopped or the display device was reset.
STATUS_INVALID_PARAMETER	Parameters were validated and determined to be incorrect.
STATUS_NO_MEMORY	This routine could not complete because of insufficient system memory.
STATUS_NO_VIDEO_MEMORY	This routine could not complete because of insufficient video memory. The video memory manager attempts to virtualize video memory. However, if the virtualization fails (such as when virtual address space runs out), the memory manager might return this error code.

Remarks

A user-mode graphics client can call D3DKMTCreateAllocation2 to create allocations and resources. An allocation can be associated with a resource or it can stand alone.

D3DKMTCreateAllocation2 can also be called to add additional allocations to a resource at anytime. The only restrictions are that all shared allocations must be associated with a resource and additional allocations cannot be added to an existing shared resource.

Examples

Creating a stand-alone allocation in video memory that isn't associated with a resource

The following code example demonstrates how a user-mode graphics client can use D3DKMTCreateAllocation2 to create a stand-alone allocation in video memory that is not associated with a resource.

D3DKMT_HANDLE CreateStandAloneAllocation(D3DKMT_HANDLE hDevice, VOID* pPrivateAllocationInfo, UINT Size)
{
    D3DKMT_CREATEALLOCATION CreateAllocation;
    D3DDDI_ALLOCATIONINFO2 AllocationInfo;

    memset(&CreateAllocation, 0, sizeof(CreateAllocation));
    CreateAllocation.hDevice = hDevice;
    CreateAllocation.NumAllocations = 1;
    CreateAllocation.pAllocationInfo2 = &AllocationInfo;

    AllocationInfo.hAllocation = NULL;
    AllocationInfo.pSystemMem = NULL;  // Vidmem allocation
    AllocationInfo.pPrivateDriverData = pPrivateAllocationInfo;  // Contains format, size, and so on.
    AllocationInfo.PrivateDriverDataSize = Size;

    if (NT_SUCCESS((*pfnKTCreateAllocation)(&CreateAllocation))) {
        return AllocationInfo.hAllocation;
    }
    return 0;
}

Creating a resource with a single system memory allocation

The following code example demonstrates how a user-mode graphics client can use D3DKMTCreateAllocation2 to create a resource with a single system memory allocation.

HRESULT CreateSysmemResource(D3DKMT_HANDLE hDevice, 
                             UINT AllocationSize, 
                             VOID* pResourceData, 
                             UINT ResourceDataSize,
                             VOID* pAllocationData, 
                             UINT AllocationDataSize,
                             D3DKMT_HANDLE* phResource,
                             D3DKMT_HANDLE* phAllocation)
{
    D3DKMT_CREATEALLOCATION CreateAllocation;
    D3DDDI_ALLOCATIONINFO2 AllocationInfo;
    VOID* pSysMem;

    *phResource = NULL;
    *phAllocation = NULL;

    // For a sysmem allocation, preallocate the memory.
    pSysMem = MemAlloc(AllocationSize);
    if (pSysMem == NULL) {
        return E_OUTOFMEMORY;
    }
 
    memset(&CreateAllocation, 0, sizeof(CreateAllocation));
    CreateAllocation.hDevice = hDevice;
    CreateAllocation.Flags.CreateResource = TRUE;
    CreateAllocation.pPrivateDriverData = pResourceData;
    CreateAllocation.PrivateDriverDataSize = ResourceDataSize;
    CreateAllocation.NumAllocations = 1;
    CreateAllocation.pAllocationInfo = &AllocationInfo;

    AllocationInfo.hAllocation = NULL;
    AllocationInfo.pSystemMem = pSysMem;
    AllocationInfo.pPrivateDriverData = pAllocationData;
    AllocationInfo.PrivateDriverDataSize = AllocationDataSize;

    if (NT_SUCCESS((*pfnKTCreateAllocation)(&CreateAllocation))) {
        *phResource = CreateAllocation.hResource;
        *phAllocation = AllocationInfo.hAllocation;
        return S_OK;
    }
    MemFree(pSysMem);
    return E_FAIL;
}

Requirements

Requirement	Value
Minimum supported client	Windows 7
Target Platform	Universal
Header	d3dkmthk.h (include D3dkmthk.h)
Library	Gdi32.lib
DLL	Gdi32.dll

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