Querying OpenCL Devices Corresponding to Direct3D 11 Devices.

cl_int clGetDeviceIDsFromD3D11KHR(cl_platform_id platform,
                                  cl_d3d11_device_source_khr d3d_device_source,
                                  void *d3d_object,
                                  cl_d3d11_device_set_khr d3d_device_set,
                                  cl_uint num_entries,
                                  cl_device_id *devices,
                                  cl_uint *num_devices)

Parameters

platform

Refers to the platform ID returned by clGetPlatformIDs.

d3d_device_source

Specifies the type of d3d_object and may be one of the following (Table 9.11.1):

cl_d3d_device_source_khr Type of d3d_object

CL_D3D11_DEVICE_KHR

ID3D11Device *

CL_D3D11_DXGI_ADAPTER_KHR

IDXGIAdapter *

d3d_object

Specifies the object whose corresponding OpenCL devices are being queried. The type of d3d_object must be as specified in the table above.

d3d_device_set

Specifies the set of devices to return, and must be one of the following (Table 9.11.2):

cl_d3d_device_set_khr Devices returned in devices

CL_PREFERRED_DEVICES_FOR_D3D11_KHR

The OpenCL devices associated with the specified Direct3D object.

CL_ALL_DEVICES_FOR_D3D11_KHR

All OpenCL devices which may interoperate with the specified Direct3D object. Performance of sharing data on these devices may be considerably less than on the preferred devices.

num_entries

The number of cl_device_id entries that can be added to devices. If devices is not NULL, the num_entries must be greater than zero.

devices

Returns a list of OpenCL devices found. The cl_device_id values returned in devices can be used to identify a specific OpenCL device. If devices is NULL, this argument is ignored. The number of OpenCL devices returned is the mininum of the value specified by num_entries and the number of OpenCL devices corresponding to d3d_object.

num_devices

Returns the number of OpenCL devices available that correspond to d3d_object. If num_devices is NULL, this argument is ignored.

Description

The OpenCL devices corresponding to a Direct3D 11 device may be queried. The OpenCL devices corresponding to a DXGI adapter may also be queried. The OpenCL devices corresponding to a Direct3D 11 device will be a subset of the OpenCL devices corresponding to the DXGI adapter against which the Direct3D 11 device was created.

Notes

Sharing Memory Objects with Direct3D 11 Resources

The goal of this extension is to provide interoperability between OpenCL and Direct3D 11. This is designed to function analogously to the OpenGL interoperability as defined in sections 9.7 and 9.8. If this extension is supported by an implementation, the string "cl_khr_d3d11_sharing" will be present in the CL_PLATFORM_EXTENSIONS or CL_DEVICE_EXTENSIONS string described in the table of allowed values for param_name for clGetDeviceInfo or clGetPlatformInfo.

As currently proposed the interfaces for this extension would be provided in cl_d3d11.h.

This section discusses OpenCL functions that allow applications to use Direct3D 11 resources as OpenCL memory objects. This allows efficient sharing of data between OpenCL and Direct3D 11. The OpenCL API may be used to execute kernels that read and/or write memory objects that are also Direct3D 11 resources. An OpenCL image object may be created from a Direct3D 11 texture resource. An OpenCL buffer object may be created from a Direct3D 11 buffer resource. OpenCL memory objects may be created from Direct3D 11 objects if and only if the OpenCL context has been created from a Direct3D 11 device.

Lifetime of Shared Objects

An OpenCL memory object created from a Direct3D 11 resource remains valid as long as the corresponding Direct3D 11 resource has not been deleted. If the Direct3D 11 resource is deleted through the Direct3D 11 API, subsequent use of the OpenCL memory object will result in undefined behavior, including but not limited to possible OpenCL errors, data corruption, and program termination.

The successful creation of a cl_context against a Direct3D 11 device specified via the context create parameter CL_CONTEXT_D3D11_DEVICE_KHR will increment the internal Direct3D reference count on the specified Direct3D 11 device. The internal Direct3D reference count on that Direct3D 11 device will be decremented when the OpenCL reference count on the returned OpenCL context drops to zero.

The OpenCL context and corresponding command-queues are dependent on the existence of the Direct3D 11 device from which the OpenCL context was created. If the Direct3D 11 device is deleted through the Direct3D 11 API, subsequent use of the OpenCL context will result in undefined behavior, including but not limited to possible OpenCL errors, data corruption, and program termination.

Properties of Direct3D 11 objects may be queried using clGetMemObjectInfo and clGetImageInfo with param_name CL_MEM_D3D11_RESOURCE_KHR and CL_IMAGE_D3D11_SUBRESOURCE_KHR.

Errors

Returns CL_SUCCESS if the function is executed successfully. Otherwise it may return:

  • CL_INVALID_PLATFORM if platform is not a valid platform.

  • CL_INVALID_VALUE if d3d_device_source is not a valid value, d3d_device_set is not a valid value, num_entries is equal to zero and devices is not NULL, or if both num_devices and devices are NULL.

  • CL_DEVICE_NOT_FOUND if no OpenCL devices that correspond to d3d_object were found.

Also see

Specification