clCreateFromD3D11BufferKHR

Creates an OpenCL buffer object from a Direct3D 11 buffer.

cl_mem clCreateFromD3D11BufferKHR ( cl_context context,
  cl_mem_flags flags,
  ID3D11Buffer *resource,
  cl_int  *errcode_ret )

Parameters

context

A valid OpenCL context created from a Direct3D 11 device.

flags

A bit-field that is used to specify usage information. May be CL_MEM_READ_ONLY, CL_MEM_WRITE_ONLY, or CL_MEM_READ_WRITE. (See the table for clCreateBuffer for more information.)

resource

A pointer to the Direct3D 11 buffer to share.

errcode_ret

An appropriate error code. If errcode_ret is NULL, no error code is returned.

Notes

The size of the returned OpenCL buffer object is the same as the size of resource. This call will increment the internal Direct3D reference count on resource. The internal Direct3D reference count on resource will be decremented when the OpenCL reference count on the returned OpenCL memory object drops to zero.

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 a valid non-zero OpenCL buffer object and errcode_ret is set to CL_SUCCESS if the buffer object is created successfully. Otherwise, it returns a NULL value with one of the following error values returned in errcode_ret:

  • CL_INVALID_CONTEXT if context is not a valid context.
  • CL_INVALID_VALUE if values specified in flags are not valid.
  • CL_INVALID_D3D11_RESOURCE_KHR if resource is not a Direct3D 11 buffer resource, if resource was created with the D3D11_USAGE flag D3D11_USAGE_IMMUTABLE, if a cl_mem from resource has already been created using clCreateFromD3D11BufferKHR, or if context was not created against the same Direct3D 11 device from which resource was created.
  • CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

Specification

OpenCL Specification

Also see

cl_khr_d3d11_sharing

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