NAME

       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(3clc) 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.

       General information about sharing memory objects with Direct3D 11 follows.

       The goal of this extension is to provide interoperability between OpenCL and Direct3D 11.
       This is designed to function analogously to the OpenGL interoperability. If this extension
       is supported by an implementation, the string cl_khr_d3d11_sharing(3clc) 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(3clc).

       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.

       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(3clc) and
       clGetImageInfo(3clc) with param_name CL_MEM_D3D11_RESOURCE_KHR and
       CL_IMAGE_D3D11_SUBRESOURCE_KHR as described for clGetImageInfo(3clc) and in the
       information below about accessing mapped regions of a memory object.  Accessing mapped
       regions of a memory object.PP This section describes the behavior of OpenCL commands that
       access mapped regions of a memory object.

       The contents of the region of a memory object and associated memory objects (sub-buffer
       objects or 1D image buffer objects that overlap this region) mapped for writing (i.e.
       CL_MAP_WRITE or CL_MAP_WRITE_INVALIDATE_REGION is set in map_flags argument to
       clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc)) are considered to be undefined until
       this region is unmapped.

       Multiple commands in command-queues can map a region or overlapping regions of a memory
       object and associated memory objects (sub-buffer objects or 1D image buffer objects that
       overlap this region) for reading (i.e.  map_flags = CL_MAP_READ). The contents of the
       regions of a memory object mapped for reading can also be read by kernels and other OpenCL
       commands (such as clEnqueueCopyBuffer(3clc)) executing on a device(s).

       Mapping (and unmapping) overlapped regions in a memory object and/or associated memory
       objects (sub-buffer objects or 1D image buffer objects that overlap this region) for
       writing is an error and will result in CL_INVALID_OPERATION error returned by
       clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc).

       If a memory object is currently mapped for writing, the application must ensure that the
       memory object is unmapped before any enqueued kernels or commands that read from or write
       to this memory object or any of its associated memory objects (sub-buffer or 1D image
       buffer objects) or its parent object (if the memory object is a sub-buffer or 1D image
       buffer object) begin execution; otherwise the behavior is undefined.

       If a memory object is currently mapped for reading, the application must ensure that the
       memory object is unmapped before any enqueued kernels or commands that write to this
       memory object or any of its associated memory objects (sub-buffer or 1D image buffer
       objects) or its parent object (if the memory object is a sub-buffer or 1D image buffer
       object) begin execution; otherwise the behavior is undefined.

       Accessing the contents of the memory region referred to by the mapped pointer that has
       been unmapped is undefined.

       The mapped pointer returned by clEnqueueMapBuffer(3clc) or clEnqueueMapImage(3clc) can be
       used as ptr argument value to clEnqueueReadBuffer(3clc), clEnqueueWriteBuffer(3clc),
       clEnqueueReadBufferRect(3clc), clEnqueueWriteBufferRect(3clc), clEnqueueReadImage(3clc),
       and clEnqueueWriteImage(3clc), provided the rules described above are adhered to.

ERRORS

       Returns CL_SUCCESS 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[1]

SEE ALSO

       cl_khr_d3d11_sharing(3clc), clGetDeviceIDsFromD3D11KHR(3clc),
       clCreateFromD3D11Texture2DKHR(3clc), clCreateFromD3D11Texture3DKHR(3clc),
       clEnqueueAcquireD3D11ObjectsKHR(3clc), clEnqueueReleaseD3D11ObjectsKHR(3clc)

AUTHORS

       The Khronos Group

COPYRIGHT

       Copyright © 2007-2011 The Khronos Group Inc.
       Permission is hereby granted, free of charge, to any person obtaining a copy of this
       software and/or associated documentation files (the "Materials"), to deal in the Materials
       without restriction, including without limitation the rights to use, copy, modify, merge,
       publish, distribute, sublicense, and/or sell copies of the Materials, and to permit
       persons to whom the Materials are furnished to do so, subject to the condition that this
       copyright notice and permission notice shall be included in all copies or substantial
       portions of the Materials.

NOTES

        1. OpenCL Specification
           page 104, section 9.11.7.3 - Sharing Direct3D 11 Buffer Resources