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