clEnqueueReleaseD3D11ObjectsKHR

Release OpenCL memory objects that have been created from Direct3D 11 resources.

cl_int clEnqueueReleaseD3D11ObjectsKHR( cl_command_queue  command_queue,
  cl_uint  num_objects,
  const cl_mem *mem_objects,
  cl_uint num_events_in_wait_list,
  const cl_event *event_wait_list ,
  cl_event *event)

Parameters

num_objects

The number of memory objects to be released in mem_objects.

mem_objects

A pointer to a list of OpenCL memory objects that were created from Direct3D 11 resources.

num_events_in_wait_list, event_wait_list

Specify events that need to complete before this particular command can be executed. If event_wait_list is NULL, then this particular command does not wait on any event to complete. If event_wait_list is NULL, num_events_in_wait_list must be 0. If event_wait_list is not NULL, the list of events pointed to by event_wait_list must be valid and num_events_in_wait_list must be greater than 0. The events specified in event returns an event object that identifies this particular command and can be used to query or queue a wait for this particular command to complete. event can be NULL in which case it will not be possible for the application to query the status of this command or queue a wait for this command to complete. If the event_wait_list and the event arguments are not NULL, the event argument should not refer to an element of the event_wait_list array

Notes

The Direct3D 11 objects are released by the OpenCL context associated with command_queue.

OpenCL memory objects created from Direct3D 11 resources which have been acquired by OpenCL must be released by OpenCL before they may be accessed by Direct3D 11. Accessing a Direct3D 11 resource while its corresponding OpenCL memory object is acquired is in error and will result in undefined behavior, including but not limited to possible OpenCL errors, data corruption, and program termination.

If CL_CONTEXT_INTEROP_USER_SYNC is not specified as CL_TRUE during context creation, clEnqueueReleaseD3D11ObjectsKHR provides the synchronization guarantee that any calls to Direct3D 11 calls involving the interop device(s) used in the OpenCL context made after the call to clEnqueueReleaseD3D11ObjectsKHR will not start executing until after all events in event_wait_list are complete and all work already submitted to command_queue completes execution. If the context was created with properties specifying CL_CONTEXT_INTEROP_USER_SYNC as CL_TRUE, the user is responsible for guaranteeing that any Direct3D 11 calls involving the interop device(s) used in the OpenCL context made after clEnqueueReleaseD3D11ObjectsKHR will not start executing until after event returned by clEnqueueReleaseD3D11ObjectsKHR reports completion.

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 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.

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 and clGetImageInfo with param_name CL_MEM_D3D11_RESOURCE_KHR and CL_IMAGE_D3D11_SUBRESOURCE_KHR as described for clGetImageInfo and in the information below about accessing mapped regions of a memory object.

Accessing mapped regions of a memory object

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 or clEnqueueMapImage) 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) 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 or clEnqueueMapImage.

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 or clEnqueueMapImage can be used as ptr argument value to clEnqueueReadBuffer, clEnqueueWriteBuffer, clEnqueueReadBufferRect, clEnqueueWriteBufferRect, clEnqueueReadImage, and clEnqueueWriteImage, provided the rules described above are adhered to.

Errors

Returns CL_SUCCESS returns CL_SUCCESS if the function is executed successfully. If num_objects is 0 and mem_objects is NULL then the function does nothing and returns CL_SUCCESS. Otherwise it returns one of the following errors:

  • CL_INVALID_VALUE if num_objects is zero and mem_objects is not a NULL value or if num_objects > 0 and mem_objects is NULL.
  • CL_INVALID_MEM_OBJECT if memory objects in mem_objects are not valid OpenCL memory objects or if memory objects in mem_objects have not been created from Direct3D 11 resources.
  • CL_INVALID_COMMAND_QUEUE if command_queue is not a valid command-queue.
  • CL_INVALID_CONTEXT if context associated with command_queue was not created from a Direct3D 11 context.
  • CL_D3D11_RESOURCE_NOT_ACQUIRED_KHR if memory objects in mem_objects have not previously been acquired using clEnqueueAcquireD3D11ObjectsKHR, or have been released using clEnqueueReleaseD3D11ObjectsKHR since the last time that they were acquired.
  • CL_INVALID_EVENT_WAIT_LIST if event_wait_list is NULL and num_event_in_wait_list > 0, or event_wait_list is not NULL and num_event_in_wait_list is 0, or if event objects in event_wait_list are not valid events.
  • 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, clGetDeviceIDsFromD3D11KHR, clCreateFromD3D11BufferKHR, clCreateFromD3D11Texture2DKHR, clCreateFromD3D11Texture3DKHR, clEnqueueAcquireD3D11ObjectsKHR

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.