clGetGLContextInfoKHR - Get OpenGL context information.
clGetGLContextInfoKHR(const cl_context_properties *properties,
Points to an attribute list whose format and valid
contents are identical to the properties argument of
clCreateContext(3clc). properties must identify a single valid
GL context or GL share group object.
A constant that specifies the GL context information to
query, and must be one of the values shown in the table below.
Specifies the size in bytes of memory pointed to by
param_value. This size must be greater than or equal to the size of the
return type described in the table below.
A pointer to memory where the result of the query is
returned as described in the table below. If param_value is NULL, it is
Returns the actual size in bytes of data being queried by
param_value. If param_value_size_ret is NULL, it is
||Information returned in param_value
||Return the CL device currently associated with the specified OpenGL
||List of all CL devices which may be associated with the specified OpenGL
The OpenGL object used to create the OpenCL memory object and information about
the object type i.e. whether it is a texture, renderbuffer, or buffer object
can be queried using this function.
The OpenCL specification in section 9.7 defines how to share data with texture
and buffer objects in a parallel OpenGL implementation, but does not define
how the association between an OpenCL context and an OpenGL context or share
group is established. This extension defines optional attributes to OpenCL
context creation routines which associate a GL context or share group object
with a newly created OpenCL context. If this extension is supported by an
implementation, the string "cl_khr_gl_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
An OpenGL implementation supporting buffer objects and sharing of
texture and buffer object images with OpenCL is required by this
OpenCL device(s) corresponding to an OpenGL context may be
queried. Such a device may not always exist (for example, if an OpenGL
context is specified on a GPU not supporting OpenCL command queues, but
which does support shared CL/GL objects), and if it does exist, may change
over time. When such a device does exist, acquiring and releasing shared
CL/GL objects may be faster on a command queue corresponding to this device
than on command queues corresponding to other devices available to an OpenCL
Returns CL_SUCCESS if the function is executed successfully. If no device(s)
exist corresponding to param_name, the call will not fail, but the
value of param_value_size_ret will be zero. Otherwise returns one of
• CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR when an
invalid OpenGL context or share group object handle is specified in
•CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR if a
context was specified by any of the following means:
•A context was specified for an EGL-based OpenGL
ES or OpenGL implementation by setting the attributes CL_GL_CONTEXT_KHR
•A context was specified for a GLX-based OpenGL
implementation by setting the attributes CL_GL_CONTEXT_KHR
•A context was specified for a WGL-based OpenGL
implementation by setting the attributes CL_GL_CONTEXT_KHR
and any of the following conditions hold:
•The specified display and context attributes do
not identify a valid OpenGL or OpenGL ES context.
• The specified context does not support buffer
and renderbuffer objects.
•The specified context is not compatible with the
OpenCL context being created (for example, it exists in a physically distinct
address space, such as another hardware device; or it does not support sharing
data with OpenCL due to implementation restrictions).
•CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR if a share
group was specified for a CGL-based OpenGL implementation by setting the
attribute CL_CGL_SHAREGROUP_KHR, and the specified share group does not
identify a valid CGL share group object.
•CL_INVALID_OPERATION if a context was specified
as described above and any of the following conditions hold:
•A context or share group object was specified for
one of CGL, EGL, GLX, or WGL and the OpenGL implementation does not support
that window-system binding API.
• More than one of the attributes
CL_GLX_DISPLAY_KHR, and CL_WGL_HDC_KHR is set to a non-default
• Both of the attributes
CL_CGL_SHAREGROUP_KHR and CL_GL_CONTEXT_KHR are set to
• Any of the devices specified in the
devices argument cannot support OpenCL objects which share the data
store of an OpenGL object.
•CL_INVALID_VALUE if an attribute name other than
those specified in the table of supported properties for
clCreateContext(3clc) is specified in properties.
•CL_INVALID_VALUE if param_name is not
CL_DEVICES_FOR_GL_CONTEXT_KHR; or if the size in bytes specified by
param_value_size is less than the size of the return type shown above
for CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR or
CL_DEVICES_FOR_GL_CONTEXT_KHR; and param_value is not a NULL
•CL_OUT_OF_RESOURCES if there is a failure to
allocate resources required by the OpenCL implementation on the device
•CL_OUT_OF_HOST_MEMORY if there is a failure to
allocate resources required by the OpenCL implementation on the host.
The Khronos Group
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.
- OpenCL Specification
page 43, section 9.6.5 - Additions to section 9.8 of