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NAME
cl_khr_gl_sharing - Allow applications to use OpenGL buffer, texture and renderbuffer objects as OpenCL
memory objects.
cl_khr_gl_sharing
DESCRIPTION
This is a Kronos-approved extension name. If this extension is supported, "cl_khr_gl_sharing" will be
returned for CL_DEVICE_EXTENSIONS using clGetDeviceInfo(3clc).
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 clGetDeviceInfo(3clc)
An OpenGL implementation supporting buffer objects and sharing of texture and buffer object images with
OpenCL is required by this extension.
This section discusses OpenCL functions that allow applications to use OpenGL buffer, texture, and
renderbuffer objects as OpenCL memory objects. This allows efficient sharing of data between OpenCL and
OpenGL. The OpenCL API may be used to execute kernels that read and/or write memory objects that are also
OpenGL objects.
An OpenCL image object may be created from an OpenGL texture or renderbuffer object. An OpenCL buffer
object may be created from an OpenGL buffer object.
OpenCL memory objects may be created from OpenGL objects if and only if the OpenCL context has been
created from an OpenGL share group object or context. OpenGL share groups and contexts are created using
platform specific APIs such as EGL, CGL, WGL, and GLX. On MacOS X, an OpenCL context may be created from
an OpenGL share group object using the OpenCL platform extension cl_apple_gl_sharing. On other platforms
including Microsoft Windows, Linux/Unix and others, an OpenCL context may be created from an OpenGL
context using the Khronos platform extension cl_khr_gl_sharing. Refer to the platform documentation for
your OpenCL implementation, or visit the Khronos Registry at http://www.khronos.org/registry/cl/ for more
information.
Any supported OpenGL object defined within the GL share group object, or the share group associated with
the GL context from which the CL context is created, may be shared, with the exception of the default
OpenGL objects (i.e. objects named zero), which may not be shared.
┌─────────────────────────────────────┬────────────────────────────────────┐
│ GL internal format │ CL image format (channel order, │
│ │ channel data type) │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA8 │ CL_RGBA, CL_UNORM_INT8 or CL_BGRA, │
│ │ CL_UNORM_INT8 │
├─────────────────────────────────────┼────────────────────────────────────┤
│GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV │ CL_RGBA, CL_UNORM_INT8 │
├─────────────────────────────────────┼────────────────────────────────────┤
│GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV │ CL_BGRA, CL_UNORM_INT8 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA16 │ CL_RGBA, CL_UNORM_INT16 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA8I, GL_RGBA8I_EXT │ CL_RGBA, CL_SIGNED_INT8 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA16I, GL_RGBA16I_EXT │ CL_RGBA, CL_SIGNED_INT16 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA32I, GL_RGBA32I_EXT │ CL_RGBA, CL_SIGNED_INT32 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA8UI, GL_RGBA8UI_EXT │ CL_RGBA, CL_UNSIGNED_INT8 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA16UI, GL_RGBA16UI_EXT │ CL_RGBA, CL_UNSIGNED_INT16 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA32UI, GL_RGBA32UI_EXT │ CL_RGBA, CL_UNSIGNED_INT32 │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA16F, GL_RGBA16F_ARB │ CL_RGBA, CL_HALF_FLOAT │
├─────────────────────────────────────┼────────────────────────────────────┤
│ GL_RGBA32F, GL_RGBA32F_ARB │ CL_RGBA, CL_FLOAT │
└─────────────────────────────────────┴────────────────────────────────────┘
Lifetime of Shared Objects
OpenCL Functions That Allow Sharing.PP Click an item in the table for details about that function.
┌─────────────────────────────────┬───────────────────────────────────────┐
│clGetGLContextInfoKHR(3clc) │ Query the device. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clCreateFromGLBuffer(3clc) │ Creates an OpenCL buffer object from │
│ │ an OpenGL buffer object. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clCreateFromGLTexture(3clc) │ Creates an OpenCL image object, image │
│ │ array object, or image buffer object │
│ │ from an OpenGL texture object, │
│ │ texture array object, texture buffer │
│ │ object, or a single face of an OpenGL │
│ │ cubemap texture object. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clCreateFromGLRenderbuffer(3clc) │ Creates an OpenCL 2D image object │
│ │ from an OpenGL renderbuffer object. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clGetGLObjectInfo(3clc) │ Query an OpenGL memory object used to │
│ │ create an OpenCL memory object. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clGetGLTextureInfo(3clc) │ Get additional information about the │
│ │ GL texture object associated with a │
│ │ memory object. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clEnqueueAcquireGLObjects(3clc) │ Acquire OpenCL memory objects that │
│ │ have been created from OpenGL │
│ │ objects. │
├─────────────────────────────────┼───────────────────────────────────────┤
│clEnqueueReleaseGLObjects(3clc) │ Release OpenCL memory objects that │
│ │ have been created from OpenGL │
│ │ objects. │
└─────────────────────────────────┴───────────────────────────────────────┘
SPECIFICATION
OpenCL Specification[1]
SEE ALSO
EXTENSION(3clc), clGetGLContextInfoKHR(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 39, section 9.6 - Creating CL context from a GL context or share group