clCreateFromGLRenderbuffer

Creates an OpenCL 2D image object from an OpenGL renderbuffer object.

cl_mem clCreateFromGLRenderbuffer ( cl_context context,
  cl_mem_flags flags,
  GLuint renderbuffer,
  cl_int * errcode_ret)

Parameters

context

A valid OpenCL context created from an OpenGL context.

flags

A bit-field that is used to specify usage information. Refer to the table at clCreateBuffer for a description of flags. Only CL_MEM_READ_ONLY, CL_MEM_WRITE_ONLY, and CL_MEM_READ_WRITE values specified in the table at clCreateBuffer can be used.

renderbuffer

The name of a GL renderbuffer object. The renderbuffer storage must be specified before the image object can be created. The renderbuffer format and dimensions defined by OpenGL will be used to create the 2D image object. Only GL renderbuffers with internal formats that map to appropriate image channel order and data type specified in the table of supported Image Channel Order Values and the table of supported Image Channel Data Types for cl_image_format can be used to create the 2D image object.

errcode_ret

Returns an appropriate error code as described below. If errcode_ret is NULL, no error code is returned.

Description

If the state of a GL renderbuffer object is modified through the GL API (i.e. changes to the dimensions or format used to represent pixels of the GL renderbuffer using appropriate GL API calls such as glRenderbufferStorage) while there exists a corresponding CL image object, subsequent use of the CL image object will result in undefined behavior.

The clRetainMemObject and clReleaseMemObject functions can be used to retain and release the image objects.

The table below describes the list of GL renderbuffer internal formats and the corresponding CL image formats. If a GL renderbuffer object with an internal format from the table below is successfully created by OpenGL, then there is guaranteed to be a mapping to one of the corresponding CL image format(s) in that table. Renderbuffer objects created with other OpenGL internal formats may (but are not guaranteed to) have a mapping to a CL image format; if such mappings exist, they are guaranteed to preserve all color components, data types, and at least the number of bits/component actually allocated by OpenGL for that format.

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_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

Errors

Returns a valid non-zero OpenCL image object and errcode_ret is set to CL_SUCCESS if the image 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 or was not created from a GL context.
  • CL_INVALID_VALUE if values specified in flags are not valid.
  • CL_INVALID_GL_OBJECT if renderbuffer is not a GL renderbuffer object or if the width or height of renderbuffer is zero.
  • CL_INVALID_IMAGE_FORMAT_DESCRIPTOR if the OpenGL renderbuffer internal format does not map to a supported OpenCL image format.
  • CL_INVALID_OPERATION if renderbuffer is a multi-sample GL renderbuffer object.
  • 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.

Specification

OpenCL Specification

Also see

cl_khr_gl_sharing, clCreateBuffer, cl_image_format, clRetainMemObject, clReleaseMemObject

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